Comparative analysis of the competition of stands of different species composition in relation to the Siberian stone pine undergrowth

Nikolai Tantsyrev,V.V Chepinoga,K.P Ma

doi:10.1051/bioconf/20213800127

Abstract

Under the canopy of the parent native berry-green-moss Siberian stone pine forest and derivatives berry-green-moss pine and birch forests on the Urals, using the previously proposed complex of light, root, and integral competition indices of the stand, a comparative analysis of the parameters of the Siberian stone pine undergrowth is carried out. Under the canopy of Siberian stone pine forest two main determining factors have a negative complex effect on the growth of the Siberian stone pine undergrowth: the light competition of the stand (the level of photosynthetically active radiation interception by its canopy) and, almost equal to it, the root competition for soil nutrition. Under the pine forest canopy with the combined negative effect of factors of light and root competition of the stand on the development of Siberian stone pine undergrowth, light competition is decisive. The effect of the root competition is less than almost two times. Under the birch forest canopy the main factor determining the development of Siberian stone pine undergrowth is the light competition of the stand. The connection with the root competition of stand is not expressed.

Highlights

The solution to the problem of sustainable forest reproduction is based on a comprehensive study of complex structural and functional relationships with external environmental factors and between all components of forest ecosystems
Siberian stone pine undergrowth of different ages in the studied forests is found both in glades and under a closed canopy, where the penetrating photosynthetically active radiation (PAR) does not exceed 10-20%
In the Siberian stone pine forest (Fig. 1a-c) a sharp twice decrease in the average of vertical increase of terminal shoots of Siberian stone pine undergrowth over the last five years is observed with an increase in the value of Ilsc to 20 and of Irsc for soil nutrition in the range of values 0.04-0.06

Summary

Introduction

The solution to the problem of sustainable forest reproduction is based on a comprehensive study of complex structural and functional relationships with external environmental factors and between all components of forest ecosystems. Until recently, when studying the processes of Siberian stone pine (Pinus sibirica Du Tour) regeneration and development of its forests, the main attention was paid to the number and vitality of its undergrowth and the parameters of the stand. Despite the heterogeneity and parcellar structure of forest ecosystems [1], only the average statistical parameters of environmental conditions, primarily the level of penetrating photosynthetically active radiation (PAR) were considered. The lack of light caused by the interception of PAR by the canopy of the stand is considered the main determining factor in limiting the growth and development of all plants of the lower tiers in all forest ecosystems [2-5 et al]. More intensive growth of Siberian stone pine undergrowth was repeatedly noted in the glades of stands than under the closed canopy, where it is in a depressed state [6-9 et al.].

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