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Appendix E   Relative efficiencies Previous topic Parent topic Child topic Next topic

This appendix contains the results and the literature references supporting the conclusions summarized in the dot points in Box 19.

Table 22: Relative efficiency of using the national versus UMD GFC based F/NF and change maps for Gabon

Country: Gabon
Type of reference data: independent interpretation of satellite imagery
Type of map/remotely sensed data
Biome/type of forest
Target variable
Relative efficiency of using national vs global map
% reduction in sample size
UMD GFC tree cover with 30% cover threshold F/NF 1 ha MMU map
Tropical rainforest
Forest area
9.5
89.4
UMD GFC tree cover with 30% cover threshold F/NF no MMU map
Tropical rainforest
Forest area
9.2
89.1
UMD GFC tree cover with 70% cover threshold F/NF 1 ha MMU map
Tropical rainforest
Forest area
3.8
73.6
UMD GFC tree cover with 70% cover threshold F/NF no MMU map
Tropical rainforest
Forest area
3.8
73.8
UMD GFC tree cover with 30% cover threshold F/NF 1 ha MMU map
Tropical rainforest
Net forest change area
2.0
49.7
UMD GFC tree cover with 30% cover threshold F/NF no MMU map
Tropical rainforest
Net forest change area
2.6
61.0
UMD GFC tree cover with 70% cover threshold F/NF 1 ha MMU map
Tropical rainforest
Net forest change area
4.6
78.3
UMD GFC tree cover with 70% cover threshold F/NF no MMU map
Tropical rainforest
Net forest change area
2.6
61.6
Reference:
Sannier, C., McRoberts, R. E., & Fichet, L. (2016). Suitability of Global Forest Change data to report forest cover estimates at national level in Gabon. Remote Sensing of Environment. 173:326–338.

Table 23: Relative efficiency of using the national and UMD GFC based F/NF and change maps against sample data for Gabon

Country: Gabon
Type of reference data: independent interpretation of satellite imagery
Type of map/remotely sensed data
Biome/type of forest
Target variable
Relative efficiency of using map
% reduction in sample size
National F/NF Map
Tropical rainforest
Forest area
57.7
98
UMD GFC tree cover with 30% cover threshold F/NF 1 ha MMU map
Tropical rainforest
Forest area
6.1
83.6
UMD GFC tree cover with 30% cover threshold F/NF no MMU map
Tropical rainforest
Forest area
6.3
84.0
UMD GFC tree cover with 70% cover threshold F/NF 1 ha MMU map
Tropical rainforest
Forest area
15.3
93.4
UMD GFC tree cover with 70% cover threshold F/NF no MMU map
Tropical rainforest
Forest area
15.1
93.4
National F/NF Map
Tropical rainforest
Net forest change area
2.66
62.4
National F/NF Map
Tropical rainforest
Net forest change area
1.12
10.9
UMD GFC tree cover with 30% cover threshold F/NF 1 ha MMU map
Tropical rainforest
Net forest change area
0.57
n/a
UMD GFC tree cover with 30% cover threshold F/NF no MMU map
Tropical rainforest
Net forest change area
0.44
n/a
UMD GFC tree cover with 70% cover threshold F/NF 1 ha MMU map
Tropical rainforest
Net forest change area
0.24
n/a
UMD GFC tree cover with 70% cover threshold F/NF no MMU map
Tropical rainforest
Net forest change area
0.43
n/a
Reference:
Sannier, C., McRoberts, R. E., & Fichet, L. (2016). Suitability of Global Forest Change data to report forest cover estimates at national level in Gabon. Remote Sensing of Environment. 173:326–338.
Desclée, B., Mayaux, P., Hansen, M., Lola Amani, P., Sannier, C. Mertens, B., Haüsler T., Ngamabou Siwe, R., Poilvé, H., Gond, V., Rahm,M., Haarpainter, J., Kibambe Lubamba, J.P. (2014) Evolution of forest cover area at a national and regional scale and drivers of change in The forests of the Congo basin—State of the forest 2013. Eds : deWasseige C., Flynn J., LouppeD., Hiol Hiol F.,Mayaux Ph. – 2014.Weyrich. Belgium. 328 p.

Table 24: Relative efficiency of using the national and UMD GFC based F/NF against sample data for Tanzania

Country: Tanzania
Type of reference data: National inventory of ground plots (first 6 cases; photo interpretation of visual images (cases 7 and 8)
Type of map/remotely sensed data
Biome/type of forest
Target variable
Relative efficiency of using map
% reduction in sample size
UMD global map (tree cover and Landsat digital numbers from mosaics).
Calibrated to local forest definition.
Miombo woodlands
Forest area
1.4
29%
UMD global map. Tree cover with 10% cover threshold.
Miombo woodlands
Forest area
1.0
0%
UMD global map. Tree cover with 20% cover threshold.
Miombo woodlands
Forest area
1.2
17%
Global ALOS PALSAR forest/non forest map. Calibrated to local forest definition.
Miombo woodlands
Forest area
1.7
41%
Global ALOS PALSAR forest/non forest map.
Miombo woodlands
Forest area
1.5
33%
RapidEye optical satellite images. Calibrated to local forest definition.
Miombo woodlands
Forest area
2.0
50%
UMD global map (tree cover). Calibrated to local forest definition.
Miombo woodlands
Forest area
1.8
44%
RapidEye optical satellite images. Calibrated to local forest definition.
Miombo woodlands
Forest area
1.7
41%
Reference:
Næsset, E., Ørka, H.O., Solberg, S., Bollandsås, O.M., Hansen, E.H., Mauya, E., Zahabu, E., Malimbwi, R., Chamuya, N., Olsson, H. & Gobakken, T. 2016. Mapping and estimating forest area and aboveground biomass in miombo woodlands in Tanzania using data from airborne laser scanning, TanDEM-X, RapidEye, and global forest maps as auxiliary information: A comparison of estimated precision. Remote Sensing of Environment, 175: 282-306. Ørka, H.O. 2015. Accuracy assessment of global forest maps and high-resolution satellite imagery for forest area estimation in a first phase of MRV for REDD+. Report to the Norwegian Space Centre, 29 June 2015, unpublished, 19 pp.