Estimating biomass and biomass change of tropical forests: a primer. (FAO Forestry Paper - 134) (1997): 3. METHODS FOR ESTIMATING BIOMASS DENSITY FROM EXISTING DATA: 3.1 APPROACH 1: BIOMASS DENSITY BASED ON EXISTING VOLUME DATA: (introduction...)

Estimating biomass and biomass change of tropical forests: a primer. (FAO Forestry Paper - 134) (1997)

3. METHODS FOR ESTIMATING BIOMASS DENSITY FROM EXISTING DATA

3.1 APPROACH 1: BIOMASS DENSITY BASED ON EXISTING VOLUME DATA

		*(introduction...)*
		3.1.1 GENERAL EQUATION
		3.1.2 VOLUME-WEIGHTED AVERAGE WOOD DENSITY (WD)
		3.1.3 BIOMASS EXPANSION FACTOR (BEF)
		3.1.4 EXAMPLES OF CALCULATIONS OF BIOMASS DENSITY
		3.1.5 ADJUSTMENTS TO APPROACH USING VOLUME EXPANSION FACTORS (VEF)
		3.1.6 USE OF INVENTORIES OF OPEN FORESTS AND WOODLANDS

(introduction...)

The method presented here is based on existing volume per ha data and is best used for secondary to mature closed forests only, growing in moist to dry climates. It should be used for closed forest only because the original data base used for developing this approach was based on closed forests. The primary data needed for this approach is VOB/ha, that is inventoried volume over bark of free bole, i.e. from stump or buttress to crown point or first main branch. Inventoried volume must include all trees, whether presently commercial or not, with a minimum diameter of 10 cm at breast height or above buttress if this is higher. If the minimum diameter is somewhat larger, the VOB/ha information can be used with some adjustments as shown below. However, such adjustments to the primary data introduce larger errors in the estimate.