High winds on the Trelissick estate

Recent high winds have brought down several large trees around the estate, including a majestic sessile oak that had been a familiar presence, presiding over the bowl-shaped bottom of Nanphillows field. ‘Nanphillows’ is the name given to one of the valley fields on your left as you drive along the narrow, walled road into Trelissick. Historically, Nanphillows was one, self-contained farm but all that has long-since disappeared and the area has long been a parkland field and part of the wider Estate.

On your walks around the countryside at Trelissick, you may notice a great deal of other fallen or dead trees, left where they have tumbled like arboreal skeletons, to rot down and return to the earth. You might also have wondered why we don’t gather up all this wood and turn it into logs and timber or simply tidy it away so it doesn’t clutter up the countryside. It is these questions –often heard as we are working – that have prompted us to write a series of posts on our management, and the outcomes of our management, on these hugely important trees.

The above multi-stemmed lime tree was one victim of high winds. A cavity had formed within the main stem of the tree which was then colonized by a ‘white rot’ fungus. This severely weakened the tree and it subsequently collapsed in several different directions as you can see here.

It is our policy, within the National Trust, not to dismantle or remove fallen or dead trees wherever practically possible. We work hard to give each tree  a chance to re-establish, thus preserving both the provenance and the genetics of each individual which can stretch back hundreds – in some cases thousands – of years and have a great impact on the success and longevity of trees. Nowhere is this truer than in our parkland at Trelissick, which has very shallow soil and constant exposure to the saline elements of the sea, often making it difficult for imported trees to establish themselves. Seed material taken from trees that have developed and thrived over millennia in the locality will obviously have a genetic predisposition to these fairly challenging circumstances and a much better chance of survival and success.

A large number of tree species, after yielding to the influence of an almighty wind, might seem shattered and broken but, from that splintered stump, they will often begin to grow again, forming a ‘pollard’ (see the photograph above). This natural occurrence retains a great deal of value for wildlife because trees, especially the older they become, offer a range of habitats within their crown, stem and roots. As well as general appeal for bats and birds, these micro-habitats might be adopted by ‘specialists’ that rely on very particular conditions. These specialists include insects, fungi, lichen, ferns and bryophytes.

Even when a tree has no chance of coming back (such as with the sessile oak mentioned earlier) we remove the less substantial ‘brush-wood’ for safety reasons and retain the framework (or skeleton, if you like) of the tree and allow it to rot down, providing habitat and sustenance for a wide variety of wildlife for the next 20-30 years.  If we were to tidy away or burn this material we would be eliminating an essential and enormously beneficial stage of the woodland ecosystem.

Several years ago, we employed a team of insect experts to survey and record saproxylic invertebrates (the scientific name given to insects that live and feed on decaying wood) at Trelissick. This team identified and recorded many examples, including several very rare species, some of which exist only here on the estate and a few other sites in Britain.

Receiving extremely affirmative records such as these is one of the highlights of our job as countryside rangers – it reinforces why it is that we carry out the work we do and gives us the belief to make decisions that shape the countryside around us.

The next blog post will shine a spot-light on these remarkably evolved dead-wood invertebrates we are so lucky to provide a home for on the Trelissick estate…

The National Trust ranger team, Trelissick and North Helford