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?