Autoecology of sweet-chestnut stands in Andalucia (Spain)

Abstract

This paper is a characterization of the chestnut stand biotopes in Andalucia (Spain). The distribution of these stands is quite iregular, with four areas of chestnut tree dominant presence, located in Granada, Huelva, Malaga y Sevilla respectively, totalling over 9.000 ha. In these locations, 23 forest sites have been evaluated by computing a set of 34 phytoecological parameters and 7 silvicultural parameters. The sampling design was based on the Spanish Forest Map (Ceballos, 1966) overlaid on the Biogeoclimatic Classification of the Peninsular and Balearic Spain (Elena, 1996).

This information has made it possible to establish the physioclimatic and edaphic habitat of the chestnut stands in Andalucia and to characterize their current silvicultural situation. As result, chestnut forest sites in Andalucia show the following features:

1. Chestnut woodstands display strong heterogeneity, as a result of their human use, with four areas of discontinuous presence, absence of forestry uniformity and very different conservation and stability conditions.

2. The most restrictive parameters in the chestnut stand biotopes have turned out being those retaled to thermic conditions (over 15 _C of anual temperature average) and to the soil reaction (moderately acid in all the cases).

3. Chestnut stands occupy heterogeneous biotopes, with a high elevation range, marked summer aridity conditions and very varied edaphic textures that produce highly different conditions of permeability, soil water holding capacity and edaphoclimatic behaviour.

4. The analysed soils are mainly classified as Cambisols and Luvisols, with predominant dystric and chromic units.