Forests,
Journal Year:
2022,
Volume and Issue:
13(8), P. 1168 - 1168
Published: July 23, 2022
In
the
process
of
modeling
height–diameter
models
for
Mongolian
pine
(Pinus
sylvestris
var.
mongolica),
fitting
abilities
six
were
compared:
(1)
a
basic
model
with
only
diameter
at
breast
height
(D)
as
predictor
(BM);
(2)
plot-level
mixed-effects
(BMM);
(3)
quantile
regression
nine
quantiles
based
on
BM
(BQR);
(4)
generalized
stand
or
competition
covariates
(GM);
(5)
(GMM);
and
(6)
GM
(GQR).
The
prediction
bias
developed
was
assessed
in
cases
total
tree
(H)
predictions
calibration
without
calibration.
results
showed
that
extending
Chapman–Richards
function
dominant
relative
size
individual
trees
improved
accuracy.
Prediction
accuracy
significantly
when
H
calibrated
all
models,
among
which
GMM
performed
best
because
random
effect
provided
lowest
bias.
When
least
8%
selected
from
new
plot,
relatively
accurate
low-cost
obtained
by
models.
predicting
values
stand,
BMM
preferable
if
there
available
measurements
calibration;
otherwise,
GQR
choice.
Frontiers in Forests and Global Change,
Journal Year:
2025,
Volume and Issue:
7
Published: Jan. 7, 2025
Tree
attributes,
such
as
height
(H)
and
diameter
at
breast
(D),
are
essential
for
predicting
forest
growth,
evaluating
stand
characteristics
developing
yield
models
sustainable
management.
Measuring
tree
H
is
particularly
challenging
in
uneven-aged
forests
compared
to
D.
To
overcome
these
difficulties,
the
development
of
updated
reliable
H-D
crucial.
This
study
aimed
develop
robust
Larix
gmelinii
by
incorporating
variables.
The
dataset
consisted
7,069
trees
sampled
from
96
plots
Northeast
China,
encompassing
a
wide
range
densities,
age
classes,
site
conditions.
Fifteen
widely
recognized
nonlinear
functions
were
assessed
model
relationship
effectively.
Model
performance
was
using
root
mean
square
error
(RMSE),
absolute
(MAE),
coefficient
determination
(R
2
).
Results
identified
Ratkowsky
(M8)
best
performer,
achieving
highest
R
(0.74),
lowest
RMSE
(16.47%)
MAE
(12.50%),
statistically
significant
regression
coefficients
(p
<
0.05).
Furthermore,
M8
modified
into
5
generalized
(GMs)
adding
stand-variables
(i.e.,
height,
volume
their
combination),
results
indicate
that
GM2
0.82%
13.7%.
We
employed
mixed-effects
modeling
approach
with
both
fixed
random
effects
account
variations
individual
plot
level,
enhancing
predictive
accuracy.
explained
71%
variability
trends
residuals.
calibrated
response
calibration
method,
through
EBLUP
theory.
Our
findings
suggest
stand-level
variables
representing
plot-specific
can
further
improve
fit
mixed-
models.
These
advancements
provide
authorities
enhanced
tools
supporting
Forest Ecology and Management,
Journal Year:
2020,
Volume and Issue:
460, P. 117901 - 117901
Published: Jan. 23, 2020
The
purpose
of
creating
regression
equations
is
often
to
predict
unmeasured
features
based
upon
more
easily
obtainable
ones.
Species-specific
height–diameter
(H–D)
models
trees
are
an
example
this
situation
and
can
be
defined
as
either
simple
or
generalized.
Simple
H–D
express
height
a
function
tree
diameter
at
the
breast
height.
They
applicable
without
additional
measurement
but
do
not
take
properly
into
account
variability
in
H-D
relationship
between
stands.
Meanwhile,
generalized
also
include
stand-level
predictors.
data
sets
characterized
by
grouped
structure.
mixed-effects
modeling
approach
mainstream
method
employed
for
these
types
forestry
data.
In
study,
we
created
model
young
silver
birch
stands
on
post-agricultural
lands
central
Poland.
This
was
chosen
from
among
11
nonlinear
goodness
fit
residual
behavior.
We
accounted
two
predictors
that
did
require
measurements
beyond
height:
quadratic
mean
basal
area.
Fixed-
random-effect
predictions
were
then
calculated
illustrate
increases
number
measured
improves
predictions.
Moreover,
gain
predictive
power
largest
if
extreme
(i.e.,
extrema
range)
used
prediction.
Journal of Forestry Research,
Journal Year:
2021,
Volume and Issue:
33(3), P. 883 - 898
Published: July 24, 2021
Abstract
Modelling
tree
height-diameter
relationships
in
complex
tropical
rain
forest
ecosystems
remains
a
challenge
because
of
characteristics
multi-species,
multi-layers,
and
indeterminate
age
composition.
Effective
modelling
such
systems
required
innovative
techniques
to
improve
prediction
heights
for
use
aboveground
biomass
estimations.
Therefore,
this
study,
deep
learning
algorithm
(DLA)
models
based
on
artificial
intelligence
were
trained
predicting
Nigeria.
The
data
consisted
1736
individual
trees
representing
116
species,
measured
from
52
0.25
ha
sample
plots.
A
K-means
clustering
was
used
classify
the
species
into
three
groups
ratios.
DLA
each
species-group
which
diameter
at
beast
height,
quadratic
mean
number
per
as
input
variables.
Predictions
by
compared
with
those
developed
nonlinear
least
squares
(NLS)
mixed-effects
(NLME)
using
different
evaluation
statistics
equivalence
test.
In
addition,
predicted
estimate
biomass.
results
showed
that
100
neurons
6
hidden
layers,
9
layers
7
1,
2,
3,
respectively,
outperformed
NLS
NLME
models.
root
square
error
ranged
1.939
3.887
m.
also
height
estimation
brought
about
more
than
30%
reduction
relative
NLME.
Consequently,
minimal
errors
created
classical
methods.
Scientific Reports,
Journal Year:
2021,
Volume and Issue:
11(1)
Published: May 14, 2021
Site
productivity
remains
a
fundamental
concern
in
forestry
as
significant
driver
of
resource
availability
for
tree
growth.
The
site
index
(SI)
reflects
the
overall
impact
all
environmental
factors
that
determine
height
growth
and
is
most
commonly
used
indirect
proxy
forest
estimated
using
stand
age
height.
SI
concept
challenges
are
local
variations
climate,
soil,
genotype-environmental
interactions
lead
to
variable
patterns
among
ecoregions
cause
inappropriate
estimation
productivity.
Developing
regional
models
allow
us
more
appropriately.
This
study
aimed
develop
Scots
pine
Poland,
considering
natural
region
effect.
For
modelling,
we
trajectory
data
855
sample
trees,
representing
entire
range
geographic
locations
conditions
Poland.
We
compared
development
nonlinear-fixed-effects
(NFE)
nonlinear-mixed-effects
(NME)
modelling
approaches.
Our
results
indicate
slightly
better
fit
model
built
NFE
approach.
showed
differences
between
regions
I,
II,
III
located
northern
Poland
IV,
V,
VI
southern
NME
developed
show
pines
revealed
acknowledgement
independent
could
improve
prediction
quality
estimation.
Differences
climate
soil
distinguish
affect
patterns.
Therefore,
extending
this
research
directly
describe
with
variables,
such
properties,
topography,
can
provide
valuable
management
information.
Forest Ecology and Management,
Journal Year:
2022,
Volume and Issue:
514, P. 120209 - 120209
Published: April 8, 2022
Height
is
a
key
variable
for
forest
management.
However,
tree
height
measurements
are
expensive
and
time-consuming,
requiring
more
effort
to
measure
in
the
than
diameter
breast
measurements.
Indeed,
height-diameter
(h-d)
models
increasingly
used
overcome
difficulty
measuring
heights.
Therefore,
accurate
h-d
needed.
The
mixed-effects
modeling
approach
mainstream
method
estimate
models.
This
technique
was
model
relationship
first
24
years
of
growth
sweet
chestnut
(Castanea
sativa
Mill.)
high-forest
stands
timber
production.
A
dataset
10,868
observations
57
plots
local-inventory
data
were
considered
individually.
Simple
considering
grouping
structure
(plot-level)
obtained,
generalized
developed
by
expanding
fixed
simple
with
stand-level
variables.
Several
alternative
forms
tested
terms
accuracy,
applicability
measurement
effort.
Different
alternatives
calibrated
predictions
at
plot
level
analyzed,
considerations
on
trade-off
between
easy-to-use
equations
field
practice
high-accuracy
inventory
tested.
selected
Richards
M1a
simultaneously
provides
random
parameters
from
variables
using
same
model.
analysis
showed
that
inclusion
dominant
as
predictors
improved
accuracy
Draudt
one
best
approaches
improve
tree-level
prediction
mixed-effects.
applied
quite
feasible
100–500
m2
plots.
use
these
suggested
calibration
process
will
significantly
reduce
costs
fieldwork
teams
heights
management
planning
while
ensuring
high
accuracy.
greater
density
and,
therefore,
young
adult
stands.
Forests,
Journal Year:
2025,
Volume and Issue:
16(2), P. 271 - 271
Published: Feb. 5, 2025
Forest
mensuration
is
important
to
gain
knowledge
and
information
about
forest
stands.
Because
tree
height
often
proves
more
difficult
measure
than
diameter,
different
statistical
models
are
used
for
their
estimation
instead.
In
this
paper,
the
data
of
986
spruce
trees
(Picea
abies
KARST.
(L.)),
measured
in
federal
states
Salzburg
Tyrol
(Austria),
were
train
compare
random
with
traditional
approaches
such
as
linear
non-linear
mixed
a
classical
uniform
curve.
For
model
comparison,
RMSE,
percent
bias,
bias
used.
further
visualization
differences,
residual
plots,
partial
dependence
conditional
plots
shown.
The
results
show
that
(RMSE
2.23
m)
can
compete
methods,
2.14
2.24
or
curves
2.92
m),
but
not
able
outperform
those
especially
when
it
comes
extrapolation
prediction
areas
where
training
sparse
available.
Furthermore,
incorporation
additional
covariates
improve
certain
models.