Estimating coarse roots biomass in young silver birch stands on post-agricultural lands in central Poland. Silva Fennica vol. 47 no. 2 article id 963. 14 p. Highlights • Age and size of the tree are the most important factors that influence the amount of belowground biomass. • Allocation of the biomass to the coarse roots also depends on age and size of the tree.
Highlights• We developed equations for aboveground biomass components of young silver birch stands on post-agricultural lands in central Poland for single tree level. • Simplified equations were based exclusively on diameter at ground level or breast height, while expanded ones were based on the appropriate diameter and tree height. • For large trees, diameter at breast height is a more appropriate explanatory variable than diameter at ground level. • Biomass estimations based on models from neighboring countries were consistent with our results.
AbstractWe determined empirical models for estimating total aboveground as well as stem, branches, and foliage dry biomass of young (age up to 16 years) silver birch (Betula pendula Roth.) growing on the post-agricultural lands. Two sets of allometric models for trees with a height below or above 1.3 m (small and large trees respectively) were developed. Simplified models were elaborated based exclusively on appropriate tree diameter (diameter at ground level for small trees, diameter at breast height for large trees), while expanded models also included tree height. Total aboveground biomass was estimated as the sum of biomass of all tree components. To assure additivity of the developed equations, the seemingly unrelated regression approach for the final model fitting was used. Expanded models in both tree groups were characterized by a better fit to the data (R 2 for total aboveground biomass for small and large trees equaled 0.8768 and 0.9752, respectively). Diameter at breast height appeared to be a better predictor than diameter at ground level -simplified models had better fit for large trees (R 2 for total aboveground biomass equals 0.9611) than for small ones (R 2 = 0.7516). The developed equations provide biomass predictions consistent with available Latvian, Estonian, Finnish, Swedish, and Norwegian models for silver birch.
The study makes an attempt to evaluate the effect of resin-tapping on the radial increment of Scots pine (Pinus sylvestris L.). Increment cores were taken from two groups of trees: resin-tapped trees and normal trees growing in a 148-year-old pine stand in the Lidzbark Forest District. The cores were taken with the Pressler increment borer from two heights on the tree trunk: 1,30 m and 3,30 m. Using dendrochronological methods, real chronologies were built for each of the four analysed groups of cores. The value and variability of increments for each group were investigated in 20 and 40 year time periods, before and after the start of resin-tapping. In next step, the chronologies were compared and their coefficients of conformity were calculated. As a result, we can state that the radial increments were larger are at 1,3 m height after resin-tapping than before resin-tapping. There was also significant effect of resin-tapping on radial growth at the height 3,3 m, above the resin-tapping face.
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