Firewood extraction affects carbon pools and nutrients in remnant fragments of temperate forests at the Mexican Transvolcanic Belt

Abstract

Globally, remnant fragments of forests represent the main carbon reservoir of terrestrial ecosystems, but they suffer strong degradation due to uncontrolled wood extraction mainly by tree cut for household fuel use and charcoal production. The present study evaluates the degradation caused by wood extraction on carbon pools and soil nutrient dynamics in temperate forests distributed in remnant fragments located in central Mexico. Four sites with different intensity of wood extraction were chosen for measuring carbon pools and nutrient fluxes during two years. Both, aboveground carbon biomass and soil organic carbon values decreased with the intensity of forest degradation. The degraded forest (DF) showed total carbon content 55 % lower than that shown by the seminatural forest (SF). Additionally, litterfall production was reduced in DF as compared to SF; the decomposition rate of standing litter was higher in the latter site. As a consequence, DF had lower organic matter inputs to the soil than that presented by SF. Soil extractable ammonium and microbial biomass- carbon and -nitrogen were lower in DF than in SF. It was concluded that the uncontrolled wood extraction in these remnants of temperate forest in Mexico significantly reduced the carbon pools, carbon and nutrient fluxes through litterfall and consequently, the soil nutrient dynamics were disrupted.