@danon5,
That's interesting. I have always assumed that the city was windy.
Here is the beginning of an interesting article.
http://www.nytimes.com/2011/05/24/science/24vine.html?nl=todaysheadlines&emc=tha210&pagewanted=print
May 23, 2011
A Tree Hugger, With a Twist
By HENRY FOUNTAIN
BARRO COLORADO ISLAND, Panama — Stefan Schnitzer paused along one of the trails that crisscross this forested island in the Panama Canal waterway. Around him were trees, their high canopies muting the light from the tropical sun, the occasional woody vine, or liana, climbing up their thick trunks.
But Dr. Schnitzer’s attention was turned to a break in the forest just a few yards off the trail.
There, in harsher sunlight, a tree stump was all but obscured by a riot of lianas, their tangled stems forming a heavy thicket. Clearly the tree had come down at some point, which created an opening in the forest canopy that allowed the vines to run amok.
“This is really typical of lots of tropical forest,” said Dr. Schnitzer, a biologist at the University of Wisconsin-Milwaukee and an associate of the Smithsonian Tropical Research Institute, which is based in Panama City and operates a field station here, about halfway across the isthmus. “Where you get some disturbance, you get this massive influx of vines. They come down in the disturbance, but they don’t die. They just start putting out these stems everywhere.
“This is the liana-tree interaction at its most horrible.”
Dr. Schnitzer knows as much about liana-tree interactions as anyone, and what he knows is troubling. In a recent paper in Ecology Letters that looked at all the research on the topic, he confirmed what was first documented nearly a decade ago: that throughout tropical forests in Central and South America, vines are slowly taking over.
“Lianas are increasing in tropical forests, no doubt about it,” he said. “But what’s most important is that they are increasing relative to trees.”
Now, through a series of experiments here, Dr. Schnitzer is trying to determine why these changes are taking place.