Results and Discussion

The output FCD map generated from the semi-expert system (Fig. 11) is sliced in to five density classes and same density stratification is also followed in object oriented image analysis (image segmentation) (Fig. 12) and visual image interpretation of digital data. Details of each density class are shown in the Table 6. Overall analysis of forest canopy density in all the cases indicates that majority of the forests in the study area have canopy closure of 40% to

80%. However, some deviation has been observed between these techniques, class I (> 80 %) shows very high per cent difference, it is also observed that the deviation is reduced with decrease in the canopy density (Table 6 and Fig. 13).

Figure 11: FCD map derived from Landsat TM and ETM+ (A: 14 Sep. 1996 and B: 16 Oct. 2002)
Figure 12: Forest canopy density map derived from object oriented image segmentation
Table 6. Forest canopy density classes and area comparison between different techniques

Interpretation (ha)

FCD Mapper Semi-expert (ha)

Object oriented Image Analysis (ha)

> 80%

8493.21

2917.73

3435.30

60 to 80%

11411.82

12803.76

10421.25

40 to 60%

15002.10

10808.26

6284.70

20 to 40%

8506.53

10832.58

12718.16

< 20%

7715.52

4966.11

7012.98

Non-forest

13701.40

26103.78

3088.08

Riverbed

3599.64

25472.70

Total

68430.22

68432.22

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