Virginia Puzzolo Sten Folving

1. A GIS integration of topographic, geological and climatic data for the analysis of the Mt Etna forests distribution (Sicily, Italy) Virginia Puzzolo Sten Folving

2. The aim of this work was to provide a description of the forests distribution in the study area in relationship to some environmental characteristics: • Geological substrata • Volcano slopes • Elevations • Aspects • Slopes • Precipitation and temperature

3. Geological substrata and lava flowslocation play an important role in the forests distribution on an active Volcano • Volcano slopes are another characteristic which has to be considered when the analysis is conducted on a Volcano which has a conic shape • Differences exposures (aspect), availability of soil nutrients (slope) and humidity (elevation) are also important features • Precipitation and temperature are the first parameters that have to be considered to understand why a type of forest can survived or no in a certain area

4. Study Area Location The study area is located in the eastern part of Sicily on the Mt Etna which is the biggest active Volcano in Europe with an extension of 1570 km2 and an elevation of about 3350 m a.s.l..

5. The forests of the study area are mainly dominated by: • Evergreen oak (Quercus ilex) • Deciduous oaks (Quercus pubescens sl., Quercus cerris) • Pine (Pinus laricio) • Beech (Fagus sylvatica) • Birch (Betula aetnensis) • Chestnut (Castanea sativa)

6. Evergreen oak forest

7. Pine forest

8. Beech forest Island (Dagala)

9. Forest-lava boundary

10. Data Layers • Forest vegetation map was extracted from the Mt.Etna vegetation map at scale 1:50.000 (Poli Marchese & Patti, 2000) that it was previously digitised using a standard image processing approach by supervised classification and post-classification smoothing (Lawrence et al., 1996); • Geological map at scale 1:50.000 (A.A.V.V., 1979) was digitised with the traditional hand method using the software ArcInfo and later it was converted from the vector to the raster format; • Elevations, Slopes and Aspects maps were derive from a 20 m resolution Digital Elevation Models using the spatial analyst ArcView software; • Temperature and Precipitation data were obtained from the study area meteorological stations beginning from 1960 to 1996.

11. Flowchart of the work Vegetation map DTM Digitization Forests map Geological map Elevations map Aspects map Slopes map Forests mask Meteorological data Correlation tables Volcano slopes masks Forests spatial distribution analysis

12. Mt Etna Forests Map

13. Forests cover (%)

14. The forests distribution was strongly influenced by the volcanic activity of the Mt.Etna in different ways: • it destroyed part of these forests during the lava flows • it always interrupts the soil evolution with the pyroclastic material • the volcanic substrata have different petrographic characteristics depending on their origins and from its shape.

15. Geological Map of the Mt Etna Forests

16. Relationships between the Forest type and the Geological formations Mongibello Unit

17. Almost all of the Etnean forests are located on the Mongibello unit and mostly on the undated laves and on the products of Leone and Ellittico eruptive centres • the beech forests were also developed on the volcanic rocks of the "Trifoglietto" eruptive centre • the chestnut woods were planted on the upper tuffs and lahars

18. Forests distribution in relation to the Volcano slopes

19. Elevations Map of the Mt Etna forests

20. Forests distribution in relation to the elevations

21. The forests extend from the base of the Volcano to 1800-2300 m. a.s.l. and them altitude range changes in function of the forest type. • The basal belt is characterised by the Evergreen Mediterranean vegetation forests • The mountain belt is dominated by the other types of species and, in particular, by oak, pine, beech and birch in function of the different Volcano slopes.

22. Aspects Map of the Mt Etna forests

23. Forests distribution in relation to the aspects

24. The aspects are strongly connected with the Volcano slope where the forest is located. • The evergreen and deciduous oak forests are the less restrictive • the other forests have, more or less, the same exposure of the them slope

25. Slopes Mapof theMt Etna forests

26. Forests distribution in relation to the slopes

27. All these forests prefer no very high slopes • They are normally located on slopes between 0 and 20 %. • An exception is the beech forest located on the SE Volcano slope that it reaches, in some points, slopes with more of the 50 %.

28. The temperature changes uniformly with the altitude around the Volcano.

29. The rainfall changes irregularly on the different Volcano slopes and it reaches the highest values on the eastern one because of its exposure to the sea.

30. Conclusions • Geological, topographic and climatic information is needed to extract useful information for improving forest management systems. • All these variables can be weighted and combined using GIS techniques that provide an efficient tool for handling multi-source data. • The results obtained during this study have showed how it is possible to combine all these environmental characteristics to better understand the forests distribution on an active Volcano, like Mt Etna

31. Thank you very muchfor your attention!