Improving the ability of 3‐PG to model the water balance of forest plantations in contrasting environments

Abstract

Because water availability is a primary factor that influences growth of forest plantations, quantifying plantation water use is an important part of the decision-making process when selecting new plantation areas. The 3-PG model (Landsberg and Waring, Forest Ecology and Management 95: 209-228, 1997) has been used successfully to model forest growth for several species. However, some studies have demonstrated limitations in 3-PG's ability to accurately model the soil and plant water balance. This paper addresses these limitations through the development and validation of a modified water balance submodel that models canopy interception, soil evaporation, tree transpiration, drainage, run-off, soil water content and available soil water in the root and non-root zone. The new submodel was tested and validated using detailed, long-term observed growth and water balance data from contrasting environments in Australia and Brazil and showed improved estimation of available soil water, even when only monthly weather data were available. However, the new submodel requires more soil texture-dependent parameters than the original submodel. Sensitivity analysis of these new parameters shows that values of soil field capacity, wilting point and soil depth may have strong impacts on the prediction of run-off, soil water content and available soil water.

Cardinal temperatures for the leaf development of Corymbia citriodora and Eucalyptus urophylla seedlings

“…Thus, the optimum temperature was 17.1ºC, determined by the arithmetic mean of the average temperatures for the sowing date with the greatest vegetative development (Lisboa et al, 2012), for both species. These values are biologically realistic and resemble those found for photosynthesis (10.0 to 15.0°C) and growth (16.0ºC) of E. globulus (Battaglia et al, 1996;Almeida & Sands, 2016) and P. ponderosa (20.0ºC) (Landsberg et al, 2003) and, also, for the olive cultivars Arbequina (16.1ºC) and MGS ASC315 (14.7ºC) (Lisboa et al, 2012).…”

“…In the present study, the values of Tb estimated for Corymbia citriodora (8.7ºC) were close to the values reported for leaf development of other perennial crops, such as: E. saligna, 8.0°C ; Acer pensylvanicum, Acer rubrum, and Betula popifolia, 7.5°C (Chiang & Brown, 2007); and the olive cultivar Olea europaea 'Grappolo', 9.6ºC (Souza & Martins, 2014). As to growth (Almeida & Sands, 2016), leaf area index (Battaglia et al, 1996), and photosynthetic process (Sands & Landsberg, 2002) of Eucalyptus globulus, Tb values of 8.5, 7.8, and 7.5ºC were observed, respectively. Regarding the vegetative development of annual crops, close values of Tb were observed, as from 7.0 to 8.0ºC, in ryegrass (Müller et al, 2009), and 8.0 to 10.9ºC in irrigated rice (Lago et al, 2009).…”

“…Nonetheless, such information is very useful to know the most adapted species to the climatic conditions of cultivation Souza & Martins, 2014), as well as to provide planning, management, and crop treatments in field conditions. In addition, these values are constantly used in air temperature functions which make part of development and production models (Soltani & Sinclair, 2012;Martins et al, 2014;Almeida & Sands, 2016).…”

Analysing the spatial and temporal dynamics of species interactions in mixed-species forests and the effects of stand density using the 3-PG model

“…No consideration is given to which species overtop others, unlike light absorption, where vertical structure must be considered. It is important to note that this interception calculation is a considerable simplification, because interception is more accurately modelled at time scales of single rainfall events (Landsberg and Waring, 1997;Almeida et al, 2007;Feikema et al, 2010b;Almeida and Sands, 2015).…”

“…3-PG mix uses all net radiation that was not absorbed by the trees to predict soil evaporation. Vertical gradients in radiation and VPD, as well as the separation of transpiration and soil evaporation, have also recently been added to a monospecific version of 3-PG with a detailed water balance (Almeida and Sands, 2015).…”