Forest biomass stocks and dynamics across the subtropical Andes. (7th October 2020)

• Record Type: Journal Article
• Authors: Blundo, Cecilia; Malizia, Agustina; Malizia, Lucio R.; Lichstein, Jeremy W.
• Is Part Of: Biotropica. Volume 53:Number 1(2021)
• Page Start: 170
• Page End: 178
• Publication Date: 2020-10-07
• Subjects: biomass dynamics -- biomass stocks -- forest structure -- forest‐use history -- montane forests -- rainfall -- temperature; Biotic communities -- Tropics -- Periodicals; Applied ecology -- Tropics -- Periodicals; Biology -- Tropics -- Periodicals; 577.80913
• DOI: 10.1111/btp.12858
• Languages: English
• ISSNs: 0006-3606

Abstract

Abstract: Forest biomass plays an important role in the global carbon cycle. Therefore, understanding the factors that control forest biomass stocks and dynamics is a key challenge in the context of global change. We analyzed data from 60 forest plots in the subtropical Andes (22–27.5° S and 300–2300 m asl) to describe patterns and identify drivers of aboveground biomass (AGB) stocks and dynamics. We found that AGB stocks remained roughly constant with elevation due to compensating changes in basal area (which increased with elevation) and plot‐mean wood specific gravity (which decreased with elevation). AGB gain and loss rates both decreased with elevation and were explained mainly by temperature and rainfall (positive effects on both AGB gains and losses). AGB gain was also correlated with forest‐use history and weakly correlated with forest structure. Mean annual temperature and rainfall showed minor effects on AGB stocks and AGB change (gains minus losses) over recent decades. Although AGB change was only weakly correlated with climate variables, increases in AGB gains and losses with increasing rainfall—together with observed increases in rainfall in the subtropical Andes—suggest that these forests may become increasingly dynamic in the future. Abstract in Spanish is available with online material Abstract : AGB stocks remained constant with elevation due to increasing basal area and decreasing plot‐mean wood specific gravity. Although AGB gain and loss rates decreased with elevation, AGB net change remained constant with elevation and near to zero in subtropical Andean forests. Forest use history in our plots did not affect AGB stocks; however, plots established in undisturbed old‐growth forests had higher rates of AGB gain than old‐growth forests with grazing. Resumen: La biomasa forestal juega un papel importante en el ciclo global del carbono. Por lo tanto, comprender los factores que controlan el stock y la dinámica de la biomasa aérea es clave en el contexto de cambios globales. Analizamos datos de 60 parcelas forestales en los Andes subtropicales (22–27.5 ° S y 300–2300 m snm) para describir patrones e identificar los factores que los determinan. Descubrimos que la biomasa aérea se mantuvo aproximadamente constante con la elevación debido a los cambios compensatorios en el área basal (que aumentó con la altitud) y el promedio de la densidad de madera por parcela (que disminuyó con la altitud). Las tasas de ganancia y pérdida de biomasa disminuyeron con la altitud y se explicaron principalmente por la temperatura y la lluvia (efectos positivos tanto en las ganancias como en las pérdidas de biomasa). La ganancia de biomasa también se correlacionó con la historia de uso del bosque y se correlacionó débilmente con la estructura del bosque. La temperatura media anual y las precipitaciones mostraron efectos menores en el stock de biomasa y el cambio neto de biomasa (ganancias menos pérdidas) en las últimas décadas. Aunque el cambio neto en biomasa se correlacionó débilmente con las variables climáticas, las altas tasas de ganancia y pérdida de biomasa en los bosques con mayor precipitación anual, junto con los aumentos observados en la lluvia en los Andes subtropicales en las últimas décadas, sugieren que estos bosques pueden volverse cada vez más dinámicos en el futuro.