Allometric above-belowground biomass equations for Nothofagus pumilio (Poepp. & Endl.) natural regeneration in the Chilean Patagonia

In the present study, allometric biomass equations were developed for Nothofagus pumilio natural regeneration relating foliage, stem and branches (aboveground), roots (belowground), and total biomass to basal diameter and total height, based on destructive measurements of 390 naturally regenerated seedlings and saplings. Basal diameter was the most important independent variable in all equations and accounted for more than 88% of the variability of the different biomass components. The addition of height as a second independent variable slightly improved the predictions. The best-fit biomass components equations that were based on combinations of basal diameter and height as independent variables had adjusted R-2 values between 0.80 and 0.95 and a mean percent standard error between 21.3% and 26.6%. Based on the best-fit biomass equations and the natural regeneration development in a 14-years chronosequence in forests managed under shelterwood cuts, the total biomass varied from 0.9 Mg ha(-1) (0.5 Mg ha(-1) above and 0.4 Mg ha(-1) belowground) for the primary forest, before the shelterwood cuts, to 19.5 Mg ha(-1) (13.6 Mg ha(-1) above and 5.9 Mg ha(-1) belowground) 14 years after the seed cut. In the same period, carbon storage varied, from 0.5 Mg ha(-1) to 9.8 Mg ha(-1).