Base cations and micronutrients in forest soils along three clear-cut chronosequences in the northeastern United States

Abstract

Determining effects of clear-cutting on base cations and micronutrients is essential for ensuring the sustainability of forestry for biofuels and wood products. The objective of this study was to quantify long-term changes in forest floor and mineral soil base cations (Ca, Mg, and K) and micronutrient (Mn, Zn, and Cu) concentrations and pools following clear-cutting in forests aged 1–120 years. We studied forest soils along three clear-cut chronosequences located in the Adirondack Ecological Center in Newcomb, NY, Bartlett Experimental Forest in Bartlett, NH, and Harvard Forest in Petersham, MA. We utilized a strong-acid extraction to quantify base cations and micronutrient concentrations and pools, which may better assess nutrients over the chronosequences than the conventional exchangeable extraction. Generalized linear mixed-effect models (GLMMs) show forest floor and mineral soil Ca, Mg, Mn, and Cu concentrations and pools decreased with increasing forest age across the three study areas. Potassium and Zn concentrations and pools were not significantly different with stand age and neither did soil C and N pools and pH using GLMMs. We calculated that 32–67% of the Ca pool decrease can be attributed to uptake by regenerating vegetation but only 0.02–9% of Mg, Mn, and Cu after harvest. Thus, leaching was likely to the dominant loss process for Mg, Mn, and Cu following clear-cutting. Our results suggest nutrient pools decreased for over a century following clear-cutting, but it is unclear if this will impact plant growth.