Some thoughts on Ancient and Veteran trees- another rather long read!
The excellent NRN new year 'long read' on trees provoked sadness at what we are losing but also spurred me to action to share what little I know. Our ancient and veteran trees are valuable in so many ways and there is more that can be done to understand them and look after them.
My work in historic landscapes involves defining what we value, what is rare or special- ‘significant’; I have specialised in conserving old avenues, so I have spent a lot of time tussling over what is important and why.
Ancient or Veteran?
We talk about ancient and veteran trees but what are they? The Ancient Tree Forum explains the difference. Ancient trees are in their old age, older than others of the same species. That means that their crown and trunks are no longer increasing and in fact they may be growing down or ‘retrenching’. You can see this very clearly in long lived trees like ancient oaks or sweet chestnuts. They can be gnarled, knobbly, huge, bent and hollow but are still very much alive and support a complete ecosystem of insects, birds, and lichens.
Veteran trees can be much younger. The tree may have developed some of the features found on an ancient tree, but not necessarily as a consequence of time. The bear ‘scars’ of decay in the trunk, branches or roots, fungal fruiting bodies, or dead wood. These veteran features will still provide a vital wildlife habitat. Ancient veterans are ancient trees, not all veterans are old enough to be ancient.
Why are they so important?
Amazingly, the UK has about 80% of Europe’s ancient trees and not only that, our closest park, Blenheim, has the biggest and most important collection of ancient oak trees in Europe, with nearly 1000 ancient and veteran trees1. Management of our parks has allowed more of these fantastic trees to survive than in the rest of Europe, but you will also find ancient trees in hedgerows--there are several on the Garden Village site and they illustrate land use over centuries. Some of these will have been boundary markers; often boundary trees are pollarded, cut regularly above animal browsing height providing a supply of fuel or small wood for fences etc. This was a practice dating to at least the medieval period2. A pollarded tree can live to a great age. You can see some great pollarded willows in the meadow at Park Cottage Eynsham. Ancient support an ecosystem of insects, birds, lichens etc: it may take several hundred years for this special habitat to be created and be suitable for many rare and specialised fungi and animals. The decaying wood of an ancient tree is one of the most important habitats that exist in Europe and therefore it is vital to conserve all our ancient trees. For instance, the invertebrate fauna within High Park, Blenheim, includes three Red Data Book (endangered) beetles3.
Our ancient trees are complex living records of our history and the UK has a special responsibility to protect them.
How do you date a tree?
The very basic rule of thumb for estimating the age of trees is to measure round the trunk (girth) at 1.5m above the ground, and then for an average tree in average conditions it should add inch (25.4mm) of girth for every year of growth. In practice it is much more complicated and ancient trees are more complex still. A methodology for estimating the age of veteran trees has been developed by the Forestry Commission4.
How old is an ancient tree?
The exact age at which you’d call a tree ancient depends on the species of tree and other factors including the site and soil, and whether it is crowded or not. A birch tree could be considered as ancient if it lived 150 years, but an oak tree needs to be at least 400 years old. Many of the oaks at Blenheim are much older. The largest oak in High Park (east and south of Combe lodge) – The King Oak – was measured in 2009 by veteran tree expert Ted Green with a circumference of 9.2m giving an estimated age of 920 years and there are other trees of a similar size5. The age of the trees was estimated using the Forestry Commission method6. It is quite likely that the largest trees have been in existence since the time High Park became established as a royal deer park in the early twelfth century and over 60 trees date from the middle ages – a remarkable achievement of continuity7.
Released:January 20th, 2021 04:49 AM
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