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SOIL POISONING by BEECH TREES
Hi!
Is there a Forester or Tree Person out there who has expert knowledge of this subject? I have been told that the leaves from a Beech tree will poison the ground beneath so that no other species of plant will grow. Is there scientific proof of this? Another source suggests that this is a fallacy and that the situation is caused by the heavy leaf litter which piles up, being slow to decompose, and allowing no new growth to get through. Having just moved into a suburban garden with several massive Fagus Sylvatica I desperately need to know. |
SOIL POISONING by BEECH TREES
In article , Dave Roberts writes: | | Is there a Forester or Tree Person out there who has expert knowledge | of this subject? I have been told that the leaves from a Beech tree | will poison the ground beneath so that no other species of plant will | grow. Is there scientific proof of this? Don't be so gullible! Not merely is it complete twaddle, that is trivially checked by observation. | Another source suggests that this is a fallacy and that the situation | is caused by the heavy leaf litter which piles up, being slow to | decompose, and allowing no new growth to get through. Even that is wrong. Beech leaves are not slow to decompose. | Having just moved into a suburban garden with several massive Fagus | Sylvatica I desperately need to know. The lack of growth underneath is caused by the lack of light and water in the summer, as with most other trees. Most of the winter-growing, deep woodland plants (bluebells and many others) will grow though. No plant that needs to grow in summer will. Regards, Nick Maclaren. |
SOIL POISONING by BEECH TREES
Dave Roberts writes
Hi! Is there a Forester or Tree Person out there who has expert knowledge of this subject? I have been told that the leaves from a Beech tree will poison the ground beneath so that no other species of plant will grow. Is there scientific proof of this? Another source suggests that this is a fallacy and that the situation is caused by the heavy leaf litter which piles up, being slow to decompose, and allowing no new growth to get through. Having just moved into a suburban garden with several massive Fagus Sylvatica I desperately need to know. With any large tree, the uptake of water by the tree and the shade effect is enough to prevent growth underneath without recourse to poison theories. Bluebells will grow in beech woodland. Either they are taking advantage of higher water levels in spring coupled with more light because the trees are not in leaf, or they have the ability to breakdown the poison produced by the leaves. I'm not aware of any warnings to omit beech leaves from leaf mould, which would be necessary if they were poisonous. I have recently been told the same 'poisoning the ground' theory about horse chestnuts. -- Kay |
SOIL POISONING by BEECH TREES
In article , Malcolm writes: | | I've not heard of beech leaves poisoning the ground. They do indeed | build up a heavy leaf litter, which as it decomposes makes a fine source | of mulch for the borders. More important, or so I have always | understood, is that the canopy of a beech tree is much denser than most | other species and so, in a beech wood, insufficient light reaches the | ground beneath to encourage much plant growth. This should be less of a | problem with well spaced trees. I don't think that it is because it is denser, as such, as it is lighter than oak, elm etc. - beech leaves are very translucent. But beeches tend to form a solid canopy, whereas oaks, elms, etc. tend to lose whole branches and have gaps. When a beech tree starts dropping branches, it is not long before it dies completely - they have very little resistance to fungal decay, once it starts - VERY unlike oaks. I agree with you about your remark about freestanding beeches - there are LOTS in the south, and most have even grass growing well fairly close to the trunk (thinly, true). Regards, Nick Maclaren. |
SOIL POISONING by BEECH TREES
In article , K writes: | | I have recently been told the same 'poisoning the ground' theory about | horse chestnuts. Which brings to mind the good ol' Yankee expression "horse puckey". It is true to some extent for conifer and yew needles, and to a very limited extent for some deciduous trees (e.g. SOME walnuts), but it is a suburban myth to believe that it is a widespread phenomenon or stops ALL plants from growing. Some plants will grow even under conifers, though not in a conifer plantation. Regards, Nick Maclaren. |
SOIL POISONING by BEECH TREES
On Fri, 5 May 2006 23:22:34 +0000
Dave Roberts wrote: Hi! Is there a Forester or Tree Person out there who has expert knowledge of this subject? I have been told that the leaves from a Beech tree will poison the ground beneath so that no other species of plant will grow. Is there scientific proof of this? Dave, You're concerned about the allelopathy of the species Fagus. I don't think you need worry. Here's a paper from U of Georgia in the US that discusses the relative allelopathies of different trees. You'll note Fagus is in the "slight effect" section. http://www.urbanforestrysouth.org/Re...load/file_name If for some reason this doesn't work for you google "fagus allelopathy." The most notorious species in this respect is Juglans nigra. I have heard that a mature specimen can effect other plants as far as 60 feet away. For most of us, the only issue is that Juglans regia is sometimes grafted on nigra, which could be a problem in the garden environment. HTH -E -- Emery Davis You can reply to ecom by removing the well known companies |
SOIL POISONING by BEECH TREES
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I've a huge copper beech that dominates my garden. Every 2 years, I have 25% of the canopy removed to allow light into the garden. Below the tree I have planted a suite of beds with cottage garden plants and others that attract wildlife. Plenty of compost goes into the beds in the autumn and lots of water in the growing season. The beds look wonderful and there's certainly no adverse effects from the beech tree.
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SOIL POISONING by BEECH TREES
In article , Janet Baraclough writes: | | That wasn't my experience with R. ponticum, where many plants were put | in immediately it was removed, without replacing the soil, and thrived. | Mainly camellias, other rhododendrons (azaleas) and magnolias. | | I mentioned natural regeneration by seed, which rp chemically inhibits. | see P 5 of http://www.cebc.bham.ac.uk/Documents/CEBC%20SR6.pdf Well, it doesn't say that. I makes a reference to Cross, but does not describe details. That implies that, like Juglans niger, it is root exudation that is the cause. I may look at the reference if I get time, but my point is that a lot of these effects are seriously exaggerated and often apply only under some conditions. For example, despite frequent claims, J. niger (the classic plant that does this) does NOT have a sterile zone under its canopy in the UK - look at examples and see! The reference you gave does strongly imply that the main cause of the sterile zone is the physical blocking of light and rain, to which I can definitely add the physical prevention of the germination of small seeds. My guess is that is why many woodland trees go in for very large seeds (oak, camellia, hazel etc.) Regards, Nick Maclaren. |
SOIL POISONING by BEECH TREES
"Nick Maclaren" wrote in message ... I have Web access, but had to retype :-( Here is the relevant source in Cross, which shows how these urban myths develop by the simplification and extrapolation of ambiguous scientific results. Doekson (1964) found that ground up leaves of rhododendrons caused a reduction in the number of earthworms (Lumbricus rubellus Hoffmeister) in peaty soil. The substance responsible was soluble in acetone, but not in ethanol, ether or benzene. He also observed a reduction in the numbers of L. rubellus and Allolobophora callignosa Savigny in the soil in which rhododendrons were planted, even without the addition of ground-up leaves. However, Lumbricus rubellus is common in the Rhododendron humus in the Killarney woods. Although the soils at sites 18-10 would have been greatly influenced by Rhododendron, being almost pure stands, there is no obvious difference with other soils. It is, however, probable that in common with other ericaceous species, Rhododendron has a deleterious effect on the soil, mobilising cations, directly or indirectly by the production of phenols. Rangaswami & Verkatswarku (1966) report the presence of polyphenols in other species of the genus, and Raudnitz (1957) has found a humic acid in the leaves to be a water-soluble, surface-active polyphoric ester. ... Yeah, well. One person has found a reduction in earthworms, and another has found little or no reduction. Several people have detected common plant toxins (surprise, surprise!) Not a lot of evidence there. In several other places in that paper (quoted), it referred to the physical effects I described, and one that I did not - rhododendron humus apparently forms a hard surface when baked in the sun. Frankly, I don't believe that the toxin effects of either R. ponticum or J. niger are important - whereas the physical ones of many thicket- and canopy-forming plants with large leaves most definitely are. You just have to look for yourself to see the latter! But it is amazing how few scientists ever do look for themselves, as Rackham points out! Regards, Nick Maclaren. I am totally with you on this one. At my previous house we used the leafmould in volume from beneath the Rhododendrons as a seed and potting compost without any bad effects. It was also noticeable that the areas that had been scraped clear of debris became host to a majority of the common garden weeds. |
SOIL POISONING by BEECH TREES
The message
from "Rupert \(W.Yorkshire\)" contains these words: "Nick Maclaren" wrote in message ... Frankly, I don't believe that the toxin effects of either R. ponticum or J. niger are important - whereas the physical ones of many thicket- and canopy-forming plants with large leaves most definitely are. You just have to look for yourself to see the latter! But it is amazing how few scientists ever do look for themselves, as Rackham points out! I am totally with you on this one. At my previous house we used the leafmould in volume from beneath the Rhododendrons as a seed and potting compost without any bad effects. It was also noticeable that the areas that had been scraped clear of debris became host to a majority of the common garden weeds. I think you may both be confusing the state/ results of soil under a small local population of rhododendrons such as one might find in a domestic garden, with the soil left after huge dense very old ones are cleared from hilsides and woodland . It's very noticable here that when large areas of mature woodland are cleared of their longterm 20ft tall solid understorey of rhododendron ponticum, the only seeds that germinate the following spring, are rhododendron ponticum. The rhododendron leaf litter will have been swept away by winter gales leaving visible bare soil. All around are seeding trees, but it will takeat least two years before their seeds, or grasses or wildflowers, start to germinate on or colonise the naked bare soil on, light-filled woodland floor. Janet. |
SOIL POISONING by BEECH TREES
In article , Janet Baraclough writes: | | I think you may both be confusing the state/ results of soil under a | small local population of rhododendrons such as one might find in a | domestic garden, with the soil left after huge dense very old ones are | cleared from hilsides and woodland . It's very noticable here that when | large areas of mature woodland are cleared of their longterm 20ft tall | solid understorey of rhododendron ponticum, the only seeds that | germinate the following spring, are rhododendron ponticum. The | rhododendron leaf litter will have been swept away by winter gales | leaving visible bare soil. All around are seeding trees, but it will | takeat least two years before their seeds, or grasses or wildflowers, | start to germinate on or colonise the naked bare soil on, light-filled | woodland floor. Well, there are two possible explanations that do not involve toxins. One is the hard layer referred to in the Cross reference. The other is that the pre-rhododendron weed seeds will be buried deeply under rhododendron humus, and the new ones will not have arrived yet. The latter case could be excluded if the effect you refer to applies to cases when rhododendrons are cleared before midsummer, and the former would be trivial to test by experiment. I am not saying that the effect you claim exist can't happen, but I am saying that 95+% of such claims are bogus and I have seen no references that provide convincing evidence. In many cases of urban myths, there is some truth in the myth, but it has been exaggerated beyond all reason. In your case, you got the walnut effect wrong (it is the roots, not the leaves, of J. niger), which is a trivial mistake, but is how myths develop. And, as far as I know, the effect is minor and has never been observed in other species of walnut (in particular, J. regia). You also may well be right that there is a short-term effect in the case of R. ponticum, though I should like to see definite evidence (memo to self: DO ask what the Athens password is, to check the literature). But you then claimed "it will be many years before the toxins fade sufficiently for other species to seed into the bare soil left behind." That is a MUCH stronger statement than the one you have just made! Regards, Nick Maclaren. |
SOIL POISONING by BEECH TREES
Many years ago oak and beech were contrasted in a natural history programme
on the BBC-it could have been radio3. Beech has a shallow root system, and also holds on to its dead leaves well into the winter thus denying nutrients to other trees. Oak with a deep root system lost its leaves early in the season thus allowing deep borrowing earth worms plenty of time to drag the leaves down. On this account extensive beech woods do not develope a very dense undergrowth. Regards David Taylor "Emery Davis" wrote in message ... On Fri, 5 May 2006 23:22:34 +0000 Dave Roberts wrote: Hi! Is there a Forester or Tree Person out there who has expert knowledge of this subject? I have been told that the leaves from a Beech tree will poison the ground beneath so that no other species of plant will grow. Is there scientific proof of this? Dave, You're concerned about the allelopathy of the species Fagus. I don't think you need worry. Here's a paper from U of Georgia in the US that discusses the relative allelopathies of different trees. You'll note Fagus is in the "slight effect" section. http://www.urbanforestrysouth.org/Re...load/file_name If for some reason this doesn't work for you google "fagus allelopathy." The most notorious species in this respect is Juglans nigra. I have heard that a mature specimen can effect other plants as far as 60 feet away. For most of us, the only issue is that Juglans regia is sometimes grafted on nigra, which could be a problem in the garden environment. HTH -E -- Emery Davis You can reply to ecom by removing the well known companies |
SOIL POISONING by BEECH TREES
In article , "david taylor" writes: | | Many years ago oak and beech were contrasted in a natural history programme | on the BBC-it could have been radio3. | Beech has a shallow root system, and also holds on to its dead leaves well | into the winter thus denying nutrients to other trees. | Oak with a deep root system lost its leaves early in the season thus | allowing deep borrowing earth worms plenty of time to drag the leaves down. | On this account extensive beech woods do not develope a very dense | undergrowth. Grrk. That sounds simplistic to the point of being misleading. The delay in dropping leaves will merely delay the return of the nutrients, not reduce it. More plausibly, a shallow root system will also deny seedlings access to surface nutients and (more seriously) water - you can see that effect even with herbaceous plants. However, it is a myth, anyway. For a comparable level of cover, there is very little difference between oak (Q. robur and pedunculata) and beech in terms of undergrowth. Look at the trees, and woodlands comprised of them, to see. Also, only YOUNG beech trees hold onto their leaves beyond autumn - and hedges, which are artificially rejuvenated. Large beeches drop their leaves later than oak, but still leaving plenty of time for worms to drag the leaves down. Regards, Nick Maclaren. |
SOIL POISONING by BEECH TREES
I do not stand corrected. I was quoting what an authoritative source said on
the radio. Many natural and unatural events depend on sequences of operations with first in gaining major advantage. Regards David T "Nick Maclaren" wrote in message ... In article , "david taylor" writes: | | Many years ago oak and beech were contrasted in a natural history programme | on the BBC-it could have been radio3. | Beech has a shallow root system, and also holds on to its dead leaves well | into the winter thus denying nutrients to other trees. | Oak with a deep root system lost its leaves early in the season thus | allowing deep borrowing earth worms plenty of time to drag the leaves down. | On this account extensive beech woods do not develope a very dense | undergrowth. Grrk. That sounds simplistic to the point of being misleading. The delay in dropping leaves will merely delay the return of the nutrients, not reduce it. More plausibly, a shallow root system will also deny seedlings access to surface nutients and (more seriously) water - you can see that effect even with herbaceous plants. However, it is a myth, anyway. For a comparable level of cover, there is very little difference between oak (Q. robur and pedunculata) and beech in terms of undergrowth. Look at the trees, and woodlands comprised of them, to see. Also, only YOUNG beech trees hold onto their leaves beyond autumn - and hedges, which are artificially rejuvenated. Large beeches drop their leaves later than oak, but still leaving plenty of time for worms to drag the leaves down. Regards, Nick Maclaren. |
Many thanks Nick, Janet and all the others for your input The discussion has been/is immensely interesting, although somewhat confusing. But that's gardening. On the Rhodo ponticum issue the BBC did interview a forester on a Welsh hillside some time ago whose fulltime job was removing them. His clear statement was that "They poison the ground and nothing will grow here for 5 to 10 years". In retrospect however he might not have been referring to an actual toxin, but indicating that the soil was in some way, - due to an alternative multitude of causes, significantly damaged as regards supporting any species except its own. Personally I suspect that outside of the bench science of the laboratory the nature of soil is so infinitely complex that we are unlikely ever to thoroughly understand what is going on down there at any moment. So! members. Do I spread all this Beech leaf mulch around or take it to the local tip? Dave |
SOIL POISONING by BEECH TREES
In article , "david taylor" writes: | | I do not stand corrected. I was quoting what an authoritative source said on | the radio. Many natural and unatural events depend on sequences of | operations with first in gaining major advantage. Oh, I don't expect you to, and am certainly neither denying that it is a factor, nor that an authoritative source said that it was the cause. I am merely pointing out that, like so many such statements, it sounds (and probably is) simplistic to the point of being misleading. I am, as so often, basing my opinions on my own observations and analysis from the basics. While I do fairly often contradict received wisdom and have to retract later, over the past 40-50 years, I have my views rather more often confirmed by a change in received wisdom. You are welcome to make your own judgement as to which is likely in this case :-) I should point out that, in addition to what you say, authoritative sources have also said that the reason is that beech produces a denser canopy that oak, and I contradicted that too. Both sets of received wisdom cannot be right, so I must be right in denying it at least once! Regards, Nick Maclaren. |
SOIL POISONING by BEECH TREES
In article , Dave Roberts writes: | | Many thanks Nick, Janet and all the others for your input The | discussion has been/is | immensely interesting, although somewhat confusing. But that's | gardening. And, in particular, uk.rec.gardening :-) | On the Rhodo ponticum issue the BBC did interview a forester | on a Welsh hillside some time ago whose fulltime job was removing them. | His clear statement was that "They poison the ground and nothing will | grow here for 5 to 10 years". In retrospect however he might not have | been referring to an actual toxin, but indicating that the soil was in | some way, - due to an alternative multitude of causes, significantly | damaged as regards supporting any species except its own. He wasn't called Dai the Gloom, by any chance, was he? :-) Don't trust what you hear on television/radio, especially the sayings of such people. They are often selected for 'colour' rather than rationality. | Personally I suspect that outside of the bench science of the | laboratory the nature of soil is so infinitely complex that we are | unlikely ever to thoroughly understand what is going on down there at | any moment. Well, you're right there! | So! members. Do I spread all this Beech leaf mulch around or take it to | the local tip? Spread it around. DEFINITELY. The Victorians prized it very highly, and all their gardening books said that gardeners should go out of their way to make it. Regards, Nick Maclaren. |
SOIL POISONING by BEECH TREES
Nick Maclaren wrote: In article , Dave Roberts writes: | | Many thanks Nick, Janet and all the others for your input The | discussion has been/is | immensely interesting, although somewhat confusing. But that's | gardening. And, in particular, uk.rec.gardening :-) Ah yes. It started with beech and went on to others. So, I'll add another. Elder berry (sambucus) does seems to have a nasty habit of being able to wipe out its immediate neighbours, especially within a privet hedge | On the Rhodo ponticum issue the BBC did interview a forester | on a Welsh hillside some time ago whose fulltime job was removing them. | His clear statement was that "They poison the ground and nothing will | grow here for 5 to 10 years". In retrospect however he might not have | been referring to an actual toxin, but indicating that the soil was in | some way, - due to an alternative multitude of causes, significantly | damaged as regards supporting any species except its own. He wasn't called Dai the Gloom, by any chance, was he? :-) Don't trust what you hear on television/radio, especially the sayings of such people. They are often selected for 'colour' rather than rationality. | Personally I suspect that outside of the bench science of the | laboratory the nature of soil is so infinitely complex that we are | unlikely ever to thoroughly understand what is going on down there at | any moment. Well, you're right there! | So! members. Do I spread all this Beech leaf mulch around or take it to | the local tip? Spread it around. DEFINITELY. The Victorians prized it very highly, and all their gardening books said that gardeners should go out of their way to make it. Regards, Nick Maclaren. |
SOIL POISONING by BEECH TREES
In article .com, "a.c." writes: | | Ah yes. It started with beech and went on to others. | So, I'll add another. Elder berry (sambucus) does seems to have a nasty | habit of being able to wipe out its immediate neighbours, especially | within a privet hedge Not in my garden, it doesn't, nor in any of the (mainly whitethorn and blackthorn) ones that I was familiar with in Wiltshire. But it could well happen sometimes. There are known to be many dozens of ways, physical, chemical and probably other, by which many species attempts to discourage others. The big mistake is when people extrapolate an observation that there is SOME effect under ONE circumstance into the claim that there is an ABSOLUTE effect under ALL circumstances. And, with a VERY few exceptions, SOME in the above is a synonym for SMALL. The same thing applies to ants, aphids and broad beans :-( Regards, Nick Maclaren. |
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Many Thanks Nick - Will spread it around. Can't beat the Victorians for knowing what they are doing. Whilst on this, (allelopathy ? ), subject may I mention the vine Solanum Crispum - 'Glasnevin'. For myself I would take a lot of convincing that this does NOT poison its immediate root area. I have on three different occasions, in three diferent gardens, lost substantial shrubs, - Viburnum tinus, Berberis darwinii, and such like, by a process of gradual die-back, when close to it. Although I like this vine - and it has its uses, I would never plant it in the open ground again. In a container, maybe. Dave |
SOIL POISONING by BEECH TREES
In article , Dave Roberts writes: | | Whilst on this, (allelopathy ? ), subject may I mention the vine | Solanum | Crispum - 'Glasnevin'. For myself I would take a lot of convincing that | this | does NOT poison its immediate root area. I have on three different | occasions, | in three diferent gardens, lost substantial shrubs, - Viburnum tinus, | Berberis | darwinii, and such like, by a process of gradual die-back, when close | to it. I have never seen that, and there is still a possible physical explanation! It is a moderately drought-resistant plant, and could well be good at extracting water. B. darwinii, at least, isn't as nearly as drought-resistant as its leaves would imply. From a gardener's point of view, there is little difference. Regards, Nick Maclaren. |
SOIL POISONING by BEECH TREES
In article , Janet Baraclough writes: | The message | from Dave Roberts contains | these words: | | Whilst on this, (allelopathy ? ), subject may I mention the vine | Solanum | Crispum - 'Glasnevin'. For myself I would take a lot of convincing that | this | does NOT poison its immediate root area. | | Haven't found that. I have one growing in a very large pot (and in | flower atm). For the last year and a half the soil surface in the pot is | almost completely covered with self-seeded purple leafed violets (also | inflower atm) and verbena bonariansis, which flowered well last year and | looks very healthy atm. I am very fond of quoting Oscar Wilde, but he is very relevant to such ecological issues: The truth is rarely pure and never simple. Regards, Nick Maclaren. |
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Hi! Nick. My concern with the Solanum species and its poisonous effects arises not only from my gardening experience, as noted, but from reading of the potato's, (virtually the same plant), association with solanine and other toxics. Check out: - http://en.wikipedia.org/wiki/Potato - bottom of the page. Quote: - " Potatoes contain glycoalkaloids, toxic compounds, of which the most prevalent are solanine and chaconine " " Solanine is also found in other plants, in particular the deadly nightshade " My suspicion is that if these componds are down there in the tubers/roots; then there must be a possibility,at least,of some "leakage" into the surrounds. The fact that these substances are toxic to humans, of course, doesn't mean they are necessarily soil pollutants with regard to other species. However!!!!!! Who knows??? Would explain my practical experience. Regards dave |
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