The decline phenomenon of stands can be defined as the totality of effects that damage the normal vegetation state of trees and stands. There are two types or two models of decline, the acute one with fast development and the chronical one with slow development in space and time. Accurate capturing of the phenomenon has direct implications for the forest management measures. A first step in this direction is the analysis of the development model and of its dynamics. Forests which have Quercus species in composition are affected more by this phenomenon than other forests. There were identified oak stands presenting decline phenomenon in 9 forest Districts in Northwestern Transylvania and 22 experimental plots were analyzed. These plots were located in middle aged stands that were affected in different ways. The study was performed in 2013-2015 and focused on crown level assessments of trees, taking into consideration the shape and size, defoliations, percentage of dead or missing slender branches, number of dead thick branches, presence of epicormic branches or dormant buds on the stem, presence of pathogens or pests. These elements were used for calculating some technical indicators of the health and vegetation state: degree of dieback, damage and devitalization, synthetic index damage, annual mortality rate. In 7 out of 22 stands the overcoming of the incipient stage and beginning of active dieback stage was observed. The strongest correlation occurs between the annual mortality rate and the synthetic index damage.

 

 

This abstract was accepted to be presented at the conference entitled “40 Years of Horticulture Education in Cluj-Napoca†Cluj-Napoca, September 27, 2017, being included in ‘Book of Abstracts’ of this special-anniversary event (http://conference.shst.ro). All accepted papers will be published in a special issue of Notulae Botanicae Horti Agrobotanici Cluj-Napoca journal.