Altitudinal variation of forest fuel loads in a fragmented Pine-Oak forest in the Tacaná Volcano, Mexico

Abstract

The accumulation of forest fuels on the forest floor is a determining factor in the risk of fires, mainly when they are arranged continuously. The fuel load (both woody and leaf litter) was quantified by applying the planar intersection technique in a gradient spanning between 3145 and 3825 m in a fragmented pine-oak forest in the Tacaná Volcano Biosphere Reserve, Chiapas, Mexico. For this purpose, four study sites were established and 20 linear transects were placed in each site; woody fuels were evaluated at different length intervals of each line. The litter was evaluated in squares of 1 m². The results showed an increase in fuel loads with increasing altitude, except for leaf litter, which presented a negative correlation. The evaluated sites presented significant differences in woody fuel loads, except for 10-h and 1000-h rotted fuels, where a greater accumulation of total fuels was observed at 3717 m altitude (54.52 Mg ha^-1; p = 0.0088). Leaf litter fuels had the highest load at the lowest altitude site (3145 m), with a total of 27.576 Mg ha^-1. The correlation between altitude and 1000 h fuels was low. With the exception of leaf litter, the proposed hypothesis is rejected, since fuel loads increased as altitude increased. The results are useful to define forest fire management strategies in the study area.