NONDESTRUCTIVE BIOMASS ESTIMATION OF SEEDLINGS USING IMAGE-ANALYSIS

The biomass of Pinus sylvestris, Pinus contorta and Pinus cembra seedl ings that were raised in three different growing media, as well as of naturally regenerated P. sylvestris saplings, was estimated using func tions based on variables measured non-destructively. These included st em diameter, seedling height, number of needles and branches, length o f the longest needle, and projected seedling or sapling crown area. Pr ojected area of a two-dimensional video image of the seedling or sapli ng was measured using computer-based image analysis. The variables wer e tested in all possible combinations to achieve the best biomass esti mate. Projected area alone explained more than 97% of the variation in seedling or sapling mass. Addition of stem diameter increased the deg ree of explanation to more than 98%, whereas the other variables did n ot contribute further. Separate functions for species and growing medi a resulted in more precise estimates than if general functions were us ed.