Abstract

HERNANDEZ-RAMOS, Jonathan et al. Aboveground biomass and expansion factors in commercial forest plantations of Eucalyptus urophylla S. T. Blake. Agrociencia [online]. 2017, vol.51, n.8, pp.921-938. ISSN 2521-9766.

Aboveground biomass is critical to assess the amount of carbon stored in forest covers. One way to obtain accurately estimates of the aerial biomass is through expansion factors, which use standing trees volume data, taken during forest inventories. Our objective in this study is to estimate total and structural aerial biomass using allometric models and biomass expansion factors (FEB), in order to evaluate their applicability in forest inventories for Eucalyptus urophylla S. T. Blake clones in commercial forest plantations at Tabasco, Mexico. Random samplings on seven plantations was utilized to select 93 trees, from one to seven years old trees, from which the total biomass and structural components were determined. We propose two systems allometric models fitted as seemingly unrelated equations in order to estimate aerial biomass. The average bole biomass percentage (B s ), branches (B b ) and foliage (B f ) was of 91.42, 5.54 and 2.03 respect to the total biomass (B t ). The B s ratio increased with tree size and B b and B f decreased after three years. The average FEB of the B t and B s was 510.09 kg m-3 and 472.56 kg m-3 of bole volume. The biomass conversion factor from the bole to total biomass was 1.17. Data from a forest inventory allowed to estimate an average of 156.08 m-3 ha-1 of timber volume and 80 Mg ha-1 of aerial biomass in the plantations. The fitting, bias and percentage of aggregate difference statistics indicated that the proposed systems are reliable for aerial biomass estimation.

Keywords : cellulosic; Eucalyptus urophylla; forest inventories; forest management; allometric relations.

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