What is the most resource-efficient way to establish new woodland?

Image: Stephane Mignon (CC BY 2.0)
Image: Stephane Mignon (CC BY 2.0)

The Government’s 25-year environment plan, and now Scotland’s Forestry Strategy, have set growth targets for rural and peri-urban woodland, and the UK’s "tree champion" Sir William Worsley recently reaffirmed the Government’s commitment to plant 11 million trees across the British countryside, including in the proposed Northern Forest where planting has already begun.

Some have questioned though whether such mass planting is the more resource-efficient way for local authorities and other land managers to create or restore woodland habitats with their associated social and environmental benefits.

Cited approvingly in the 25-year environment plan, Knepp Castle Estate (see below) is held up as a successful example of natural "rewilding". One of those behind the West Sussex project is Isabella Tree, whose book Wilding was a surprise 2018 best-seller. She wrote recently that labour- and input-intensive methods of tree establishment are "expensive even with a volunteer workforce" as well as "manifestly inefficient" due to losses to drought and grazing, and to slow establishment, while imported plant material "carries a risk of importing disease".

She said organisations such as the Woodland Trust depend on "a grant system that requires precise costs, targets and predictability" and on the appeal to donors and volunteers of "physically digging a hole and planting a tree".

But Woodland Trust chief executive Beccy Speight says Tree’s views "show a lack of understanding regarding our own approach", arguing: "Whilst natural regeneration is a strong approach for all the reasons outlined in her article, it simply will not get us the increase we need in woodland in the UK."

She adds: "Where there is no natural seed source or a high deer population, planting trees with protection is sometimes the only solution, ensuring in excess of 80% survival." Its UK Sourced & Grown accreditation scheme for nurseries "minimises tree disease risk", says Speight.

"The rapid degradation of our natural world and the urgency of the situation regarding climate change cannot be solved by a single approach to creating more trees and woods in our landscapes," she continues. "We need to embrace them all and use the right approach in the right place."

Site history

Ian Rotherham, professor of environmental geography at Sheffield Hallam University, argues in his recent book Shadow Woods: A Search for Lost Landscapes that an appreciation of a site’s history should inform present-day management.

"Through detailed site work with the help of volunteers logging findings on GPS, we have turned up indicators of a lost landscape of wood pastures from the Middle Ages," he says. "These would have extended up the hillside, becoming more scrubby up to the moors. The last 200 years mask what was there before. It was a fluid landscape, which is what we want."

He argues: "By planting we are intervening — stamping a human footprint on the landscape when a more ecological approach may get better results. It takes longer but the long-term result is richer. Left alone, degraded heathland will come back quite strongly as wood pasture at low cost. It's already a biodiverse landscape and even has the mycorrhizal fungi in the soil."

As for the Northern Forest, Rotherham says: "In such upland landscapes those trees that have survived will be gnarled remnants which may be markers of biodiversity. Shadow woods are where the biodiversity is that can colonise an area. Elsewhere, some supplementary planting may be necessary. We can identify where pockets of diversity remain. The important thing is to recognise it."

This offers an alternative source of employment, he notes. "You need people who know when not to intervene and when to give nature a helping hand."

Natural regeneration typically involves a transition phase of scrub, and "the problem is how cities view it", he adds. "Scrub used to be expansive, especially in the west of Britain, and is often the most biodiverse part of the landscape, but it often gets cleared by site managers.

"Even in post-industrial sites you get really good natural regeneration. There's a degree of unpredictability, which is exciting." But he acknowledges: "In urban situations if you don't intervene you won't get anything much for 20-30 years."

As a former "city ecologist" for Sheffield, Rotherham adds: "We oversaw huge amounts of planting in what had been heavily farmed land, where we now have a young forest. It has worked well, so there is a time and a place. A lot of local authorities planted large areas of woodland in the 1980s and 90s that now need management to allow them to function like proper woodlands, with glades and deadwood, rather than plantations. But there may be no mechanism or funding for that."

Knepp Castle Estate - paying its way 

Knepp Castle Estate owner Sir Charles Burrell, who also chairs the Rewilding Britain group, explained to the Oxford Farming Conference how the estate pays for itself through a mixture of Environmental Stewardship payments, the Basic Payment Scheme (for now) and income from free-range meat, tourism, camping and leasing former farming buildings. "We have sold 60% of our ‘safaris’ for the year ahead," he said. "It’s money up front".

According to rural property agency Savills "we've made more money than the average home farm" in five of the eight years since Knepp switched, he added.

But Burrell admits: "We wouldn’t have got out of the starting blocks without funding. We had to put in 40 miles of fencing and take out 114 miles. We needed a relationship with Natural England to go forward."

As to whether Knepp’s "hands-off" approach to planting would work on more challenging sites, he tells Horticulture Week: "Look at south Norway. It used to be deforested as the UK uplands are now. After rural depopulation and seed dispersal by birds, it’s back to trees again."

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