Litterfall contribution and its association with environmental conditions in temperate forests of the Sierra Norte de Oaxaca, Mexico

Abstract

Litterfall accumulated on soils is considered a significant source of organic matter. Therefore, it is crucial to investigate litterfall patterns in each region and particularly understand its relationship with various environmental factors. The primary objective of this study was to determine the contribution of litterfall to the soil in both coniferous and oak forests and its association with environmental, biological, and disturbance conditions in the temperate forests of the highlands in the Sierra Norte de Oaxaca, Mexico. We established sampling sites along an altitudinal gradient ranging from 1,950 to 3,250 m a.s.l. At each sampling site, we conducted vegetation sampling, collected leaf litter over a period of 250 days, and measured various environmental, biological, and disturbance variables. Notably, the forests in our study area exhibited higher litterfall amounts compared to those reported for forests in other parts of the world, with mixed forests producing 7.06 Mg ha^-1 year^-1, oak forests 6.33 Mg ha^-1 year^-1, and coniferous forests 4.03 Mg ha^-1 year^-1. Our findings revealed that litterfall was closely associated with environmental conditions, with a more pronounced impact on oak, influenced by factors such as temperature and precipitation intensity. In contrast, for coniferous, the most significant variable affecting litterfall was the intensity of disturbance, particularly the number of stumps. Coniferous trees exhibited a higher contribution of litterfall to the soil, showing peaks of litterfall during specific times of the year. Interestingly, oak trees in the study area did not contribute any leaf litter during the rainy season.