Analysis of anomalies in the structure and size of annual rings in mossy and ledum pine forests

Abstract

The paper presents new experimental data and reveals the regular variability of the formation of density fluctuations, frost and fallen annual rings in mossy (Pinetum pleurozium) and ledum (Pinetum ledosum) pine forests. The main statistical characteristics of generalized tree-ring chronologies are analyzed, statistically significant differences (p < 0.05) in the average, maximum and minimum width of annual rings depending on the type of forest are established. It has been experimentally established that in ledum pine forests the number of anomalies is 3.34 times greater than in mossy pine forests. There were 229 density fluctuations in mossy pine, 530 in ledum, frost damage – 28 and 159, fallen tree rings – 10 and 202, in compliance. The most unfavorable years, which were reflected in the radial growth of mossy pine forests, were 1979 and 1980; the maximum number of detected anomalies (91,4%) occurred in 1907, 1928, 1958, 1971, 1985, 1990, 1992, 1994, 1999, 2010 and 2017. The most unfavorable years, which were reflected in the radial growth of ledum pine forests, were 1906 and 1940 ; the maximum number of detected anomalies (89.7%) occurred in 1928, 1937, 1944, 1946, 1963, 1965, 1974, 1977, 1981, 1982, 1991, 2000 and 2016. There are no coincidences of the formation of anomalies and minima of growth in mossy and ledum pine forests, as far as the degree of responses to changes in external conditions in these types of forests is different. The conducted studies have shown that the structure of annual rings of common pine can be considered as a reflection of the features of seasonal growth of trees, while the formation of anomalies of the structure is largely determined by soil-hydrological conditions of growth.