Restoration of stand on the site of burnt spruce forest in the Central Forest reserve

Abstract

With the warming of the climate, the intensification of droughts and the drying up of coniferous forests, the number of forest fires is also increasing. Therefore, the study of the post-fire dynamics of stands and prospects for reforestation on burnt areas is especially relevant. The research was carried out in the Central Forest State Natural Biosphere Reserve (southern taiga) on the burnt area formed in 1999 as a result of a thunderstorm. The purpose of the work was: to describe the state of vegetation 22 years after burnout; to find out the characteristics of the stand formed on the burnt area and the possibility of their use for reconstructing the history of disturbancies in old spruce forests. The objectives of the study included: monitoring vegetation changes in the 1999 burnt area; studying the growth of spruce undergrowth in the burnt area; finding out the number and ratio of preliminary and subsequent renewal of tree species; analyzing the distribution and amount of coals in the sample plots (depending on the intensity of burnout and the state of the pre-fire stand). To study the state of vegetation after the burnout of the blueberry-wood sorrel and wood sorrel – nemoral-herb spruce (Picea abies (L.) H. Karst.) forests, 14 sample plots (100 m2 each) were laid in the northwestern part of the burnt area. The sample plots covered 1.5 hectares. 22 years after the fire, a mixed small-leaved forest with a predominance of birch and a significant participation of spruce has been forming on the site of burnt spruce forests. Spruce is represented mainly by post-fire renewal. In the undergrowth, the ratio of pre- and post-renewal spruce is about 1 : 3. In the ground cover, a small number of nemoral herb species is recorded, and in the stand and undergrowth – almost complete absence of broad-leaved species. A lot of coals were found in soil digs in 4 sample plots (30%); there were no coals in 3 (20%) sample plots, and small coals in small amount were found in 7 (50%) sample plots. Assessing the possibilities of identifying the first post-fire generation of spruce in old stands, it must be said that none of the characteristics of a post-fire spruce stand is universal for its recognition. Only a set of features allows to identify the history of the stand. Distinctive features of the first post-old generation: the presence of coals in 30% of samples or more; a large admixture of birch and aspen; a large diversity of the aspen part of the stand; if there are broad-leaved species, they will be much younger than the spruce; the presence of a sharp decline, and then a rise in growths in a significant part of the oldest spruce trees; the main generation of spruce has initial radial growths on an average of 2.1 mm/year, and the absence of synchronous sharp rises of the growths at the beginning of life. The age of aspen most accurately corresponds to the year of the fire.