Ground vegetation development after shelter – wood cutting in Scots pine forests of hemiboreal zone, Lithuania

Abstract

The structure of forests is determined by climate, geomorphology, soils, historical factors and different kind of disturbances. Natural or anthropogenetic disturbances initiate secondary forest ecosystem succession. In managed forests the main disturbance factor is cuttings. Clear and shelter wood cuttings are the most important and have the greatest impact on forest ecosystems. Shelter wood cuttings are common type of commercial timber harvesting in pine forests in Lithuania. Tree layer density and composition affect composition of the ground vegetation. Abiotic and biotic conditions such as microclimatic variables (light intensity and duration, relative humidity, air temperature) and soil factors (pH, organic carbon, total nitrogen, available phosphorus, soil moisture and temperature) change after cuttings. Changes in tree layer also lead to the changes in the ground vegetation. The aim of this work was to investigate the changes of ground vegetation (mosses, lichens and shrubs) in pine forests after shelter wood cuttings. The study area was located in south-eastern part of Lithuania and falls in the transitional deciduous coniferous mixed forest boreonemoral zone of Europe. The chronosequence approach was used to describe the succession by taking sites in similar environments but of different time periods after cuttings. 40 plots (10x10m) were selected in the shelter wood cuttings of the pine stands of different age (1-5 year). The resulting vegetation sequence was assumed to be the successional sequence. The species composition and projection cover (in per cent) of undergrowth, herbs and mosses were recorded. The highest number of pine seedlings was recorded in second year after shelter wood cutting. Number of pine seedlings decreased in older shelter wood cuttings, while seedlings of Betula pendula reached higher number after 4 years of shelter wood cuttings