Degree of previous cutting in explaining the differences in diameter distributions between mature managed and natural Norway spruce forests

• Main Authors: Siipilehto, Jouni, Siitonen, Juha
• Format: Article
• Language: English
• Published: Finnish Society of Forest Science 2004-01-01
• Series: Silva Fennica
• Online Access: https://www.silvafennica.fi/article/410

The degree of naturalness was assessed in 37 mature (stand age 80 198 yrs) Norway spruce dominated stands located in southern Finland by measuring the number (0 610 haâ1) and basal area (0 33 m2 haâ1) of cut stumps. The Johnsonâs SB distribution was fitted for living spruce trees to describe the dbh-frequency and basal area-dbh distributions. Regression models were constructed for predicting the parameters of the SB distribution using traditional stand parameters (median diameter, basal area, stem number) and the cut stump variables (number, basal area). Stump variables improved the models and enabled to explain the differences in diameter distributions between stands with varying intensity of past cutting. Model for basal area-dbh distribution was more accurate than dbh-frequency model in terms of regression statistics, but less accurate in terms of generated stand variables. The number and basal area of cut stumps seem to be useful and simple measures of stand naturalness which have potential uses in stand modelling and biodiversity-oriented forestry planning.