Farmland abandonment and reduction of grazing activity, mainly in mountain areas with remote access and
ageing population, have been contributing to shrub encroachment in such territories and, consequently, to increase
fuel load available for triggering wildfires. Accordingly, it is necessary to use vegetation management
practices in order to reduce wildfire risk, prescribed fire being one of the most common techniques used in the
Mediterranean region. This research focused in the effects of a prescribed fire (PF) applied in Montesinho Natural
Park (PNM), NE Portugal, on the temporal dynamics of carbon storage in mineral soil, litter layer (organic
horizon), and shrub biomass. Before PF and thirty-six months after PF, aboveground shrub biomass was collected
in areas of 1 m2 in 11 plots randomly distributed in the experimental shrub area. Also, in the same plots, litter
thickness was measured and soil samples were collected before, two, six and thirty-six months after PF, in order
to assess carbon concentration, bulk density and coarse elements content. Despite low to moderate fire intensity,
carbon storage changes were observed in all compartments evaluated. Thirty-six months after PF, carbon storage
in aboveground biomass of shrub species (7.4 Mg C ha- 1) was roughly two-thirds of that recorded prior to PF,
and in litter layer (1.6 Mg C ha- 1) it was about half of that in the original situation (before PF). In contrast, the
mineral soil showed a 10% carbon increase (6.4 Mg C ha- 1). Based on the balance between losses (shrub species
and litter layer) and gains (mineral soil), at the end of the monitoring period (36 months), there was an annual
positive rate of carbon storage, equivalent to 0.2 Mg C ha-1 year- 1. Even after anthropogenic disturbances, such
as prescribed fire, shrub communities constitute important terrestrial carbon pools; hence, these ecosystems
might play an important role in mitigating climate change.
