TEAK PLANTATIONS IN NILAMBUR - Kerala Forest Research Institute

Type
of
work
1M
2M
1S
2S
3S
FT
FF
Total
Table : 3.11
Average yield of teak plantations and site quality observed in Nilambur Divisions
No.of
Plantations
26
43
57
48
65
86
47
372
Total Mean Mean Lowes decile
area age Yield I S.Q. Yield S.Q.
(ha)
(m 3 ha -1 )
(m 3 ha- 1 )
888.565 6 4.641 III/IV 1.172 Failure
1906.204 8 5.994 IV 2.365 Failure
2411.523 13 5.291 Failure 0.425 Failure
2082.508 19 4.917 Failure 0.159 Failure
2101.210 28 15.672 II/III 3.444 Failure
1829.303 41 15.615 II 4.461 IV
1316.844
53 99.128 III/IV 39.543 Failure
12536.157 151.258 IV 51.569
Source : Results of productivity analysis
Highest decile
Yield S.Q.
(m3ha -1 )
10.434 III/IV
11.459 III/IV
8.643 IV
10.989 III/IV
26.963 I/II
26.029 I
204.475 II
Failure I 298.992 I II/III
As the same set of plantations were used for comparing the site quality based
on top height and site quality based on actual yields an identical distribution is
expected. But the ,data obtained show that it is not so (Tables 3.9 and 3.10).
While the site quality of plantations based on top height concentrated in the
higher classes, the site quality based on actual yields is seen shifted to much
lower classes. To examine this issue further, plantations having data on yield
for more than one operation were sorted. Details regarding such 30
plantations are given in Table 3.12. Site qualiy based on top height and that
based on actual yield obtained for the same plantation are compared in the
Table. As was seen earlier, the site quality information availablein the
Working Plans cannot be relied upon to predict the yields in different
operations. A general observation is that the site quality based on top height
measured between the age of 10 and 20 does not hold good during later years
and the thinning and final felling yields are far below that indicated by the site
quality. In most of the plantations, a progressive deterioration in site quality
28