Abstract
Data from three forest sites in Sumatra (Batang Ule, Pasirmayang and Tebopandak) have been analysed and compared for the effects of sample area cut-off, and tree diameter cut-off. An 'extended inverted exponential model' is shown to be well suited to fitting tree-species-area curves. The model yields species carrying capacities of 680 for Batang Ule, 380 species for Pasirmayang, and 350 for Tebopandak (tree diameter ≥ 10 cm). It would seem that in terms of species carrying capacity, Tebopandak and Pasirmayang are rather similar, and both less diverse than the hilly Batang Ule site. In terms of conservation policy, this would mean that rather more emphasis should be put on conserving hilly sites on a granite substratum. For Pasirmayang, with tree diameter ≥ 3 cm, the asymptotic species number estimate is 567, considerably higher than the estimate of 387 species for trees with diameter ≥ 10 cm. It is clear that the diameter cut-off has a major impact on the estimate of the species carrying capacity. A conservative estimate of the total number of tree species in the Pasirmayang region is 632 species! In sampling exercises, the diameter cut-off should not be chosen lightly, and it may be worth adopting field sampling procedures which involve some subsampling of the primary sample area, where the diameter cut-off is set much lower than in the primary plots.
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Claims 10
Claim · model-written summary
The extended inverted exponential model fit tree species-area curves well.
Not reportedComparator
Verbatim
e0“An 'extended inverted exponential model' is shown to be well suited to fitting tree-species-area curves”
t0“Tree”
Claim · model-written summary
Estimated species carrying capacity was 680 at Batang Ule.
Verbatim
e0“The model yields species carrying capacities of 680 for Batang Ule, 380 species for Pasirmayang, and 350 for Tebopandak (tree diameter ≥ 10 cm)”
t0“Tree”
Claim · model-written summary
Estimated carrying capacity was 380 species at Pasirmayang.
Verbatim
e0“The model yields species carrying capacities of 680 for Batang Ule, 380 species for Pasirmayang, and 350 for Tebopandak (tree diameter ≥ 10 cm)”
t0“Tree”
Claim · model-written summary
Estimated carrying capacity was 350 species at Tebopandak.
Verbatim
e0“The model yields species carrying capacities of 680 for Batang Ule, 380 species for Pasirmayang, and 350 for Tebopandak (tree diameter ≥ 10 cm)”
t0“Tree”
Claim · model-written summary
Tebopandak and Pasirmayang had similar carrying capacities, both lower than Batang Ule.
Verbatim
e0“Tebopandak and Pasirmayang are rather similar, and both less diverse than the hilly Batang Ule site”
t0“Tree”
Claim · model-written summary
Pasirmayang had an estimated 567 species with a 3 cm diameter cutoff.
Verbatim
e0“For Pasirmayang, with tree diameter ≥ 3 cm, the asymptotic species number estimate is 567, considerably higher than the estimate of 387 species for trees with diameter ≥ 10 cm”
t0“Tree”
Claim · model-written summary
Pasirmayang had an estimated 387 species with a 10 cm diameter cutoff.
Verbatim
e0“For Pasirmayang, with tree diameter ≥ 3 cm, the asymptotic species number estimate is 567, considerably higher than the estimate of 387 species for trees with diameter ≥ 10 cm”
t0“Tree”
Claim · model-written summary
A conservative estimate for the Pasirmayang region was 632 tree species.
Verbatim
e0“A conservative estimate of the total number of tree species in the Pasirmayang region is 632 species”
t0“Tree”
Claim · model-written summary
The authors advise careful choice of diameter cutoff in sampling.
Verbatim
e0“the diameter cut-off should not be chosen lightly”
t0“Tree”
Claim · model-written summary
The authors suggest subsampling with a lower diameter cutoff.
Verbatim
e0“it may be worth adopting field sampling procedures which involve some subsampling of the primary sample area, where the diameter cut-off is set much lower than in the primary plots”
t0“Tree”