Oak Trees- why won't the leaves fall?



Oak Trees- why won't the leaves fall?

Fri Nov 03, 2006 9:54 pm

Just a question. I have a yard full of oak trees. This time of year I dread. I am constantly picking up leaves. The strange thing is... I have one oak, out of atleast twenty, that won't drop it's leaves until spring. Therefore, in the spring, I am picking up leaves again. Is there a reason why this is happening? Too much fertilizer on the lawn around it?
Just stubborn? Any suggestions or comments would be appreciated.
Thanks!!
P.S-- All of the oaks are the same kind.
joolybean28
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Sat Nov 04, 2006 2:15 am

Hi Jooleybean,

You don't say what type of oak, but pin oak is famous for doing that. Many of the pyramidal shaped oaks also retain their leaves until spring, especially the younger ones.
http://www.dnr.state.oh.us/forestry/trees/oak_pin.htm

Newt
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Re: Oak Trees- why won't the leaves fall?

Sun Dec 03, 2006 9:21 pm

I have a live oak in my front yard that does the same thing. The other oaks in my yard lose their leaves, but the live oak stays green all year, dropping old leaves in the spring. You might take a small limb to your local nursery to see if they can identify it for you. :)




joolybean28 wrote:Just a question. I have a yard full of oak trees. This time of year I dread. I am constantly picking up leaves. The strange thing is... I have one oak, out of atleast twenty, that won't drop it's leaves until spring. Therefore, in the spring, I am picking up leaves again. Is there a reason why this is happening? Too much fertilizer on the lawn around it?
Just stubborn? Any suggestions or comments would be appreciated.
Thanks!!
P.S-- All of the oaks are the same kind.
soshablue
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Sun Dec 03, 2006 10:33 pm

Leaves fall off of trees due to low temperatures. The low temperature stimulates the productions of plant horemones (I think it is giberrellins but, I may be mistaken as I'm thinking that giberellins are root horemones.) that cause the excission of leaf connections.

Anyway, the short of the long is that if you have had a mild fall and winter, the leaves will not fall. Temperatures need to be consistantly cool for the leaves to fall.
opabinia51
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Mon Dec 04, 2006 5:22 am

Soshablue, live oaks are evergreens and retain their leaves all winter. They shed their old leaves in the spring and grow new ones.

Jooleybean never responded, but there are sites where one can look at the different types of leaves and acorns for id as well. I didn't post them since there was never an answer.

Newt
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Mon Dec 04, 2006 6:53 am

Interesting Newt, Oaks are evergreens in your neck of the woods? They are definately not evergreens here but, have retained their leaves for much longer this year.

Goes to show that climate has a lot to do with the physiology of a plant.
opabinia51
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Mon Dec 04, 2006 3:07 pm

Live oaks aren't evergreen here in zone 7. Actually, I've not seen one in zone 7 as it's a bit too far north for them. I have seen them with their leaves on in February in New Orleans (zone 9 I think). I'm referring to Southern live oak - Quercus virginiana. There are several species of evergreen oaks. Take a look at this short bit of info.
http://en.wikipedia.org/wiki/Live_oak

Newt
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Mon Dec 04, 2006 10:56 pm

Even more intersting, I live in zone 7a with 7 and 7b strewn around the area and Quercus gariana is quite prevalent around here.

Actually, before the last ice age the entire Island was covered with Garry Oak and now only some residual pockets remain.
opabinia51
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Sun Jan 07, 2007 3:41 am

Interesting that this topic is here. I was looking for exactly this information. We have numerous trees here, columnar that hold their leaves all winter, dropping them only on the late winter, early spring regardless of the temps. I'm thinking of getting them to use as a screen in my yard. We have a hot tub that we would like to shield from neighbours on one side. Summer is easy, winter not so much.

Anyway I've seen the leaves on these trees and they sure look like oaks. I've been trying to identify the cultivar to determine the soil, light needs, and how the root systems grow.

I've come up with an english oak of some sort, but am still looking. If any of you come up with it could you post here??

thanks..
opp2
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Sun Jan 07, 2007 7:22 pm

Newt wrote:Live oaks aren't evergreen here in zone 7. Actually, I've not seen one in zone 7 as it's a bit too far north for them. I have seen them with their leaves on in February in New Orleans (zone 9 I think). I'm referring to Southern live oak - Quercus virginiana. There are several species of evergreen oaks. Take a look at this short bit of info.
http://en.wikipedia.org/wiki/Live_oak

Newt


In Central and North Florida, oak trees do not drop their leaves until February, and then by the end of March they have new leaves already. The ones I am thinking of were live oak and water oaks.
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Grey
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Sun Jan 07, 2007 9:37 pm

Actually, I found a couple of web sites with some info and it appears the Quercus robur 'Fastigiata' else known as the columnar English Oak doesn't drop it's leaves until spring when the new buds form. It's growth is being encouraged throughout southern ontario (z4-5). The leaves are not evergreen however, they turn copper brown in the fall and hang on until spring. Very nice when you see them actually. I am seriously thinking of getting a couple now. I'll have to see if I have to replace any of the junipers I got as replacements last fall...

http://www.ces.ncsu.edu/depts/hort/cons ... giata.html
http://www.coopext.colostate.edu/4DMG/T ... lumnar.htm
http://pas.byu.edu/tree_tour/columnar.htm
opp2
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Oak Trees- why won't the leaves fall?

Sat Dec 06, 2008 6:21 pm

Hey, just heard the answer to your question this am on a local L&G Show, so I can't take credit for the 'knowledge'... however, here 'tis!

Marcescence is the retention of dead plant organs that normally are shed. It is most obvious in deciduous trees that retain leaves through the winter. Several trees normally have marcescent leaves such as oak (Quercus), beech (Fagus) and hornbeam (Carpinus). Marcescent leaves of pin oak (Quercus palustris) complete development of their abscission layer in the spring. The base of the petiole remains alive over the winter. Many other trees may have marcescent leaves in seasons where an early freeze kills the leaves before the abscission layer develops or completes development. Diseases or pests can also kill leaves before they can develop an abscission layer.

The term "marcescent" is also used in mycology to describe a mushroom which (unlike most species, described as "putrescent") can dry out, but later revive and continue to disperse spores.[1] Genus Marasmius is well-known for this feature, which was considered taxonomically important by Elias Magnus Fries in his 1838 classification of the fungi.[2]


[edit] Benefits
In plants, marcescence is considered a juvenile characteristic because it is more common on younger trees and on the lower, more juvenile, parts of older trees. One possible advantage of marcescent leaves is that may deter feeding of large herbivores, such as deer and moose, which normally eat the twigs and their nutritious buds. Dead, dry leaves make the twigs less nutritious and less palatable.

Marcescent leaves may protect some species from water stress or temperatures stress. For example, in tropical alpine environments a wide variety of plants in different plant families and different parts of the world have evolved a growth form known as the caulescent rosette, characterized by evergreen rosettes growing above marcescent leaves. Examples of plants for which the marcescent leaves have been confirmed to improve survival, help water balance, or protect the plant from cold injury are Espeletia schultzii and Espeletia timotensis, both from the Andes.[3][4]
GeorgiaBoy
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Wed Dec 10, 2008 12:27 am

One reason I don't like Pin Oak is that they don't drop leaves in autumn.

I like Live Oak. We had those during our short 8 month experiment living in Georgia.

Up here in Oregon, I was noticing how 1/2 our purple beech leaves were still clinging on this week. Seems that's not the norm. But we just planted them last summer.
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mdvaden
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Sat Dec 20, 2008 6:01 am

Shumard oak (quercus shumardii) is a deciduous oak that retains its leaves until spring. Though they stay on the tree, after the first frost they will turn brown and die similar to a Beech tree.
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bewildered_nmsu
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Wed Feb 03, 2010 6:43 pm

I saw this site while researching the leaf drop patterns of deciduous trees, an interesting subject. I have a very plausible reason why oaks and beeches retain their leaves, one I have never read anywhere. They retain the leaves to keep them from burying their nuts. Actually, they very rarely retain any leaves above the twenty or so foot level. So there is a pattern where the taller trees have leaves on the bottom, and are bare on top. The shortest oaks and beeches retain all of their leaves. At higher levels the wind is able to blow the leaves far enough away so they won’t cover the nuts.

Throughout evolution it was easier for squirrels and other nut spreading animals to find nuts that were not covered. Both oaks and beeches have a fairly hard wood compared to say apple. The oaks are the hardest because their leaf shape retains more ice and snow. The beeches’ pointy downward facing leaves shed ice and snow better than the oaks so they do not need to have as hard a wood. It’s still pretty hard, but not as hard as the oaks.

Fruit bearing trees shed their leaves and have a softer wood. During the winter there are plenty of acorns still under the oak trees, but any fruit is long gone or at least spoiled so there is no advantage to fruit trees retaining leaves. Trees like maple that spread their seeds through the air also drop their leaves and have a soft wood.

I live in Massachusetts and I have not seen any black walnuts or horse chestnuts in over 20 years. I did find one short statement on the web that mentioned autumn leaf retention for black walnut, but could not find any such pertinent info on horse chestnuts. I do wonder though if they have a similar leaf retention pattern as the oaks and the beeches.

Another evolutionary observation worth sharing is that weeping willow has a very soft fragile wood. To compensate for this weakness it has very small leaves that swing rather freely on ropelike stems. If it had rigidly fixed broad leaves its branches would surely break.

One evolutionary observation in trees that I have puzzled over is why do pine trees drop the pine cones on the lower branches in the fall, yet retain the ones on the upper branches until spring?
RagweedFarmer
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