Base cation distribution and requirement of three common forest ecosystems in eastern Canada based on site-specific and general allometric equations

Abstract

Base cations (Ca, Mg, and K) are essential nutrients for forest growth. Many studies have reported important decreases in the soils of several forests in eastern North America, partly because of atmospheric acid deposition and forest harvesting. To quantify the impacts of these perturbations on forest base cations, accurate estimation of tree biomass and nutrient content is needed. However, most of tree nutrient contents are calculated with general allometric equations, leading to inaccurate estimates. We thus calculated tree biomass and base cation content for three common forest types in eastern Canada using site-specific allometric equations and compared them with those calculated with general allometric equations and nutrient concentrations of tree compartments taken from the literature. General allometric equations resulted in above-ground tree biomass estimates in the same range as ours (±15%), but the use of nutrient concentrations taken from the literature resulted mainly in overestimation of above-ground tree nutrient content (–13% to +81%), leading to inaccurate wood requirement estimates (–63% to +86%). Therefore, the development of site-specific equations to estimate above-ground tree base cation content is recommended.