Aigars Indriksons
Department of Silviculture, Latvia University of Life Sciences and Technologies, Latvia
The work analyses an impact of a drainage system, established in 1939. on overgrown pine tree stand in longer period of time. For the purposes of study 14 sample plots, established by scientists K. Buss and P. Zalitis during the 50’s and the beginning of 60’s, were remeasured. Sample plots were organized in the Myrtillosa turf. mel., Vacciniosa turf. mel., and Callunosa turf. mel. forest site types. Stands basal area increased in all compared forest site types, maximal being 41.7 m2 ha-1 in Myrtillosa turf. mel. forest site type in 2016. Average diameter and average height of a tree in the stand was also bigger in Myrtillosa turf.mel. forest site type plots. The stand volume in Myrtillosa turf. mel. in 2016 was 384.8 m3 ha-1, in Vacciniosa turf. mel. it comprised 326 m3 ha-1, but in Callunosa turf. mel. it was 259.7 m3 ha-1. The average stand volume in 2016 was 323.5 m3 ha-1. Analysis of statistical parameters showed the substantial impact by the forest site type on diameter and height of the tree. For the inventory of ground cover vegetation, the point-square method was used. 37 plant species from 32 ecological groups were detected at Myrtillosa turf. mel. forest site type plots, 26 species from 23 ecological groups – at Vacciniosa turf. mel., and 23 species from 17 ecological groups – at Callunosa turf. mel. forest site type plots. Ellenberg indicator values, Chekanovsky similarity index and Shannon index for ground cover plants showed the changes of ground cover plant coverage caused by forest drainage. Study results confirm the hypothesis: forest drainage has positive impact on overgrown Scots pine stands dendrometrical parameters and stands growing stock increase. The beneficial effect of hydrotechnical melioration continues even 50 years after reaching the cutting age.
Key words
drained forests, Scots pine, dendrometrical indices, tree increment.
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