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 43 seed dispersal, wind DHJanzen100811.jpg high resolution
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| Where do the seeds come from? Forest invasion of old pastures and fields is basically the biology of seed dispersal and plant establishment. The first plants to move into an ACG dry forest pasture are largely wind-dispersed. Here, a female mahogany tree - Swietenia macrophylla (Meliaceae) - stands leafless in the early dry season but with a full crop of pale gray mature fruits in the crown. These woody fruits, drying in the dry season winds of the first half of the dry season, will split open naturally (see DHJanzen100812.jpg below) and release their winged seeds into the winds that can gust as high as 100 kph, and blow incessantly for weeks (except that they often die down to nearly zero between 11 pm and 4 am, which is the best time for controlled fires such as when burning fire breaks, and is the easiest time to extinguish a wildfire - this is also the coolest time of the 24 hours). Nearly all wind-dispersed tree species (and individuals) of the ACG dry forest produce their mature fruits during the first half of the dry season, almost none bear mature fruit during the (largely windless and soggy) rainy season. | ||
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