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Fri, Jan 27, 12 at 17:50
| Looking out of my window today I realized that two of my neighbor's trees, namely a pin oak and Shumard oak, were almost bare. Being typically upwind in the spring from them I've added large amounts of leaves from these trees to my compost pile at that time of year. After experiencing this for many years it seems unusual that they are bare now. Looking at my own shingle oak from a large window in the living room I also now see through to my neighbor's house via a half-foliaged tree, one that usually adds a bunch to my compost pile in the spring. I deliberately planted that tree as a "winterscreen."
We have been in a pretty serious winter drought here, actually a continuation of a fairly dry fall. My thought is, does drought somehow cause marcescent trees to defoliate sooner and does it affect the timing of abscission? Anyone else notice this in their area? hortster |
Follow-Up Postings:
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- Posted by wisconsitom 4/5 WI (My Page) on Fri, Jan 27, 12 at 17:53
| First I'll have to look up 'marcescent' lol, but what has been learned is that for trees which normally lose all their leaves in fall, drought can interfere with this process. But I'm thinking you already know that, and that you are asking something else! +oM |
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| hortser, I don't specifically know the answer to you question, but I would say that's as good a hypothesis as any. IIRC during severe drought trees can and will partly close the vascular system and form a partial accession layer to the leaf in an effort to conserve water, and in preparation to abort the leaves if it becomes necessary. Assuming that is correct, then when fall roles around more of the vascular system is closed, more vascular closing, and more accession layer in prep for winter. Assuming this is correct, then move leaves completely detaching would seem like a likely outcome. Again, assuming there are no flaws in my reasoning. Arktrees |
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| arktrees, your explanation absolutely makes sense to me. I am looking for a realistic answer, one of those technical horticultural additions of knowledge to what we do. Two or three layers of cells shut down causing abcission. My wonder is that if drought causes weakness or extra layers or "whatever" during drought, do leaves fall sooner? If anyone has another hypothesis I would love to hear it! It struck me today as a likely possibility...I am always willing to learn. Horticulture never provides absolute solutions but maybe those that have deeper knowledge might have a theory...at this point yours works for me. hortster |
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| Abscission - GAHHHH, I had a mental block earlier today and could not remember how to spell it correctly. LOL. Been too long since I had Botany and Plant Path. Like I said I don't KNOW that is why, but it's what came to mind. Sorry your still in the clutch of drought. Ours ended about the end of October when the wetlands finally filled, and stayed filled. But I look at the drought maps every week, and I know that the drought is uncomfortably close. It begins about 100 miles to the west. So how have your trees held up? And the trees in your area? Between this years heat, drought, record cold, record flooding, and the worst ice storm on record, we are experiencing a forest succession event locally as the mature trees are taking a beating that is catching up to them and blowing holes in the canopy for the climax shade tolerant species to fill. Arktrees |
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| There are several trees that defoliate in response to drought in an effort to save the tree. Bald Cypress and Cottonwood come readily to mind. Noticed that a large percentage of Cedar Elm trees leaves turned color in late September instead of November and dropped leaves early also. There's probably more species that do similar things but I haven't paid attention. |
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| I'll add betula nigra to scotjute's list as the ground is covered with leaves under my tree during a dry August. Marshall |
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