Result and Discussion

Developed GHG database at Pasir mayang area
The land cover maps of Pasir mayang area in 1993 and 1995 were indicated as Fig. 2. Estimation of above ground carbon stock is calculated by multiplying the unite value by total area of each land cover using the land cover maps of Pasir mayang area in 1993 and 1995. The same method was applied for calculating the total emission of GHG. These results are shown as table 1 and table 2. Logged forest was the most dominant land-cover in Pasir mayang, followed by rubber and secondary vegetation (rubber jungle), fallow land (bush/shrubs), grassland and bare land (clear cut area) (Table 1).

Fig. 2 Land cover maps of Pasir mayang area and changes in 1993 and 1995


Table 1 Land cover and above ground carbon stock changes in Pasir Mayang between 1993 – 1995

Land cover	Carbon stock per ha (ton/ha)	Area in 1993 (ha)	Total above ground Carbon stock in 1993 (ton)	Area in 1995 (ha)	Total above ground Carbon stock in 1995 (ton)
Logged forest	155.2	68,529.5	10,634,270.75	63,235.5	9,812,758.4
Bush/Shrubs	15.0	10,224.8	153,372.0	10,450.3	156,754.5
Rubber and sec. Vegetation.	35.5	6,541.8	232,233.9	11,414.3	405,207.7
Grass land	6.0	3,156.5	18,939.0	3,468.3	20,809.8
Bare land	0.0	986.3	0	870.5	0
Total in 1993		89,438.9	11,038,815.7	89,438.9	10,395,530.4

Note: Above ground biomass was estimate using allometric equation, conducted by Biotrop


Table 2 Soil green house gas emission changes of Pasir Mayang between 1993 and 1995

Land-cover	Carbon dioxide (ton/hour)		Nitrous oxide (kg/hour)		Methane (kg/hour)
	1993	1995	1993	1995	1993	1995
Logged forest	241.4	222.8	7.343	6.776	-9819.3	-90607.7
Fallow land	59.4	60.7	2.041	2.086	-4.5	-4.6
Rubber and sec. vegetation	31.0	54.0	1.328	2.317	-1.3	-2.2
Grassland	19.1	20.9	0.347	0.381	0.0	0.0
Bareland	6.1	5.4	0.326	0.117	-73.2	-64.6
Total	357.0	363.8	11.194	11.679	-9898.3	-9132.1

Note : Calculation was made based on mean value of 10 months (10 time) measurement conducted
The measurements were made in Jan., Feb., Mar., June, July, Aug., Sep., Oct., Nov. and Dec

Between 1993-1995, logged forest area decreased of about 5,300 ha, while rubber jungle and fallow land increased 4,872 ha and 225 ha, respectively. Due to this, above ground carbon stock of the area decreased from 11.1 million ton to 10.4 million ton, or have loss of about 0.7 million ton.

Table 2 summarized the GHG emission of soil in 1993 and 1995. Comparison of the total GHG flux of the two period time studies based on land-cover have showed that there was an increase flux of nitrous oxide and carbon dioxide and absorption reduction of methane.

Developed GHG database at Jambi Province area in Sumatra

Land cover changes
Land cover patterns in 1986 and 1992 is presented in Table 3. Proportion of primary forest decreased from 33.9% in 1986 to 25.8% in 1992. Fallow lands (shrubs) decreased from 19.3% to 12.5% in 1992. Further analysis of each land cover types is presented in Fig. 3. It shows that about 24% of primary forest area were converted into logged forest, shrubs (fallow lands), cash crop plantation, cultivated and settlement areas. About 30% of logged forest were converted into shrubs, cash crop plantation, a mixture of cultivated and settlements.
Table 3 Land cover and above ground bio-mass changes between 1986 and 1992

LAND COVER	1986			1992
	Area (sq. km)	% of total area	Total carbon (106 ton)	Area (sq. km)	% of total area	Total carbon (106 ton)
Primary forest	16521.20	33.91	416.89	12569.86	25.80	317.19
Secondary forest	0.00	0.00	0.00	1274.34	2.62	7.40
Logged forest	10022.39	20.57	155.53	12448.65	25.55	193.18
Fallow land	9401.68	19.30	14.10	6072.66	12.47	9.11
Grassland	535.99	1.10	0.32	523.19	1.07	0.31
Bare land	3.67	0.01	0.00	3.67	0.01	0.00
Cash crops plantation	912.78	1.87	2.56	3303.17	6.78	9.25
Paddy field	1002.78	2.06	0.75	649.16	1.33	0.49
Upland field	0.00	0.00	0.00	235.84	0.48	0.18
Cultivated lands and Secondary Vegetation	7036.29	14.44	24.97	7933.39	16.29	28.16
Cultivated lands and Settlement	1339.84	2.75	0.50	1630.68	3.35	0.61
Urban area	0.00	0.00	0.00	132.17	0.27	0.00
Water surface/lake	42.41	0.09	0.00	42.27	0.09	0.00
No data	1896.60	3.89	-	1896.6	3.89	-
Total	48715.65	100.00	615.62	48715.65	100.00	565.88

Note: Above ground biomass was estimate using allometric equation, conducted by BIOTROP


Fig. 3 Land cover Changes from 1986 to 1992