Above Ground Leafless Woody Biomass and Nutrient Content within Different Compartments of a P. maximowicii x P. trichocarpa Poplar Clone

In this study the quantification of biomass within all relevant compartments of a three-year-old poplar clone (P. maximowicii x P. trichocarpa) planted on abandoned agricultural land at a density of 5000 trees ha(-1) is presented. A total of 30 trees within a diameter range of 1.8 cm to 8.9 cm, at breast height (dbh at 1.3 m), were destructively sampled. In order to analyze the biomass, the complete tree, stem, as well as all branches, were divided into 1 cm diameter classes and all buds from the trees were completely removed. Total yield was calculated as 11.7 odt ha(-1) year(-1) (oven dry tonnes per hectare and year). Branches constituted 22.2% of total dry leafless biomass and buds 2.0%. The analyses revealed a strong correlation of the dry weight for all the three compartments with diameter at breast height. Debarked sample discs were used to obtain a ratio between wood and bark. Derived from these results, a model was developed to calculate the biomass of bark with dbh as the predictor variable. Mean bark percentage was found to be 16.8% of above ground leafless biomass. The results concur that bark percentage decreases with increasing tree diameter, providing the conclusion that larger trees contain a lower bark proportion, and thus positively influence the quality of the end product while consequently reducing the export of nutrients from site.