Plant Health Week: Planting woods for the future
To mark Plant Health Week, we're highlighting five projects that are creating new woodlands that are resilient to the threats of climate change, pests and diseases.
Pests and diseases are shaping how foresters create and manage woodlands. Diseases such as ash dieback, Phytophthora ramorum and Dutch elm disease have already altered the landscape and newer threats like Ips typographus are now putting swathes of productive woodland at risk. Climate change is exacerbating these threats as extreme weather events increase the vulnerability of trees to pests and pathogens.
This Plant Health Week, we’ve compiled five case studies from our Grants for Resilient Woodlands programme. Each of them shows how landowners and foresters are future-proofing their woodlands. While a single-species woodland is at risk of being wiped out by a single disease, woods planted with a diversity of species are far more resilient.
A template for the future: Simons Wood, Cambridgeshire
At Simons Wood near Peterborough, ash dieback led the team at Milton Estates to rethink how they restocked their wood. The 22.7-hectare ancient semi-natural woodland had been dominated by ash and oak since being planted in 1900, but by the wet winter of 2020, 90% of the ash had to be felled. Rather than replanting like for like, Forestry Manager Dan Cammarata-Hall wanted to introduce a greater number of species to prevent a similar event from happening again.
With support from an RFS Grant for Resilient Woodlands, 1,700 young trees of nine different species were planted across a two-hectare compartment in 2022. This included pedunculate oak, hornbeam, black walnut, yew and wild privet. This restocked compartment is intended as a template for the wider estate, where principles of continuous cover forestry (CCF) begin to be introduced.
The site also sits just outside the extended demarcation zone for Ips typographus, the larger eight-toothed European spruce bark beetle. The pest has decimated spruce forests across central Europe and since being discovered in England in 2018, the beetle poses an existential threat to the UK’s most common productive tree, Sitka spruce.
“Where once we had just ash and oak with a hazel understory in this compartment, we now have nine species,” says Dan. “This adds biodiversity and ensures the woodland would continue if a new pest or disease impacts any one species of tree.
“The long-term objective will be to create a productive and diverse forest, structurally and in species composition. This will reduce risks posed by future changes in climate and biotic threats.”
Planting for resilience: Candacraig Estate, Aberdeenshire
When Storm Arwen swept through Candacraig Estate in Strathdon in 2019, it caused significant wind blow, but it also created an opportunity for experimental restocking and restructuring. The 1,700-hectare estate, sitting within the Cairngorms National Park, had relied almost exclusively on Sitka spruce and Scots pine, making the woodland vulnerable to storms and disease.
With an RFS Grant for Resilient Woodlands, RTS Forestry helped restock the damaged compartments with over 20,000 trees across approximately ten hectares, trialling an ambitious mix of twelve species, including Serbian spruce, western red cedar, Douglas fir, western hemlock, aspen and rowan. Data collected will inform future planting and assess tree health, measuring resistance to weevils, recording height variations and tracking mortality rates.
The estate is also experimenting with protection methods, trialling traditional deer stalking alongside Trico, a scent-based deterrent derived from sheep fat, to safeguard the new plantings.
Climate change, future pathogens and increasingly severe weather events all influenced the species selection. As the estate’s forestry team notes, a warming, wetter north-east Scotland may eventually make even Sitka less suitable, so the time to experiment is now.
Replanting after disease: Harewood Estate, West Yorkshire
Sometimes, plant health decisions are hard to explain to the public. At Harewood Estate near Leeds, a stand of 1960s poplars had to come down. They had succumbed to butt rot and posed a risk to road users on the busy A61 and to walkers on the estate’s popular circular walk.
With around 50,000 vehicles a day passing the site, the felling was met with concern from drivers and walkers. The estate responded proactively, communicating the reasons through parish magazines and social media. They explained how felling the trees will boost resilience and add greater biodiversity, among other benefits.
The estate received a grant to plant 1,900 trees and shrubs of multiple species in winter 2021–2022. This included pedunculate oak, wild cherry, Scots pine, sweet chestnut and a fringe of mixed shrubs including hazel, hawthorn, and elder. Open areas were left to encourage wildflower recovery, and Scots pine was chosen specifically to support the estate’s growing population of red kites.
The replanting has not been without its challenges. Drought followed by prolonged wet weather took a toll, but the sub-compartment is already more diverse than it has been for decades, the growth of ground flora has been extensive and public support for the project was strong.
Beyond Sitka: Windy Gap, County Tyrone, Northern Ireland
At Aughentaine Estate in County Tyrone, a 4.44-hectare compartment known as Windy Gap is testing whether any species can rival Sitka spruce for productive timber on challenging upland sites. There is currently a major reliance on Sitka spruce for timber production and while Ips typographus is not present in Ireland, experiments like these will help determine alternative species for upland regions where Ips poses more of a threat.
The estate has managed commercial conifer woodlands for over 60 years and owner, James Hamilton Stubber, wanted to “investigate if there are alternative species which could be of value to the industry.”
Nearly 10,000 trees of seven species, including grand fir, Japanese cedar, European larch, western red cedar, western hemlock, Douglas fir and Norway spruce, have been planted in pure blocks for direct comparison. Disease resilience is factored in from the start. The estate hopes that European larch, unlike its hybrid cousin grown elsewhere on the property, may prove resistant to Phytophthora, a disease that has already caused them losses. Pine weevil will be monitored every six months for the first five years.
The results will be shared with woodland owners, timber growers and processors across Northern Ireland to help support the wider forestry sector in Northern Ireland.
Planning for a future climate: Eucalyptus in North Yorkshire
At Constable Burton Estate near Leyburn, owner Charles Wyvill and his son D’Arcy are asking whether eucalyptus could be part of Britain’s woodland future. The eucalyptus tree is native to Australasia and is used in productive forestry across South America, parts of Asia and warmer parts of Europe.
As they look to the future, Constable Burton Estate is considering species which are expected to thrive in the climate expected in Yorkshire in 50-80 years’ time.
Four species were chosen for their cold tolerance and productivity, planted among naturally regenerating birch, which acts as a nurse crop. The first years were a challenge with an exceptionally hot, dry summer followed by a harsh winter, which led to a 70–80% failure rate in some blocks. But eucalyptus, as the estate discovered, can be deceptively resilient. Many trees that appeared to have died have since regrown. The beat-up plantings are now in place and expectations remain positive for first thinnings within six to seven years.
These five case studies show us that the best defence against pests and disease is a woodland that doesn’t put all its eggs in one basket.
Whether responding to ash dieback, Phytophthora, bark beetle or possible future threats, these foresters share a common approach of planting diverse sepcies, monitoring progress closely, and sharing with others what they learn.
The Royal Forestry Society’s Grants for Resilient Woodlands, funded by Train Hugger and Green The UK, are open year-round to RFS and RSFS members.
