Climate Change, Biodiversity Gain and Tree Planting

Rewilding on the Knepp Estate, West Sussex

Climate change is rarely out of the news these days, and tree planting is one of the solutions put forward to take carbon out of the atmosphere.  It can certainly work in the short term; a good conifer plantation grows at over 20 cubic metres per hectare per annum, which is awful lot of carbon.  Native species such as oak are slower growing, usually less than 10 cubic metres per hectare per annum.

The very first Forestry Commission trees were planted at Eggesford in Devon.

Government policy has promoted tree planting for many years.  The Forestry Commission was founded in 1919 (one hundred years old this year), specifically to help replenish timber stocks after the First World War.  Grants to farmers encouraged a big increase in broadleaf planting in the 1990’s but this has ground to a halt this century.

But now there is a focus once again on woodland clearance, notably rainforest in the Amazon basin.  As a student the figure frequently quoted was that an area the size of Wales was being lost every year; last week I read that it was now an area the size of the UK each year.  Yet planting in England has declined dramatically in recent years, with only 1420 hectares planted last year, against a government target of 5,000 hectares.

Will actions match the rhetoric, and what sort of planting do we want?  George Monbiot is advocating rewilding as a solution for both carbon sequestration and halting biodiversity decline.  Initial results from rewilding projects in Sussex and the Netherlands suggest that benefits accrue very quickly even within quite limited areas of land.  Cornwall Council have launched a “Forest for Cornwall” campaign to plant 8,000 hectares, or 2% of the county’s area, in response to the ‘Climate Emergency’ which the Council have declared. As yet there is no clear funding mechanism or detail, and some professionals are concerned about landscape and other environmental impacts.

The benefits from re-wilding in terms of biodiversity gain can be rapid and spectacular, and in a county like Cornwall could also create many spin off jobs in eco-tourism.  Re-wilding, or wilding, schemes in intense agricultural areas such as England, require perimeter fencing to contain free roaming herbivores.  This is expensive, as is the cost of management.  In the absence of high level predators (lynx or wolf), herbivores such as deer, pigs and cattle need to be kept at suitable population density through culling.  Arguably the nearest we can get to a ‘wild’ environment is a very low intensity form of agriculture.  This builds up carbon in the soil as well as the scrub and trees which develop on former agricultural areas.  The enormous increase in invertebrate populations in turn leads to an increase in bird and bat numbers.

New woodlands provide a different range of benefits which are much more tried and tested:

  • Reduce our dependence on timber imports
  • Contribute low carbon renewable energy
  • Provide eco-friendly, renewable building materials
  • Help fix carbon dioxide from the atmosphere
  • Create rural employment
  • Provide good wildlife habitat (but only if well managed)
  • Help link together existing woodlands, join up populations of species and increase resilience to change
  • Be a wonderful place to go for a walk, cycle ride or just a cup of tea and cake.

Continuous cover forestry on the Tavistock Woodlands Estate

So for now a brief personal perspective.  We do need to plant more trees in this country, and we do need to make sure they are an economic asset as well as good habitat.  And that includes conifers, essential for a wide range of timber uses.  Broadleaves can produce low carbon renewable fuel supplies that are also excellent wildlife habitat.  Some estates manage their woods on the principles of continuous cover forestry (CCF): harvesting by thinning and encouraging natural regeneration.  The Tavistock Woodlands Estate in Devon pioneered a system of CCF, the Bradford Hutt system.  It gives a very varied structure to woodlands, minimises landscape impacts, reduces soil erosion and can work for both broadleaves and conifers.  Adopted more widely it has the potential to deliver a range of benefits, enhancing the ecology while also meeting demand for timber production.

The challenges of woodland creation are perhaps greater than ever, but there is time for change.  On the paperwork side, the tree planting grants available through Countryside Stewardship and the Woodland Carbon Fund are more complicated than ever.  The Basic Farm Payment Scheme is touted as being a subsidy for farmers to look after our countryside, yet woodlands, one of the most valuable semi-natural habitats, do not qualify. Time for some changes please, Theresa Villiers?

Thinning Treragin Wood (planted by the author) is providing sustainable wood fuel and allowing natural regeneration

There are also ecological challenges: deer numbers at record levels trying to browse off young saplings (venison steak anyone?), and grey squirrels stripping bark off older trees, ruining many a hardwood timber crop.  A few more pine martens would be a good idea, if we can persuade gamekeepers to accept them back into the woodland ecosystem, as they are a brilliant natural predator of grey squirrels.

If you don’t have a spare acre or ten to plant your own wood, then the Woodland Trust has launched a “Big Climate Fightback“, seeking people to pledge to plant or sponsor to plant a tree, with a target of one million pledges.  To borrow a phrase, every little helps!

Stephen Lees