Trunk diameters

[JennyS]

Not quite sure where to post this as its not an identification request but advice is needed.
I've been recording lichens on tree trunks and have noted the trunk diameter of the trees that species were recorded on.

Problem is I don't know at what approximate trunk diameters the different categories of sapling, mature, veteran etc etc apply. Help would be much appreciated please!

[Dorts]

This is very dependant on the species of tree and its eventual mature height and girth.
But generally trees under 1 year old are refered to as 'seedlings'.
A 'sapling' is a young tree, from one to two years of age, but before the diameter of the trunk reaches 3-4". For example, in order to fell a tree we often need permission, but not until the tree reaches these dimensions. So 'saplings' with a trunk dimesion below 3-4" may be felled without permission. Though of course some species, like a laburnum for instance, may reach 'maturity' and still only have a girth of 4-5".


A tree is 'mature' when it is approaching its predicted height and girth for its species.
An old tree is one that is beyond the 'mature' age, though it may have lost height, its girth will probably have increased.
Dorts.

[JennyS]

Thanks Dorts - and a few more questions!

I realise its difficult to generalise as mature size is dependent on the species but I've been recording from (mainly) ornamental Acer, Malus and Sorbus often with trunk diameters of approximately 3-5 inches.
They're older than 2yr old saplings but not yet mature (3-6yr possibly) and I wondered whether there is an accepted term that covers them?

At what (very approximate) age's would deciduous trees class as 'old' - Lime and Acer's with trunk diameters of 20-24 inches?

Your help is much appreciated
Jenny

[Besnard Lake]

Hello Jenny,

You have hit upon a very grey area in arboriculture. The age classes we generally use are young, semi-mature, early-mature, mature, over mature and veteran, with some arboriculturalists omitting certain classes for unknown reasons. Helliwell has a chart with estimated life spans of various species,although this is not overly accurate, as no chart can be when estimating the age of a tree that may live for circa 80 years (Silver birch) or circa 1000 years (oak) or circa 3000 as the Yew may. It also depends upon the environment the tree is growing. Highway trees will generally have a much shorter life span than their rural siblings.

Nurseries use semi-mature and mature to mean something very much different to what arboriculturalists use. These we would still class as young. You cannot always measure the age by the trunk diameter, as trees in a woodland would show much less circumferential growth than an open grown tree.

A mature lime could be anything from around 40 to 200 years and upwards. It is a lengthy period.

Often, the best way of finding out the age of young trees is to find out who planted them and ask directly. If the trees are situated on a recent housing estate they were probably planted by the landscapers during the build so how old are the houses? and so on......

Regards

Besnard

[Cotham Marble]

Originally Posted by JennyS

Thanks Dorts - and a few more questions!

I realise its difficult to generalise as mature size is dependent on the species but I've been recording from (mainly) ornamental Acer, Malus and Sorbus often with trunk diameters of approximately 3-5 inches.
They're older than 2yr old saplings but not yet mature (3-6yr possibly) and I wondered whether there is an accepted term that covers them?

At what (very approximate) age's would deciduous trees class as 'old' - Lime and Acer's with trunk diameters of 20-24 inches?

Your help is much appreciated
Jenny

Nothing to add to Dorts and BN's advice, except to say maybe it's best to avoid the problem of age classification altogether and simply note the bole diameter at a given height and let anyone accessing your data make their own assessment about age.

Age of tree may have only a poor relationship with the age of the lichen colony so tree age may have little data value if the intention is achieve analysis of lichen growth. There maybe a relationship between bole surface area and colony establishment so bole size rather than age maybe a more useful route of analysis and you can collate precise figures for that, along with location and aspect.

CM

[Dorts]

If you contacted the Forestry Commission at Alice Holt in Surrey they may be able to help.

Some years ago, a dear old friend of mine Alan Mitchell, who had written a number of Field Guides to Trees of Britain, produced a book for the Forestry Commission for whom he worked, called;
Champion Trees in the British Isles, Alan Mitchell with V. E. Hallett & J. E. J. White. Forestry Commission Field Book 10. 1985.
This book followed many years of his research to find the largest and oldest tree of each species known in Britain and I believe also County-by-County. Copies may still be available.
Dorts.

[JennyS]

Thank you Besnard, CM and Dorts for the additional and very helpful information - I had a feeling it was probably a rather 'grey' area!

This wasn't a detailed site survey (I haven't the experience or competence ), more an attempt to obtain an overview of the species present on planted urban trees in several different towns. I noted trunk diameters when recording so I've included that and opted for using sapling, semi-mature and mature as very general descriptions in each brief site synopsis.

Age of tree may have only a poor relationship with the age of the lichen colony

It can be relevant to the range of species present though but it was interesting to find some saplings with an abundant lichen flora. There seem to be far more lichens present on planted ornamental trees than on native trees in the same area's.

Champion Trees in the British Isles, Alan Mitchell with V. E. Hallett & J. E. J. White. Forestry Commission Field Book 10. 1985.

Yes, a beautiful book, unfortunately I think Ireland is a bit short on veteran and ancient trees!

Thank you again to all of you,
Jenny