Simulation modeling of the effects of short and long-term climatic variations on carbon balance of apple trees.

摘要

Effects of short- and long-term climatic variation and foliar pests were modelled with an improved version of a simplified apple tree carbon balance model. New and improved submodels were developed on (a) spring leaf area development and autumn leaffall, (b) partitioning of carbon to the organs of the tree, and (c) fruit growth and abscission based on carbon balance. Simulations of known effects of low light and foliar pest damage on apple fruit growth and abscission were realistic and similar toexperimental results. Similarly, long-term simulations were run of leaf area development, light interception, canopy photosynthesis and canopy respiration in different climates using temperature and radiation data from New York and Washington, USA; and New Zealand. Simulations suggest that mid- to late-season differences were the most distinguishing among climates, and that early season differences were less when expressed as time after budbreak. Total canopy photosynthesis over the season was approximately 18, 23 and 25 kg fixed CO2 for a mature slender spindle tree at 2000 trees/ha using New York, Washington and New Zealand weather, respectively. Simulated seasonal canopy respiration was about 13-15% of the fixed carbon for all climates. Simulationsof short-term responses to low light and foliar pests and the long-term climatic simulations suggest that the model in general is behaving realistically.