In recent years there have been many pledges by governments, organisations, and private individuals in the UK to plant a certain number of trees – be it 50 or 20 million. However, if these bold and headline grabbing pledges are not done properly they can lead to unsuitable forests planted in unsuitable places. We must go beyond just planting trees if the goal is effective reforestation or rewilding.
From a forestry perspective, the focus on “tree planting” oversimplifies a complex issue. The underlying sentiment: a desire to increase forest coverage in a country like the UK, where only 13% of land area is forest, is very welcome for a wide range of environmental reasons. These include, but are not limited to: carbon capture, biodiversity, aesthetics, and flood control.
However, reestablishing forests is not just about planting trees – and in practice does not necessarily require any tree planting at all, forests can and often do reestablish themselves if efforts are made to ensure grazing animals are excluded from an area of land. This is particularly true if there are plentiful tree seed banks nearby (i.e. in regions where there are already existing forests, or the area was deforested only relatively recently). However, it is also true that in the UK, these conditions do not prevail over large areas of farmland, and reestablishing trees often requires some help.
A few quotes from Oliver Rackham’s classic book Woodlands – essential reading for anybody with an interest in forests and woodland in the UK:
- “Plantations can have many different fates through design, accident or neglect”.
- “About 40% of vascular plant species in ancient woodland (in the UK) have been unable to colonise new woodland even after 400 years”
- “Creating new woodland by letting ‘scrub’ take over abandoned land has been forgotten, although it happens daily before the eyes of millions of commuters on trains”
- “Effects of replanting vary from trivial to catastrophic. Whether the planted trees survive and whether they become dominant depends on the species previously existing, the species planted, the site, the degree of maintenance and neglect”.
- “Plantations are clearly not adequate substitutes for ancient woodland even if they consist of native trees. Farmers should give priority to conserving ancient woodland if they are lucky enough to own some, and developers should not pretend that plantations are adequate substitutes for ancient woodlands that they propose to destroy”.
Alongside these ecological issues, there’s a complex range of social and economic issues involved with forest re-establishment, particularly in a country like the UK which is heavily populated and where there is strong demand for land for alternative uses. To re-establish forests it is first necessary to convince land-owners that this is in their own interests, and in the past even fairly generous grants have been insufficient to encourage tree planting, which after all requires that they tie up land that could used for agriculture or other development for decades at a time, and over which they may lose nearly all control once it becomes a woodland and therefore subject to felling license requirements and tree conservation orders.
For these reasons, while the sentiment should be welcomed, it is prudent to be rather sceptical of tree planting pledges made for short term political gain. From an environmental perspective, there are many good reasons for the UK to better protect existing woodlands and to seek to expand the area where the conditions are right, but it is questionable whether the UK has a sufficiently strong comparative advantage in commercial forestry to encourage a large scale expansion in forest cover. Other countries (like the US) are better placed in this respect, having much larger area of under-utilised land, much of which has never been converted, or only for a short period, and which retains deep natural soils and extremely well stocked tree seed banks.