Description Usage Arguments Details Value Author(s) References See Also Examples
This function uses Chave et al. 2014's pantropical models to estimate the above-ground biomass of tropical trees.
1 | computeAGB(D, WD, H = NULL, coord = NULL, Dlim = NULL)
|
D |
Tree diameter (in cm), either a vector or a single value. |
WD |
Wood density (in g/cm3), either a vector or a single value. If not available, see |
H |
(optional) Tree height (H in m), either a vector or a single value. If not available, see |
coord |
(optional) Coordinates of the site(s), either a vector giving a single site
(e.g. c(longitude, latitude)) or a matrix/dataframe with two columns (e.g. cbind(longitude, latitude)).
The coordinates are used to account for variation in height-diameter relationship thanks to an environmental
proxy (parameter E in Chave et al. 2014). Compulsory if tree heights |
Dlim |
(optional) Minimum diameter (in cm) for which aboveground biomass should be calculated
(all diameter below |
This function uses two different ways of computing the above-ground biomass of a tree:
If tree height data are available, the AGB is computed thanks to the following equation (Eq. 4 in Chave et al., 2014):
AGB = 0.0673 * (WD * H * D^2)^0.976
If no tree height data is available, the AGB is computed thanks to the site coordinates with the following equation, slightly modified from Eq. 7 in Chave et al., 2014 (see Réjou-Méchain et al. 2017):
AGB = exp(-2.024- 0.896*E + 0.920*log(WD) + 2.795*log(D) - 0.0461*(log(D)^2))
where E
is a measure of environmental stress estimated from the site coordinates (coord
).
The function returns the ABG in Mg (or ton).
Maxime REJOU-MECHAIN, Ariane TANGUY, Arthur PERE
Chave et al. (2014) Improved allometric models to estimate the aboveground biomass of tropical trees, Global Change Biology, 20 (10), 3177-3190
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 | # Create variables
D <- 10:99
WD <- runif(length(D), min = 0.1, max = 1)
H <- D^(2 / 3)
# If you have height data
AGB <- computeAGB(D, WD, H)
# If you do not have height data and a single site
lat <- 4.08
long <- -52.68
coord <- cbind(long, lat)
## Not run:
AGB <- computeAGB(D, WD, coord = coord)
## End(Not run)
# If you do not have height data and several sites (here three)
lat <- c(rep(4.08, 30), rep(3.98, 30), rep(4.12, 30))
long <- c(rep(-52.68, 30), rep(-53.12, 30), rep(-53.29, 30))
coord <- cbind(long, lat)
## Not run:
AGB <- computeAGB(D, WD, coord = coord)
## End(Not run)
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