The impact of surface fires on ground cover in pine forests of southern taiga

Abstract

The patterns of restoration of the ground vegetation after experimental fires of different intensity (924–4275 kW/m) in the southern taiga pine forests of the Nizhnee Priangar’e region are considered. Forest fires, depending on their intensity, lead to a decrease in species diversity (Shannon index), species richness, projective cover and ground biomass of grasses and shrubs. On the 12th and 13th years of the pyrogenic succession, the species richness of the grasses and shrubs was 60–75 % represented by species of the pre-fire community. The percent cover of the dominant ground layer Vaccinium vitis-idaea L. was 66–84 % of the pre-fire value. The aboveground biomass of the grasses and shrubs was 43–68 % of the pre fire value. Fires of medium and high intensity led to the death of the moss-lichen layer. After a fire of low intensity, the mosses were preserved in the areas not covered by fire. In the 12th and 13th years after the fires, the percent cover of the moss-lichen layer was 15–26 % of the pre-fire value. Pre-fire mosses as Pleurozium schreberi (Willd. ex Brid.) Mitt. and Dicranum polysetum Sw. are restored in the ground cover, and pioneer lichens of the Cladonia genus as: Cladonia botrytis (K. G. Hagen) Willd, Cl. cenotea (Ach.) Schaer., Cl. cornuta (L.) Hoffm., Cl. deformis (L.) Hoffm., Cl. gracilis (L.) Willd appear. Ground fires led to a change in the structure of pre-fire plant microgroups. In the 12th year after the low-intensity fire, pre-fire microgroups of Vaccinium vitis-idaea-herbs green moss and Vaccinium vitis-idaea-green moss prevailed. In the 13th year after a medium-intensity fire, within the boundaries of the pre-fire microgroup of Vaccinium vitis-idaea-lichen-green moss a monodominant microgroup of Vaccinium vitis-idaea was formed. The high-intensity fire led to an increase in the number of plant microgroups. In the ground layer were dominated by plant microassociations as – Cladonia-Polytrichum, Vaccinium vitis idaea-Polytrichum, herbs-Polytrichum, Polytrichum, Maianthemum bifolium, Vaccinium vitis-idaea-Lycopodium Polytrichum, Vaccinium vitis-idaea-Cladonia, Cladonia.

Keywords

• pine stands
• fire succession
• experimental burning
• ground vegetation
• species diversity
• ground phytomass
• plant microgroup
• nizhnee priangar’e
• krasnoyarsk krai