Forest dynamics

Trees come in many sizes – but some tend to be very large indeed. This is a Ceiba (Bombacaceae) with a commanding presence on Barro Colorado Island. If I were in this picture, I would only reach two thirds the height of the main buttress. Large individuals like this one have a disproportionate impact on the forest, out-competing others for resources like light and water. Winners stay winners, just as in human economies, it is very difficult for a small company to out-compete a large company even if its products are better.

Of course, everything with a beginning has an end – large trees eventually will die. In death, the impact of a large tree is tremendous – as it falls, it can destroy dozens of other large trees and countless of small ones. The resulting gap left by this demolition is full of light – a valuable resource for other plants. The survivors and new germinants compete heavily for light, resulting in a tangle of new vegetation – and ultimately, the growth of more large trees, to repeat the cycle!

Last week our team laid down a 50 meter transect line through one section of forest. When we returned, we couldn’t find the meter tape, nor did the forest look familiar. Some time over the weekend, this beast of a tree fell down, collapsing a large section of forest and burying our equipment. I am very glad we were not working at the time this fell down!

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