HEIGHT INCREMENT OF NATURALLY REGENERATED YOUNG FOREST STANDS OF SCOTS PINE PINUS SYLVESTRIS L. IN MYRTILLOSA FOREST SITE TYPE

Abstract

One of the most important stand productivity and competition indicators is height annual increment, which is affected by various factors such as soil preparation, initial density as well as various management risk factors. Empirical material for the research was collected in the northern part of Latvia. In four pure Scots pine stands in Myrtillosa forest site type 29 circular plots tree diameter, height and the last five years annual height increment was measured and visual state of health was described. The aim of this research is to analyse Scots pine height annual increment in naturally regenerated young forest stands in Myrtillosa site type forest stands and to give an evaluation of the impact of the initial stand density and the health status on height growth. The mean height increment in studied stands is 0.26 ± 0.009 m and the average periodical increment is 0.37 ± 0.042 m. The annual height increment has been in the height range from 0.23 to 0.53 m. Initial stand density affects the annual height increment significantly. In the stand with an initial density of 5770 ± 961 trees the height increment during the last five years has risen by 36%, but in stand with initial density of 12,650 ± 1,581 trees (P = 51.8 % and R = 6.0 %) the height increment during the five-years period has increased by only 12 %. The tree health status does not affect the tree height increment significantly.