The relationship between height and diameter trees of Scots pine (Pinus sylvestris L.) and the extent of crown defoliation in the Kampinos National Park

Forests in Kampinos National Park contain some of the most valuable tree populations in Poland. Particularly interesting are stands of Scots pine (Pinus sylvestris L.) that are more than 130-years-old. Periodic observations of the health of tree crowns in these stands facilitates a wide range of research investigations. This article evaluates statistical relationships between allometric features of trees and the occurrence and severity of crown defoliation. Observations were made of 5 pine populations in 2017 and 2019, in which detailed data were collected for 250 trees. The percentage loss of the assimilation apparatus and level of stand damage were calculated. The results revealed a significant increase in defoliation between 2017 and 2019. The deterioration of crown condition was particularly evident on the most fertile sites. The degree of crown damage was not correlated with tree height or diameter. The greatest increase in defoliation between 2017 and 2019 was observed for the most severely damaged trees growing on fertile sites. This study contributes analyses aimed at correlating the allometric features of a stand with its health. Such information is valuable as it describes the status of the analysed stands, as well as providing information about how trees have responded to environmental conditions. In this study, crown defoliation coincided with a period of drought in Poland, which appears to have affected pine stands. For these reasons, the results are of both scientific and practical value.