The Differences in the Lignification of Earlywood and Latewood in Larch (Larix sibirica Ldb.)

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Physiological Method for Evaluation of Vigor State of Pine Stands

Vigor state of middle-aged pine stands was estimated during 2002-2008 at permanent sample plots by two methods: 1) visual estimation of stand vigor rank according to the 6-point scale of Forest Regulations of RF and 2) method of induction of tree defense response (injection of stem with high molecular extractives from Ceratocystis laricicola mycelium and registration of parameters of stem phloem necrosis). The stands of similar origin and structure were preliminarily divided into background and polluted ones on the basis of different amount of polluting substances in snow cover. Estimation of external tree signs according to 6-point scale didn't reveal significant differences between stands in monitored period. In contrast to this morphological method parameters of specific necrotic response of stem inner bark to fungal extract differed significantly in background and polluted stands. Parameters of the necrotic spots on the phloem were shown to depend on effect of creeping fire. The necrosis size increased and the necrosis "moved" toward crown during two years after the fire. The results are in accordance with the hypothesis that the size of phloem necrosis induced by the effect of extractives from phytopathogenic fungus mycelium on stem vascular tissues was determined by the tree state - it increased in damaged tree and decreased with tree state improvement. The injection method can inform about changes of physiological condition of tree and stand at the latent stage when exterior characteristics of a tree haven't changed yet