Fire has been an integral part of ecosystem functioning in many biomes for a long time, but the increased intensity and frequency of wildfires often affect plant diversity and carbon storage. ...Prescribed burning is one of the alternatives to forest fuel management where the fire is controlled and carried out under a determined set of weather conditions and objectives. The effect of prescribed burning on plant diversity and carbon (C) storage has not been studied widely. The objective of this study was to evaluate the effect of prescribed burning on plant diversity indices, biomass stocks, and soil C storage in the tropical highland forests of Southern Mexico. We assessed plant diversity and carbon stocks at 21 sampling sites: seven with prescribed burning, seven non-burning, and seven with wildfires. We calculated tree biodiversity indices, stand structural properties, and species composition among burning treatments. We quantified C stocks in vegetation biomass by using an allometric equation and forest litter by direct sampling. We analyzed 252 soil samples for soil organic C content and other properties. The results showed that the biodiversity index was higher in sites with prescribed burning (Shannon index, H = 1.26) and non-burning (H = 1.14) than in wildfire sites (H = 0.36). There was a greater similarity in plant species composition between non-burning and prescribed burning sites compared to wildfire sites. Prescribed burning showed a positive effect on soil carbon storage (183.9 Mg C ha−1) when compared to wildfire (144.3 Mg C ha−1), but the difference was not statistically significant (p > 0.05) in biomass stocks. Prescribed burning in this study conserved plant diversity as well as soil carbon stocks compared to non-burning, the opposite of what we found in wildfires.
Se realizó un estudio para evaluar la composición botánica y calidad de la dieta seleccionada por bovinos pastoreando un sistema silvopastoril intensivo (50,000 árboles por hectárea) de Leucaena ...(Leucaena leucocephala) asociado con Chontalpo (Brachiaria decumbens) (T1) en comparación al sistema monocultivo de la misma gramínea (T2). Se utilizaron seis becerras en crecimiento de raza Jersey en cada tratamiento. La composición botánica se realizó siguiendo la técnica descrita por González (1990), en la calidad de la dieta, para el caso de Proteína Cruda (PC), Ceniza (Ce) y Materia Orgánica (MO) con la técnica de AOAC (1990), Fibra Detergente Neutra (FDN) y Fibra Detergente Ácida (FDA) fueron determinadas según la técnica de Van Soest (1983). Los datos se analizaron mediante un modelo completamente al azar y la comparación de medias se realizó a través de la prueba de Tukey. El T1 presentó un consumo del 68.41 % de la gramínea y 31.59 % de la arbórea, para el T2, la dieta contenía 100 % de gramíneas. Respecto a la calidad de la dieta seleccionada, se encontraron diferencias estadísticas (P<0.05) para el caso de proteína cruda (T1= 11.9, T2= 7.8 %). Se concluye que la presencia de la arbórea Leucaena en el sistema, mejora la calidad de la dieta seleccionada de los bovinos en función de una composición botánica más diversa.
Agroforestry practices that include trees on grazing lands could enhance atmospheric CO
2
sequestration and storage. However, carbon sequestration rates and storage capacity of intensively grazed ...agroforestry systems vary due to the diversity in species composition, stand structure, system age, and management practices. The objective of this study was to evaluate carbon stocks and accrual rates in
Leucaena leucocephala
+
Cynadon plectostachyus,
and
Brachiaria decumbens
grass silvopastoral systems and compare them with conventional open grazing lands. The study was carried out in Chiapas in southern Mexico, one of the hotspots of deforestation driven by the expansion of livestock farming. We measured above- and belowground carbon stocks in 18 silvopasture (SP) plots, with the plantation age ranging from 2 to 10 years. Nine plots of adjacent conventional full-sun grasslands (open pasturelands) grazed rotationally were sampled for comparison. The average tree biomass stock in SP was 5.5 ± 1.9 Mg C ha
−1
and differed with SP age. Mean annual biomass accrual rates ranged from 0.25 to 2.57 Mg C ha
−1
year
−1
, indicating that SP systems are CO
2
sinks, excluding other sources of GHG such as methane emissions from enteric fermentation. The average soil organic carbon (SOC) sequestration rate of SP was 0.143 ± 0.043 Mg C ha
−1
year
−1
to 50 cm depth. The SOC sequestration rates correlated positively with SP age at the beginning and decreased after about 8 years. The results suggested that the age and lifespan of trees play a significant role in aboveground C sequestration through the
Leucaena leucocephala
SP, while SOC storage varied with soil properties. Further research on the relative response of active and stable SOC fractions along with soil CO
2
fluxes could explain the results on the SOC storage potential of these agroforestry systems.
