Сибирский лесной журнал (Oct 2019)
Reconstruction of fires in virgin forests at Sym-Dubches interfluve in the Holocene
Abstract
Results of reconstructions of ground forest fires on bogs of middle taiga subzone in the Priyenisei Siberia are presented for the Holocene. The stratigraphy analysis of the peat deposit, layer-by-layer peat 14С dating and morphological study of the pyrogenic interlayers allowed to estimate the time of fires, their periodicity and intensity. It was established that the intensity and periodicity of fires were different in southern (the key plot «Krivlyak») and northern (the key plot «Razvilki – Khoiba») parts of the Sym-Dubchess interfluve. 6 pyrogenic interlayers were revealed in the bog peat deposit on the key plot «Krivlyak», and their age was the following: 8015 years ago (y. a.), 6795, 2675, 2280, 1780, 1550 y. a. The interval between fires according to the data of «Mochazhina» profile was 4515 years, the one of the «Bugor» profile was 5340, 895, 230 years. All the fires were low intensive and didn’t greatly influence bog formation process. The 16 pyrogenic interlayers were recorded in stratigraphy of the bog on the key plot «Razvilki – Khoiba». It was stated that the low intensive fires took place 7790, 7412, 5958, 5745, 5030, 2339, 1351, 1099 y. a. The high intensive fires which had a considerable impact on the change of bog phytocoenoses and on the rate of peat accumulation occurred 12237, 7174, 5940, 5427, 4914, 2187, 2072, 1957 y. a. The interval between fires in each profile of this plot varies greatly. Frequent repeatability of forest fires was noted in the Atlantic and in the first half of the Subatlantic periods. In the late Holocene the change in forest and forest-bog phytocoenoses of heavily flooded swamp hummock ridge – bog hollow complexes with dominating Sphagnum fuscum (Schimp.) H. Klinggr.in moss cover took place. The impact of forest fires on the peripheral part of bogs in key plots stopped during this period. The fires on the studied bogs contributed to the revitalization of forest forming process. Post-fire successions were mainly manifested by birch and birch-pine grass phytocoenoses.
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