The Veteran Tree Project
Managing Ancient and Veteran Trees
It is true to say that on the whole trees manage themselves, and that they have a wealth of strategies at their disposal to ensure that long-term survival. They have a mission to accomplish as do the multitude of hosts who also rely on the trees continuity for their mutual survival.
Throughout its life the trees natural defence mechanisms enable it to fight off unwanted hosts yet encourage its friends to stay. It has the unusual but proven ability to adapt in the most amazing ways to not only unwanted predators, but also to the rigours of our changing environment. It does this through a range of growth adaptations and strategies the results of which add to the special and unique visual qualities you might see in any tree that you may encounter.
When the tree is young it aims high. It needs to succeed. It spreads its crown spreads its roots and becomes a proverbial food factory. Its aim is to ensure the continuity of the species and it will do all in its power and within the constraints of nature to achieve this goal. As it ages however, that imperative changes, and it is now less about the survival of the species, but more about survival of itself. When old and frailer why expose yourself to the worst that nature throws at you, and the answer is that you do not have to and indeed they don’t.
As the tree gets older then, what happens? Well it shrinks. The term for this particular adaptation is retrenchment, and it achieves this by shedding the higher more exposed branches, until it becomes squatter and as such more secure in its setting, it is then far more capable of survival in its twilight years!
Man has intervened in the past and this intervention has had a markedly beneficial impact on tree survival with many worked trees, including coppice and pollards having an extended life span as a result of this practice.
So, should we intervene? The answer I think is yes but only if by so doing we can prevent the premature demise of this tree from the conflict which is human kind!
How old is that tree?
There are varied ways to answer this question, whilst avoiding the temptation to take the tree down and count its rings. However, those rings could be counted by observing a core taken from an increment borer. There are obvious limitations with this method in view of the invasive nature of this tool.
Far better if you can refer to local records or historical references, however this is not always possible and these too may not necessarily be accurate and it might well be prudent to adopt alternative methods to check or verify these finds.
The alternative accepted method is to measure the girth of a tree. This is done in the knowledge that trees grow at varied rates depending upon the species.
A method has been devised by White (1994;1998) which was based on species of tree, its girth at breast height and the trees growth conditions, a variable that will have an influence on that annual increment. This method was developed based on comparing trees whose planting date was known, in addition to having an understanding of how a tree grows and how they might be influenced by variable growing conditions.
An interesting point to bare in mind here however is that girth/age relationships only holds good if the tree is continuing to grow at what might be described its optimum growth phase. As the tree gets older and reaches what is termed the decline phase its girth dramatically slows down which means it becomes increasingly difficult to accurately estimate the age using the girth estimation method. In view of this fact it will be always be a more reliable method in terms of measuring and estimating veteran as opposed to ancient tree specimens.
The general rule of thumb with regard to veteran tree status is that a tree will qualify if it has a girth of at least 3M when measured at 1.5 M.
Mature trees with a full crown growing in good conditions are estimated to grow at 2.5cm (1 inch) per year, however young trees do grow faster than older trees. The 2.5cm figure is an average of that fast initial growth and the slower growth phase averaged over time.
The genetic makeup of a tree does have a bearing on growth rates, but it has to be said that a trees general growing condition rather than the species itself plays a significant role in the long term development of that tree. As an example a tree with a girth of 3M would be 100 years old if it is growing in good conditions, but would be 200 years old if growing in a wood!
Veteran Tree species guide
|Veteran Tree Type||Growth|
|Field Maple, Rowan, Grey and goat willow, Hornbeam, Holly, Cherry, Alder||2.5M|
|Oak species, Ash, Scots pine, Yew, Elm species||3M|
|Lime species, Sycamore, Horse chestnut, Poplar species, Other pine trees, Beech, Sweet Chestnut, White and crack willow||4.5M|
Exceptions to the rule:
There are trees that fall into the exceptional category, these are those that grow considerably faster than the average and those growing considerably slower than the average.
Tree Growing at less than 2.5cm (1”) per year
Scots Pine, Norway Spruce, Horse Chestnut, Common Lime, Yew and small trees generally
Trees growing at 5-7.6cm (2”-3”) per year
Wellingtonia (can occasionally be up to 15cm), Coastal Redwood, Lows fir, Grand Fir, Cedar of Lebanon, Monterey Cypress, Sitka spruce, Douglas fir, Western Red Cedar, Western Hemlock, Cricket bat willow, Black Italian and other hybrid poplars, Wingnuts, Nothofagus spp, Red and chestnut leaf oaks, Hungarian and Turkey Oaks, Tulip Tree, London Plane and most Eucalyptus spp
Estimates of age for certain tree species with girth 2.5-5.0M
There are various ways to identify trees. You can use Keys which will look at individual features and comparison charts, and in a science based context are extremely useful. You can use reference books with descriptions and images to help with that identification, and there are also a number of plant id apps out there that you can use on your phone or computer or lap top.
It is initially very useful if you know the key characteristics of a plant; evergreen or deciduous, Broadleaf or conifer. We can then go on to look at characteristics such as leaf type or shape, simple or compound, ovate or obovate, and type of leaf margin.
In the winter we need to be able to recognise the bud shape, type and arrangement in order to successfully identify those deciduous woody plants’
In order to help with this particular project there are plans to run a number of tree identification workshops, dates of which will be made available on our news page
Useful tree id links…