Secondary forests from agricultural abandonment in Amazonia

Douglas Morton, NASA GSFC, douglas.morton@nasa.gov (Presenter)
Pipa Elias, UCSUSA, pipa.elias@gmail.com

Secondary forests lie at the center of several ongoing debates. In the tropics, secondary forests may provide important habitat for biodiversity, compensate for emissions from deforestation and forest degradation, or offer the possibility for low-carbon expansion of agriculture or biofuel production. However, the quantitative information on the extent and turnover of secondary forests necessary to evaluate these tradeoffs is largely unavailable. Here, we mapped secondary forest from agricultural abandonment in the Brazilian and Bolivian Amazon using time series of Landsat and MODIS data from 2000-2011. Secondary forest from agricultural abandonment was defined as two consecutive years of agricultural use (e.g., 2000-2001), followed by increasing dry season NDVI until the end of the study period (2011). Our results suggest that rates of long-term land abandonment to secondary forest were <3% of deforestation rates during this period, or only 1/10th of the rates of land abandonment reported for previous decades. In addition, secondary forests from land abandonment were widely distributed across the arc of deforestation small patches. The amount, spatial distribution, and size of secondary forests in Amazonia likely limit future use of these lands for some activities, such as mechanized agriculture or large-scale plantations for biofuels. Similarly, our findings suggest that net carbon uptake from secondary forests in Amazonia during this period was much smaller than previously reported from bookkeeping approaches. Our study provides a model for how satellite-based studies can provide contemporary information on land use transitions with potential applications for ongoing efforts to harmonize historic land use information with data from the satellite era. Our findings also help to reframe the discussion of the global land reserve based on the limited availability of secondary forest for carbon sequestration, biodiversity, or alternate land uses in Amazonia.

Presentation Type:  Poster

Session:  Global Change Impact & Vulnerability   (Tue 11:30 AM)

Associated Project(s): 

• Hurtt, George: Modeling the Impacts of Major Forest Disturbances on the Earth's Coupled Carbon-Climate System, and the Capacity of Forests to Meet Future Demands for Wood, Fuel, and Fiber ...details
• Related Activity

Poster Location ID: 249