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The study presents the assessment of damage to beech stands using four methods, including that taking into account the radial increment. The condition of stands in 2016, and the growth response of trees to the environmental changes since 1956 are described. The measurements and observations were carried out on 18 sample plots (tab. 1) located in south−western Poland. The mean defoliation accounts for 32.5% ranging from 16.9 to 56.9%, while the average defoliation class value is 1.62 ranging from 0.75 to 2.38. The proportion of trees was found to be the highest (approx. 60%) in class of moderate damage (fig. 1a). The mean value of vitality is 1.17 (ranging from 0.75 to 2.38). The proportion of trees in vitality classes differs significantly from that in defoliation classes. The highest number of trees (approx. 80%) was found to be within damage class of weakened trees (fig. 1b). The assessment of damage to trees based on synthetic damage index (defoliation and vitality combined using formula [1]) is similar to the assessment method based on tree vitality. The mean value is 1.07, ranging from 0.63 to 1.70. The largest proportion of trees (over 80%) was found to be within class 1 (fig. 1c). The index SynZ combines defoliation and vitality, as well as the growth response of trees over the last 15 years according to formula [2]. Its values range from 0.82 to 1.79 with 1.21 on average. The largest proportion of trees (over 70%) was found to be within damage class 1 (fig. 1d). The response of trees to environmental changes is an important indicator of the growth conditions. The proportion of trees with negative growth responses increases from period to period, while the proportion of trees with neutral and positive responses decreases (fig. 2). The analysed beech stands show fairly large differences in the level of the damage. The most likely cause of this situation are droughts occurring in recent growing seasons, especially in 2012. Of the methods deployed to assess damage to beech trees, the morphological−growth one is the most accurate, but the most laborious. Therefore, it is preferable to use a synthetic damage index as both tree defoliation and vitality can also be assessed outside the growing season.
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