Scots pine (Pinus sylvestris L.) on the southern border of its range in Siberia: growth dynamics in a changing climate
I. A. PETROV1,2, V. I. KHARUK1,2, A. S. SHUSHPANOV1,3, S. T. IM1,2,3, D. S. ONDAR4
1Krasnoyarsk Science Centre of the Siberian Branch of Russian Academy of Science, V. N. Sukachev Institute of Forest of SB RAS, Krasnoyarsk, Russia
2Siberian Federal University, Krasnoyarsk, Russia
3Reshetnev Siberian State University of Science and Technology, Krasnoyarsk, Russia
4Tuvan State University, Kyzyl, Russia
Keywords: pine range, change of plant ranges, burning of pine forests, warming and growth of pine trees, relict pine forests
Abstract
Under climate warming, changes in the growth, vital condition and habitats of woody plants are predicted mainly on the border of their ranges. We studied the effect of the changing hydrothermal regime on the condition of pine forests growing on the southern border of the Pinus sylvestris L. range (Tuva basin). During the “warming restart” in the 21st century, the values of the pine growth index (GI) exceeded the previously observed GI maxima, due to the relative improvement in humidification conditions in the last decade. At the same time, the frequency and area of fires increased (the fire return interval decreased to 5 ± 1 years in fragments and to 3 ± 2 years in the whole territory). The number of viable undergrowth in the burning areas (on average up to 10 thousand/ha) is potentially sufficient for successful post-fire regeneration of pine forests. However, repeated grass-roots fires periodically destroy the undergrowth. Currently, an increase in air temperature combined with satisfactory humidification contributes to the growth of pine trees. Improvement of humidification is predicted under all climatic scenarios (SSP4.5, SSP7.0 and SSP8.5) in the studied pine habitats. However, the current level of burning (which leads to the destruction of undergrowth in the areas traversed by fire) threatens the preservation of relict stands of pine trees at the southern limit of its range. Under warming conditions, the preservation of pine trees in the south of its range is due to a combination of two factors - the dynamics of burning and humidification.
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