III. Estimating Biomass in plantation
III-1 Estimating Total Dry Weight of each sample tree
Total dry weight (TDW) of each organ of a sample tree can be calculated from its total fresh weight (TFW), the fresh weight of its organ sample (SFW) and its dry weight (SDW).

[Boughs, Leaves, Twigs]
Equation 2

[Trunk, Bark]
Equation 3

III-2 Estimating Biomass using allometric relation
[Allometric relation]
Fig 4Biomass by each organ in the site can be estimated from the allometric relations between DBH and the total dry weight (TDW) of each organ obtained from sample trees (Fig 4). Allometric relation is expressed in the following equations;

Equation 4
or,
Equation 5

where a and b are coefficients. The coefficients can be applied to estimating biomass of other sites of the same species near the test site.

(Fig 4 Example of the allometric relation between DBH and Total Dry Weight of stem (TDWstem) obtained from sample trees.)

TDW of each organ of every standing tree in the site can be estimated, using the equations and DBH distribution data of the site.

[Biomass]
Biomass per unit area is calculated as follows;

Equation 7

where,
sumTDW : the sum of the total dry weight of every standing tree in the target site (t dry matter)
AREA : the area of the target site (ha=10000m2)
BM : the biomass of the target site (t dry matter/ha)
In converting the dry matter to carbon unit, 0.5 is generally used as a conversion coefficient.

Mean annual increment (MAI, t dry matter/ha/year) is calculated as;

Equation 7

where t is the age of the target site.

III-3 Leaf Area Index (LAI)
LAI is calculated as follows;

Equation 8

where,
BMleaf : Biomass of leaf of the site (t dry matter/ha)
LAsample : Leaf area of the sample for LAI (cm2)
DWsample : Dry weight of the sample for LAI (g dry matter)
Note: After the leaf area for LAI is measured and noted, the leaf samples must be dried in a circulating oven for two days before being weighed in the laboratory.


IV. Estimating Biomass in Bush or in Regenerated Vegetation
Total dry weight (TDW) of each organ can be calculated from total fresh weight (TFW), fresh weight of organ sample (SFW) and its dry weight of sample (SDW).

Equation 9

Then each biomass (BM; t dry matter/ha) is calculated as follows;

Equation 10

where,
TDW: Total dry weight of each organ (kg)
A: Plot area (m2)




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