Aboveground biomass and soil carbon in pine-oak stands under silvicultural treatments

Abstract

Timber harvesting modifies the patterns of partition and accumulation of structural biomass and forest compartments; determining this accumulation is important to know the effect of the silvicultural treatments (TS) applied. The objective was to analyze the aboveground biomass and soil carbon (C) in stands under TS applied in the period 2013-2014, in San Juan Lachao, Oaxaca. In 2022, 12 sites (UM) were selectively established in four treatments, three TS: 1st thinning (1A), free thinning (AL), regeneration cutting (CR), and an unmanaged area (ASM). Tree and forest floor inventory was carried out and undergrowth, to estimate structural and compartment biomass. The treatments were differentiated using a generalized linear model and comparison of means (Duncan, 0.05); The MUs were classified by cluster analysis. The treatments generate different amounts (p < 0.01) in the biomass of shrubs, leaf litter, humus and apparent density of the soil; but not in the total aboveground biomass (p > 0.05). The area with CR showed the highest amount of biomass in the herbaceous and shrubby compartment with 0.24 t ha-1 and 3.80 t ha-1, respectively. The ASM, AL and 1A showed a significant difference in biomass in humus (p < 0.01) compared to CR (3.93 t ha-1), with respective increases of 160%, 265% and 275%. The ASM presented the highest accumulation of total aboveground biomass (180.49 t ha-1), while the TS on average recorded 166.97 t ha-1. The content of organic matter (11.6%) and C (6.7%) in the ASM soil was significantly different (p ≤ 0.01) from that of the TS. TS modify the biomass of the forest floor compartments, which can be reversed with the application of complementary treatments.