I was often asked something like this when I started undertaking new tree planting schemes. There is of course no right or wrong answer, but there are a few guidelines:
** Five years of careful weeding may be needed when trees are first planted. (And they will have had two or three years in the tree nursery before that)
** Ten years is about the time before the canopies of the trees meet up, and start forming a closed woodland structure.
** Twenty years is more common for the first thinning, though it can depend a lot on species planted and local conditions.
** Four hundred years is the time taken for an ancient woodland to develop – the virtues of woods that have been in continuous cover since 1600, are much extolled by conservationists. 1600 is roughly when we have good maps to refer to, and ancient woodlands are most highly prized for conservation.
** Ten thousand years is the marker for primary woodland: woods that have been present since the retreat of the last Ice Age.
Having started relatively young, I have had the privilege of watching Treragin Wood develop over the last twenty years, from open fields of barley and daffodils, to a wood now undergoing it’s first thinning. And I think I have now got a proper woodland!
When preparing management plans, or undertaking ecological surveys, one of the things we look at is the groundflora, and the presence or absence of indicator species for ancient woodland. These tend to be less common plants that are sensitive to change and have a tendency to be found in only very old or ancient woodland. However, it is important to take into account the whole range before making any judgements. In the south west in particular the diverse flora of our hedgerows provides a remnant of woodland, a valuable corridor for wildlife and a source of seed for plants colonising new woodland areas.
So in Treragin, a young baby in woodland terms, we have a number of ancient woodland indicator plants. Before writing this article I had a look at a list of ancient woodland indicators, and immediately found that we had eight in our wood. These are:
|Sessile Oak||Hard Fern|
I am now making a resolution to undertake a proper survey and listing of the wildflower species at Treragin this summer! I expect to find more, but of course this does not make Treragin ancient. In fact, a good wood is likely to have as many as 30 indicator species in it. But I think that eight is a good start.
The majority of these species have come from hedgerows, although some good species have germinated from a previously dormant seed bank. Last year we counted 152 Broad-leaved Helleborines, a record number. They are now spreading throughout the wood, having once been confined to a small area of ride along the bottom of the wood. Nature can be pretty resilient.
Planting new woods adjacent to existing ones can speed up natural colonisation, and many charities are now expanding their reserves with new planting work, as part of a move to landscape scale conservation. These new planting schemes are incredibly important for the future; in some areas we are now seeing significant improvements in nature conservation and wildlife, instead of years of rearguard actions and fighting decline. Seeing Treragin contribute to that change gives an enormous feeling of satisfaction.