Effet des techniques de coupe et des variations du milieu sur la croissance en hauteur des cépées dans un taillis de châtaignier (Castaneasativa)

Abstract

The frequency of cuttings and the age of the stumps can make coppices particularly sensitive to cutting technique and to microenvironment changes. The influence of these two factors on height growth has been studied on a 1- and 3-year-old sweet chestnut (Castaneasativa Miller) coppice regrowth. The stand is located in west-central France on a 15% slope and covers an area of 0.5 ha. The experimental design is a randomized complete block trial with three blocks oriented perpendicularly to the slope. The local environment of each stump is described by its location on the slope (block effect) and by the depth of soil above the granitic arena. Initial cutting was made with two different tools (axe and chainsaw) and at two different heights (10 and 30 cm). The height of the 1-year-old regrowth is affected by initial stump diameter, which explains 34% of the variance, and to a lesser extent by the environment; the cutting technique has no significant effect. The height increment between 1 and 3 years is mainly affected by two environmental factors, namely soil depth and block effect. These effects became dominant at age 3. The effect of the cutting technique on height increment between 1 and 3 years is highly significant, and cutting technique also has a highly significant interaction with the block effect. Because of this interaction, one cannot make any general conclusions about the positive or negative effect of a given cutting technique.