TITLE:
Bertalanffy-Pütter Models for the Growth of Tropical Trees and Stands
AUTHORS:
Norbert Brunner, Manfred Kühleitner
KEYWORDS:
Bertalanffy-Pütter (BP) Differential Equation, Growth Model, Normalized Root-Mean-Squared-Error (NRMSE), Simulated Annealing
JOURNAL NAME:
Open Journal of Modelling and Simulation,
Vol.8 No.4,
September
7,
2020
ABSTRACT: The
Bertalanffy-Pütter (BP) five-parameter growth model provides a versatile
framework for the modeling of growth. Using data from a growth experiment in
literature about the average size-at-age of 24 species of tropical trees over
ten years in the same area, we identified their best-fit BP-model parameters.
While different species had different best-fit exponent-pairs, there was a
model with a good fit to 21 (87.5%) of the data (“Good fit” means a normalized
root-mean-squared-error NRMSE
below 2.5%. This threshold was the 95% quantile of the lognormal distribution
that was fitted to the NRMSE
values for the best-fit models for the data). In view of the sigmoidal character of this model
despite the early stand we discuss whether the setting of the growth experiment may have
impeded growth.