How do palm trees survive hurricanes?
Hurricane footage often shows palm trees valiantly weathering the wrath; here's how these graceful beauties stand their ground.
When hurricane footage floods the airwaves it’s always intense … the lashing winds and flying waves, torrents of rain and water taking over the streets. But this always makes me wonder: Pieces of houses and big trees are tossed around like toys during extreme weather, but palm trees seem able to stand their ground. Given their choice of location they are obviously well suited to stand up to big angry storms, but how?
Trees are masters of engineering – Mother Nature really has a handle on things, and this is especially true with the tall slender members of the botanical family Arecaceae. Plant ecologist Dan Metcalfe explains that palm trees have three distinctive features that help them survive the punishing conditions of hurricane and cyclones, and even tsunamis.
First of all, most palm trees have a large number of short roots spread across the upper levels of the soil, which work to secure a large amount of soil around the root ball. As long as the soil is relatively dry to start off with, this works to create a super large, heavy anchor. As opposed to having just a few very strong roots, this wider network creates a bottom-heavy base that helps keep the tree in place.
A wiry trunk
The trunk of a pine or oak tree grows in a radial pattern; the annual rings effectively make a series of hollow cylinders inside each other, says Metcalfe. Meanwhile, the stem of a palm tree is made of many small bundles of woody material, which Metcalfe likens to the bundles of wires inside a telephone cable. He writes:
The cylinder approach provides great strength to support weight (compressive strength) which means that an oak tree's trunk can support a huge weight of branches, but limited flexibility compared to the bundle approach, which allows the palm stem to bend over through 40 or 50 degrees without snapping.
Palm trees do get snapped in extreme conditions, but they are much tougher in this regard than other trees.
Very clever leaves
While most trees rely on their beautiful canopy of branches, twigs and leaves to spread out and grab as much sunlight as possible, the canopy can also grab a lot of wind and water. In a bad storm, the canopy can act as a sail and pull the poor thing over; branches can easily be shorn off, as well as the detachment of the whole canopy.
Meanwhile, think of a palm tree. They have no wide-spreading branches, rather huge leaves with a central, flexible spine – like enormous feathers, notes Metcalfe. In nice weather the fronds spread out and make a fine canopy, but in instances of strong wind and water … what do the fronds do? They fold up! With less resistance against the elements they are much more likely to make it through intact. Of course some leaves may suffer and palm detritus is part and parcel of storm clean-up, but as Metcalfe writes of lost leaves, “they are much 'cheaper' for the palm to replace than a whole canopy of branches would be.”
So there you have it. If you're like me and feel twinges of empathy when seeing palms battling the harshest of elements, you can at least take solace in knowing that they are likely up to the task.