Getting rid of ivy!!

[CambridgeJC]

2 hours ago, agg221 said:

Two oak trees, approximately 15 miles apart. Both growing on field boundaries, both mature and retrenching.

 

I have driven past the first tree pretty much every day for the past 20yrs on the way to work. 20yrs ago the ivy was halfway up. Compare:

 

https://www.google.com/maps/@52.1139856,0.2215654,3a,75y,310.13h,94.01t/data=!3m6!1e1!3m4!1s01WKkDfSwnmfb5MXstbNwA!2e0!7i13312!8i6656

 

with:

 

https://www.google.com/maps/@52.1139713,0.2214872,3a,75y,309.72h,96.41t/data=!3m6!1e1!3m4!1sK9yHR8YmAaxB2ALHdqa8Hg!2e0!7i16384!8i8192

 

(you have to look carefully but note that in the first image the tree is in leaf which covers most of the crown, whereas in the second it is in winter so the leaves are all ivy (much darker green)).

 

The two branches sticking out to the right are alive but pretty much all the epicormic growth which was developing as a retrenchment crown has been swamped. It has certainly progressed to the top of the crown and swamped it, before the tree was dead. There are several oaks in a wood about 300yds from that spot which are similarly covered all the way to the top. They are not all dead (I keep an eye on them as I have an arrangement to fell and mill any trees which die) but all those which have been covered in ivy have died while adjacent trees (sometimes less than 6' apart) without ivy have not. The wood is overcrowded and should have been thinned so the trees are all stressed.

 

The second tree is on the corner of our field, which we bought 9yrs ago. The ivy was similarly halfway up the crown. I cut back all ivy from the ground up as far as I could reach standing on the ground except the major stem and everything down to the crown break in about 2015. In doing so, I found that all the epicormic growth under the ivy was dead, notably around the major wound on the trunk (caused by a lorry misjudging the turn some years before). In the subsequent 7yrs, epicormic growth has returned to those areas I cleared off. I have kept the low area clear but left the upper part. The ivy has now grown out from the crown break most of the way up the major limbs. I will be cutting it back again shortly.

 

https://www.google.com/maps/@52.0617419,0.4871101,3a,75y,0.59h,109.05t/data=!3m7!1e1!3m5!1ssO1xab7dSnESqQzOtMkXDA!2e0!5s20210401T000000!7i16384!8i8192

 

My observation is that ivy can overwhelm the crown of a retrenching oak, whereas if not present the epicormic growth can enable retrenchment, the ivy therefore being a causal factor in the death of the tree.

 

Alec

 

Here are the two images taken from your links. Please describe them with the time difference. Thanks 

[agg221]

If you click on the link and look in the top left hand corner you will find they are all date stamped.

Alec

[CambridgeJC]

45 minutes ago, agg221 said:

If you click on the link and look in the top left hand corner you will find they are all date stamped.

Alec

I tried but don’t see date stamps. I do see that these two are compiled image sequences which utilise different age images. I can see two images of the sane tree at top of the same road as attached here. And the new Croudace development in Linton is shown at the same time as my long gone car from about 2005 so around 17 years ago!! See the same tree with and without ivy!

Your links are really informative!

[CambridgeJC]

https://www.thefreelibrary.com/Heteroblasty--a+review.-a0259155098
 

Hedera helix changes from Juvenile leaf/shoots which spread and explore the ground and plant growth looking for suitable bushes and trees on which to climb. When found the ivy is signalled to climb and changed to the mature reproductive form with the bushy ivy that is seen in the canopy. This ability to mature and change is called heteroblasty. 
This link takes you to a very comprehensive review of this which is highly relevant to ivy. Worth a read when you have time. 

[Stere]

My personal opinions/local observations  (non scientific):

 

Ivy has increased abit overall.

 

I think a mild winters have favoured ivy and also proabaly are less people removing it from trees. Also think some host ivy colonized trees might be weakened  due to combination erratic climate, summer droughts etc and new tree diseases.

 

 

You see  ivy higher up on crown/trunk unions on, healthy ash, larch  birch,  any tree sp the cast less dense shade than say others like sycamore beech etc, theese don't favour ivy as much. Taken to the extreme, rarely seen it flowering in a holly or yew crown. Also more ivy on  on single isolated trees, or trees with narrower crowns that cover less area. So its all due to light lvls...

 

 

 

Ivy can  cover the crowns of any tree if they are in poor health/decline...(as the light lvls increase due to a thinning crown)

 

An increase of the amount of ivy  in the unmanaged  hedgerow tree crowns(more light than in woodlands), esp on ash (adb) &  hawthorn/blackthorn trees. . Alot of hawthorn tree crowns, do seem to get covered with ivy then the trees fall/blow over. Some trees are still alive and some are dead when they blow/fall over...

 

Unsure if death of theese hawthorn is due to the ivy or other reasons as if trees were 100% healthy doubt would ivy manage to cover and shade out the crowns?

 

Also has noticed an increase of ivy in flailed hedges.  Flailing annually to the same "knuckle" seems to weakens the hedges vigour and thus favours ivy.

 

Cutting on say a 3 yr cycle instead  would allow the hedge to shade out the ivy more imo.

 

Ivy doesn't  as often claimed doesn't  throttle/girdle a tree like honeysuckle can, or tree guards left on do, though maybe  in rare circumstances this could happen?

 

 

Negative impacts on the "host" tree are only due to either:

 

Competition for light.

The increased wind sail effect.

 

 

Edited February 12, 2022 by Stere

[john87]

13 hours ago, Sutton said:

Start a new thread with pics about your trees and your plans. People may give you some useful advice.

Yes i will!! That is a really good idea!!

 

john..

[agg221]

11 hours ago, CambridgeJC said:

I tried but don’t see date stamps. I do see that these two are compiled image sequences which utilise different age images. I can see two images of the sane tree at top of the same road as attached here. And the new Croudace development in Linton is shown at the same time as my long gone car from about 2005 so around 17 years ago!! See the same tree with and without ivy!

Your links are really informative!

From your screenshots, it looks as though you are accessing Google maps through a smart phone or tablet. If you access it through Chrome on a standard computer then the images are all date stamped in the top left-hand corner. If you click in that box, it also shows you which other images are available from the same location. This can be very helpful in trying to obtain referenced data over an extended time period.

 

As an aside, in your two images it looks like in the earlier image the tree has recently been reduced and had the crown thinned. It may also have been lifted. All of these will increase the amount of light passing through/around the tree, potentially being the enabling factor for the subsequent establishment of the ivy.

 

Alec

[john87]

48 minutes ago, agg221 said:

From your screenshots, it looks as though you are accessing Google maps through a smart phone or tablet. If you access it through Chrome on a standard computer then the images are all date stamped in the top left-hand corner. If you click in that box, it also shows you which other images are available from the same location. This can be very helpful in trying to obtain referenced data over an extended time period.

 

As an aside, in your two images it looks like in the earlier image the tree has recently been reduced and had the crown thinned. It may also have been lifted. All of these will increase the amount of light passing through/around the tree, potentially being the enabling factor for the subsequent establishment of the ivy.

 

Alec

What does lifting the crown mean??

john..

[sime42]

What does lifting the crown mean??
john..

It means cutting off the lowest branches all around the tree so as to visually "lift" the crown. (Increase the height of bare trunk before the crown starts).

[CambridgeJC]

1 hour ago, agg221 said:

From your screenshots, it looks as though you are accessing Google maps through a smart phone or tablet. If you access it through Chrome on a standard computer then the images are all date stamped in the top left-hand corner. If you click in that box, it also shows you which other images are available from the same location. This can be very helpful in trying to obtain referenced data over an extended time period.

 

As an aside, in your two images it looks like in the earlier image the tree has recently been reduced and had the crown thinned. It may also have been lifted. All of these will increase the amount of light passing through/around the tree, potentially being the enabling factor for the subsequent establishment of the ivy.

 

Alec

Ok. Great thanks. I was using iPhone. Attached same tree today…