The management of holm and downy oak coppices in the garrigues of the Gard department: analysis of the environment and the productivity of the stands

Abstract

Medium term management of ageing Holm Oak (Quercus ilex L.) and Downy Oak (Quercus pubescens Willd.) coppices in the Gard requires a thorough understanding of the natural environments and yields of the plantations. This paper puts forward a method for analysing the environment and plantation in order to assess the yield of the oak coppices. 118 small stands were studied in different types of coppice. In general, two environmental parameters determined the dominant height of the stand: geopedological conditions (rock, parent material and soil) and topoclimate which depends on the position of the plantation (orientation and topography). The growth height is affected by the structure and composition of the plantation, together with the forestry and plant growth characteristics. Multivariate analyses enabled 9 types and sub-types of sites to be distinguished with particular environmental conditions (soil and topoclimate). The type of site is closely correlated to the variation in the dominant height of the plantations. Growth classes are proposed for the Holm Oak (3 classes) and the Downy Oak (4 classes). These results should assist plantation management selection: the best coppices should possibly be allowed to develop as standards, plantations of average fertility should be treated as simple coppices, coppices with low growth rate should be allowed to grow on.