Defoliating oak trees?

[Bonsai Nut]

I am thinking about defoliating an oak next year in order to develop remification and reduce leaf size. I have defoliated maples, elms, figs, and other deciduous trees before, but never oaks. Anyone with any experience here? My plan would involve letting the tree bud fully and develop mature foilage in the early Spring, and then defoliating and pruning in early Summer before the heat arrives. The oak in question is a cork oak Quercus suber.

 

[Rick Moquin]

Don't have experience with oaks perse, but leaving the terminal bud/leaf on is a preferred method on a lot of trees vice total defoliation as there still exist a communication between the roots and the leaves. Of course it goes without saying to keep the petioles in place. I wouldn't however attempt this much past the end of June in order to allow the new foliage time to lignify and strengthen before the onset of fall/winter.

 

[Bob]

Good question Bnut. I have a young Cork Oaks and I live in zone 6. In the winter they are kept in an unheated garage and do not drop leaves. They seem to hold onto their leaves for at least two seasons. Are they still considered deciduous? Will they react to defoliation in the same way as a tree that drops its leaves consistantly every autumn? More rookie questions looking for experienced answers.

 

[Tachigi]

I wouldn't however attempt this much past the end of June in order to allow the new foliage time to lignify and strengthen before the onset of fall/winter.

Rick, you gave good advise. However I believe Greg could press a little further if he chose. He doesn't sit on the door step of the Artic Tundra like yourself

 

[Tachigi]

In the winter they are kept in an unheated garage and do not drop leaves. They seem to hold onto their leaves for at least two seasons. Are they still considered deciduous?[/

Hi Bob, Oak is deciduous with out a doubt. Like beech they will hold there leaves well through most of the winter. Since you shelter your trees my belief is that the trees aren't exposed to the elements and therefore can hold on to them much longer.

I can remember growing up as a kid in Oak Park a suburb of Chicago. The enormous amounts of Oaks that stood sentry up and down the streets was beautiful and amazing. I do recall trying to negotiate with my Dad about raking the lawn in fall. I knew that just as soon as I was done we would have one of those gusty winter storms and it would knock down the reset of the Oak leaves so I could rake all over again.

So being protected would definaltly make them hold longer. Just wish I could of figured away to do that as a kid when lawn chores came around.

 

[Rick Moquin]

Rick, you gave good advise. However I believe Greg could press a little further if he chose. He doesn't sit on the door step of the Artic Tundra like yourself

Thanks Tom my bad I see it know

 

[bisjoe]

I'm not saying it's the same, but my coast live oak is evergreen, losing only a few leaves each year. I give it good winter protection, the coldest I let it get is just above freezing. I have in the past snipped off some leaves (at the stem) that have come out larger than the others. They have been replaced by smaller ones when I do it in spring/early summer before the big growth spurt when all the new growth comes in red.

 

[Bonsai Nut]

I'm not saying it's the same, but my coast live oak is evergreen

The cork oak in question is evergreen in my backyard. I will take a photo of it and post it. I am trying to figure out how to develop fine ramification on it - the growth is so aggressive and develops thick branching so quickly...

 

[Attila Soos]

I have several cork oaks myself, and I live in your zone. Never killed one in the past 10 years.

My experience is that you should only defoliate fully lignified branches. Letting them grow in the spring and defoliating the still young and soft branches, easily leads to killing the branch.

Defoliate during the active growing season, which is the warmer part of spring and the whole summer. You can also defoliate during the heat of the summer, cork oaks like hot summers.

Until you are experienced with defoliation on your tree, partial defoliation is the safest and virtually risk-free: what I mean by this, is that you defoliate half of your tree at one time, and as soon as the new growth comes out, defoliate the other half. By doing this, you lessen the shock caused by total leaflessness.

This is very important: only defoliate tree with established roots. Never defoliate an freshly re-potted or root-pruned tree.

By the way, your plan in the initial post sounds good: defoliating mature foliage in early summer. But I would still do it in two stages, about 3 weeks apart.

 

[Rick Moquin]

The cork oak in question is evergreen in my backyard. I will take a photo of it and post it. I am trying to figure out how to develop fine ramification on it - the growth is so aggressive and develops thick branching so quickly...

...you might also want to reduce the feed Greg, at least keeping the nitrogen in check. What does your feeding regimen look like?

 

[MICKJ]

Defoliating Oaks

I have several cork oaks myself, and I live in your zone. Never killed one in the past 10 years.

My experience is that you should only defoliate fully lignified branches. Letting them grow in the spring and defoliating the still young and soft branches, easily leads to killing the branch.

Defoliate during the active growing season, which is the warmer part of spring and the whole summer. You can also defoliate during the heat of the summer, cork oaks like hot summers.

Until you are experienced with defoliation on your tree, partial defoliation is the safest and virtually risk-free: what I mean by this, is that you defoliate half of your tree at one time, and as soon as the new growth comes out, defoliate the other half. By doing this, you lessen the shock caused by total leaflessness.

This is very important: only defoliate tree with established roots. Never defoliate an freshly re-potted or root-pruned tree.

By the way, your plan in the initial post sounds good: defoliating mature foliage in early summer. But I would still do it in two stages, about 3 weeks apart.

Attila, I have a number of newly repotted Subers; they were all root pruned and potted in Jan-March. The trees that had no foliage Burst Buds within a month, the ones with branches and foliage did not. They did lag and put on some Terminal Buds only. I then proceeded to defoliate and - viola! Buds all over. I trust your advise and am trying to decide if this Bud burst is seasonal timing or hormonal response. I am now questioning defoliating a larger Suber (now in April) in order to get Bud Burst as well. I will post images later.

 

[jquast]

The cork oak in question is evergreen in my backyard. I will take a photo of it and post it. I am trying to figure out how to develop fine ramification on it - the growth is so aggressive and develops thick branching so quickly...

Oak development was the topic of Midori's April meeting last night and John Thompson outlined this for us. It is a process of basically cutting and growing in sections to develop both taper (course to fine) from trunk to tip as well as ramification. This process takes several seasons depending on girth required for the branches especially if the tree has been collected and large branches reduced back tight to the trunk to make the tree more realistic in design.

I can send you his cheat sheets and my notes from the talk if you like. Just send me a PM.

jeff

 

[Bill S]

If rockm doesn't poke his head in pm him, I think he has some of these.

 

[Juniperus Californica]

Hey BNut,

I have Quercus Agrifolia that I completely defoliated during the winter and now they are completely leafed out. One tree was not doing well and was half died, so I repotted it in a "Smart Pot" and defoliated it - it's doing great now and even popping out on the dead side.

One thing, I did change the soil mix from just scoria and Acadama to Scoria, Acadama, Coco husks, Ocean Harvest (bat guano, worm castings, seaweed extract) and axiom - what a difference!

JC (Not Just California Junipers)

 

[rockm]

I have a southern live oak, not quercus suber. Suber is not reliably winter hardy in my zone.

Oaks are deciduous, BUT, many, like suber and southern (and western) "live" oaks drop their leaves in the spring at about the same time they get new ones. My live oak will also hold onto leaves for two years or more.

I have not defoliated mine, as I don't really want to experiment with my tree .

I have seen leaf pruning done on "real" decidous native white oaks here in the east. The procedure tended to force the tree to produce LARGER leaves and no real ramification.

I'd say, however, if there's a good candidate oak for leaf pruning, quercus suber would probably be it.

 

[Jason]

Just found this

Interesting discussion. So I was just doing a search on this subject and found this:




Title
Effects of artificial defoliation on the growth of Cork Oak.
Authors
Magnoler, A.; Cambini, A.
Journal
Forest Science 1970 Vol. 16 No. 3 pp. 364-6
ISSN
0015-749X
Record Number
19700602894
Abstract
Thirty trees of Quercus suber, aged 22 years, in Sardinia were studied to assess the effect on growth of artificial defoliation (simulating defoliation by Lymantria dispar and Malacosoma neustria larvae). In mid-June, 1965, 10 trees were completely defoliated, 10 were half defoliated (by removing alternate leaves) and 10 were left as controls. All defoliated trees produced a new crop of leaves within 30 to 40 days of the treatment, but total foliar dry-weight production was less than before defoliation in both 1965 and 1966. The immediate response to complete defoliation was a reduction of 63% in height growth and 45% in xylem ring width. The corresponding figures for 50% defoliation were respectively 19% and 26%. Reduction in the width of cork growth rings was 36% after complete and 20% after 50% defoliation in 1965, but in the next year the cork ring width did not differ significantly from that of controls. However, cork production depends also on the generating area, which is reduced by the reduction in xylem growth: with complete defoliation the combined loss of cork production was ca. 60% in the first and 32% in the second year after treatment; and with 50% defoliation the losses were respectively 42 and 10%.



Bnut, did you ever defoliate??

 

[Jason]

Oak development was the topic of Midori's April meeting last night and John Thompson outlined this for us. It is a process of basically cutting and growing in sections to develop both taper (course to fine) from trunk to tip as well as ramification. This process takes several seasons depending on girth required for the branches especially if the tree has been collected and large branches reduced back tight to the trunk to make the tree more realistic in design.

I can send you his cheat sheets and my notes from the talk if you like. Just send me a PM.

jeff

In case anyone else is interested in this thread I've resurrected, here's a link to some John Thompson stuff:


http://www.bssf.org/articles-and-stories/august-general-meeting-2/