Distribution of Carbon Fractions and Necromass in Forest Soils Across Different Vegetation Types in El Chico National Park, Hidalgo, Mexico

Soils are the most important terrestrial carbon (C) sinks in the biosphere. They play a crucial role in regulating the global carbon cycle, and are key to the provision of ecosystem services. Soil carbon sequestration and accumulation is a useful means to reduce atmospheric CO ₂ concentration and mitigate climate change. A study was conducted in El Chico National Park, Hidalgo, Mexico, with the objective of evaluating soil carbon fractions under different vegetation types. Five sampling zones (fir forest, fir-tlaxcal, cedar, fir-oak, pine-oak) were selected under similar edaphic and climatic conditions. The results showed no significant differences (p<0.05) among vegetation types in relation to organic matter (OM), organic carbon (Co), total carbon (Ct), oxidizable carbon (Cox), and non-oxidizable or recalcitrant carbon (Cnox). Only the organo-mineral fraction (Cp) presented a significant difference (p<0.05). The necromass of the five vegetation types stores an average of 6.60 t C ha ^-1 for both Ct and CO ₂ , which multiplied by the total area of “El Chico National Park” (PNCh), gives 13,302 Mg of C and 48,818.23 Mg of CO ₂ . Adding the C stored in the first 20 cm of soil estimates in a total of 237,793.45 Mg C and 872,701.96 Mg of CO _2, with soils under fir vegetation contributing the greatest CO ₂ retention.