Retaining walls of abandoned vineyard terraces on Tokaj Nagy Hill

Tibor József NOVÁK, József INCZE

(From previous issue No.35)

Dry constructed stone built terrace retaining walls are characteristic landscape elements in historic vine regions of Europe. Since the cultivation of these terraced slopes is mostly very expensive and labor-intensive they were abandoned in large extension during the last century. On abandoned vineyards trees and shrubs overgrow the walls, which failure and collapse without further management and corrections. Collapse of terraces and walls means not only loss of cultural heritage and destruction of soil archives, but has also environmental consequences as inducing increase of erosion and nutrient fluxes and cause slope failures. We investigated dry built stone terrace walls on abandoned vineyards on Tokaj Nagy-Hill, which is one of the most famous vine-producing region of Hungary, and a World Heritage site as cultural landscape as well. On the hill altogether 1.16 km2 terraced slopes were mapped and 90.9 km long stone walls were delineated.

Extension of slopes transformed by terraces and retaining walls on Tokaj Nagy Hill

Extension of slopes transformed by terraces and retaining walls on Tokaj Nagy Hill (source: Tibor József NOVÁK – József INCZE)

Based on the substructure of the walls four types of lithological constitution could be specified. In the first case walls are built on loess or redeposited loess material. In the second type lithological discontinuities could be observed, in which lay directly below the wall colluvic material, settled over weathered volcanic rocks. In the third case the walls were built directly on rock outcrops. The fourth type’s construction is initiated by digging a ditch at lower part of the parcels, and stones emerging due to cultivation were removed and putted in the ditch, since they fill the ditch and raised in form of a wall. In all wall construction types also soils on level of reference groups according to WRB were classified, and Cambisols, Regosols, Calcisols, Leptosols, Luvisols and Phaeozems were found. The further management and protection of this heritage is currently legally unclear. In the absence of legal protection e.g. in form of nature conservation areas, there are no any guarantees for persistence of walls, and implied natural and cultural values.

Introduction

Vineyard terraces and their retaining walls are characteristic landscape elements associated with viticulture since thousands of years. Terraces increase the exploitation of radiation surplus resulting from the morphology, and provide efficient protection against slope erosion processes. Vine cultivation is recently highly mechanized, since the cultivation of terraced slopes is very laborious, expensive, and require significant initial and continuous investment, their extension significantly decreased everywhere in the last century. Modern viticulture does not focus on terraced field, with the exception of vineyards producing the very top quality of wines. For this reason, former terraced vineyards were abandoned in huge extension throughout Europe. Vineyards with terraces can be found only in the most famous areas and vineyards providing the best quality of wine; e.g. in the Rhine and Mosel valleys in Germany, the Cinque Terre region in Italy, the Rhône valley in France, Wachau along Danube in Austria, along Douro in Portugal or Pelješac Peninsula in Croatia. The rate of abandonment of terraced vineyards can be characterized through the example of Germany, where terraced vineyards in the 16th century were estimated in 45,000 ha, while recently just 11,300 ha remained. Another good example is France, where 40,000 ha terraces were cultivated in the 15th century, which hardly exceeds actually 6,000 ha. Dry built stone walls and steps, which are used to retain terraces and cover the steepest slopes, are typical landscape features of historical vineyards. They can be called ‘historic’ not only for their traditional way of cultivation, but also because their maintenance and renovation is no longer in use, not to mention their rebuild or reconstruction. Terrace cultivation and the construction of retaining walls are very rare in Hungarian wine regions and they are restricted to the best sites of the most excellent wine growing regions. Thus terraced slopes with the dense network of stone built retaining walls occur mostly on the slopes of volcanic hills of Balaton Uplands and Tokaj-Hegyalja wine region.

Reconstructed and replanted terraced vineyard with retaining walls in Szil Valley

Reconstructed and replanted terraced vineyard with retaining walls in Szil Valley (Tarcal). In the lower and the higher slope sections abandoned terraces, and retaining walls can be found overgrown by arbor and shrub vegetation (photo: Tibor József NOVÁK)

Abandonment of terraced vineyards on Tokaj Nagy Hill has already begun after the phylloxera disaster. Nowadays numerous abandoned (former) vineyards are nature conservation areas, where valuable and protected flora and fauna could find habitat in biocenosis due to the successional processes after they was left fallow. The natural values and the human constructed landscape elements of traditional viticulture in unique constitution consists the cultural landscape declared as World Heritage. The registration, evaluation, and further management of once cultivated but longabandoned vineyards are key objectives of the management plan of World Heritage sites currently being drawn up. On the construction methods of retaining walls we have only indirect information. Balassa8 claims (based on archival sources) that the construction of stone dams was definitely a skilled work and was carried out by seasonal workers from Mecenzéf (settlement in Abaúj county with population of German origin; actually: Medzev in Slovakia), who manufactured wide range of wrought iron products and they were practiced road-constructors as well. Generally on-site stones were used and they were rarely transported far away. Processed sources of Balassa8 also mention that the motivation of stone dam construction was not the terracing process of slope in several cases but to put the stones to the edge of the parcel while they were cultivating the area hence they occupied smaller area from cultivated vineyard. The most of retaining walls are not results of onefold construction but they developed under a continuous process during the cultivation when debris and blocks of stones were excavated and put into the stone dam (can be assumed due to practice existing still nowadays).

Geological and pedological characteristics of terraced slopes in Tokaj Nagy Hill

Loess and redeposited loess with varied thickness are the most characteristic parent materials of Nagy Hill. The thickness of the loess can reach 15-17 m but it might completely absent as well where the places are highly exposed, steep and eroded. Intermediate volcanic rocks, like dacite13, 14, 15 and different variety of dacite can be found under loess due to the result of volcanic activities in the Miocene. Among loess layers from the Würm (the last glacial stage of the Pleistocene) and volcanic rocks interlayer reddish-clayey weathered material formed during Tertiary and interglacial climate in a few decimeter thickness. Consisting the superficial layers at least two different substrates form the above mentioned ones occur a special lithological discontinuity in the soil profile, having the recent weathering front different lithology from the topsoil. With respect to the relief the terraced slopes of southern and south-western exposure dominates, but otherwise exposed terraces occur as well.The majority of the terraced slopes (based on the slope gradient) falls within the categories between 17-25% and 12-17% but terraces occur on much steeper slopes too. Most of the terraces can be found at a height of 200-250 m a.s.l. but retaining walls were found even at 340 m above sea level. According to Stefanovits Ramann brown forest soil and chernozem are zonal soils but the soils of Nagy Hill are quite diverse due to the spatial diversity of lithology and geomorphology. In the Hungarian soil classification soils developed on volcanic weathered material are called “erubáz” soils. These soils cover the highest part of the mountain18 on weathered clay material rich in illite and montmorillonite. The soils developed on red clay were classified mostly as Phaeozems, Luvisols, Cambisols and Leptosols in this study. By Füleky20 humic Umbrisol was described on the hill as well. This type of soil also developed on the weathering products of volcanic materials. Considerable eroded profile is a common feature of former cultivated soils. Skeletal and slope sediment soils were formed due to erosional processes, which are considered to classify as Leptosols, Cambisols and Regosols according the WRB.

/read the rest of this post in issue No.35/

Tags: , , , ,

Comments are closed.