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Modelowanie przyrostu pierśnicowego pola przekroju jodeł w drzewostanach rębnych

100%

Skrzyszewski J., Pach M., Krzysztof R., Szafron M., Stenka Z.

Sylwan

2017

tom 161

nr 06

Because of the very long regeneration period, final cuts in silver fir stands are always accompanied by the growing stock maintenance, which aims to maximize the revenue by increasing the share of harvest, trees with the highest timber value. We remove trees that have reached the maximum value and leave those whose value is still increasing. The remaining trees are the more valuable, the faster their value grows. The increase of a tree diameter is one of the factors that determines the value increment. The mature silver fir stand consists of trees that in youth grew in favourable light conditions and those that survived the long period of shade, achieving small dimensions. In such stands, the adjacent trees may vary greatly in diameter not related to their age. The aim of the study was to create a model describing the relationship between the increment of silver fir basal area (BAI) and the stand morphological features, age, and the dynamics of growth in early age. The research was carried out in the Brzesko Forest District and Forest Research Station in Krynica (S Poland). The sample size equalled 45 and 57 trees respectively. We used the composite form of linear mixed model. The significant positive effect on BAI (model 1) was found for the initial breast height diameter (dbh), the relative crown length as well as the age when trees reaches the 30 cm dbh. The negative impact was observed for Lorimer C18w index. The negative relationship with the relative BAI (model 2) was found for the initial dbh, slenderness, C18w index as well as the age when trees reaches the 30 cm dbh. Conditional and marginal determination coefficients reached 48 and 42% for model 1, and 62 and 38% for model 2 respectively. The results indicate the great possibility and purpose of growing stock maintenance in the pruned silver fir stands. Selecting the trees for the removal should be based on the target dbh. Had it been reached, the firs can still be characterized by a very good current BAI values. One should leave thinner firs with a relative crown length higher than average. Treatments releasing the crowns of the remaining firs, also at the cutting stage, are justified. Smaller growth at a young age (caused e.g. by shading), does not limit the possibility of obtaining trees with significant dimensions.

Ograniczanie wyników

1 Sylwan

1 Krzysztof R.

1 Pach M.

1 Skrzyszewski J.

1 Stenka Z.

1 Szafron M.

1 2017

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Modelowanie przyrostu pierśnicowego pola przekroju jodeł w drzewostanach rębnych