Small Woodland Owners' Group

Ivy

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Re: Ivy

Postby Treeation » Wed Jan 08, 2014 9:08 pm

Thanks for that very interesting read Oldclaypaws. It certainly does have many wildlife benefits. The suggestion to remove all ivy from tree crown after severing I think this is unnecessary. The dying off ivy provides a good deadwood habitat and by not removing it you still have a great skeletal habitat for the birds, bats and bugs. IMO once severed you have already reduced the potential risk of windthrow as the ivy leaves fall off and the remaining ivy wood dries out so is relatively light.

By your comments you are clearly a believer in leaving nature to do its thing and I understand ash's is extra succeptability to ivy infestation. If you believe ivy does not affect the health of trees why do you intervene with the ivy on ash?
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Re: Ivy

Postby Stephen1 » Thu Jan 09, 2014 1:35 pm

You're quite right Paws Ivy is not a cause for concern in a woodland situation. The question of the need for Ivy management is an interesting one; 'expert' opinion on the matter divides neatly into two camps - tree surgeons and all other tree 'experts'. Obviously it's the tree surgeons who claim the need for the infestation to be dealt with and silver to cross hands.

Unfortunately I can't find the reference just now - will post it up when I come across it - in a long term study (40 years) undertaken by the, as then was, Forestry Department at Oxford University no difference was found to the growth (height, diameter, total increment, change in basal area) of oak, beech, Norway Spruce and one other species I can't remember) of Ivy infestation. Importantly it was also found that no distortion to the trunk was reported for any of these species from Ivy 'infestation'. People often see the effect of Honeysuckle rapidly causing dramatic distortion of stem growth and incorrectly assume Ivy can have a similar effect - they grow in a very different way and Ivy does not cause this problem.

The one situation where Ivy may cause issue is in open grown Ash - i.e. Ash that is unshaded on all sides - so not in healthy 'woodland ash'. As has been mentioned already on this thread even healthy Ash has a relatively open crown allowing plenty of light through it to the Ivy - typically however even in these caases most ash grows sufficiently vigorously to deal with this situation. In open grown trees, and most particularly for large standards within 'coppice with standards' woodlands in the first few years following cutting of the coppice - Ivy can cause stability issues in high winds due to the 'sail effect'.

Where Ivy binds over a narrow fork it can sometimes appear to grow into the tree - this is only the case where the fork angle is such that bark is also being 'included / occluded' into these inherently instable anyway narrow fork angles.

Interestingly Ivy seed has a very short period of viability - very little will germinate after a year. This combined with a quite high light requirement for germination means that lots of ivy within woodland is usually a sign of some past disturbance - this can be anytime upto sixty or perhaps more years ago - but ancient woodlands that are relatively unmanaged i.e. not coppiced etc. typically do not have a lot of ivy in them - and a lack of ivy is usually a good indicator of a long term lack of disturbance on Ancient Woodland Sites.

No offence intended Treeation - I don't doubt your sincerity and best intentions - but feel you're opinion undoubtedly reflects what you were taught as part of your training as a tree surgeon. Of course it's to the benefit of tree surgeons pockets that trees with ivy on them require management and in these days of litigation you're in a difficult position if asked for an opinion. I think the problem arises when people try to treat trees within woodland in the same way as open grown trees (the situation that most tree surgeons understanding of trees is based upon)- how trees grow in these two situations is very different in terms of how they lay down wood (reaction wood etc.) to increase stability, how they respond to fungi, how they respond to light etc. As I say I really mean no offence Treeation but I have to agree with Paws on this, and wouldn't want anyone here who is unfamiliar with the issue of Ivy to have any anxieties that the Ivy on their woodland trees is in any way a cause for concern or has a need for management.
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Re: Ivy

Postby Treeation » Thu Jan 09, 2014 6:36 pm

Hi, so would you honestly advice a woodland owner with a high value timber tree choked in ivy the best management would be to leave it? Or a veteran or notable tree that had high amenity value the ivy should be left?

Also, I think your comments about tree surgeons is a little unfair for a start have spent much more time doing woodland management than tree surgery!just assuming that tree surgeons are money grabbers is quite short sighted.Advising a client to sever ivy with his or her handsaw is certainly not going to line anyones pockets with gold. :D
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Re: Ivy

Postby Stephen1 » Fri Jan 10, 2014 2:02 pm

Of course you're right -it's rarely fair to generalise. As I said I don't doubt your best intentions with the advice you provide - I don't think your position on ivy management reflects poorly on you in any way - I believe it reflects poorly on the way that tree surgeons are taught/trained with respect to Ivy, and given the overwhelming empirical evidence for the lack of problems Ivy causes in a woodland context, then it is hard to come to any conclusions other than the business benefits for why tree surgeons I speak to seem always to report that they were taught Ivy should be removed.

You ask what I would advise " woodland owner with a high value timber tree choked in ivy the best management " to do. I note your use of the word "choked" ! Yes. Even for someone with potentially veneer quality stems - indeed there is some evidence that the shading of the stem the ivy provides reduces the incidence of epicormic growth on the stem which would reduce its value. The only impact of the ivy is to add to the cost of harvesting and preparation before transporting. That is a decision for the woodland owner to balance his position on the conservation to maximum profit scale. But the timber itself won't be affected.

You also ask "Or a veteran or notable tree that had high amenity value the ivy should be left?" Remember I'm talking about trees within woodland - not in gardens or open grown parkland trees. If the immediate environment around such a tree has been changed i.e. other trees surrounding that tree have been felled, then depending on the condition/size/extent of the ivy, I would note the increased risk of damage in winter storms that the ivy would lead to (increased sail/surface area to catch the wind) and discuss with the owner the potential pros/cons to enable him/her to make an educated decision based on their motivations for ownership. This might be ivy removal/reduction, or depending on the species, age, condition and growth form of the tree it could be as drastic as a crown reduction or even re-pollarding. But overwhelmingly, in an undisturbed woodland context, my advice would be Do nothing or very little!

I don't assume tree surgeons are money grabbers - I assume they are in a hard dangerous line of work and in a difficult position when asked for advice. If a client asks a tree surgeon about the stability of a tree and the tree surgeon gives the opinion nothing needs doing, but then it comes down in a storm the TS loses twice - he didn't get the pennies for the job and his reputation suffers by word of mouth - if he sucks through his teeth and dismantles the tree he wins he gets paid and there's no tree left to fall over. So don't get me wrong I don't doubt how hard a position tree surgeons are in - but I think/ feel (i.e. don't know for a fact) that the training they receive errs on the side of intervention. When this is transferred to a woodland context this often translates into massive over-intervention. I'm talking about my experience of tree surgeons in general here and am making no suggestions about how you personally operate within woods.

However in trying to recreate old growth features in younger woodland tree surgeons skills can be very valuable - see; http://www.naturalforestpractice.com/ho ... rgeon.html

I add that my position is in general one of advocacy for the development of "Old Growth" conditions in certain woods - obviously not every ancient woodand site is suitable (or even historically/culturally appropriate)- and in the medium term this approach leads to a drop in biodiversity - but with long term benefits. I point this out because clearly my position is not the one currently in vogue of getting plenty of light down to the forest floor throughout a woodland. It's not that I see myself as biased, but that I'm an advocate for a position less commonly held in the U.K. and feel it's probably appropriate that I make that clear!
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Re: Ivy

Postby Brown » Sun Aug 03, 2014 8:52 pm

It's down to opinion. If you leave the ivy alone, you're managing the woodland, if you kill it or control it you're doing the same. It's all very good for the fc man to say leave it on, but for some woodland to exist, they need to be commercially viable and ivy isn't necessarily desirable in these cases. In my experience ivy will smothers and strangle young and old trees alike. The extra weight will also bring down trees, especially in winter storms. Perhaps the answer, is some sort of control without getting too fastidious about it. After all, we're all into woodland management and not simply letting our woods go to their own devices.
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Re: Ivy

Postby Brown » Sun Aug 03, 2014 9:32 pm

In my experience ivy doesn't discriminate between old and young trees and is rarely good for the health of a tree. It adds considerable weight and will bring trees down, particularly in winter storms. No doubt ivy is a vital part of woodland ecosystems. However, most of us are into woodland management and that may involve some sort of control to maintain the health of a woods main assert.......trees.
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Re: Ivy

Postby oldclaypaws » Sun Aug 03, 2014 10:08 pm

If you leave the ivy alone, you're managing the woodland


No, your just choosing not to interfere so much and trust the natural balance. The ecology of the wood such as bats, birds and insects will be richer by leaving beneficial plants alone. There is more to a wood than just trees. While wood is a useful product I enjoy harvesting, I get more pleasure from the studying the plants, animals, fungi and insects. You're missing out if you are unaware of these extra dimensions to a woodland.

for some woodland to exist, they need to be commercially viable


I think you'll find many woods and forests exist happily without being commercially managed, or making a minimal return. The Amazon did quite nicely without man, the problem arose when people did try to commercially over exploit it. 'Value' is subjective; a rare plant has no intrinsic commercial value, but its ecological and botanical value can be immense.

In my experience ivy will smothers and strangle young and old trees alike


All my healthy trees, whether saplings or 400 years old, have little or no Ivy. Doesn't seem to fit your theory.

The extra weight will also bring down trees, especially in winter storms


Only if the tree is ailing anyway. Healthy trees (except Ash) will have little Ivy on them, good structural integrity, and don't tend to come down in storms so much as rotting veterans.

Perhaps the answer, is some sort of control without getting too fastidious about it


Or taking a more relaxed ecologically sound approach

After all, we're all into woodland management and not simply letting our woods go to their own devices


Letting a wood 'go its own way', such as natural regeneration or minimal intervention is a respected philosophy which has many advocates, especially among those naturalists or wildlife enthusiasts who are knowledgeable about the delicate balance and complexites of woodland habitat, rather than just seeing it as a commercial crop of trees. Many species thrive in 'neglected' woods. Those of us who view a wood as I do as primarily as an ecosystem are inclined to act sensitively, reduce our impact as far as possible, and greatly enjoy observing nature and its cycles rather than interfering with or fighting against it all the time.

When you have an Ancient wood as I do, with trees eight times as old as myself, a wood is a wonderful and delicate long established system that needs to be observed, respected and learnt from, not imposed on or dramatically altered or forced.

A wood doesn't 'have to be' actively managed, to choose to do less isn't necessarily neglect, its an alternative thoughtful approach that has merit. Consultants and naturalists who've visited my little wood have described it as perhaps the most beautiful they've ever seen, it seems more than coincidental that its also had no significant felling or proactive management for 130 years, less can be more. :geek:
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Re: Ivy

Postby Treeation » Sun Aug 17, 2014 12:57 pm

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Last edited by Treeation on Sun Aug 17, 2014 1:35 pm, edited 1 time in total.
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Re: Ivy

Postby Treeation » Sun Aug 17, 2014 1:31 pm

response to oldsclaypaws.......

I fully respect and honor your passion in respecting nature’s way in trying to preserve a natural balance within woodland ecosystems. I think you solely are judging your own woodland management experience as an overall model to manage all woodlands which I'm afraid does not work! Its one thing to privately own a small woodland which you can enjoy as a hobby and manage accordingly. No doubt funding the minimal management activity from your won pocket or by EWGS funding and processing a little firewood here and there, clearing up a few windblowns etc etc. This is great and I'm sure your woodland is as beautiful as you say it is and is very lucky to have such caring guardian.

You talk about the intervention of the amazon as an example of how forest would be better without mans intervention. This is possibly is the most extreme end of the spectrum of deforestation which the planet is facing and I have to be honest is a pretty weak argument in context to the way we (the British) manage our woodlands. The loss of amazon forest is 100% for mans commercial gain (true) with ecological impacts that are horrendous BUT this isn’t a type of forest management. This is just man removing all forest without any attempts to sustain and replace the loss all without any respect for ecological loss. In Britain we have a very high level of sustainable woodland management knowledge, literature and clearly can be seen in visiting managed woodlands and reading from our leaders Ben Law- Oliver Rackham etc etc

Now, what seems to get your goat up (and I have debated this with other ecologists) is when the word "commercial" is mentioned. Commercial does not mean deforestation!!!it doesn’t have to be perceived with negativity! It DOES NOT MEAN THAT A WOODLAND CANNOT BE MANAGED WITH STRONG ECOLOGICAL OBJECTIVES TOO!! I am a professional woodland manager who has a massive love and respect for nature and ecology (as every woodlands manager i know does) BUT also I am in the real world and realise that we have to manage woodlands as a local resource with a strong conservation vision as well. There are many woodland management models that tick both commercial and conservation objectives out there that just illustrates our evolution in having a more dynamic approach to woodland management and just for the record I always have atleast 10% of any woodland I manange as non-intervention.

What about using woodlands as a local resource? A place which can provide local timber for our houses, local fuel to keep us a warm?? A local place for a couple of guys to get a fantastic job opportunity??A place to provide wild and organic foods?? A local place to make charcoal?? To run woodland courses for education? ?A place to camp?? A place where horse loggers can get work?? Well all these things are "COMMERCIAL" and the true potential of woodlands is massive and its also true that there’s thousands of under managed woodlands which have not reached their ecological optimum which don't have kind caring guardians like yourself or landowners to inject money into them. Its our job to get these woodlands up an running, to remove invasive species, to remove over dominant nurse crops, to recoppice overstood coppice, to build new tracks, to make sure the ecological potential is met, to create job opportunities, to monitor and survey wildlife AND if we can make woodlands pay for themselves in the process then we have really ticked all the boxes.

What’s the alternative?... minimum intervention as a positive management model???.... Well lets keep on importing wood from Scandinavia, rely on overpriced oil and gas to heat our houses, keep on importing crap lump wood charcoal from the deforestation of mangrove swamps, lets let deer and squirrels eat the next generation of our woodland.........I think not!! Man lives on this planet as well as trees and we can coexist in a symbiotic relationship.
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Re: Ivy

Postby oldclaypaws » Sun Aug 17, 2014 1:46 pm

I agree with much of that, but the discussion was about Ivy. I do take a degree of commercial approach to my own wood, as well as an ecological one, its a balance. What I won't do is clear fell or send in logging crews to devastate the understorey, I'm going out of my way to fell or harvest gradually and sustainably with minimum impact. I intend to harvest some of my crowded oaks and either sell the timber or make products from it. On the older oaks that I leave though, I shan't be taking off the Ivy, and deadwood heaps will be built for the bugs and small mammals. That was the advice of all the consultants and experts who've seen the wood, including the FC.

I maintain that Ivy does not damage or choke healthy trees, with the exception of Ash, and should be left on as a beneficial part of the total ecosystem. You can have a commercial wood, but still manage parts sympathetically for wildlife, that includes measures such as leaving Ivy and some brambles, both are good habitat and food.

I have no problem with an element of commercialism in Forestry, provided due thought is given to wildlife and its done sustainably. I'm not a fan of monoculture and clear felling vast swathes at once, treating the countryside like an industrialised tree factory. My own approach would be best described as gradually thinning a PAWS wood dominated by crowded 19th Century Oak towards a more diverse wood with a greater diversity of tree ages and species, harvesting valuable timber gradually where appropriate and actively coppicing, with an appreciation of wildlife and flora.

The fact I understand and respect the approach of more natural purists who do not fell and have a none-interventionalist approach doesn't mean this is my own model or appropriate for my wood. Indeed I recently put the case to two naturalist friends that instead of running their large wood almost entirely as a zero-felling nature reserve, it would do no harm to harvest some of their very many oaks, get in some light, and vary the habitat. They won't as they are too busy recording butterflies.
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