Traditional shifting agriculture: tracking forest carbon stock and biodiversity through time in western Panama

Abstract

Reducing Emissions from Deforestation and forest Degradation (REDD+) requires developing countries to quantify green-house gas emissions and removals from forests in a manner that is robust, transparent, and as accurate as possible. While shifting cultivation is a dominant practice in several developing countries, there is still very limited information available on how to monitor this land-use practice for REDD+ as little is known about the areas of shifting cultivation or the net carbon balance. In the present work, we propose and test a methodology to monitor the effect of the shifting cultivation on above-ground carbon stocks. We combine multi-year remote sensing information, taken from a 12-year period, with an in-depth community forest carbon stock inventory in Palo Seco Forest Reserve, western Panama. With remote sensing, we were able to separate four forest classes expressing different forest-use intensity and timesince-intervention which demonstrate expected trends in above-ground carbon stocks. The addition of different interventions observed over time is shown to be a good predictor, with remote sensing variables explaining 64.2% of the variation in forest carbon stocks in cultivated landscapes. Multi-temporal and multi-spectral medium resolution satellite imagery is shown to be adequate for tracking land-use dynamics of the agriculture-fallow cycle. The results also indicate that, over time, shifting cultivation has a transitory effect on forest carbon stocks in the study area. This is due to the rapid recovery of forest carbon stocks, which results in limited net emissions. Finally, community participation yielded important additional benefits to measuring

Carbon emissions from dryland shifting cultivation: a case study of Mexican tropical dry forest

“…Above-ground biomass for the study area is at the lower end of the scale, as a result of the fact that the area has been impacted by human uses like agriculture and cattle ranching at least since Mexico's colonial era and heavily used for shifting cultivation over the last fifty years. Our results agree with other reports that above-ground carbon stocks increase rapidly in the years following cultivation, the early forest successional stages (Read and Lawrence 2003;Chazdon et al 2007;Lebrija-Trejos et al 2010;Williams-Linera et al 2011;Pelletier et al 2012). Where the fallow phase is long, the carbon stocks would reach levels similar to those of old growth forests after 20 years, although more of this carbon is in the soil and less in the above-ground pools.…”

“…Hence, continuous "harvesting" of the trees, such that the average tree population remains youthful, may result in higher average annual uptake of carbon. Recent research in humid tropical forests (rainforest in the Maya region of Central America, Amazon and Panama) has suggested that shifting cultivation is much less damaging to carbon stocks than had been earlier thought (Pelletier et al 2012;Nigh and Diemont 2013). Whether the new plot is cut in previously un-touched (primary) forest or in a secondary forest may, however, have important consequences for CO 2 emissions and carbon sequestration (Detwiler and Hall 1988;Fukushima et al 2008;Lawrence et al 2010).…”

“…What is clear is that in most cases SC does not lead to permanent (> 20 years) removal of tree cover, which is what is implied by "deforestation" in the context of REDD+. For the purposes of REDD+ it is therefore more appropriate to consider SC as a cause of forest degradation rather than of deforestation (Houghton 2012;Pelletier et al 2012).…”

Conventional tree height–diameter relationships significantly overestimate aboveground carbon stocks in the Central Congo Basin

“…If future demand for agricultural crops exceeds the yield of the traditional agricultural activities, agricultural intensification will become a necessity. This intensification could eventually require less land than currently to sustain the local population 33,34 , thereby securing the remaining forest and its carbon stock. However, the choice of agricultural system will critically affect the carbon balance.…”

Identification and quantification of drivers of forest degradation in tropical dry forests: A case study in Western Mexico

“…Determining the proximate and underlying causes of deforestation and forest cultivation in rainforests where clearings are on average + 2 ha (Pelletier et al, 2012).…”