Stamtal en dunning : een orienteerend onderzoek naar de beste plantwijdte en dunningswijze voor den djati
1928
Hart, H.M.J.
Thinning trees by form and defects (tree-class thinnings) and practical or free thinning (according to the surrounding trees) were unsuitable for comparing thinning methods by the subjectivity of the involved tree classification methods.A thinning criterion based on 'top height' and 'stem number' proved objective. By assuming different ratios between crown diameter and height at a certain developmental stage of the trees, reduction in stem number could be obtained, related to the mean 'top height', which was height, measured and averaged on the 100 highest trees, uniformly distributed over 1 ha. Assuming different ratios gave different stem number reductions. Thus the results of different objective thinning grades could be compared.Initial stem number was determined by the ratio crown diameter: height and by the relation between spacing and amount of thinning. In spacing experiments the influence of spacing on stem form and the tree defects already yielded conclusions about stem number (not too low; higher on worse soil), mixed plantations and the way of planting (planting in rows was recommended). Conclusions on amount of thinning were not yet possible. The method was simple in practice, even for other tree species.
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