Sometime within the past month I looked up at this young cecropia tree and thought – what happened to its crown?
I started surveying the others in the area, and found this one is not unique. So what’s going on?
Here was one of the happy little cecropias along the roadside in August.
Here it is now, in October, after Herbivore Wars.
And here’s that peculiar formation at its tip (rectangle area in previous image).
Here we see an obvious baby leaf on the right, a battered gray leaf on the left, and a sharp-pointed green something-or-other at the tip.
Further, this something-or-other is present on both the young cecropias that I transplanted earlier this year:
In this last image we can begin to see what’s happening. New leaves, or a new leaf, is forming under this sharp-pointed green something-or-other.
I did a web search on Google Scholar for cecropia biology, and found this extremely helpful article on cecropia and its ants in Costa Rica. (More on those ants another time.) It turns out that the green something-or-other is a “sheathing stipule.” The botanical definition of a stipule is a “small leaflike appendage to a leaf.” In this case, it looks like the stipule is protecting the young leaf as it develops.
So, what happened to the cecropia crown? Here’s what I’m guessing, based partly on material I read in the article just mentioned. Cecropia grows taller by adding internodes – those sections that make the cecropia trunk look like bamboo. Each internode bears a single leaf. When the leaf is fully developed it resides at the top of the tree and, because the leaves are so large, nothing looks unusual. As a cecropia matures, branches develop, and internodes are added at the end of each branch, so the tree as a whole has an umbrella-like crown. In the image of the mature cecropia below, at least one internode is visible with its sheathing stipule.
I never would have noticed it, had it not been for the peculiar look of the immature tree.
Hi Mary, I’m very late to be commenting on this article. I’ve been trying to remember if I made this comment before, but I couldn’t find it so here goes:
We had several of these trees growing on the ‘wild’ hill that I told you about. Last winter during the worst of the (Honduras) rainy season, they began falling down! They were easily 25 – 30 feet tall and when they fell they would take out everything in their path, destroying other more desirable trees by knocking all the branches off on one side or knocking the whole tree down.
One by one over the winter and even into the summer, they all fell. Now we have a dozen babies coming up and I really think I’m going to remove them to prevent future damage to the other trees or our muro. It’s a shame because I do like the tropical look of them.
I think they are short-lived trees but the ones that fell were still alive. Because they were growing on the side of the hill and not at the bottom, I don’t think the soil was that saturated. My only guess is that they had some sort of root rot or maybe damage from the ants that you mentioned. (I’m going to read that article now.)
I just thought I would mention this. Maybe it isn’t a problem in Panama, but you might want to make sure that none are growing close to your house, just in case.
I haven’t commented lately, but I want you to know that I do enjoy your blog and feel that I learn so much from you.
La Gringa,
That’s a very interesting episode you’ve described. When I see cecropias, and from what I’ve read about the ease of chopping them down with a single slash of the machete, I think of them as very light and delicate, so the idea of them knocking down other trees is astonishing to me.
But we all know that in a tornado a piece of paper can be driven into the trunk of a mighty tree, so no doubt the act of falling was sufficient to knock down the other trees.
From what I’ve read about the ants, they may help the trees by fencing off herbivores and even by cutting away vines. The biology of the tree itself, though, might make it vulnerable to storms. I haven’t lived here long enough to make such observations.
Thanks for your suggestion about not planting cecropia close to the house. The shoots I transplanted are indeed far away, near the edge of the property where I want something growing fast to act as a visual screen. I’ve also planted native pines in the same area, and by the time the cecropia are gone, the pines should be tall enough to serve the purpose.
As far as learning from my blog – thank you. I’m learning from it too, since I have to do so much reading before I can even post anything!