Climate change is one of the truly global issues of our time, and forests play an important role in it. Changes in the cover, use, and management of forests produce sources and sinks of carbon dioxide which are exchanged with the biosphere. Estimation of the magnitude of these sources and sinks requires reliable estimates of the biomass density of forests. This is the background to the "primer" for estimating biomass and biomass change of tropical forests. It focuses on tropical forests whose high potential biomass gives any changes taking place in them a particular significance and it is concerned with one important component of the total biomass, namely above-ground woody biomass in trees with a diameter of at least 10 cm at breastheight.
Describing the state and change with regard to biomass requires observations of the state and change of area and of biomass per unit of area (biomass density in the terminology of this report). As reliable observations of biomass per unit of area are generally scarce, this "primer" endeavours to...
· outline methods that are available for estimating biomass per hectare of tropical forests using mainly existing data,
· describe primary data and measurement requirements for assessment of biomass per hectare and
· presents biomass per hectare estimates for many tropical countries using the methodologies given. It is meant to be useful to planners of forest inventories and in training for forest inventory.
The idea of a "biomass primer" to be used by planners of forest inventories and in training for forest inventory was first launched at a UNEP/FAO Expert Consultation on Environmental Parameters held in Nairobi, Kenya, in December 1992. This Forestry Paper could be realized thanks to cooperation from Dr. Sandra Brown of the University of Illinois, currently on temporary assignment to the US Environmental Protection Agency.
M. Hosny El-Lakany
Forest Resources Division