Linking process-based and empirical forest models in eucalyptus plantations in Brazil.

Abstract

The 3-PG model (Landsberg and Waring, 1997) was parameterized to predict potential productivity across 170 000 ha of Eucalyptus grandis hybrid plantation distributed in 19 regions in eastern Brazil. The regions were defined on the basis of meteorological measurements made by automatic weather stations. Mean annual increments estimated by the model for a 6-year rotation were compared with available observations made annually in permanent sample plots (PSPs). The goodness of fit between estimated and observed growth was determined by R2=0.92. Comparisons between model estimates and measurements such as basal area and total volume are presented. An empirical model called E-GROW ARCEL was developed and fitted using PSP data from the same region. The model is based on recovering the parameters of the Weibull probability density function by matching their moments to estimated stand level variables. Stand models were fitted for projections of stand basal area, mortality, dominant height, tree height, DBH (diameter at breast height) variance and stem taper. Volume of log types in the DBH distribution can be estimated. Mean annual increment (MAI), one of the outputs of 3-PG, was used to establish a hybrid approach, linking the two models by matching the relationship between MAI and site index from E-GROW ARCEL. Growth curves and yields are generated. The hybrid approach is being established as a basis for decision making and management of fast-growing E. grandis hybrid plantations in eastern Brazil.

Effects of site management on growth, biomass partitioning and light use efficiency in a young stand of Eucalyptus grandis in South Africa

“…The partitioning of carbon, fixed during photosynthesis, is imperfectly understood (Landsberg and Gower, 1997;Gholz and Lima, 1997) and therefore, further research should focus on measuring wholeforest fluxes of carbon and water. An improved physiological understanding of carbon partitioning at the stand level could facilitate extrapolation of trial results and decision-making in forest management (Gholz and Lima, 1997;Binkley et al, 2004;du Toit and Dovey, 2005), especially through the use of process-based models (Waring, 2000;Mäkelä et al, 2001;Coops and Waring, 2001;Dye, 2001;Esprey, 2001;Landsberg et al, 2001;Sands and Landsberg, 2002;Almeida et al, 2003Almeida et al, , 2004Binkley et al, 2004).…”

Use of 3-PG and 3-PGS to simulate forest growth dynamics of Australian tropical rainforests

“…However, it is a highly detailed and comprehensive system, specific to current Australian conditions. Previous work with the 3-PG (Physiological Principles Predicting Growth) and the 3-PGS (3-PG using Satellite data) has shown that these models can be used to explore forest dynamics in a wide range of systems (Almeida et al, 2003;Coops and Waring, 2001b;Dye, 2001;Esprey et al, 2004;Landsberg et al, 2001Landsberg et al, , 2003Nightingale et al, 2004;Sands, 2004;Sands and Landsberg, 2002;Waring, 2000). Although NCAS provides a comprehensive capability within Australia, there is still a need for relatively simple, flexible and widely applicable decision support and scenario analysis systems.…”

Potential climate change impacts on the probability of wind damage in a south Swedish forest

“…The modification of an empirical forest growth model to account for climate change could involve the gradual adjustment of the driving variable used, such as the site index (SI). For example, Almeida et al (2003) linked a process-based model and an empirical growth and yield model, using a relationship between mean annual increment and SI. Matala et al (2005) updated a variable expressing the competition status of the tree using climatic parameters in an empirical growth and yield model (Matala et al 2006).…”