Thinning regime in young spruce stands
2008
Zalitis, P., Latvian State Forestry Research Inst. Silava, Salaspils (Latvia) | Libiete, Z., Latvian State Forestry Research Inst. Silava, Salaspils (Latvia)
The article analyses the growth rate peculiarities of young spruce stands in connection with the mean height of the stand at the moment of thinning. The data from 34 permanent sample plots established from 1963 to 1982 in the forest of Forest Research Station 'Kalsnava' are used. These systematically re-measured sample plots provide unique information about the growth of spruce stands. In the thinned stands with 1500-2000 trees per ha the productivity reaches 20 m**3 haE-1 yearE-1; however, at the mean height of 17 m the volume difference sharply decreases and often becomes negative. The productivity of the stand is the highest if the number of spruces is reduced to 1500-2000 trees per ha before the mean height of the stand reaches 5 m. The removal of the suppressed stand after the mean height of the stand has reached 10 m does not provide positive influence upon the productivity of the dominant stand. In the drained forests it is recommended to remove downy birch at the same time as the drainage system is established, if the number of conifers including vital spruce undergrowth reaches 1000 tree per ha. In 20 years the volume of thus reconstructed stand exceeds the volume of the unthinned birch stand.
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