RHYTHMIC LAWS OF FORMATION OF SEASONAL TREE-RINGS GROWTH OF CONIFERS AT MIDDLE TAIGA
The article gives a climatic interpretation of biological rhythms of Siberian pine (cedar) ( Pinus sibirica Du Tour) and Siberian fir ( Abies sibirica Ledeb.) growth at middle taiga in continental climate conditions. Estimated by complex-valued Morlet wavelet, growth recurrences are similar for both species and at the same time display stable low-frequency waves with variable wavelengths of 27-32, 18-21 and 9-11 years, thus may have geophysical nature. Using a particular method of finding biological and climatic rhythms synchronization, we have identified a climate related cyclic component of two different bio-indicators variation. Good coincidence of growth extremums indicates that these signals have exogenous origin, represented by a complex of environmental factors. Among drivers of near 20-years adaptive biorhythm we suspect March and October monthly average temperatures, having antiphase coherency with it. Features of classical approach based on response functions analysis for causal relationship estimate of tree growth are restricted without limiting factors; therefore, a technique based on the idea of establishing synchronism between exogenous cycles and biorhythms is more robust, since there is a little likelihood for accidental coherence of two harmonics related to different noisy time series.