Estimation of newly grown needle area in Norway spruce based on simple biometrical tree parameters.

Estimation of newly grown needle area, as the most active part of assimilation appa-ratus, is important for better understanding of biochemical processes of trees. This paper investigates the relationship between the projected area of newly grown need-les and other biometric tree parameters (tree height HTREE, diameter at breast height DBH, projected crown area and crown length) of Norway spruce trees. The total pro-jected area of newly grown needles of seven sampled trees was estimated using a detailed inventory of the number and length of shoots. The relationship between this value and other readily measurable biometric tree characteristics was tested to find the best model for estimating total area of newly grown needles. The model using HTREE*DBH with a coefficient of determination of 0.96 had the best performance. The DBH and HTREE inventory of all trees in the studied plot was used to estimate the total projected area of newly grown needles of the entire forest stand (4506.7 m2 per hec-tare). We also investigated specific leaf area (SLA) of newly grown needles in vertical profile of tree crown. SLA increased constantly from the tree top (28.7 cm2.g2) to the crown base (80.3 cm2.g2). [ABSTRACT FROM AUTHOR]