Conserving the forest for the future
Sherwood Forest has one of Europe’s biggest collection of ancient oaks – that is, aged 400 years and above – which is really important for the life of the forest as these trees provide homes for more species than any other native trees.
Each is capable of supporting hundreds of different creatures, from bats and birds in hollow trunks and knots in branches to a host of fungi – and some of the forest’s smallest inhabitants, who may be tiny but are hugely significant.
“These ancient oaks are home to a nationally and internationally important collection of insects associated with decaying wood (saproxylic insects) including the rare cardinal click beetle,” explained RSPB ecologist, Andy Skinner.
“The decay of wood is largely driven by fungi including the rare oak polypore which is found at only a handful of sites across the UK including Sherwood. Decaying wood insects are one of the most threatened group of insects in Europe and Sherwood is one of the top 10 sites in the whole of the UK for them.”
Whilst we have an enviable collection of old trees, the jewel in the crown being the magnificent Major Oak – much of the rest of the forest is comparatively young. The popularity of Sherwood timber, which helped build naval ships as well as churches up and down the country including St Paul’s cathedral, took away thousands of trees in a relatively short space of time.
There has been replanting since but it’s relatively recent, leaving the forest with a ‘missing generation’ of trees.
This creates a problem. Once our current ancients have died and rotted, there aren’t the numbers of ‘up and coming’ ancients we’d like to take their place. So there will be far fewer trees to provide homes for our rare insects which depend on hollow trunks and rotting heartwood, and are vital to the well-being of the forest.
This month (February) we are planning work which will help us to deal with this dilemma, and begin to bridge the generation gap, bolstering the numbers of trees with ancient features, which we call veterans.
Working with ancient tree experts and thanks to consent from Natural England, we have a programme of veteranisation work as part of Back from the Brink – one of the most ambitious conservation projects ever undertaken.
It aims to save 20 species from extinction and benefit over 200 more through 19 projects that span the whole of England. The work at Sherwood Forest is part of the Ancients of the Future project, which is designed to protect precious treescapes.
Veteranisation is a process used on younger trees which introduces the effects of nature and aging. The techniques used are referred to as biomimicry as they aim to replicate key habitat features that would naturally occur.
Emma Gilmartin, Woodland Trust’s Conservation Advisor for Trees, explains; “Dead wood and fungal decay is a natural part in the life story of a tree.
“Over time, trees accumulate features such as decaying branches, water-filled pockets, hollows and cavities.
“These features are what make our trees so important for wildlife – and we need more of them! Where trees aren’t particularly old, it might be necessary to help them seem older than they are. “Veteranisation is a useful tool which is underpinned by research and mimics the natural events that a tree might experience.”
By removing a branch or making a small hole in the bark – the kind of feature resulting from high winds or a woodpecker drumming – we can kick-start processes in the tree which will create the kind of features seen in older trees.
At Sherwood, a small number of young oaks have been handpicked for this, in areas where we currently have very few ancients and veterans.
Arboriculturist, Reg Harris, from Urban Forestry, is carrying out the work.
“It’s very important to stress that the trees selected would ordinarily have been felled as a part of on-going silvicultural works in the forest,” he said.
“From research carried out for the International Veteranisation Project (in Norway, Sweden and the UK) there has been very encouraging results from the biomimicry carried out, with several endangered species already using key features cut into the trees.”
He added that veteranisation work is quite noticeable at first but after a few months it weathers and is often hard to spot with the untrained eye.
It is hoped that in years to come, by adding to the number of veteran trees coming through the ranks, the forest will reach a point where there is always another tree coming through to replace those that are lost. The oaks will be able to grow to their maximum potential and decline gracefully with minimum intervention.