We’ve had a couple of wind storms up here that had me looking nervously at the tall cedars out back. I’ve always thought that trees evolved to survive their conditions. Thus, tall trees are flexible because they wouldn’t survive if wind snapped them. I was wondering if trees have a ‘clenching’ mechanism. That is, when winds are stronger than usual, are they able to regulate their fluid transfer to make parts of their trunks more resistant to breaking. That is, they ‘think’ ‘Hey, this part of my trunk is bending a little too much. Better get a grip.’
According to the movie Poltergeist they do.
If you’ll forgive me for being a pedant while ignoring your actual question:
Remember that evolution only selects for “usually good enough to reproduce”, not maximal physical strength (or speed, or intelligence, or whatever). So if cedars reach sexual maturity within 10 years, and most can survive the typical 10-year storm, there won’t be any selection for trees that can survive the 100-year storm.
Also, the ceders in your hard probably evolved in a different environment. Trees in a forest won’t experience anywhere near as much wind as the more isolated trees in your yard.
Point taken. These wind storms happen every year. Of course a 10-year-old cedar isn’t tall enough to be damaged. (I don’t know when they reach sexual maturity.)
These are ‘forest’ trees. They weren’t planted there.
If you’ll forgive me for being a pedant but I believe you meant “yard” instead of “hard”.
To answer the OP, I don’t know of anything short-term, but medium-to-long-term, I think that in most tree species, stress on one section of trunk tends to result in growth that strengthens that section (particularly things like oaks, where the trunk is obviously thicker right below a major limb). Don’t know how true this is in cedars.
Well, couple things there. First, the average tree won’t hit its first 100 year storm when it’s 100 years old, but rather when it’s 50.
Second, unless trees stop reproducing at some age, there will be selective pressure for trees to keep surviving indefinitely long. But of course, there’s also selective pressure to invest as little as possible in strong trunks, etc, so there will be a balance between nuclear-bomb-proof and invest nothing in strength.
Maybe more important to the big coniferous trees: There is ample evidence that these trees grow best in established old stands. We’re still understanding the degree of interconnection, but a revent Nature episode on PBS showed an experiment in which a branch of a mature redwood was exposed to radioactive markers. A month later, those markers appeared at a relatively high concentration in a young tree nearby. It had to have been exchanged through the root system. I believe the same is true of other major conifers that grow in forests/stands and this is probably the reason that longevity is highly selected for in those trees.
Anyway, back to the main point: less woody plants can certainly “clench” to achieve things like sunflowers facing the sun and morning glories winding around fence wire. I don’t think a similar effect would work in a woody plant, or be of much use in resisting heavy wind.
No, that is wrong.
Back to the OP; In the short term, trees aren’t really an active participant in their fluid transfer. Evaporation creates negative pressure that is passed down cell to cell to the roots. In the long term trees can allocate resources and growth to areas that help them sustain in high winds.