The self-thinning exponent in overcrowded stands of the mangrove, Kandelia obovata, on Okinawa Island, Japan
Weller’s allometric model assumes that the allometric relationships of mean area occupied by a tree , i.e., the reciprocal of population density , , mean tree height , and mean aboveground mass density to mean aboveground mass hold. Using the model, the self-thinning line of overcrowded Kandelia obo...
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Published in | Journal of oceanography Vol. 68; no. 6; pp. 851 - 856 |
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Main Authors | , , , , |
Format | Journal Article |
Language | English |
Published |
Japan
Springer Japan
01.12.2012
Springer Nature B.V |
Subjects | |
Online Access | Get full text |
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Summary: | Weller’s allometric model assumes that the allometric relationships of mean area occupied by a tree
, i.e., the reciprocal of population density
,
, mean tree height
, and mean aboveground mass density
to mean aboveground mass
hold. Using the model, the self-thinning line
of overcrowded
Kandelia obovata
stands in Okinawa, Japan, was studied over 8 years. Mean tree height increased with increasing
. The values of the allometric constant
and the multiplying factor
are 0.3857 and 2.157 m kg
−θ
, respectively. The allometric constant
and the multiplying factor
are −0.01673 and 2.685 m
−3
kg
1−δ
, respectively. The
value was not significantly different from zero, showing that
remains constant regardless of any increase in
. The average of
, i.e., biomass density
, was 2.641 ± 0.022 kg m
−3
, which was considerably higher than 1.3–1.5 kg m
−3
of most terrestrial forests. The self-thinning exponent
and the multiplying factor
were estimated to be 1.585 and 16.18 kg m
−2α
, respectively. The estimators
and
are dependent on each other. Therefore, the observed value of
cannot be used for the test of the hypothesis that the expectation of the estimator
equals 1/3, i.e.,
, or 1/4, i.e.,
. The
value was 0.6310, which is the same as the reciprocal of the self-thinning exponent of 1.585, and was not significantly different from 2/3 (
t
= 1.860,
df
= 191,
p
= 0.06429), i.e.,
. Thus the self-thinning exponent is not significantly different from 3/2 based on the simple geometric model. On the other hand, the self-thinning exponent was significantly different from 3/4 (
t
= 6.213,
df
= 191,
p
= 3.182 × 10
−9
), i.e.,
. Therefore, the self-thinning exponent is significantly different from 4/3 based on the metabolic model. |
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Bibliography: | ObjectType-Article-1 SourceType-Scholarly Journals-1 ObjectType-Feature-2 content type line 23 |
ISSN: | 0916-8370 1573-868X |
DOI: | 10.1007/s10872-012-0135-7 |