Changing Trends of Biomass and Carbon Pools in Mediterranean Pine Forests

Abstract

The amount of biomass in forest ecosystems is critical information for global carbon cycle modelling. Determination of forest function as a sink or source of carbon is likewise relevant for both scientific applications and policy formulation. The quantity and function of forest biomass in the global carbon cycle is dynamic and changes as a result of natural and anthropogenic processes. This dynamism necessitates monitoring capacity that enables the characterization of changes in forest biomass over time and space. By combining field inventory and remotely sensed data, it is possible to characterize the quantity of biomass for a single date, or to characterize trends in quantity and function of forest biomass through time. Field inventory data provides accurate information for calibration of spatially extensive remotely sensed data models and for model validation as well. Historical, repeat measures of the same field plots facilitate the estimation of temporal trends in biomass accrual or removal, as well as carbon pooling processes. Remotely sensed data enable the inference of trends over large areas, and historical data archives can support retrospective analyses and the establishment of a baseline for future monitoring efforts. This chapter describes some of the opportunities provided by synergies between field measures and remotely sensed data for biomass and carbon assessment over large areas, and describes a case study in the Mediterranean pines of Spain, in which biomass and carbon pooling for the period 1984 to 2009 are estimated with a time series of Landsat imagery supported with data from the Spanish National Forest Inventory.