More on pigments in red leaves
I just found a nice description of why autumn leaves change color at Earth Friendly Gardening. Included in the comments section was a note by firefly on how anthocyanins (the pigments that make leaves red) may leach from dropped leaves into the soil and help prevent competition by causing toxicity to root cells.
This information made me wonder about the older, reddish leaves of the nance tree (Byrsonima crassifolia), which is one of the dominant trees in our local savanna.
I don’t believe the young nance leaves are red (I will have to watch for new growth), but it is certain that the older leaves of this tree turn red and drop to the ground even though the tree itself is evergreen.
The nance tree, like most small trees in this savanna, needs all the help it can get from competition. Here, for instance, are multiple shoots around a Miconia tree. At least one of the shoots is of a Clusia tree, which can turn into a strangler.
I’ve not yet found any studies of the impact of the fallen red leaves underneath the nance tree, but the nance does produce new leaves, and drop its old ones, year-round. It’s an intriguing idea that it may be keeping its competition away through anthocyanin.
