Site Index Change in the 1950s-1990s according to Estonian Forest Inventory Data : Causes and Consequences of Accelerating Tree Growth in Europe. Proceedings of the International Seminar

1999

S. 87-100

5 Abb., 5 Tab., 20 Lit

Unselbständiges Werk

200059061

Ocular estimations of mean height and age at total forest inventories in the 1950s and the 1990s were used in this study. Site indices for 21,409 subcompartments that mostly coincided at both occasiosns were calculated and compared (H50 1950 and H50 1990) using a difference equation of stand height depending on stand age, main species and site factors. The change in site index from the 1950s to the 199s (the difference between H50 1990 and H50 1950) was calculated and used as a dependent variable to indicate and to analyse the actual change in forest growth. On the basis of 21,409 sub-compartment data records, site index H50 was found to have increased on an average by 2.1 meters. Increase in site index depends on many factors, mostly on drainage, main species, change of stand generation and forest district. The average increase of site index H50 was 2.1 meters for pine stands, 1.6 meters for spruce stands and 2.5 meters for birch stands.