Home – Home – Jornals – Siberian Journal of Forest Science 2021 number 2

To date, various aspects of the formation of spruce forests as a result of felling of small-leaved stands with the preservation of the preliminary generation of spruce Picea A. Dietr. have been studied. One that is poorly studied is the question of the development and growth of spruce in connection with the parcel structure of the stands after such felling. The aim of this work is to study formation and growth of spruce forests in parcel structures with the same spruce density after felling a birch forest, but at different stages of age development. The studies were carried out in the sub-zone of the southern taiga (Rybinsk District of the Yaroslavl Oblast) at the Northern Experimental Station of the Institute of Forest Science, Russian Academy of Sciences. The study object is forest stand formed after cutting a 55-year-old birch forest. The felling was carried out using the technology of narrow strips with preservation of the preliminary generation of spruce. The analysis is based on the data of 20 years of observations on permanent sample plots in two groups of parcels: spruce in the young stand stage, spruce in the pole stand stage. The density of spruce in the groups of parcels after birch Betula L. felling is, respectively, 4.53 and 4.58 thousand trees per ha, and the average age is 25 and 33 years, respectively. The response of spruce to birch felling has been observed already in the first ten years. In the considered groups of parcels, the condition of the spruce improves and the growth of trees increases. In the poles, the growth increases more intensively than in the young. The timber stock of the upper layer (trees above 4 m per year of felling) in the first layer increases by almost 30, in the second - by 100 m³. In the pole stand, productivity of the stand increases from class V to class IV bonitet. In the second decade, the state of the population in young trees deteriorates as a result of increased intraspecific competition (the proportion of normal trees decreases from 55 to 40 %). In the pole, the opposite process was observed - the proportion of normal trees increased from 60 to 80 %. During this period, the growth of the wood stock in young stands was more intensive than in the pole ones. However, the wood stock in spruce forest, formed from the perch, reached almost 300 m³ per ha 20 years after felling. In spruce forest, formed from the young stand, wood stock was almost 3 times less. The bonitet of the perch has reached III, the young - IV class. When felling birch forests with preservation of the undergrowth and thin spruce for the fastest recovery of spruce stands, birch forests should be considered the most promising, under the canopy of which the preliminary generation is represented by a spruce pole stand 40 years old. Such stands should be assigned to the felling first.