Environmental Engineering Reference
In-Depth Information
method estimates the whole or partial weight of a
tree from measurable tree dimensions, including
trunk diameter and height, using allometric
equations. This is a non-destructive method and
is thus useful for estimating temporal changes in
forest biomass by means of subsequent mea-
surements. However, the site- and species-spe-
ci
stemmed trees published from 1984 to 2000, Sa-
enger (
2002
) cited 43 allometric equations on
AGB. His review and subsequent studies by Tam
and Wong (
1995
), Ong et al. (
2004
), Comley and
McGuinness (
2005
) and Soares and Schaeffer-
Novelli (
2005
) provide a good overall survey of
the relevant literature. They found that species-
speci
c dependencies of allometric equations pose a
problem to researchers because tree weight
measurement in mangrove forests is labour
intensive. Based on studies of forest biomass
using the allometric method and other characters,
Kira and Shidei (
1967
) summarized the so-called
summation method for estimating the net primary
production (NPP) of forests. In this method, the
rates of growth increment, death and consump-
tion by herbivores are summed to obtain the
NPP. The gross primary production (GPP) of
forests can then be calculated by adding the rate
of metabolic respiration to the NPP. Recently,
interest has grown in the study of carbon
c trait of allometry (i.e.,
the allometric
equation) is signi
cantly different among man-
grove tree species. Clough et al. (
1997
) found
different relationships in different sites, although
Ong et al. (
2004
) reported similar equations
applied to two different sites for
Rhizophora api-
culata
. This issue is important for practical uses of
allometric equations. If the equations are segre-
gated by species and site, then different expres-
sions can be established for each site (Table
4.3
).
On both the species- and site-speci
c issues of
allometry, Chave et al. (
2005
) and Komiyama
et al. (
2005
) proposed the use of a common
allometric equation for mangroves. The common
allometric equation that Komiyama et al. (
2005
)
proposed is based on the pipe model (Shinozaki
et al.
1964
) and the static model of plant form
(Oohata and Shinozaki
1979
). These models
predict that the partial weight of the trunk at a
certain height physically sustains the weight of
the upper tree body, regardless of tree species
and locality. By using these two theories,
Komiyama et al. (
2005
) derived equations with
trunk diameter and wood density as parameters
and found good
uxes
of an entire ecosystem, which includes carbon
emissions from soil respiration. Net ecosystem
production (NEP) is a sophisticated criterion to
judge carbon
fl
xation from the NPP and the rate
of soil respiration. One method for estimating the
NEP is through the eddy covariance. Essentially,
this consists of taking rapid measurements of the
vertical component of air velocity and the con-
centration of carbon dioxide/water vapour in the
air above forest canopies and taking their
covariance. However, this method requires large
equipment in mangrove forests, high-priced
instruments and complex computation.
Allometric equations for mangroves have
been developed for several decades to estimate
biomass and subsequent growth. Most studies
have used allometric equations for single-stem-
med trees, but mangroves sometimes have mul-
tistemmed
ts with 104 sample trees com-
prising 10 mangrove species from Thailand and
Indonesia (the data, Tamai et al.
1986
; Komiy-
ama et al.
1988
, are included in this common
equation). The common equation of Chave et al.
(
2005
) was established based on statistical anal-
ysis but nevertheless consisted of the same two
parameters used by Komiyama et al. (
2005
)
(Table
4.3
). These two common equations have
the advantage of requiring only two parameters,
even though Soares and Schaeffer-Novelli (
2005
)
list a large number of parameters in their allo-
metric equations for mangroves. The measure-
ment of trunk diameter or girth is more practical
than other parameters, especially for those
working in closed and tall canopies where tree
height is dif
tree
forms,
as
often
seen
in
Rhizophora
species
(Clough et al.
1997
; Dahdouh Guebas and Koe-
dam
2006
). Clough et al. (
1997
) showed that the
allometric relationship can be used for trunks in a
multistemmed tree.
Moreover, for dwarf mangrove trees, allome-
tric relationships have been used to estimate the
biomass (Ross et al.
2001
). For studies on single-
,
Avicennia
and
Excoecaria
cult to accurately measure. Wood
