Understanding The Terroir of Burgundy part 4.4: Erosion: a challenge to the authenticity of terroir

Erosion Vosne wider implications

Our best understanding of soils of the Côte de Nuits:

In trying to grasp the relationship of the wines made soil from particular crus, many writers, myself included, have come to many fundamentally incorrect conclusions regarding terroir. My version could be summarized into this:

I believed that chemical and mechanical weathering of the limestone bedding naturally created soil types that were dictated by their position on the slope. Highest on the slope, the compact limestone soils were produced by the simultaneous production of clay and the erosion of clay. Lower on the slope, where transported clay enriched the otherwise arid, colluvial soils, I believed that if farmed carefully, clay production could remain in a relative of a state equilibrium with clay erosion. While, it most of these vineyards may not absolutely been in their natural state as when the Romans arrived, of many mid-slope Burgundy vineyards, I felt were relatively authentic in their terroir.  

A challenge to the authenticity of terroir:

Vosne-Romanée Les Damaudes, sitting upon the upper-most slope, with a 12% grade had equal parts clay and gravel in 2004. This is despite already having lost 54mm depth of clay sized particle since 1952. In the foreground, Vosne Malconsorts is allowed to grow it's grass in June of 2012. photo: googlemaps
Vosne-Romanée Les Damaudes, sitting upon the upper-most slope, with a 12% grade had equal parts clay and gravel in 2004. This is despite already having lost 54mm depth of clay-sized particle since 1952. In the foreground, Vosne Malconsorts is allowed to grow its grass in June of 2012. photo: googlemaps

The 2008 study on the changes to soil composition following a heavy rain event by Quiquerez, Brenot, Garcia, Petit, and Catena, presents, in my view, far greater implications than the study’s more simple intent of establishing hard erosional data following heavy rain events.

The study’s plot site, high up on the hillside, with a long, 12% grade, would challenge the perception that upper-slope, Burgundian soils naturally carry low percentages of clay or silt. This vineyard, with its 40% clay content, at the onset of the study, is doubly surprising, given that the data showed these materials exhibited a high erosional rate out of the plot area. What the soil recording reveal natural soil composition of this hillside originally contained far more clay than we could have ever expected based on the compact gravel “soil” condition of even the best of the upper slope vineyards today.

This study not only gives us a prophetic view of this vineyard’s future soil but also clearly illuminated a much more fertile soil in the past. Just as this vineyard once had an exceptionally high clay content, there is every reason to believe this was also true across the breadth of Burgundy vineyards, indicating a very different erosional story played out regarding the ‘arid’ soils of elite mid-slope vineyards. This information directly challenges our perception of the authenticity of the terroir within many of today’s Burgundy vineyards. 

What the study of this vineyard tells us is that, at least on this site, there has been a relatively tight erosional timeline, with much of the damage occurring over the past half-century. Additionally, the erosion is projected to finish its ‘third act’ in Les Damaudes over the next 25 years, at which point it will have a classic Burgundian compact limestone soil.  While it would appear that mechanized farming as the most erosive in this vineyard’s largely unreported history, we know that there was massive erosion in other vineyards over the centuries. The remaining question is: What about the historical farming of this vineyard allowed its clay to remain in this parcel of Les Damaudes?

*This article is based on the findings a pair of studies chronicled in Part 4.3, and centers upon the upper hillside plot of Vosne-Romanée’s village cru of Les Damaudes.

Why is this study so important to our understanding of Burgundy?

It has slowly become apparent that the problem in talking about the terroir of Burgundy is this: We really don’t know what the wines of Burgundy might have naturally been, had men had both the knowledge and forethought to do what it would take to preserve these vineyards centuries ago. However, a study like this (click here) gives us the ability to hypothetically see both where this vineyard is going, and what it might have been like before man caused so much erosion upon the hillsides. We were lucky that the researchers chose this particular vineyard at the top of VosneRomanée for their study. Les Damaudes is a steep hillside vineyard (in the most revered of villages) that is only midway through its journey of erosional destruction.  A study of a vineyard from any of the other lesser appellations could easily be dismissed as not being applicable to les grands villages de Bourgogne. But with a vineyard within VosneRomanée, there is no doubt as to the applicability of the information, as this vineyard is in the immediate vicinity of some of the greatest vineyards in the world, including La Tache and Romanée-Conti.

soil projection
The projected future soil composition of Les Damaudes over the next 5 storms (roughly 25 years) Click to enlarge.

It has become increasingly clear through the research in preparing this series of articles, that vineyards like Ruchottes-Chambertin have been so seriously degraded by the techniques of the farming employed there, that the terroir we talk about today is one that wears immense repercussions of the farming practices of the past centuries. However, it seemed plausible, that the upper slopes could naturally have developed a compact limestone soil, (one that is 85 to 90% crushed limestone and only 10 to 15 % clay). But these studies re-orient our thinking, forcing us to realize that this is not a soil type that is natural to Burgundy. Because of that, it is not a terroir that is natural to Burgundy.

It is not to say that these vineyards, with their degraded soils, do not produce beautiful or interesting wines, but we must realize that this is a vineyard condition that has been inflicted by man. In the truest sense, Burgundy now has a terroir that has been drastically altered, metamorphosed by the actions of man.

Note: at the bottom of this article I discuss data gaps and the certain information the study might have provided which would have been key to a more complete understanding of the soil of Vosne Les Damaudes. 

2004: Establishing a soil base-line

Although the changes to the soil makeup after the 2004 storm were covered in-depth the latter half of Part 4.3, it is the basis for projecting what the soil make up was in 1952, so it bears a brief retelling now.

Click to enlarge. Adapted from the paper "Soil degradation caused by a high-intensity rainfall event : implications for medium-term soil sustainability in Burgundian vineyards" Quiquerez/Brenot/Garcia/Petit, Catena 73, 2008
Click to enlarge. Adapted from the paper “Soil degradation caused by a high-intensity rainfall event: implications for medium-term soil sustainability in Burgundian vineyards” Quiquerez/Brenot/Garcia/Petit, Catena 73, 2008

In June of 2004, a storm, which was unusually large for Burgundy, dropped 40 mm of water on Vosne Romanee over a 24 hour period. The effects of that storm were studied, and the researchers determined that the vineyard plot had irrevocably lost between 1.8 mm and 4 mm soil due to erosion, a vast majority of which were very fine particles under 63 μm in size.  The material lost was clay and silt since erosion most efficiently targets these tiny particles. (1)

To the right is a graphic I adapted from the study to show the grain size distribution of the soil after the 2004 storm. Each rectangle represents a range of particle size. I also included the before level of clay and silt sized particles to illustrate the loss of those materials, which was shown as 25% in a graph in the study.

 

1952: the soil content of the past

Given the study’s data, we can extrapolate, at least conceptually, what the clay content on these slopes the vineyard was planted in 1952.(2)  Starting with the fact 2004 the hillside contained roughly equal parts clay and gravel at 40+% each; the balance being sand, that we can add 54 mm more super-fine material (smaller than 63 μm) that it did in 2004.  If we assume that past soil loss rates were similar to that of the 2004 storm, we can postulate how much clay would have been present in 1952.  This figure would be much easier to arrive at if the researchers had given us the soil depth, which would allow us to estimate the volume of gravel (colluvium) and allow us a much more accurate estimate, but that information was not within the scope of the study.

Click to enlarge. Adapted from the paper "Soil degradation caused by a high-intensity rainfall event : implications for medium-term soil sustainability in Burgundian vineyards" Quiquerez/Brenot/Garcia/Petit, Catena 73, 2008
Click to enlarge. Adapted from the paper “Soil degradation caused by a high-intensity rainfall event: implications for medium-term soil sustainability in Burgundian vineyards” Quiquerez/Brenot/Garcia/Petit, Catena 73, 2008

The soil loss projections of the next five large storms, predicts that erosion will remove up to 20 mm in-depth in places. The lost material, it is expected would continue to consist of primarily be smaller than 63 μm in size. 

However, would it not be logical assume soil losses of previous storms were similar to that of the 2004 storm? If so, it would not be unreasonable to apply the projected soil loss, in order to estimate the vineyards clay percentage in the past.  If these big storms (of 40+mm rainfall per event) happen every 5 or so years, we can estimate that thirty years ago this same hillside may have had as much as a 70% clay content. How much clay existed before the plot was planted in 1952 can not readily be determined without establishing a rough estimate of the volume of gravel in the vineyard, but it is likely that the vineyard, may have had clay content 85%.  Such a high percentage suggests that either this plot was either not farmed before it was planted in 1952, or was farmed quite differently in the past than it is now. 

In Retrospect

We should not have been surprised that the soils of Burgundy are not as nature created them. We should have suspected something was amiss long ago because the soil type in Burgundy today is one of an arid climate. France, and the surrounding Burgundian countryside, however, do not have an arid climate at all. Rather the climate is classified as semi-continental, where rain is frequent and happens virtually year around. These soils would naturally have at least some petrogenetic development, which it is doubtful that any vineyard in the Côte d’Or does. We were told and simply wanted to believe that the wines of Burgundy are naturally and uniquely sparse of nutrients and clay. Additionally, we have not wanted to believe that, in the course of making these great wines, man has precipitously hastened the decline of the greatest vineyards of the world, though poor farming decisions that have been made throughout the centuries. This has never been truer since the organization of vineyards for the mechanization of farming.


 

Gaps in the data: deficiencies in quantification

As transformative as this study is to our understanding of the wines of Burgundy, the paper, unfortunately, omits some fairly important information. First and foremost, it is unclear how the samples for the data were collected, and secondly how well the data actually represents the soil of the slope in the root zone. The report does say that the soil of the vineyard was homogeneous in its makeup, and no petrogenetic development was observed; meaning the entire vineyard was the same, with no observable generation of new soil. This indicates that what little organic deterioration may develop was washed away by erosion, and no soil horizons (layering) could develop  Lack of soil development and soil horizons would be caused the dual soil disruptions created by regular tilling and erosion.

However, the problem lies in the word “homogeneous”. Even if at some point the soil was homogeneous from topsoil to bedrock, erosional changes to the soils would primarily affect only the material nearest to the surface, and then most acutely in the rill affected inter-rows. Now, even after one storm, the soil is no longer homogeneous in its makeup, because the soil at a certain (unknown) depth would contain more clay and silt sized particles than the topsoil. Now there would be two soil types.

Because of this, we must assume that the researchers collected a shallow soil collection for the sample in order to determine particle size.(3)  Quantifying the depth of this sample is critical, was this a  sample from the first 25mm (1 inch) or 50mm  (2 inches) or from deeper, say 200 mm (8 inches) of depth which is the deepest that most tilling reaches? Further, when the samples were collected: ie before or after anthropogenic resupply of the sediment was returned to the slope, and before or after the soil was tilled, are both important factors in understanding the distribution of soil.  Additionally, knowledge samples at various depths of the sample would be instructive as the effective depth of the erosional change. This is ever truer after workers had returned the sediment to the hillside, and tilled back into the soil.

Root development through soil
The root zone on a hillside vineyard is often restricted to no more than 300mm (12in) to 460mm (18in) represented by the brown strip in the graphic above.  Original graphic of unknown origin.

It would appear that the study only represents changes to the surface soil: those that would most be affected by erosion, and anthropogenic resupply of the sediment to the hillside. it is possible but less likely, that the soil sample may have been taken down to a 200mm depth (8in), which is the standard reach of a plow shear. But even if samples were taken from the 200mm depth, that is only 2/3s of the minimum depth required by a vine for its root zone.

Despite questions and any doubts these numerical omissions might create regarding the validity of the numbers and projections from the study, the value of this information far exceeds reaches far into the black hole of understanding that existed before. For this reason, I accept these numbers and build in a fairly wide mental fudge-factor when considering the above.

 

 

Puligny Folatieres after a rain
A tractor moves on the road between Paul Pernot’s “Clos des Folatières” and Les Clavillons in Puligny-Montrachet photo source: googlemaps

 

Musigny anthopogenic resupply
“Anthropogenic resupply” of redepositing the sediment back upslope is now done with heavy machinery at Comte de Vogüé. photo: Steen Öhman
Musigny anthopogenic resupply 2
Heavy machinery at Comte de Vogüé. Given a major cause of erosion is compression, it’s hard to imagine this is really helping the situation much. photo: Steen Öhman

*Special thanks to Steen Ohman, sleuth, and vineyard historian who writes the excellent winehog.org, for providing me with the 1827 cadastre Map show above.

 


(1) The variance between the 1.8mm figure and the 4mm figure was not explained, but it is likely that lower sections of the vineyard, which were subject to a higher volume of rainwater runoff, and had developed rill erosion, were subject to greater levels of erosional loss.

(2) While the study lumps both clay and silt into a grouping of material by size under 63 μm, according to Wikipedia, as well as other sources, say that silt is primarily made up of the parent materials feldspar or quartz. Feldspar is prone to chemical erosion, just as is limestone, both of which metamorphose into clay (phyllosilicate minerals + water and air), while quartz will not erode due the same contact with the carbonic acid in rainwater.  Although granite (the major source of quartz-silt) is common in the areas surrounding the Cote, like in Beaujolais, it is not found near the surface in the immediate area. Although silt has been washed onto the Cotes by alluvial action and transported to the soils of the Cote by wind erosion, I have to assume that silt-sized quartz fragments are a very small minority in the area’s soil makeup. For that reason, I often refer to the study’s grouping of material under 63 μm, simply as clay. Clay, of course, is actually smaller than silt. Although the size definition varies between disciplines 1–5 μm, the metamorphological change that occurs upon clay is the ultimately defines clay, not its size.  * an underlying reason that I identify this material may also be that — no wine writer has ever attributed any of Burgundy’s success to silt. Am I cowering in conformity?

 

(3) How else could one explain a 15% change in a clay content?  The planting bed must be at least 30cm  (12 inches) for vines to be viable. Most vineyards have this with a much lower clay content, often to 30% less. If we were to use 30cm depth as a baseline, it stands to reason that the depth is likely 30% more than 30cm, being at a minimum 40cm of soil over the base rock though there is likely more. So, if the soil is 400mm deep, and 240mm of that are clay minerals, a 4mm decrease in the clay represents only a 1.7% decrease in clay content in the soil.

 

 

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Understanding the Terroir of Burgundy Part 4.3 Erosion and Rills: Studies in Vosne-Romanée and Monthélie

Erosion in Vosne Romanee

In the water’s path

Erosion comes in two forms: the seen and the unseen.

Rill erosion is the most obvious form of erosion and typically occurs in heavier downpours of more than 30 mm (1.2 inches) over a 24 hour period. They begin in spots where soil aggregates are weakened, and will collapse with weight and friction of the water above it, forming the aqueduct-like channels into which the runoff will funnel. Rills often generate in flow zones,  gathers in the depressions between rows. Here water can consolidate, growing in volume and velocity as moves with increasing rapidity down the hillside. With the water growing in mass and speed, larger and larger soil particles are pulled with it, releasing from both the bottom and sides of the rill, developing their typically U-shaped trough. As rills go unrepaired, they can grow substantially,  that can be difficult to control, if measures are not already in place to prevent them.

Sheet erosion (aka surface erosion) is a precursor to, and happens simultaneously with, rill erosion. In this case, rainwater runoff moves in sheets across the surface of the vineyard, but between and through the vines in places where rills won’t, or have not yet, formed. Surface runoff has a less concentrated volume of water than the runoff that travels through rills, so it yields a lower speeds and less velocity. Because of this limited velocity, the water of surface runoff is capable of carrying particles with a lower suspension velocity than rills are capable. These may include sands, but unless the downpour was heavy, would primarily include clays and silts. In less intense storms (< 20mm) surface runoff can cause sheet erosion, but these actions are considered slightly erosive, typically transporting finer materials in weak aggregates. From year to year, soil loss to sheet erosion goes largely unnoticed as the topsoil loss directly beneath the vines disappears down the hillside forever.

  • For an explanation of erosional factors and concepts click here for part 4.2
  • For history of erosion and vineyard restoration in Burgundy click here for Part 4.1
  • For the history of erosion and man in Burgundy click here for Part 4.

 

2006 Study of erosion in Vosne-Romanée, Aloxe-Corton, and Monthélie

Two sibling studies, preformed by the same research team, illustrates very well the processes of erosion (detailed in part 4.2), and how it affects the wine we drink. These are multi-discipline studies by conducted by the team of Amélie Quiquerez, Jean-Pierre Garcia, and Christophe Petit from the Université de Bourgogne, and Jérôme Brenot from Géosciences Université de Rennes.

The first of the two studies was published in the Bolletino della Società Geologica Italiania 2006, with contributions by Philippe Davy, Université de Rennes. Entitled “Soil erosion rates in Burgundian vineyards (link).” It examined the erosion rates in the villages of Vosne-Romanée, Aloxe-Corton, and Monthélie. I highly encourage you to look at these important studies to get their analysis, which in some ways is limited by the rigors of science which require the researcher to prove what they already know to be true. My overview of the information revealed by their study applies my own perspective and insights.

The researchers selected three steep, upper-hillside vineyards from which to gather data, all which carried essentially the same average grade, with a mean of 10.5% for Vosne and Aloxe-Corton, with Monthelie the steepest, with a mean slope of 10.7%.  Additional selection criteria were all three were they must meet these three (very traditional Burgundian) vineyard practices.

  1. The rows ran vertically down the hillside.
  2. None of the plots were allowed to have grass grow between the vines.
  3. Frequent plowing or tractor crossings (up to 15 times per year)

However, I note two marked differences between the vineyards. 

  1. How much the slope changed within the plot boundaries.
  2. The length of the slope. 
Vosne Damodes
Vosne Damaudes photo: google earth

The study’s most uniform slope was a vineyard in Vosne, with a fairly consistent 10% to 12% grade. It also had, by far, the longest slope studied, at 130 meters.(1)  This longer slope length, one might expect, would allow water to gain volume, speed, and velocity. These three factors all increase the runoff’s ability to carry larger and heavier particles with higher suspension velocities. Conversely, it was the only slope studied which had a murger (stone wall) at its base, slowing the runoff enough to allow sedimentation to occur, and it would appear to be the only plot with a level spot for sedimentation to rest. 

Although unnamed by the study’s author, I have concluded this vineyard is Les Damaudes on the Nuit-St-Georges border. Clues to its identity include a maximum elevation of 345 meters – the highest in Vosne, and uniform slope of 10-12%. Identifying the parcel location is possible as well, as only one location in Les Damaudes is long enough to fit the 130-meter plot length of this study. When subtracting in the dirt roads at the top and bottom of the vineyard, which are natural erosional breaks, the total length is 126 meters. This vineyard was studied in-depth, over a multi-year period, and spawned the two studies I will detail in this article.

The vineyard in Aloxe-Corton may contain a significantly steeper section than the vineyard in Vosne, with a 17% grade, but overall the Aloxe-Corton vineyard had the same average gradient as the plot in Vosne, at 10.5%. This indicates that part of that vineyard had to contain no more than a 5% grade. Additionally, this vineyard was the shortest plot at 53 meters, meaning as long as fast-moving runoff could not enter the plot freely from above, runoff should not be able to attain the same velocity as it might in Vosne. Because of this, we might anticipate erosion lower erosional levels. There is no specific information that might allow us to identify this vineyard. And while the author Jérôme Brenot included a photo and a brief reference to the grand cru vineyard of en Charlemagne (regarding rill erosion down to the limestone bedrock), the lieu-dits  of en Charlemagne is in neighboring PernandVergelesses, not Aloxe-Corton

Monthelie Clou du Chenes
The section of Monthélie studied is snug against the Volnay border. Here in 2012, some grass is now being allowed to grow between the vines. The vineyard above, La Pièce-Fitte, has one plot that is in pretty poor shape, with gaps between vines, and rills that because of the slight off camber row orientation cut right up against the vines, rather than directly between the rows. photo: googlemaps click to enlarge

The slope in the study with the steepest section, by far, was in Monthélie. The plot there reaches a maximum pitch of 24.5%, but the average gradient is only slightly greater at 10.7%, which again indicates much of the vineyard is gentile in its declivity. This vineyard, which would become a 1er cru shortly after the study was published, is the vineyard of Le Clou des Chênes,(2) and this parcel appears to share a border with Volnay’s ez Blanches vineyard. The study measured nearly twice the plot-wide erosion at 1.7 mm (± 0.5 mm year) as they did in either Vosne or Aloxe-Corton. However, in some locations within Le Clou des Chênes had far greater erosional levels: measuring as deep as 8.2 mm (± 0.5 mm) per year.

Notable is that the time under vine is much shorter, having been planted 32 years before the study. This makes the losses all the more alarming for these steeper slopes because the knowledge of how to resist erosion has improved so dramatically in the past twenty years.  

Data collection and methodology

This much erosion surely has had a tremendous influence on the character of the wines produced from these vines.
This much erosion surely has had a tremendous influence on the character of the wines produced from these vines.

Determining these numbers involved a massive data collection effort, imputing vine measurements on a meter by meter scale. With 10,000 plants planted per hectare, this translates into thousands of data points are required to arrive at the final calculations.

Soil loss was determined by measuring the exposed main framework roots from the current soil level to the point of the graft cut. The graft is typically made 1 cm above the soil level at the time of planting, and with this measurement original soil level at the time of planting can be established (NEBOIT, 1983; GALET, 1993). By dividing this measurement by the number of years since planting, a relatively accurate average rate of erosion can be established. This method of using plants to give a historical record is called dendrogeomorphology, which is a geologic adaptation of dendrochronology, the study of trees and plants to determine the historical climatic record.

An unequal field of study

Photo: Jérôme Brenot et al
Photo: Jérôme Brenot et al

In the end, there was a single factor that differentiated these study vineyards: the road and the stone wall below the Les Damaudes vineyard in Vosne. Because of this road and wall, it also was the only vineyard that had an area at the base of the slope that was able to retain alluvial sediment. This proved to be an important last gasp defense regarding soil loss and allowed that sediment to be returned to the slope. With this material, workers could fill the rills in Vosne, that would grow into gullies down to the base rock in Aloxe-Corton and Monthélie.

The return of the sediment to fill the rills was preformed bi-annually in the Les Damaudes parcel. However, the owners of this vineyard were lucky rather than preventative. The wall was built as the headwall of the small clos that surrounds the vineyard below, and the access road that runs between the vineyards proved to provide the necessary flat collection area for the alluvium.

Inexplicably, the author chose to simply say that in Monthélie, the practice of returning  soil to the hillside had never been done, whereas in Vosne it had been practiced every two years. Strictly speaking this was true.  However when looking at satellite images of the vineyard, this statement appears somewhat disingenuous. In reality, the decision to plant the entire area Le Clou des Chênes in long rows without any roadways or other vineyard breaks, when coupled with the  parcel’s physical position on the hill, created a highly erodible vineyard in which no level “toe of the slope upon which might sediment gather. Returning sediment, that doesn’t exist, to the hillside is simply not possible. That does not excuse the vineyard owner from not removing vines to build a walls or taking other erosion prevention measures, but it also gives and indirectly assigns blame for this lack vineyard maintenance. The Aloxe-Corton parcel (where ever it was) is not mentioned as the owners never having returned alluvial sediment to the hillside, although this was apparently the case.

In 2006, the researchers took the adjacent photograph of Le Clou des Chênes, showing that rills had developed into gullies due to the lack of effective intervention by the grower. They also included photo looking up towards the Bois de Corton (which I have not included), with a rill/gully that extends down to the raw limestone base rock below.  In each photo, the vines roots can be clearly seen, having been exposed by the continuing erosion of these gullies. 

Study design: did the study reveal unexpected results?

In some ways, the wall below the parcel in Vosne was problematic to the study. The stone wall, and ability the return of the sediment by the grower directly impacted the amount of erosion recorded. The study’s author reports this in the write-up as: “by a factor of two”.  It not clear that the researchers anticipated this would be such a weighty factor when they formulated the study, since the focus of the study did not seem to take into account the effectiveness of wall in diminishing erosional forces. However the effect of the wall and the “anthropogenic factors” (meaning in these studies: the actions by man of returning the sediment to the hillside) certainly did have a dramatic effect on reducing the total soil lost, and the authors rightly took the opportunity to underscore the roll and value of murgers and clos as a primitive, but effective form of erosion control. (4)

But because of the wall (and the author’s eventual focus on it), other opportunities were lost. Since Les Damaudes in Vosne possessed the longest slope which also had the most consistent gradient, knowing how those factors affected erosion would have been instructional.  Had the erosion measurements been made before the anthropogenic resupply of the sediment to the slope, this information might have been gained. But since the measurements were taken after the rills were filled, ascertaining the impact of degree of slope and the length of the run can not be readily determined if the Vosne parcel is included in the analysis.

Further analysis of  meter by meter grid data, might answer some of these questions surrounding how much erosion is affected by increasing slope gradient and increasing slope length. Here the shorter Aloxe vineyard could have been compared to the top 53 meters of the steeper Monthélie vineyard. What were the erosional differences within these sections? What was the difference between erosion between the upper slopes and the lower slopes of the vineyards. Could these differences have been attributed to gradient or soil type? What were the soils left behind in the inter rows? Were they significantly different to the soils directly under the vines where the soil is more protected from rain strike and rill erosion? Then, if the full length of the Aloxe vineyard could be included, would there be greater erosion on the steeper sections where gravity has more effect? What about on the lower sections of the plot where increase water volume, speed and velocity might be expected to increase? It does not appear that these questions were asked by the study’s researchers in 2006.

It would be interesting if the data still exists and can be analyzed to examine those questions as well. It certainly would shed a more quantitative light on erosional forces on Burgundian hillside vineyards.

Study’s Opinion

In the opinion of the study, while in the short-term, erosion didn’t affect the vines production as long as the root system was not exposed, over time, the overall surface soil level declined despite the best efforts in Vosne to return the alluvial sediment to the hillside. At the time of the study, the most alarmed of growers had begun been attempting to restrict erosion by allowing grasses to grow between rows, shortening the length of rows and rebuilding walls. The authors suggest these processes be applied to all hillside vineyards.

The study of a single rain event in Vosne-Romanée

The second study released by this team in 2007 is far more detailed, focusing solely on the Damaudes vineyard. Entitled,Soil degradation caused by a high-intensity rainfall event (3) the paper details soil loss related to a single storm on June 11, 2004. This study is much more focused and is far more precise and instructional in its findings.

Vosne Damaudes erosion study
Click to enlarge.

The study’s centers on the erosional path, volume, and sediment type, as well as the net erosion levels measured in the vineyard after workers had returned sediment to the hillside, post-storm.

Soil analysis of the plot

The soils native to the vineyard are within this description from the text of the study. The prose is tight and dense so I will quote the author, Emmanuel Chevigny, here.

“The texture is rather homogeneous over the whole plot and is composed of 40% of clays and silts, 50% of gravels (2 mm to 10 mm) and a low sand and boulder content. The topsoils are ploughed (Mériaux et al., 1981). The argillaceous aggregates with polyhedral blunted to grained form are slightly structured. No pedogenetic segregation has been observed.”

The soil, as described, is a marl, with what I would think has a surprisingly high clay content for being this high on the slope. A better breakdown of clay and silt would be informative, because (as detailed in Part 2.1  and 2.2 regarding soil formation), clay is metamorphosed from limestone and other materials, and very fine in size, while silt is larger (between 0.0039 to 0.0625 mm), and not metamorphosed. Silts are often parented from quartz, which unlike limestone is not prone to chemical alteration, and thus will not produce clay minerals. The origin of this silt must have been transported from farther up-slope, having arrived in Les Damaudes through erosion.

The vineyard’s soil has a low sand content.

The author then writes about argillaceous aggregates, which are clay aggregates. In this sentence, they are writing about the type of soil structure found in the vineyard. Clays tend to form into blocky structures, where each clay units sides is the same shape or a cast of the aggregate next to it. In other words, when the blocky structures form, they are literally cast so that they fit together like a puzzle. Here he is saying that the edges of these casts of the aggregates have been blunted making them more grain like.  There is a soil type, classified as granular (grain-like), that is common to soils in grasslands with a high organic content, and Chevigny is clearly saying these are not granular soils.

Lastly, Chevigny notes that the researchers observed no pedogenetic segregation, meaning they could observe no identifiable soil creation nor the beginnings of soil horizons (sedimentary layering). This would lack of soil generation could be caused, in part, by plowing which disrupts soil horizons and encourages the erosion of weak young soils that have not developed into stronger aggregates. More on the concept of what soil is and pedogenesis later.

The gravel, or scree, which constitutes 45 percent of the vineyard’s soil makeup, (by definition) has slid into the vineyard by gravitational erosion, from higher on the hill. With the clearing of land and subsequent planting of the vines, this gravel has long ago been plowed into the clay-silt mixture. It is never mentioned by the study author, whether the scree is primarily limestone or not. Limestone is not a factor for these researchers, the particle size is squarely considered to be the issue.

By the numbers

While study revolves around the analysis of a tremendous amount of numerical data, to examine each piece of analysis is beyond the scope of this article, but their findings are none-the-less important and tells the story of erosion within a Burgundian vineyard very well. Below I’ve listed what I see as the most important changes to the hillside following this particularly heavy storm system:

  • Both rill and sheet erosion occurred, but rill erosion accounted for approximately 70% of all soil lost from the hillside.
  • A total of 13 rill erosion were noted, some forming a mere 30 meters from the upper plot boundary, that ran in straight lines down the slope, each time in the inter-rows.
  • Rills occurred across 59% of the inter-row area
  • The rills were U-shaped with strong vertical walls.
  • Estimated soil loss from the rills alone was 4.77 meters
  • A rill erosion for this rain event is estimated at 7.8 cubic meters (.275.5 cubic feet) and weighing roughly 6 metric tons (13,227 lbs)
  • An estimated 1.6 meters erosional material was deposited into 7 alluvial fans at the base of the plot.
  • The sedimentary fans consisted primarily of very fine sand to coarse sand that was between 63 μm (roughly the thickness of paper) to >2 mm. Only 10% of the fan sediment was silt clay fractions of less than 63 μm
  • Fan #4 had a total sediment area one-half of a meter cubed (.5m3).
  • The two rills that fed fan #4 had a total eroded area of .93m3  *
  • If 10% of the rill volume is sand, then 70 percent of the fan debris came from the rills while a remaining 30% must have come from surface erosion which fed into the rills and were deposited into the fans.
  • Topographic soil loss in inter-rows with rills was 3.9 mm, or 48 metric tons per hectare (105,800 lbs)  even after anthropogenic resupply of fan sediment to the hillside.
  • Mean (average) soil in non-rill effected vineyard area, was 1.4 mm, or 24 metric tons per hectare (52,900 lbs)

*1 cubic meter is equal to 1000 liters, or 6.29 oil barrels or 264 U.S. fluid gallons.

Storm size and frequency

Annual rainfall in the  Côte de Nuits is between 700 and 900 mm (27 inches to 34.4 inches) per year writes Chevigny, citing the Météo France weather service’s Atlas climatique de la Côte dOr 1994.*  The study also cites that storms with rainfall of more than 30 mm per day, occurred 10 times between 1991 and 2002. Nine of these rain event dropped between 30 and 50 mm, (1.1 inches to 2 inches) and a single storm dropped 63 mm (2.5 inches) of rain water per event/day. Based on this, we might expect that there have been 50 such events between planting and the 2006 study.

The storm event of June 11, 2004, was uniquely powerful because 40 mm fell in a two-hour period, which caused causing 3 times the annual erosion rate established by the 2006 study of 1 mm per year. Perhaps most importantly, the erosion of this single event is averaged into that 54 year period. This indicates that some years little erosion occurred. Because the study only includes storm records from 1991-2002, we can’t estimate the distribution of erosion over the span of these 54 years.

With global warming, storm intensity seems to be on the upswing in Burgundy, just as scientists have noted in other parts of the world. The severe hail events of 2012, 2013 and 2014, which centered over the hapless villages Pommard and Volnay, resulted in total crop loss for some growers.  In the Côte de Beaune, where precipitation and hail has recently been at its most extreme, has also been remarkably varied in its distribution. According to Jancis Robinson, in July of 2013, Volnay saw 57mm of rain (2.25 inches), while neighboring Monthelie only got 9.4mm. Needless to say, with this high degree of weather localization, these data figures are representative of the rainfall collection points only. There were likely areas of Monthelie that got much more rain, and areas Volnay that got much less rain than the data collection sites.  The massive storms of late November 2014 that saw 200-300 mm of rainfall along the Mediterranean coastline and into Austria, the Dijon saw 95 mm of rainfall over a 24 hour period. So, in terms of storms, it would appear that while the Côte d’Or gets regular, low volume rain events, it is by and large, relatively protected from major storm fronts.

*Current monthly statistics are can be found here, and the average rainfall in Dijon as of 2015 is 775 mm (30 inches) per year.

The sediment at the “toe of the slope” 

When examining sediment in the alluvial fans, researchers discovered that it was made up of 90% sand and 10% fine sediment. Fan number four, on which researchers focused their examination, contained nearly one meter of alluvial material. The fact that it contained little silt or clay, indicates that when the water became backed up at the stone wall, its movement did not slow enough for particles smaller than 63 μm (which includes all clays and silts) to fall out of suspension. This suggests there was a significant depth of water Then as the runoff began to gather enough volume to circumvent the murger, and continue downslope, it gained sufficient speed and velocity to quickly form rills in its path around the wall. The runoff carried virtually all particles smaller than fine sand out of the vineyard.

Study inconsistencies, and outdated or generic source material

Between the two articles, the explanation of soil and bedrock type differs. It is not clear why the authors of both studies would quote articles that are 35 to 45 years old, and that generic to the region rather than performing a shallow excavation themselves, in order to obtain information specific to that vineyard.

“The slopes are composed of Middle to Upper Jurassic limestones and marls (Mériaux et al, 1981) …“For example, the sandy-clayey screes (grèze litée) reach 3 meters on Comblanchien limestones in Vosne-Romanée.

In the second study they write:

“The hillslopes develop on Middle to Upper Jurassic limestones and marls, and are covered by colluvium soils of argillaceous-gravelly nature and formed by Weichselian cryoclastic deposits (grèze litées) reaching up to 3 m thick (Journaux, 1976).”

Writing of Comblanchien as a class of limestones is a red flag, as it is distinctly a singular type of limestone. Adding to the confusion is the soil percentages that at first appear to be attributed to the vineyard, are actually from the 1981 Mériaux et al study and generic to the  Côte d’Or. Later in the study, the percentage of sand is increased to >20% (from 10% sand and larger stones). 50% gravel content in the vineyard, which is cited in early in the text, is reduced to 45% later in the study write-up.

 

Computer modeling projects grain-size transition 

Computer projections of grain size changes after each major storm event.
Computer projections of grain size change after each major storm event. Click to enlarge

Because the researchers must begin their work with the soil percentages they observe, this 45% gravel, 40% clay/silt and 15% sand, was their starting point. It was quickly recognized that outgo of clay minerals, coupled with the simultaneous retention of sand would eventually change the vineyard make-up, so they developed a computer program to predict future changes in grain size distribution of the soil composition. Computer models showed after only 4-5 rain events of similar magnitude as the one in 2004, there would be significant changes to the soil makeup. The results of those projections are to the right.

Chevigny encapsulates their findings with this statement.

“…the results of our simulation clearly show that repeated rainfall events modify significantly and very rapidly surface soil grain-size distribution: after only a few events, the top soil has lost more than 30% of its fine material.”

The ultimate effect of this would be the loss of organic materials, nutrients and ultimately soil sustainability.

Study conclusion: vineyard practices enhance rill development and erosion

While the wall slows the net output of soil volume from exiting the plot, the most soils most viable for farming are being lost, while simultaneously, the soil texture and particle size are being irrevocably changed as the sand sediment is returned to the hillside, and disked back into the soil.

It is forwarded by the author, that this action, is part of the problem since rills continue to re-emerge in the same locations, year after year. They submit that ill propagation in the inter-rows is heightened by tilling and repeated passes tractors and foot traffic, and the regularity of rill spacing are evidence of this.  These practices, he writes causes decreased soil porosity (compaction) and restricts rainwater infiltration. Such wheeled ‘passage’ creates flow zones which increase the volume and velocity of runoff in a concentrated area, multiplying the quantity and size of material the runoff can carry. The evidence of these anthropologically created flow zones is the re-emergence of rills that return, repeatedly, in the same inter-rows, despite workers attempts to eliminate them by filling the rills and disking those areas.

It is clear the effort must be made to properly identify the flow zones and attempt to eliminate them but to do so is to understand their formation to begin with, and limit or eliminate that activity altogether.

For me, the results of the computer modeling and projections are not surprising. While this research team and Burgundian winemakers can only look forward to what is next, we have the opportunity to use this information to hypothesize what came before.  This will allow us to see the true arc of geomorphological progression in the vineyards, and thus how winemaking styles have and will continue to change in Burgundy.

Next UP:  Turning our understanding of the limestone Côte on its head

 

 


 

(1)  Vineyards typically are areas with no breaks or obstacles to slow or impede storm runoff, so longer vineyards tend to suffer more greatly from erosion. However, this was not identified as an erosional factor in the study write-up. The length of this Vosne vineyard was listed in the first study at 130 meters, while in the second study it was written as 126 meters.

(2)  Le Clou des Chênes’ increased prestige and vineyard value can be a tremendous incentive to better maintain a vineyard. The vines and vineyard appeared to be in good health in 2012, the last time googlemaps car drove up this stretch of road. Still, no murgers had been built as of that time.

(3) published by Emmanuel Chevigny of the Université de Bourgogne in 2007

Understanding the Terroir of Burgundy: Part 4.2 Erosion: fundamentally changing terroir

Erosion banner

 

 

Erosion is constantly changing the terroir of Burgundy, and in turn, it is altering the weight and character of the wines from virtually every vineyard on the Côte. How significant is erosion in Burgundy today? As mentioned in Part 4.1, a study during the late 1990’s measured the soil loss in unspecified vineyards of Vosne-Romanée to be 1 mm per year, and the same erosional levels were measured off of the vineyards of Aloxe-Corton.  Ath that alarming rate, losses over the next century would have averaged 10 centimeters or almost 4 inches of topsoil if corrections were not taken. On the even steeper slopes of Monthelie, a study measured almost twice the erosion at 1.7 mm (± 0.5 mm year), with sections of the vineyard which measured a shocking eroded up to 8.2 mm (± 0.5 mm) erosional rate. Luckily, many growers have improved their farming practices, particularly since 2010, and these figures should be lower today. Only future studies can tell us what improvement has been made.

The grape harvest Annonymous 16th century, Southern Holland
“The grape harvest” Anonymous 16th century, Southern Holland

For centuries the solution for this problem was to bring in soil from outside areas to replace what was lost on the slopes of the Côte d’Or. However, in the name of terroir, this is no longer allowed. Current law allows growers to redistribute only the alluvium that comes to rest within appellation boundaries. One can imagine that the laborious process of shoveling out the alluvium from the toe of the plot and redistributing higher in the vineyard is a yearly chore. What earth escapes the appellation lines however, is gone to that appellation forever.

The intention of preserving the purity Burgundy’s unique terroir by forbidding introduction of exogenous soils is somewhat paradoxical, since it is only attempting to preserve the terroir à la minute. While in reality it is ultimately is failing at that – due to erosion. 

A positive, unintended consequence of this inability to replace soil is that growers have finally realized that soil conservation is now more critical than any time in Burgundies’ 1500+ year-old viticultural history. They now know that they must fully understand the factors of soil structure and erosion, while at a municipal level, their villages must invest in effective storm water management; both of which are in various states of development or improvement. 

The long uninterrupted run of vertically oriented rows presents unrelenting erosional pressures on this section of Les Folatieres.
The long uninterrupted run of vertically oriented rows presents unrelenting erosional pressures on this section of Les Folatières. photo googlemaps

While the best modern practices are stemming the tide of erosion, vineyards still can be threatened. Even great vineyards on the mid-slope, like Les Folatières in Puligny-Montrachet, which have long, open stretches of vines without significant breaks in planting, are prone to extensive erosion. While soils are depleted not only in terms of depth, they are changing in terms of particle size and makeup. Erosion most easily targets fine earth fractions, detaching them from their aggregate groupings, and sending them into vineyards farther down slope. Light to medium runoff acts like a sieve, carrying away only the smallest particles, leaving behind material with of larger particles sizes. This in a very real way changes the vineyard’s terroir, and in turn, the wines that are grown there. Wines from vineyards that retain only course soils of large particle size (1) tend to produce wines with less fruit the and less weight, and by consequence revealing a more structured, minerally character.

Even more critical is that soil loss can threaten the vitality and health of the vines, as the soil is literally carried away from beneath them. A vine’s main framework roots is said to require a minimum 11-13 inches to anchor itself to the earth and survive. The problem arises when a section of vineyard does not have extensive fracturing, and the soil level begins to drop below that one foot level. To address this, various growers have responded by “reconditioning” their land. By using a back hoe to break up the limestone below, this can give new vines planted there the living space so the vineyard can continue. Does this change the terroir and the future wine more than inputs of exogenous soil? I should think the answer is yes, significantly. 

 

Rainfall and rain strike: the first stage of erosion

rainstrike. photo: agronomy.lsu.edu/
rainstrike. photo: agronomy.lsu.edu/

Rainfall is measured by its size and velocity. A raindrop from a drizzle is typically .5 mm in size, and has a terminal velocity (the maximum speed the drop can reach) of 2 meters per second, or 4.5 miles per hour, in still air. The speed it falls, with no assistance from the wind is determined by its ratio of mass to drag. Large raindrops of 5 mm, have more mass in relationship to its drag and accelerate to 9 meters per second, or 20 mph.

Rainfall, meaning the actual physical strike of each drop, can break down soil aggregates (fine sand,  silt clay, and organic materials) and disperse them. Splash erosion has been recorded to drive particles of earth up to 60 cm into the air, and 1.5 m from its point of origin.

Once their limited bonds are broken, the ensuing runoff can carry these materials downslope. Runoff, the most obvious form of erosion, occurs when rainwater cannot infiltrate the soil quickly enough, and exacerbated by the lack of cover crop, lack of organic material, lack of soil structure and negative effects of soil compaction. Of course, this process is most noticeable during high-intensity rainstorms, the amount of soil lost during longer but low-intensity rainfall can be significant. This slower erosion can go largely unnoticed until most of the productive topsoil has been removed by what is referred to as sheet erosion.

Seasonal protection from rainstrike

Compared to most growing regions, the Côte d’Or has a very wet growing season. Storms during this period can bring irregular and unpredictable rain events that can be heavy and long in duration. The winds during harvest tend to be westerly, with warm humid winds bringing rain first over the Hautes Côtes, then to the Côte d’Or, then out across the Saône Valley. The wet warm humid conditions often encourage powdery mildew in the wake of the storms, so there is a tendency to want to prune to open up the canopy for ventilation to prevent mildew. However, the vine canopy can provide significant protection against rainfall strike, depending of course, on the orientation the rows and the of the wind direction. So good canopy coverage for the period that half of the precipitation occurs (April – September)(2) is beneficial in terms of protection from erosion.

As winter arrives, the vines will have lost their foliage, exposing the soil directly for the entire winter and spring to whatever nature has in store.

Rain Rate

storm.1
Summer storms. Bottom right Photograph: Louise Flanagan theGuardian.com, Bottom left photo Caroline Parent-Gros of A.F. Gros, Top photo Decanter.com

Rainfall is typically measured in millimeters per hour, with a light rainfall slightly tipping the scales at up to 2.5 mm per hour or less than a tenth of an inch per hour. Moderate rainfall is considered to be from 2.5 mm per hour to 10 mm per hour. A heavy rainfall falls between the range of 10 to 50 mm, and a violent rainfall is above 50 mm per hour.

 

Light rain – drizzle 2.5 mm per hour with a terminal velocity of 2 meters per second

Moderate rain 2.5 mm per hour to 10 mm per hour

Heavy Rain  10 mm per hour to 50 mm per hour

Violent rain, above 50 mm per hour

 

Good soil structure resists damage from rainstrike and runoff

Good soil structure is the result of the binding of soil into clumps of both small and larger aggregates, meaning sections of soil will bind more strongly together, than those next to them. This allows the soil to maintain the necessary small and large pore spacing, which allows water, air and nutrient infiltration and movement through the soil. Larger amounts of older, more stable organic matter tend to strengthen soil aggregates so any farming practice that increases organic matter, and the subsequent microbiological activity will result in healthier soils.  Stable soil aggregates allow the soil to resist disintegration due rain strike and thusly helps deter erosion.  It also encourages root penetration by creating weak spots between aggregate masses.

Conversely, unstable soil aggregates are more easily dispersed by rainstrike, and the ensuing erosion clogs larger pore spaces of the surface soil. This clogging forming hard crusts on the surface which both restricts both air and water absorption and increases runoff.

The fix apparently is simple. According to soilquality.org, soil forms aggregates readily with the addition of organic manure, as well as allowing cover crops to grow, which has the additional benefit of protecting the soil from rain strike and the ensuing erosion.

Infiltration rate

Erosion Runoff Ardeche
Rill Runoff running fast in Ardeche. Photo http://www.geo.uu.nl/

The speed at which rain can be absorbed into the soil is referred to as infiltration rate. An infiltration rate of 50 mm per hour is considered ideal for farming, because even in heavy rainfall, a well-structured loam will not allow puddling. While the farmers of Burgundy do have some loam in their soils, the geological and topographical factors they face are far more and varied and thus more complex than that of the typical farming situation. I could find no studies done specific to infiltration rates of Burgundian soils, but below are the general rain infiltration rates of general soil types, starting with clay.

The infiltration rate of clay soils, with good to average soil structure, unsurprisingly, do not drain all particularly well, due to their very small-sized particles. Clays typically have an IR of 10mm-20mm per hour. And as we know, transported clay, with its aligned particles, and plasticy quality greatly restricts water flow, and while it will absorb water, it will not allow water to pass through until the entire structure is saturated, greatly slowing drainage. Worse, due to poor farming practices, clay soils can have a decayed structure, which can slow absorption to less than 10 mm per hour. Water tends to puddle on clays with poor structure, causing them deteriorate to the point of deflocculation.

The study of water and how it drains is researched acutely in areas where water is scare, whereas little study of drainage is done in France where rain and water are plentiful. Hence, my investigation of water infiltration in calcium-rich soils lead me to agricultural water policy studies conducted in Palestine and Spain. One such study found that Clayey Marl, with a plasticy character, had an infiltration rate of only 4-8 mm per hour. This low rate of infiltration suggests the soil structure had already been degraded through poor farming practices. Often the villain of low infiltration rates is a combination of frequent deep tillage, herbicide and pesticide use and compaction by walking on or working wet soils, which collapses weaken soil aggregates.  In deeper soils, like at the base of the slope, collapsed soil aggregates can result in hardpan development below ground, while on sloped vineyards, disrupted soil aggregates are very susceptible to erosion.

Clay-loam and clayey-marls, like those found on many lower-slope vineyards, that retain good soil structure, have IR rates beginning at 20 mm per hour. As the percentage of loam increases (equal parts sand, silt, and clay) the IR rate increases up to 50 mm per hour as long as it retains good aggregate stability and there is no compaction.

Loam to sandy soils, which some Bourgogne-level and Village-level vineyards possess, can have very good infiltration rates, again as long as soil structures are good.  Ideally, they can absorb 50 mm of rain per hour, which is the amount that a heavy rainstorm will produce. These vineyards, however, receive all the runoff from the slopes above, and their “well-drained” soils can be overwhelmed.

Sandy soils and Calcareous (limestone) soils can have infiltration rates well in excess 150mm per hour to 200+mm per hour. The problem is these soils drain excessively well, and tend to not retain water well, and are prone to high evaporation rates.  Off point, but quite interesting, are two studies in south-eastern Australia Bennetts et al. (2006) and Edwards & Webb (2006) found that rainwater remained relatively unchanged as it moved though these porous soils that lacked significant amounts of fine earth fractions and organic material. However, water changed its chemical signature quite significantly as it passed much more slowly through clay-rich soils. This finding certainly challenges the long-held assumption that it is the limestone lends many Burgundies their mineral character.

Infiltration Rate, Slope, and Runoff.

Vogue's parcel of Musigny. Source Googlemaps
Vogue’s parcel of Musigny. Grass growth does not seem to be encouraged here. Given Cerdà’s study regarding the erosion of bare soils, one can only wonder how much greater this vineyard could be? The mitigating factor is the vineyard runs horizontally along the top of the hill, and is not deep or highly sloped. Runoff has little opportunity to gain significant suspension velocity. Photo Source googlemaps.com

A study in Spain by A. Cerdà (Univ. de València) examined infiltration rates, runoff, and erosion, on clay, marl, limestone and sandstone. Additionally, he ran these trials with three levels of vegetation covering the soil material: bare, intermediate and vegetated.  The amount of water delivered was 55 mm per hour (which some soils easily absorbed). The study showed slower rates of infiltration on the bare soils, while more highly vegetated soils reduced and almost eliminated runoff and erosion.  Interestingly, marl soils fare the worst for both runoff and erosion rates on bare soils. Yet on vegetated soils, runoff and erosion of the marl were minimal.

They observed, of bare soils, an infiltration rate of  3 to 55 mm per hour, the runoff from 0 to 83%, and the erosion rates from 0 to 3720 grams per hour.

The easily erodible marl soils had up to 83% runoff and a maximum erosion of 3720 grams per hour. So it turns out that marl soils are particularly vulnerable to erosion which sets up an interesting dichotomy: Burgundian’s penchant for discouraging ground cover between the vines, actually encourages erosion – something they seek to, and direly need to avoid.

Clay (soil) and limestone (soil) both had what Cerdà considered to be intermediate levels of runoff and erosion; with a maximum of 46% runoff, and a maximum of 131 grams of soil material eroded per hour.

When we talk about erosion, we are implying there is a slope.

Nearly level: Level, 0% Nearly level <3%
Gently sloping: Very gently sloping >1%, Gently sloping <8%
Strongly sloping: Sloping >4%, Moderately sloping <8%, Strongly Sloping <16%

Source: nrcs.usda.gov

On the rockier terrain of upper slopes, the uneven the soil surface can slow the momentum of water coming down the hillside, despite the steeper grade. However, as the runoff moves downslope, and the soil becomes smoother, the water grows in volume as in joins other rainfall which has not yet infiltrated the topsoil. This increase in volume causes the runoff to increase in its speed and its velocity. Speed and velocity increases are exponential, as its mass allows it overcomes the friction of moving over the soil below. 

Despite the fact that these moderate slopes can attain fairly significant soil depth with normal, moderate rainfall, they are also prone to erosion when exposed to heavier storm-induced runoff. Any long, uninterrupted stretch across these moderate slopes encourages a fast, and often damaging, runoff. As the speed of the water increases, it achieves a volume sufficient to carry larger and larger particles. Cerdà’s study suggests that the marl that has developed on these slopes are particularly vulnerable to heavy runoff if no vegetative cover is allowed to grow among the rows. 

Suspension velocity

water suspension velocity
water suspension velocity source: water.me.vccs.edu/

The ratio of surface area to weight determines a soil particle or rock’s suspension velocity. This is the amount of water velocity needed to carry the object in its flow. As the flow decreases, rocks with higher suspension velocity, meaning they require fast-moving water to carry them, settle out quickly, and are said to have a low settling velocity. As the water slows, it is these, the densest objects, that fall out of suspension first.

Silt and Clay particles have a very low suspension velocity due to their extremely small size, regardless of their density. These particles are easily picked up and washed away by water movement. Unless the clay particles in suspension are adsorbed as it slowly passes a homogeneous clay body (ie. a kaolinite clay body attracts kaolinite clay particles and illite particles will flocculate with an illite body), clay particles will not settle out of solution until the water becomes still and ponds. The same is true with silt, with its slightly larger particle size.

Sand and gravel are larger, with enough density to resist slow-moving water. They are considered to have a higher suspension velocity than silt or clay. But neither sand, gravel, nor even rocks the size of the palm of your hand, are immune from alluvial transport.

Up next: Erosion 4.3 In the water’s path: Studies of Erosion in Vosne

 


(1) It could be argued that because of Burgundy’s monoculture and high erosion rates will only allow calcisol, and because of that soil development (pedogenesis) is not possible due to the filtering out of fine particles, both mineral, and organic, by erosional processes. Conservation tilling or zero till could greatly change that dynamic, and it is possible with these and other techniques, that growers could expose the truer terroir of Burgundy.

(2) The Wines of Champagne, Burgundy, Eastern and Southern France,  by John J. Baxevanis Rowman & Littlefield Publishers (October 28, 1987)

(3) Could this chemical signature change the flavor of wine? This certainly raises a whole host of questions regarding the impact of fast draining limestone on the flavor or minerality of in wine. This study would suggest the long-held belief by many that limestone gives wines a minerally characteristic is false.

 

 

Understanding the Terroir of Burgundy: Part 4.1 the history of erosion, defense, and restoration

Erosion and man

 

Historical vineyard defense and restoration

 

During the late 1990’s and early 2000’s, soil measurements in both Vosne-Romanée and Corton determined that the erosion rate for both areas were approximately 1 mm per year. Considering that the entire Vosne hillside, as well as all of the hill of Corton are either premier or grand cru sites of enormous value, one would have assumed that every effort had been made to limit erosion. But that assumption would not have been completely true.

 

Even now, 15 years later, with ever-improving an information, and a growing acceptance that erosion is significant problem that needs to be further addressed, not every farmer is making the necessary changes. While soil management may not be ideal in every plot, vast improvements have been made from the time of the Middle Ages, when erosion ravaged vineyards of the Côte d’Or.

One of Vogue's parcels of Musigny denuded of all grass. While there is no denying the quality of the wine today, what of the vineyard in the future? photo: googlemaps
One of Vogue’s parcels in Les Musigny, denuded of all grass. While there is no denying the quality of the wine today, what of the vineyard in the future? photo: googlemaps

Man has waged an epic war against erosion for centuries; which, until recently, has been largely futile. The early Burgundians were understandably ignorant of soil structure and proper tillage techniques, both factors that greatly mitigate erosion. They had no way to know that it was the way they farmed that actually caused the huge erosional problems they fought so unsuccessfully to reign in.

Change, in an old, tradition-bound culture is resisted; and that is nearly as true in Burgundy today as it was in the middle ages. New techniques such as conservation tillage can be very slow to be adopted, much less having a discussions with older generation about whether a vineyard should be tilled at all. That this ancient practice of zero tillage has been implemented with success in other areas as long ago as 1971, is of no consequence.

Many farmers still restrict the growth of ground cover by use of either pesticides and or routine tilling, both of which diminish soil structure and increase exposure to erosional factors. This can be seen even in Comte de Vogue’s perfectly neat parcels of Les Musigny, where only a few tufts of grass evade the plow blade or the hoe. While it is difficult to argue with Vogue’s results in the bottle, the unseen menace of sheet erosion exists robbing the soil of fine earth fractions, ever so slowly.(1)

Before global warming, the vines were planted in Burgundy in east-west rows, straight down the slope. This directional planting was done in belief that it opens the vines to the early morning sun, allowing better ripening. Unfortunately, any truth to this is offset by increased erosion. While the weather was often predictably cold, and complete ripening could be hit or miss, the soil is a not a renewable resource. As we examined in Part 4, soil lost over 6,000 years ago from the hillsides of central France at the hand of Neolithic men, still has not, and in all likelihood, will never really repair itself.

Burgundy’s historical defense of the vineyard

flooding gate
photo: Caroline Parent-Gros

Murgers, or stone walls, have historically been the farmers first, and perhaps only, line of defense since antiquity.  Murgers (or Clos if the wall completely surrounds a vineyard) as part of the idealized visage of Burgundy, shows itself as part of many vineyard’s name, ie. Volnay Clos des Chênes or Nuits St-Georges’ Les Murgers.

Most murgers were no more than stacked stones constructed from rock that had been removed  from between the rows of vines because they were plowing obstacles. Stacking them into walls to protect the vineyard from erosion naturally evolved in the fields. In the 18th and 19th century, some of the more wealthy landowners began to have murgers constructed from brick and mortar, then covered with a fine glaze of lime plaster.  Grandiose entrances to these murgers were hung with intricate iron gates, meant to indicate both the importance of vineyard, and the owner.  In either the case of a stacked stone wall, or a much more extravagant Clos, walls have been the leading defense the vineyards for centuries. They not only serve to direct runoff around the vines, also have the equally important function of keeping the soil that is in the vineyard from being carried out.

Folatieres wall

 

Vineyard reconstruction in the middle ages

It is now widely understood that the simple act of farming causes erosion, and poor farming techniques can cause tremendous erosion, particularly on slopes. The earliest record of man’s attempts to fix the vineyards eroded to the point where they could no longer support vines, comes from documents kept in the later Middle Ages.

Jean-Pierre Garcia, a noted scholar at the Université de Bourgogne, quotes manuscripts in which detail the fight against erosion 600 years ago, in his paper “The Construction of Climates (Vineyards) in Burgundy during the Middle Ages(from French). Translating these ancient texts from the French of the Middle Ages into modern English is challenging, but the message these manuscripts contains is clear: fighting erosion was back-breaking and exceptionally expensive, despite the luxury of cheap labor. This work was likely paid for the Dukes of Burgundy or the Church, or on possibly a smaller scale, by the Duke’s seigneurs, noblemen whose the manors covered Burgundy.

Murgers in Vosne
click to enlarge. photo: google maps

The accounts are as such: In Corton in 1375 and 1376 AD, 38 days of work were required to remove a drystone wall that had collapsed “in the vine” and rebuild it “four feet high along the vine Clement Baubat to defend of acute coming from the mountain.”  In Volnay, it was written in 1468-1469, that men had to excavate the earth below the Clos which had eroded down to rock, and “lifted from earth” returning the topsoil to the vineyard. In 1428 there is a reference of constructing a “head” “above the Clos Ducs Chenove for the defense eaues to descend along said cloux.”

By the end of the middle ages, there are the first references to “exogenous inputs of land”, meaning that earth is brought in from an outside area to replace the topsoil lost to erosion. Land was taken in 1383 from Chaumes des Marsannay and from below the “grand chemin” (highway). This was a huge undertaking that was completed over the scope of “691 workers demanding days”.

Horses and wagons were very expensive in the middle ages. Having 800 wagon loads plus the labor was a major undertaking.
Horses and wagons were very expensive in the middle ages. Having 800 wagon loads plus the labor was a major undertaking. This, a woodcutting from 1506 depicts the power associated with the horse-drawn cart, is called “The Triumph of Theology”.

Then again in 1407 through the spring of 1408, it took 128 days of work were “to flush the royes and carry the earth in the clos,” and 158 working days “to bring the earth into the Clos.” It is immediately obvious that medieval French measure was unique to the time, and is very difficult translate. In one instance, it was recorded that for 28 days carts carried earth into a vineyard in Beaune, and “28 days labor and 48 days working.” In 1431 there was this reference that “six days a horse hauler, dumped 30 days to 2 horses (are needed to dig from) the Chaumes de Marsannay and the road beneath the Clos where piles of earth were raised.” While the exact labor is impossible to gauge, it is very apparent that immense effort was made, by whatever means necessary to return the vineyards of Burgundy to agricultural viability.

Here rill erosion has stripped the soil down to the limestone base in Corton-Charlemagne. photo from an excellent study by  J Brenot et al of the Segreteria Geological Society in Rome.
Here rill erosion has stripped the soil down to the limestone base in Corton-Charlemagne. photo from an excellent study by J Brenot et al of the Segreteria Geological Society in Rome.

The practice of bringing in soils from outlying areas continued through at least through the 18th century. When the RomanéeConti vineyard (a national property) was sold in 1790, the sale documents reveal that in 1749 the “Clos received 150 carts in grass taken off the mountain” of Marsannay.

1785-1786 “dug near the bottom of the vineyard and removed 800 wagons of earth, and this was spread in areas devoid of ground and low parts.”  This practice appears to have ceased, or as Garcia writes “at least on paper” after 1919 when the Appellations of Origin was established. The INAO has certainly forbidden exogenous soil additions since it was formed in 1935.

Interestingly, while on the subject of Romanée-Conti: some of its soils are clearly foreign to the Vosne-Romanée, according to geologist Francois Vannier-Petit,  a void appears in the substrata of the south-western corner of RomanéeConti  which suggests the hillside had been quarried at some point, and filled in with “exogenous” landfill. James E. Wilson noted this void as well in his book Terrior (p 137), where he notes that seismic data suggest this void was created by a fault, but electrical resistivity data suggest an erosional scarp (meaning ancient erosion created a cut out in the hillside) into what Wilson identifies as Ostrea acuminata marl below. Wilson, in either case, assumed that subsequent gravitation induced rock slides and erosion from above filled the void with colluvium. Any of the three possibilities are viable explanations, but the manuscript from the  1785-1786 do clearly state 800 wagons of earth” were “spread in areas devoid of ground and low parts.”

The issue of a quarry in Romanée-Conti is far from clear cut. click to enlarge. photo googlemaps
The issue of a quarry in Romanée-Conti is far from clear-cut. click to enlarge. photo googlemaps

At this point, no record has been found regarding a quarry having been excavated at the site of RomanéeConti, but many governmental and clergy records were destroyed during the revolution. With this, the argument that these vineyards have “special dirt” has been laid open as fallacy. The topsoils of the Côte have been reshuffled for centuries, integrating alluvial loams and clays from the base of the slope (or from elsewhere) back into the fold of the upper slopes of the Côte d’Or. The vignerons of Marsannay who are lobbying for 1er cru classification for their vineyards would certainly point to the fact that their dirt is very similar to the dirt in Gevrey. Better yet, it is clear that a fair amount of Marsannay dirt contributes to create RomanéeConti, the greatest wine all of the Côte d’Or, and that dirt has been there for centuries.

As if by divinity, the some potential erosional problems were avoided by the fact that Burgundy’s vineyards tended to be quite small. Murgers at vineyard boundaries could then slow the velocity of the runoff as it moved down the hillside, not allowing it to gain so much momentum that a high suspension velocity can be reached. These vineyard breaks have been crucial in even wider erosional damage in many areas.

The creation of small vineyards was often caused by two factors. The first being economically large vineyards did not make sense. There wasn’t sufficient demand for wine to produce significantly more than the greater Burgundy area could consume. The poor roads and the lack of safety between villages and cities made medieval trading slow and perilous. Additionally the division and subdivisions of France and the rest of Europe meant that lords had the right to restrict passage and to impose fines and tariffs upon merchants.  These factors diminished the volume and frequency of trade within the continent, and in turn limited the amount of wine needed to be produced. Large tracts of vineyards were not necessary. The second, and perhaps the greatest limiting factor of vineyard size would be size of a plot that a single man could work in a day.

Les Glaneuses (1857) by Jean Francois Millet
Les Glaneuses (1857) by Jean Francois Millet

While ouvrées simply means worked in modern French, it was used in the past as a measurement of land based on how much land a single farmer could work himself.  Thus, one ouvrées (4.285 ares (2) or a tenth of an acre) is the amount one man can work in one day without a horse.  Madame Roty re-counts her family’s history in explaining that in the late 1800’s an earlier generation did not bother to plant their vines in rows since they could not afford a animal.

This suggests an interesting fact set of circumstances. Before the Revolution, (the Roty’s farmed Gevrey since 1710) farmers who specialized in grape cultivation, worked a handful of parcels on the local Seigneur’s manor, in the open field system described in Part 4. In this feudal society, they had the use of a shared horse and plow which belonged to the estate. However, after the ownership of land was released to the serfs following the Revolution in 1793, they may have now owned their parcels, but they so poor they could not afford the animals to farm them. This forced most of the peasants of Burgundy use to no-till farming methods. Later as economics of the region improved, a horse could be bought (perhaps in co-op one with one or more families), the Roty’s were forced to remove some of the vines so the animal and plow could pass through.

Farmers who could afford a horse, found the animal multiplied their efforts eight-fold, allowing them to plow 8 ouvrées in a day.  A family with a horse could now manage seven hectares of land, which were, of course, divided into the same feudal era parcels families of the area had always farmed, just as they do today.

The emergence of tractors opened up the capabilities substantially more, allowing growers to farm much larger areas of land. Additionally that extra time has allowed growers to farm in farther flung vineyards, in villages outside of their own.

 

Next Up: Part 4.2 Erosion fundamentals: infiltration rates, runoff and damage, and how it has changed the wines of Burgundy.

 

 


(1) Musigny has three factors in its favor. It has a shallow slope which aids in its soil retention.  It is a shallow vineyard, in that its rows are not long, and runoff can not achieve a high suspension velocity. And third, it is enclosed by walls that help protect it from some erosional forces.

(2) Ares is 100 square meters, and a hectare is 100 ares.

 

 

Understanding the Terroir of Burgundy: Part 4 the history of erosion and man

 

 

 

Erosion and man

by Dean Alexander

Erosion has had a monumental impact on the character of the wines of Burgundy. It took several decades once the INAO began preventing exogenous soil additions (early 20th century), before growers slowly began to realize that they must change the way they work their fields. They could no longer hit reset, by bringing in new soil to fix what they had damaged through poor farming practices.  The vineyards have since responded positively; with increasingly healthier soils, and far better soil retention. The region is now producing the finest wines in its long history. But without a doubt, the erosional damage of the past has been so immense and irreparable, that we will never really know what the terroir of Burgundy might have been. 

 

How long ago this happened, will certainly surprise you.

 

The First Farmers

Plow were first widely used as agricultural neolithic man move into central France around 4,000 BC .
The plow: 4500 BC

With the recession of the Ice Age, the Neolithic hunter-gatherers of the region were now free to venture northward, allowing the arrival of agricultural Neolithic man in central France, 6,500 years ago. Around that time, the first plows were developed, and with the economy of effort it provided, more food could be produced. This in turn allowed the population to grow, greatly increasing the need for arable land.

As agriculture began to be adopted by Neolithic man, particularly after the development of the plow, erosion became a significant issue across Europe.To meet that demand, they burned to clear forests for pasture and fields. This was an expedient means of what would otherwise take years of work. The unintended consequences of burns to facilitate clearing, were often massive, fast-moving wildfires that swept though forested and grassland areas.

Without the protection of trees and grasses upon the hillsides, the erosion that ensued was monumental. There may have been more erosion in the 700 years Neolithic man farmed the land of central Europe, than in the preceding 35 million years since the Côte d’Or was formed, and perhaps more than all of the time since. Although through intervening centuries have seen the reforestation of the hillsides, the damage done by Neolithic man permanently changed the landscape of France.

What did Neolithic man look like? Click here.

The Middle Ages

William Shepard, Historical Atlas 1923
Tenant Farming example. William Shepard, Historical Atlas 1923

Since the Neolithic, two subsequent periods of deforestation occurred, each time followed by large-scale erosion. The least destructive of the two was the periods between the 12th and 15th century, which despite the black plague in the middle 1300s, saw a large population growth in France.

The king, or the Duke in Burgundy’s case (1), would grant large parcels of land from the royal demesne (domaine) to his nobility, who were considered the servants of the Duke. Known as seigneurs, the nobility, would then use the land to raise money to fund the Duchey. The seigneur granted strips of land to tenants (serfs) to farm in open fields. These fields where then were farmed communally by the inhabitants of the manor. Intermixed with the tenant parcels were the demesne of the seigneur, and the demesne of the church – all of the land which was worked by the surf communally as partial payment for their tenant rights.

The rights the tenants had to the land were very strong and generational. They could not be evicted from the land by the seigneur. Additionally, the tenants were able to accumulate rights to more than one strip of land, meant parcels could be scattered across the manor. A transfer of land rights typically happened when a tenant died and had no heirs. At that time another tenant would assume the right to work that parcel. This occurred on a massive scale in the wake of the black plague, which arrived in Lyon in 1348. Lyon, which was only 155 km, or 96 miles along the main highway, the Via Agrippa, from wine villages of the Cote d’Or. There is little doubt that the plague struck the Cote d’Or very hard.

Newcomers to the manor who had no land rights worked for tenants that had more land than they could work themselves. It is estimated that half the of the agricultural community consisted of landless serfs.

Farming with plow
From an early 15th century manuscript. The Granger Collection, New York

The manor model, with its communal farming, required everyone to adhere to the norms of the region, and this discouraged innovation and adoptions of new techniques, causing production per hectare to lag behind farms in England, Holland and elsewhere in the world. The farmer’s dependence on the communal sharing of prohibitively expensive horses and plows needed to farm the heavy clay soils of central Europe only reinforced the status quo.

The inefficiencies of farming under this system meant that as the population grew, it required that the economy remained primarily both rural and agrarian. The existing estates could not supply enough food if population grew mainly in urban centers, so population tended to grow in rural areas. More mouths to feed, and more able hands to employ, meant economic opportunity for the Duchy if new arable land could be developed from the forests.

Even though the open field system inherently discouraged innovation and suppressed productivity, the system proved to be so economically successful its existence eclipsed the time of feudalism. Right up to the revolution, the open field system to continue to fund well-heeled landowners in this very capitalist endeavor. But even then, to say the open field system was gone, might be an incomplete truth. The people may have then owned the land, but their situation had not greatly changed. In fact, until only recently, the wide-spread division of small parcels ensured the impoverishment of paysans across Bourgogne-Franche-Comté, with an obvious, strong parallel to the medieval tenant arrangement. Indeed, the old lord-tenant arrangement of métayage (sharecropping) would reemerge. post-1789 revolution, between those who owned the land, and laborers who would work it. In 1929 there were 200,000 Métayers in France, farming the same 11 percent of agricultural land. This was truly not so differently as had been the arrangement in 1729, or in 1529 for that matter.

As with a population that doubled in the 3 centuries after 1000 AD, the needs for timber and hardwood also increased. Wood was needed for construction, woodworking, iron smelting and metal working, not to mention fuel for heating.  All of these needs multiplied the pressures on deforestation. Although forest management had to various degrees been practiced, it tended to be exercised on forests on properties owned by the aristocracy and the church. Elsewhere, woods fell to the ax and saw.

erosion clear cutting
photo: http://ourplanet.infocentral.state.gov

18th century: The last major assault on terroir

A devastatingly cold 17th century followed, slowing the population growth and economies. The end of that century saw the failed harvest of 1693, when the death toll, according to David Huddart, and Tim Stott of Europeans is thought to have numbered in the millions. This period of economic lull set the stage for a final epoch of deforestation and erosion of France.

By the mid 18th century, the average temperature had risen enough to achieve food security. Once again, with food in their bellies, populations rebounded, and focus on innovation brought healthy economies. Industrial development ensued, bringing expansion and colonialism.  Massive fleets were built, from forests felled for the needed timber. As the population grew again, farming and pastureland expanded once again to support the needed food supplies. The open field system prevailed through this period, and given their inefficiencies, yet more land was needed to feed the population. To these pressure, the forests fell away, leading to erosion.

The protected hunting forests of the Aristocracy, and those belonging to the Church, alone stood untouched. While these forests were often noted as early forestry, it is somewhat disingenuous call this entitlement “forest husbandry”. Indeed, by the time of the French Revolution the royal forests had become a hated symbol of privilege.(2)

Unlike the medieval period that saw erosion primarily because of deforestation, this dawn of industrialization created many new erosional sources.  Iron works and foundries required mines and open pits to be dug to excavate ore, while limestone, prized for its hardness, was quarried across the country, including within the vineyard land of the Cote d’Or.

quarriesandbeyond.org

 

It was the wealth of the times that created a demand for Burgundy’s limestone. Thousands of large building projects: for the Church, wealthy private citizens, the aristocracy, for government buildings and public works, all of which required vast amounts of building materials. The high demand created such soar value for the “marble”. I had originally concluded when first writing this article, that the value of the limestone below, outsized the value of the grape production of that location, but I have since come to what I believe to be a more valid conclusion. I submit that the quarries dug in locations in which the limestone remained unfractured, examples of which can be seen in the climates of Meursault Perrières, Clos de Beze, Bonnes-Mares, and some submit, even Romanee-Conti, made those particular locations unsuitable for quality vine cultivation, unlike the superb plots which surrounded them.

It was used in its solid slab form for wall paneling and floors, but the rubble was also burned in special kilns to produce Quick lime (calcium oxide) which is the primary ingredient of both mortar and plaster. Softer limestones were often sought for the production of quicklime, as it was far easier to excavate the softer stone than the harder, unfractured stone which was required for floors and wall paneling.

The excavation of the limestone not only changed the substratum and topography of these vineyards, but greatly affected vineyard lands to either side of these projects, and with substantial impact to the vineyards below. This is where the overburden (the topsoil and useless rubble) was cast, in the most expeditious manner, downhill.

Meursault Perrieres quarry site175 years later, the disruption of such a quarry site to the terroir of the region is easily seen in the two vineyards of Les Perrières in Meursault, and Les Charmes, which lies just below. A large quarry was cut out of the hillside of MeursaultPerrières Dessous. The location of bulk of the excavation appears to now have been declassified from Les Perrières, as well as a wide strip above the exposed limestone wall.  The sub-plot of Clos des Perrières which is owned by Albert Grivault vineyard is just below the main area of excavation, but it was certainly was part of the quarry itself. The area directly behind the removal site would certainly have been utilized for temporary buildings, for staging or even storage of limestone before transport, a loading area for horse carts, and space for any other logistical needs a quarry would require.  The slope of this entire area was more or less leveled from it previous gradient. Clos des Perrières begins that the overburden would have been spread, although. The dirt roads of the regions were also impacted, by the transit of thousands of heavily loaded wagons, itself causing extensive erosion. And then it would rain.

The likely disposition of overburden and erosion from the quarry in Les Perrières, with finer sediment with higher suspension
The likely disposition of overburden and erosion from the quarry in Les Perrières, with finer sediment with higher turbidity / suspension velocity travels farther down-slope. The original map this diagram was taken from, and more information on Les Perrières can be found at clivecotes.com.  Click to enlarge

The sections of Les Charmes-Dessus, lying just below this quarry received the discharge of overburden, deepening the soil along this half mile of roadway. That this discharge and erosion onto Les Charmes Dessus, and no doubt Les Charmes Dessous, lying just below that, is without question. The soil depth was increased by the alluvial soils eroded from the quarry site, in addition to any normal erosional deposits that would have occurred, giving the vines more depth than they require, mimicking vineyards that are actually lower on the slope.  The wines from Meursault Charmes, are fairly commonly described as fat, without the vibrancy and minerality of Les Perrières, and often given the faint praise of being rather hedonistic.

Excavations by Thierry Matrot in 1990 in his parcel of MeursaultPerrières (parcel 15 in the map to the right) found roughly one foot of topsoil before striking the limestone base. Whereas, digging into his plot of Meursault-Charmes however proved to be far more work. Here a pit of 6 feet was dug before hitting the limestone substrata.(3) This indicates, a significant amount of limestone colluvium had developed in Charmes, that has mixed with transported clay to attain this six-foot depth of marl dominated soil.. I have not been able to determine the location of the Matrot’s plot (or plots) in Les Charmes. It is a large vineyard and without the dig location, this information doesn’t have nearly as much meaning as it would otherwise. It does illustrate the dramatic effect erosion has had on the vineyards of Burgundy and the character of the wines from each location.

 ~

Much more on the effect slope position and soil depth on the character of wine can be here for vineyards on the lower slopes, and here for vineyards on the upper slopes.

 

This diagram illustrates the changes in temperature in Northern Europe, as well as major historical in intellectual periods.
This diagram illustrates the changes in temperature in Northern Europe, as well as major historical in intellectual periods.

(1) The Burgundians were an Eastern Germanic tribe which likely crossed the Rhine in 406 AD, in a combined force with the Vandals, Alans and Suebi tribes. The Roman forces there had largely departed four years earlier to deal with Visigoth king, and sometimes Roman ally, Alaric, who would ultimately be an actor in the fall of Rome. But the crossing signaled the end of Roman rule Central Europe.

The Kingdom of the Burgundies, ruled the lands east of Paris, down to the Mediterranean with various boundaries. A series of smaller Duchy, including the Duchy of Burgundy, succeeded the Kingdom of Burgundies in 1032. The Duchy was relatively sovereign, but owed its allegiance to the French crown. The influence and power of the Duchy expanded greatly in 1384 with a union with the Hapsburgs. The house of Valois – Burgundy, the ruling family of the Duchy of Burgundy at the time, ultimately expanded its control of fiefs in Holland and the Netherlands, parts of northern France and Luxembourg.  In a bid to gain independence from France, 1477 Charles the Bold was killed in battle by a combined force of the Duke of Lorraine and a Swiss Confederacy. With no heir to Charles, and a weak hold on their power, the Valois were unable to prevent the Duchy from eventually being absorbed into France.

(2) Empire Forestry and the Origins of Environmentalism, Gregory Allen Barton (p.11) Cambridge University Press


Earth Environments: Past, Present, and Future, David Huddart, Tim Stott, John Wiley & Sons,, 2013

Class and State in Ancien Regime France: The Road to Modernity?

By David Parker