The Favorable Climatic Regime in Triggering the Decline of Oak Stands

Ioan Tăut, Vasile Șimonca, Ovidiu Badea, Mircea Moldovan

Abstract


The decline of stands can be assimilated to structural or functional disorders, where several categories of disruptive or harmful factors compete and interact in different directions and meanings, but whose outcome is weakening the trees vigor, culminating with their death. Agents may be abiotic or biotic. The latter include bacteria, fungi and insects that are not able to invade in normal circumstances, and cause significant harm to healthy trees, but can be very destructive when attack devitalized trees. The present paper aims to highlight the role of echometer indices on growth regime in declining stands. A significant positive correlation was identified between the amount of precipitation surpluses and Lang Rain Index in the run-up phase in starting in vegetation growth, with positive influence on oak stands from subzone. A negative correlation is reported between the growth regime and the average temperature of bioactive season. From physiologically point of view, the explanation is the reducing (or termination) of the cambial division process under conditions of temperatures above 35°C. For the oak-wood area from the middle hydrographical basin of Someș instead, it appears that none of the analyzed climatic factors has a direct influence on the growth regime.


Keywords


climate regime, decline, oaks, echometer indices.

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