An example of the application of the methods in landscape history a case study from Southern. Pille Tomson, Robert G.H. Bunce

Transcription

1 An example of the application of the methods in landscape history a case study from Southern Estonia Pille Tomson, Robert G.H. Bunce

2 The aim of the study is to develop suitable methodology for identification the former slash and burn sites in modern landscape.

3 Study area Karula National park and Haanja Nature Park. In SE Estonia

4 Slash and burn cultivation In tropical regions it is still used today in Western Europe the slash and burn agriculture was introduced in the late Neolithic between 4300 and 2300 BC Slash and burn was practiced in some regions in Europe until the Second World War In Estonia the last records are from the beginning of 20th Century, when slash and burn was used mostly for clearing new fields. In 19th Century slash and burn was common in southern part of Estonia.

5 The areas regulary used for slash and burn cultivation were called buschlands in local Baltic German dialect.

6 . Areas regulary used for slash and burn cultivation are included in the maps from 19th Century.

7 Why do we need to study the former slash and burn areas? It is known that slash and burn cultivation has been in an important position in landscapes of Estonia and Northern Europe. The present status of these areas have paid little attention. Lots of authors have proved, that in ancient woodlands are specific, uncommon plant species. The first generation of forests in the late slash and burn sites in Eastern Finland are designated and protected as semi-natural habitats. The impact of fire and fire cultivation on vegetation and soil is high after the burning, but how continuous are these impacts and are they irreversible?. Do the former slash and burn site have any values in ecological terms?

8 Our previous studies have shown, that most of the former buschlands are covered by forests now.

9 Methods Fieldwork was carried out in 66 forest patches. 45 forest stands were in territory Karula former manor, 21 in territory former Haanja manor. The maps from 19th Century where used to identify the former land use of areas: 37 buschlands, 29 old forest. The selected stand have the age minimum 95 years to avoid the later (mechanized) agricultural impacts.

10 Why we need more methods to recognize the former slash and burn areas: Not all maps are maintained. Maps reflect only a short period. What happened before or after that period? There can be mistakes in the maps. Maps can reflect intention, not real situation. There is not available written documents about the mapping process always.

11 If the site was used as field at the beginning of 20th century, now the features of slash and burn cultivation have disappeared. If the forest colonized the area just after the end of fire cultivation, the signs of cultivation have remained.

12 Presence landscapes elements in forest stands. Large relict trees and field margins are typical to mapped buschlands (χ², p less 0,05), but differences in presence of turnip pits is not reliable ( χ², p>0,05).

13 Charcoal Amount of soil charcoal is not statsitically different ( χ²-test, p>0,05) in old forest and buschlands. Soil pits 50x50 cm were used.

14 All forms of charcoal, exept layers of microsciopic parcels, are present in buschlands more regulary than in old forests, but the differences is not statistically reliable (χ²-test, p>0,05).

15 In former buschlands the charcoal would be mixed into soil by ploughing and harrowing. Charcoal from forest fires would be in top layers, but fallen trees, roots and animals have mixed the soils in forest conditions for a long time and charcoal could be moved to the deeper horizons.

16 The higher position of soil layer with charcoal is in old forests (mean 9,6 cm, stdv 5,1 cm) than in buschlands (mean 12,8 cm, stdv 6,0 cm). The lower border of charcoal is deeper in buschlands (mean 21,5 cm, stdv 9,7 cm) than in old forests ( mean 16,4 cm, stdv 7,2 cm). These differences is satistically relible ( t test, p<0,05). In buschlands the bigger amount of charcoal ususally in the lower part of humus. The humus layer is deeper in buschlands (mean 15,9 cm, stdv 6,0 cm) than in old forests (mean 12,0 cm, stdv 5,0 cm). This difference is statistically reliable ( t test, p<0,05).

17 Calibrated radiocarbon dating of the charcoal layers show the formation of field terrace cm AD cm AD cm AD cm BC

18 In slash and burn sites the humus layer is more homogenous and not disturbed by old fallen trees and roofs.

19 CONCLUSIONS Historical maps contain a valuable information about areas used for slash and burn cultivation, but sometimes the additional information is needed. Charcoal is not good indicator to identify the slash and burn sites because it is difficult to distinguish between charcoal from forest fires and from fire cultivation. The best indicators of former slash and burn cultivation in landscapes are field teracces and homogenous humus layer with numerous charcoal in the lower part of humus layer.

20 Thank You!