Carbon stocks and changes in tropical secondary forests of southern Mexico
Periodo de realización: 2014/06/01 al 2014/01/01
Tipo: Artículo científico
Resumen: "The role of tropical secondary forests in carbon accumulation has been widely acknowledged,but the rates of
changes in carbon stocks still remain uncertain. The aim of this study was to analyze the changes in carbon
pool sizes and accumulation rates associated with growth,recruitment and mortality of trees at different ages
of forest succession in semi-evergreen tropical forests and relate these to the age of the secondary vegetation
and prior land use intensity. The study was carried out in a chronosequence of secondary and mature forests
around Calakmul Biosphere Reserve in southern Yucatan Peninsula, Mexico. Permanent monitoring plots
were established and measured in 2011 and 2012 to account all carbon stocks and changes due to tree
increments, establishment of new trees and tree mortality in different age classes of secondary forests.
We found that carbon stocks in living tree biomass increased rapidly in the early stages and decreased in
the older secondary forests. The annual carbon dynamics of trees were higher in younger secondary
forest compared to older forests due to higher tree growth and recruitment. Growth functions predict
that the secondary forests recover live aboveground biomass carbon stocks to pre-disturbance levels
(99.56 Mg C ha1) at the age of about 125 years or more, while the basal area (33.2 m2 ha1) regains this
level at the age of about 85 years. The longer carbon recovery time can be explained by the fact that
mature forests are dominated by hardwood species whereas secondary forests are composed of softwood
species and that species composition turnover during succession is relatively slow. Secondary forests of
35 years look similar to mature forests in terms of basal area, but this is located in large number of small
and medium sized trees, whereas in mature forests, most of the basal area is in trees of >20 cm diameter.
In addition, the intensity of slash and burn agriculture can negatively alter the velocity of carbon
accumulation. These findings have important implications for national forest carbon monitoring systems,
greenhouse gas emission inventories and regional level REDD+ strategies.