Simulation model for growth and nitrogen dynamics in short-rotation forests
A simulation model for the development of short rotation forests as a function of climate and management is presented in detail and with a direct link to the user's manual aimed for the person running the model. The model simulates, on a daily basis, growth based on the canopy photosynthesis, allocation of assimilates, nitrogen turnover in the soil, and nitrogen uptake based on plant N-demand and N-availability in the soil. The assimilation rate hence determines the nitrogen uptake, which in turn determines the assimilation rate. The stand is assumed to be horizontally homogeneous and divided into compartments of leaves, stems, roots, easily available assimilates, litter cohorts and humus. Driving variables are daily values on global radiation, air temperature, soil temperature, plant water reduction factor, soil water content and N-fertilization rate. As a simulation example, the model is tested for a Salix viminalis stand in central Sweden for measurements on leaf biomass, stem biomass, leaf area, leaf-fall and soil mineral nitrogen. The measurements were, with some exceptions, performed about every second week from 1985 to 1988. During this period the stand developed from a recently planted stand to a well-established stand. It was harvested during the spring of 1987 and severely attacked by fungi during the summer of 1987. All these events are considered in the simulation. The model explained 99% of the variations in stem biomass and 85% of the variations in leaf biomass.
Short-rotation forests; Simulation model; Nitrogen dynamics
Report / Swedish University of Agricultural Sciences, Department of Soil Sciences, Division of Agricultural Hydrotechnics
Publisher: Institutionen för markvetenskap, Sveriges lantbruksuniversitet
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