ISHS Acta Horticulturae 557: VII International Symposium on Orchard and Plantation Systems
SIMULATION MODELING OF THE EFFECTS OF SHORT AND LONG-TERM CLIMATIC VARIATIONS ON CARBON BALANCE OF APPLE TREES |
| Authors: | A.N. Lakso, M.D. White, D.S. Tustin |
| Keywords: | fruit abscission, fruit growth, leaf area development, photosynthesis, radiation, respiration, temperature |
| Abstract:
Effects of short- and long-term climatic variation and foliar pests were modeled with an improved version of a simplified apple tree carbon balance model (Lakso and Johnson, Acta Hort. 276:141, 1990). New and improved submodels were developed on (a) spring leaf area development and autumn leaf fall, (b) partitioning of carbon to the organs of the tree, and (3) 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 to experimental 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, New Zealand and Washington State. 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 estimated to be approximately 18, 23 and 25 kg fixed CO2 for a mature slender spindle tree at 2000 trees/ha using NY, WA and NZ weather, respectively. Seasonal canopy respiration was simulated to be about 13-15% of the fixed carbon for all climates. Simulations of short-term responses to low light and foliar pests and the long-term climatic simulations suggest that the model in general is behaving realistically. | |
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