Carbon accumulations by stock change approach in tropical highland forests of Chiapas, Mexico

Abstract

Changes in forest biomass and soil organic carbon reserves have strong links to atmospheric carbon dioxide concentration. Human activities such as livestock grazing, forest fires, selective logging and firewood extraction are the common disturbances that affect the carbon dynamics of the forest ecosystems. Here, we hypothesized that such anthropogenic activities significantly reduce the carbon stocks and accumulation rates in the tropical highland forests of the Sierra Madre de Chiapas in Southern Mexico. We sampled the Pinus oocarpa Scheide dominated forests within the elevation range of 900 to 1100 m above sea level in 2010, 2014 and 2017. We measured the stand structural properties and used the reported allometric equations to calculate the tree carbon stocks. Stock change approach was used to calculate carbon accumulation rates. The results showed a gradual increase in carbon storage over the 7-year period from 2010 to 2017, but the rate of increase varied significantly between the study sites. The aboveground carbon stock was 107.25 ± 11.77 Mg ha−1 for the site with lower anthropogenic intensity, compared to 74.29 ± 16.85 Mg ha−1 for the site with higher intensity. The current annual increment for the forest with lower anthropogenic intensity was 7.81 ± 0.65 Mg ha−1 a−1, compared to 3.87 ± 1.03 Mg ha−1 a−1 in the site with high anthropogenic intensity. Although at varying rates, these forests are functioning as important carbon sinks. The results on carbon accumulation rates have important implications in greenhouse gas mitigations and forest change modelling in the context of changing global climate.