Initial spacing has little influence on transient epicormic shoots in a 20-year-old sessile oak plantation.

摘要

Epicormics are important defects of oak timber which originate from suppressed buds placed early and develop into epicormic shoots depending on the light available, which in turn depends on stand density. In this context, our objective was to assess the epicormic shoots present in a 20-year-old experimental plantation of sessile oak and to test and quantify the effect of the three initial densities applied: 1333, 2667 and 5333 stems/ha. In the 3 stand densities, epicormic shoots were mostly transient and were rarely clustered. A significant but negligible effect of the density on the epicormic length and on the variables related to epicormic counts appeared: the longest epicormic shoots were present in densities 1333 and 2667 while their means were significantly lower for density 5333. When considering the tree descriptors, the best explanatory models of the different epicormic counts involved their relative variations, especially the relative increment (RIV) in the product V=HEIGHT.DBH2. More precisely, emergence of epicormic shoots occurred particularly when trees fell below a threshold value of RIV=0.26. Such trees belonged mainly to the two highest densities: 2667 and 5333 stems/ha. When considering only epicormics, none of the tested densities can be recommended. Trees which bear the most numerous epicormic shoots will be naturally eliminated by stand competition.