Why Lots of Elm Tree Seeds?

[Seefeld]

We have 2 elm trees ( possible Camperdown Elms, over 100 years old ) and this year there have been an enormous amount of seeds. Can you tell me why this might be?

[ron1863]

Hi Seefeld and a warm welcome to WAB. An old farmer once told me that it was a sign of a cold winter and the trees produced more seeds in order to survive. Don't know if there's any truth in it though.

[ceterach]

Enough of these old wive's (or even old farmer's) tales, I think even the Met Office is a better weather forecaster than Elms.

Since Elms are wind-pollinated it is most likely because there was a dry breezy spell when the trees were in flower.

All the best

[The Woodman]

All trees crop in a cycle. When a heavy seed crop year occurs, it is called a "mast" year, other years crops can be very small or even absent.

Your Elm will be fruiting in a mast year now and the next one may be five of more years away.

Here's a link to the subject

Mast and Mast Years | The Woodlands.co.uk Blog

[valleyforge]

Seefeld,

The scientist in me requires a 'cause and effect' solution to this phenomenon.

All fruiting plants, including trees, have optimum conditions for pollination to occur ... not too wet, light winds, and/or the presence of sufficient pollinating insects, which is partly dependent on the same weather conditions, at just the right stage of pollen development. There is usually then a fairly narrow 'window' of opportunity for the pollination process to occur in any species.

So these are primarily micro-climatic causes that will and do vary markedly from one year to the next, one place to the next. The additional fruit this year simply indicates that the pollination process was more successful this year, than you have maybe seen before.

I think this year the conditions were close to optimum over quite a large part of the country, as up here we are already seeing the formation of greater than usual numbers of rowan berries and gean (wild cherry).

So, in the event of poorer weather towards the end of the year, there should be a good supply of fruits for the wildlife that depends on it.

[The Woodman]

Using your hypothesis valleyforge, it would be possible for mast years to run concurrently if optimum conditions prevail. It doesn't appear to work like that in nature though.

Genetically modified fruit cropping trees have lost their masting capability but the native species retain it. Not all species mast in the same year either, I've noticed a good sloe crop forming recently whilst hawthorn is poor.

Although I was always aware that this phenomenon occurs, I've never understood why, but it is cyclical.

[valleyforge]

Woodman,

My hypothesis simply states a probable mechanism, nature determines the actual schedule

As I tried to say, the variability of micro-climatic conditions would almost certainly preclude any predictable cyclicity and the optimum 'window of opportunity' will undoubtably be slightly different for each species ... hence your good sloe, poor hawthorn crop.

I'm willing to be convinced otherwise of course ... I just enjoy a good argument

[The Woodman]

Far from wanting to argue about the subject valleyforge, I do understand your reasoning but I cannot understand how the cyclic heavy cropping is consistently thus.

It must be more than pure chance that conditons are optimal every five years or so with recorded regular heavy cropping events going back into the mists of time.

Since my last post and your reply, I've been out and had a look at local trees and can say that the Sycamore, Ash and one of the Lawson Cypress vars. in particular are laden with fruit. The conifer has so much weight in the cones that each branch end is drooping.

Yesterday, I noticed that a Wych Elm in a small copse was laden with fruit but didn't give it any thought.

Many things in life are taken for granted without much thought, this subject has made me realise how little I know!

Quote "My hypothesis simply states a probable mechanism, nature determines the actual schedule" - I like that, a profound statement indeed.

[ceterach]

Originally Posted by The Woodman

Far from wanting to argue about the subject valleyforge, I do understand your reasoning but I cannot understand how the cyclic heavy cropping is consistently thus.

It must be more than pure chance that conditons are optimal every five years or so with recorded regular heavy cropping events going back into the mists of time.

Where do you get your 5 year cycle from? I have known consecutive years of Beech mast. From what I have read and seen, cyclical in this context merely means that it happens now and again, I agree that if it were truly cyclical and happen with some sort of regular periodicity that would be more difficult to explain.

Different species of trees do not "share" mast years, why because they flower at different times and weather patterns differ. Many trees have a very short flowering period.

Similar things happen with orchid flowering and we know that is dependent at least to some extent on rainfall in previous seasons.

Nature determines it all but there is usually a logical explanation to it.

All the best

[The Woodman]

"Every five years or so" to be taken as a generalisation because it's not possible to be exact. Cyclical meaning reoccuring at regular intervals, however many years apart.

I am at odds with your comment that different trees do not share mast years though unless we're at a misunderstanding of the word "share". It's clear to me that the species I've looked at (and mentioned earlier) in the last couple of days have very heavy crops whilst others haven't. I'm looking at a Whitebeam, Hawthorn and Rowan at this moment and neither have anything like heavy crops or even regular crops.

The Sycamore and Ash (plus the conifer) seen earlier today, all having heavy crops, must be sharing a mast year as they are all in a similar fruiting condition. I cannot see how they are not sharing it.

Granted, all trees produce fruit every year to some degree and it just so happens that the fruit of the Beech is referred to as "mast" and the contents of the mast is the Beech nut. They do fruit every year but there will be one year when the crop exceeds that of the previous four, five or six years.

When you say that you've seen consecutive years of beech mast, do you mean a bumper mast crop?

[ceterach]

Originally Posted by The Woodman

"Every five years or so" to be taken as a generalisation because it's not possible to be exact. Cyclical meaning reoccuring at regular intervals, however many years apart.

It is the regular that I don't agree with sometimes it may be a gap of one year sometimes seven, to me that is closer to random not cyclical.

Originally Posted by The Woodman

I am at odds with your comment that different trees do not share mast years though unless we're at a misunderstanding of the word "share". It's clear to me that the species I've looked at (and mentioned earlier) in the last couple of days have very heavy crops whilst others haven't. I'm looking at a Whitebeam, Hawthorn and Rowan at this moment and neither have anything like heavy crops or even regular crops.

The Sycamore and Ash (plus the conifer) seen earlier today, all having heavy crops, must be sharing a mast year as they are all in a similar fruiting condition. I cannot see how they are not sharing it.

Agreed I was being lazy, what I meant was that trees do not necessarily share mast years because they flower at different times and the conditions may not be ideal when they flower. Interestingly Ash and Sycamore have fairly similar flowering times (although Sycamore is not necessarily wind-pollinated) although Elm certainly flowers earlier. Whitebeam, Hawthorn and Rowan flower later and are not wind-pollinated to any degree.

Originally Posted by The Woodman

Granted, all trees produce fruit every year to some degree and it just so happens that the fruit of the Beech is referred to as "mast" and the contents of the mast is the Beech nut. They do fruit every year but there will be one year when the crop exceeds that of the previous four, five or six years.

When you say that you've seen consecutive years of beech mast, do you mean a bumper mast crop?

Again lazy writing I should have said consecutive mast years.

I am not saying that this is the only factor certainly spring and summer conditions always affect fruit production but I do not believe that there is any good evidence for some inbuilt clock controlling fruiting as is often suggested.

[The Woodman]

I take your point about random / cyclical ceterach, agreeing that I've never seen any evidence that suggests any inbuilt clock, but there again I've never looked for it since being told about it as a student many years ago and accepting what might now be termed as misinformation.

Your comments have given me something to think about and I cannot find much about it in the literature that I have and will have to dig deep in t'internet.

Appreciate your posts.

[RobSutton]

I seem to remember reading somewhere that species like Beech and Oak don't have the same masting strategy in all of their range. Further south and east into Europe they fruit much more consistently than they do with us. I'm not sure whether that's true, it's a vague memory of having read something, perhaps someone can confirm this?

With things like Hawthorn (and quite a lot of fruit trees) there is a tendency for heavy flowering/fruiting in alternate years, a good cropping year is followed by a largely barren year. Interestingly the size of sap-sucking insect such as Psyllids feeding on the trees shows a similar pattern, they are measurably bigger in years when when the tree is flowering than in years when they are not - more nutrients need to be transported to the developing flowers and fruits which therefore allows them to grow bigger.

[ceterach]

Originally Posted by The Woodman

I take your point about random / cyclical ceterach, agreeing that I've never seen any evidence that suggests any inbuilt clock, but there again I've never looked for it since being told about it as a student many years ago and accepting what might now be termed as misinformation.

Your comments have given me something to think about and I cannot find much about it in the literature that I have and will have to dig deep in t'internet.

Appreciate your posts.

I know where you are coming from! Unfortunately I have reached the age where I realise most dogma is wrong but everyone tells me that is because I am just a cynical old git! Probably both are true

[The Woodman]

You are right to question dogma, it's all too easy to accept and live with what one is told when younger. As you get older and gain more experience and knowledge, an active and intelligent mind can challenge dogma.

From what you say, I doubt very much if it's anything to do with being a c.o.g.!

Rob, I have no idea about masting in Europe - sorry - only wish I could rise to this challenge! I agree with your comments on size of sap suckers, but that's only after you pointed it out. Numbers seem to higher as well. I havn't seen a shield bug on my Hawthorn this year but tomorrow I'm going to have a good look!

My apologies to the OP, but I have found this very interesting.

[Seefeld]

Thank you all for your possible answers. My elms are weeping elms , related to Wych elms and do not flower. the seeds appear first and then the leaves. Birds like greenfinches, chaffinches , goldfinches, linnets and even ocasionally goldcrests all feed on the seeds.