Saturday, April 20, 2013

It wouldn't be a good story if that was the whole story

Species name: Delonix regia

Common name: flamboyant tree, Royal Poinciana tree, flame tree (but not the true flame tree)

Location: Dominican Republic

Unfortunately, when my mom and I were in the Dominican we just happened to miss the best time of the year to view these trees in the Caribbean. I've included a picture at the bottom of this blog post to show what the tree would look like in full bloom, if we happened to see in sometime between May and September (although, it blooms at different times of the year in different countries). The flamboyant tree is native to Madagascar, where is is near-endangered. The last IUCN Red List had this species listed as endangered, but since then there have been concerted conservation efforts in the wild to not only protect this species but also to aid in the tree's reproduction and repopulation. These efforts have been mostly successful, but there is still "seed poaching" that occurs in the wild to supplement the ornamental tree trade. If you do buy this plant as an ornamental species (its flowers make it a very popular ornamental species), make sure you know the source of the plant and that it's not from wild seeds. Once introduced to an area in the tropics or sub-tropics it reproduces easily if the appropriate conditions are met, and can survive well in the wild as well. It is said to be naturalized in many countries in mainland Africa as well as throughout the Caribbean and in Asia. It isn't reported to be invasive in any of these areas, but even a slight shift in climate could lead to population explosion and it out-competing its neighbours. There's a fine line between a naturalized species and an invasive one!

The flamboyant tree produces brilliant orange, red and yellow flowers (depending on subspecies and cultivar or variety) before the leaves are produced. Once the flowers start to wither and fall off the tree, it invests all of its energy into producing the characteristic leaves of trees in the bean/pea family (or the Fabaceae): twice pinnately compound feather- or fern-like leaves (which can also be seen in the Kentucky coffeetree which you can read all about HERE). I traced one of the leaves of this tree in red so you can see just how large one leaf really is. When I was in the Dominican, this tree was in the process of shedding its leaves for the rest of the dry season, and it would regrow them in about May or June during the rainy season. Since it is salt- and drought-tolerant, it makes for the ideal Caribbean tree.

Fortunately for my blog, this isn't just an exciting tree because of its flamboyant flowers (which you can't even see! A let-down). This is what botanists call an exciting "specimen tree." A specimen tree is a tree that is unique and exciting on its own, regardless of what the rest of the species does. For one, this tree is enormous. Normally flamboyant trees reach a maximum height of 12 meters but normally they grow to about 5 meters. This tree has got to be about 10 meters tall; it's just as tall, if not taller, than the 3-storey building behind it. But that's not the only thing that makes it exciting. It's a perfect example of a micro-habitat. Hard to believe that a tree could be an example of a micro-habitat, but I invite you to walk around to the other side of the tree and tell me what you see.

The other side of the tree

Do you see what I see? It's a bit more obvious now, but that sure looks like a giant woody root running down the trunk of a tree. Could that possibly be a root?! Well, let's zoom in near the base of the tree and find out...

The base of the tree

Yep, that's definitely a root. So what the heck is growing off of that tree, and where is it coming from?! Roots grow in the ground, not out of leaves and down trunks!

The split in the trunk of the tree

Well look at that. There's actually another plant growing out of the trunk of the tree, where the main trunk splits into two. There would be just enough space in there that the rain would accumulate some sand and dirt that the wind blows on the branches of the tree, plus the falling tiny leaflets of the leaves in the spring, that if a seed happened to fall into that space it could germinate and grow for a while. Now, this plant didn't just grow for "a while"; it has actually been incredibly successful. But is that the whole story to this tree?

Wouldn't be a good story if that was the whole story!

Actually, there isn't just one plant growing in that tiny space. There are actually three different species (shown by the red arrows). The first is the one that's the lowest down, which sure looks like some kind of amaryllis or spider lily to me. Keep in mind that the first photo is as close as I could get to this tree, and I certainly wasn't about to climb it to get a good look even if I could get closer. So we'll just go with "unidentified lily-like monocot" for now unless someone else has a better guess for me! The second, marked by the upper arrow on the right hand side is also an "unidentified monocot", but I actually think I know what this one might be. I have a pretty strong suspicion it's a false bird of paradise (which you can read all about HERE) because of the arrangement of the leaves. Unfortunately for these two species, neither of them is going to survive long given the amount of space they have. Both of these species grow from either a bulb or a swollen underground stem called a rhizome; without a vast supply of nutrients from which to sustain their underground storage organs, the above-ground green parts can't survive. The top red arrow, however, points to a plant named the umbrella plant, named for its umbrella-like leaves. The species name of this plant is Schefflera arboricola, and is a very popular ornamental plant native to Taiwan. It thrives in tropical conditions, and can survive in very nutrient-poor soil. It also grows roots incredibly quickly (mainly due to the fact that they need to seek out what few nutrients there are in the soil), which is the contributing factor to the death of most umbrella tree houseplants (most of them become root-bound and the roots suffocate themselves in the pot). Thankfully for this species and its fast-growing roots, it can "escape" the death-trap that it found itself in (like the false birds of paradise and that lily-like plant) and anchor itself in the soil at the base of the tree.  The pink arrow indicates where the roots wrap around the branch and connect to the stem of the plant, showing that it really is all one plant. Eventually, if left to its own devices, the flamboyant tree will die and decay long before the umbrella tree. What will be left will be a giant hole in the middle of the umbrella tree where the flamboyant tree used to be, and it will look like it's standing on stilts. Fantastic! This creation of micro-habitats in the main branching points of trees in tropical forests is actually incredibly common; if you walk through a tropical jungle you'll notice a lot of "trees on stilts" where exactly this phenomenon happened over and over. If you manage to be the first plant that out-competes its neighbours for resources and hits the ground first, it's a fantastic place to be to avoid predators that want to munch on your bright green nutrient-filled leaves. They would have to be incredibly determined to climb a big tree to eat a seedling! There are far more of them on the forest floor that would make a better dinner.

The flamboyant tree in full bloom (courtesy of Wikipedia).

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