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N. Novita et al.
total vegetation C stocks. In contrast, tree with dbh >40 cm dominated C vegetation
in primary forest sites, comprising 74 and 60% of the total vegetation C stocks in
Beguruh and Pesalat, respectively.
Shannon’s index (H’) of forest structure was lower at the secondary forest site
(1.13) compared to primary forest sites (1.35 and 1.36 for Beguruh and Pesalat,
respectively), thus reflecting a more even-aged stand in the secondary forest. This
index poorly described structural diversity among forest sites. Simpson’s reciprocal
index of the secondary forest Tanjung Harapan was lower (8.44) than Beguruh (14.98)
and Pesalat (14.62) sites. Simpson’s reciprocal index better illustrated the diversity
of the forest structure in Tanjung Harapan, and was different from the Beguruh and
Pesalat sites. Furthermore, Pesalat and Beguruh sites had similar Shannon’s evenness
indices (0.37), which were slightly higher than Tanjung Harapan site (0.34). Lower
values of species diversity and evenness indices in Tanjung Harapan reflect signs of
early seral forest succession.
The mean basal area of the forest sites was 31.3, 28.4, and 39.6 m
2 /ha in Tanjung
Harapan, Beguruh, and Pesalat, respectively. The Tanjung Harapan site was dominated by Macaranga motleyana, a pioneer species (Davies and Ashton 1999) with
the highest basal area (15 m
2 /ha) and importance value index (82%; Fig. 10.5). The
high dominance by a single species in Tanjung Harapan site was consistent with the
low values described by Simpson’s reciprocal index. Unlike Tanjung Harapan site, no
single species dominated in the primary forests (Fig. 10.5). It is interesting to see the
presence of Artocarpus heterophyllus (jackfruit), a crop cultivated species, had the
5th highest IVI value (12.4), showing that Tanjung Harapan was formerly utilized for
agriculture. Inevitably, the Tanjung Harapan site clearly showed a different structure
and composition compared to Beguruh and Pesalat sites. The different composition
and structure at Tanjung Harapan reflects past intensive land use prior to its inclusion
in Tanjung Puting national park territory.
Aboveground C Stocks
Ecosystem C stocks are presented in Table 10.3. In primary forests, the aboveground
C stock was higher in Pesalat (206 ± 32 Mg C/ha) than in Beguruh (130 ± 30 Mg
C/ha; p < 0.001). The mean of vegetation C stock in primary forest (168 ± 31 Mg
C/ha) was not significantly different from the stock in secondary forest (140 ± 16 Mg
C/ha; p = 0.291). The tree carbon pools closely followed basal area across forest
plots. In the oil palm plantations, vegetation C stocks ranged from 7 to 19 Mg C/ha.
There were significant differences among sites in the oil palm plantation (p < 0.001),
where the highest palm C stock was found at the oldest plantation. Mean aboveground
C stocks in the primary forests were 14 times higher than in the oil palm plantations
sites (p < 0.001).
The downed wood was a significant C pool, contributing 12 and 16% to the
total aboveground C stocks in the primary forests and secondary forest, respectively.
This was especially true for oil palm plantations, where the downed wood C pool
N. Novita et al.
total vegetation C stocks. In contrast, tree with dbh >40 cm dominated C vegetation
in primary forest sites, comprising 74 and 60% of the total vegetation C stocks in
Beguruh and Pesalat, respectively.
Shannon’s index (H’) of forest structure was lower at the secondary forest site
(1.13) compared to primary forest sites (1.35 and 1.36 for Beguruh and Pesalat,
respectively), thus reflecting a more even-aged stand in the secondary forest. This
index poorly described structural diversity among forest sites. Simpson’s reciprocal
index of the secondary forest Tanjung Harapan was lower (8.44) than Beguruh (14.98)
and Pesalat (14.62) sites. Simpson’s reciprocal index better illustrated the diversity
of the forest structure in Tanjung Harapan, and was different from the Beguruh and
Pesalat sites. Furthermore, Pesalat and Beguruh sites had similar Shannon’s evenness
indices (0.37), which were slightly higher than Tanjung Harapan site (0.34). Lower
values of species diversity and evenness indices in Tanjung Harapan reflect signs of
early seral forest succession.
The mean basal area of the forest sites was 31.3, 28.4, and 39.6 m
2 /ha in Tanjung
Harapan, Beguruh, and Pesalat, respectively. The Tanjung Harapan site was dominated by Macaranga motleyana, a pioneer species (Davies and Ashton 1999) with
the highest basal area (15 m
2 /ha) and importance value index (82%; Fig. 10.5). The
high dominance by a single species in Tanjung Harapan site was consistent with the
low values described by Simpson’s reciprocal index. Unlike Tanjung Harapan site, no
single species dominated in the primary forests (Fig. 10.5). It is interesting to see the
presence of Artocarpus heterophyllus (jackfruit), a crop cultivated species, had the
5th highest IVI value (12.4), showing that Tanjung Harapan was formerly utilized for
agriculture. Inevitably, the Tanjung Harapan site clearly showed a different structure
and composition compared to Beguruh and Pesalat sites. The different composition
and structure at Tanjung Harapan reflects past intensive land use prior to its inclusion
in Tanjung Puting national park territory.
Aboveground C Stocks
Ecosystem C stocks are presented in Table 10.3. In primary forests, the aboveground
C stock was higher in Pesalat (206 ± 32 Mg C/ha) than in Beguruh (130 ± 30 Mg
C/ha; p < 0.001). The mean of vegetation C stock in primary forest (168 ± 31 Mg
C/ha) was not significantly different from the stock in secondary forest (140 ± 16 Mg
C/ha; p = 0.291). The tree carbon pools closely followed basal area across forest
plots. In the oil palm plantations, vegetation C stocks ranged from 7 to 19 Mg C/ha.
There were significant differences among sites in the oil palm plantation (p < 0.001),
where the highest palm C stock was found at the oldest plantation. Mean aboveground
C stocks in the primary forests were 14 times higher than in the oil palm plantations
sites (p < 0.001).
The downed wood was a significant C pool, contributing 12 and 16% to the
total aboveground C stocks in the primary forests and secondary forest, respectively.
This was especially true for oil palm plantations, where the downed wood C pool