Working with woodland advisers to champion natural processes

By Vanessa Burton, Woodland Trust.

​A sunny August midweek found an unusual collection of woodland ecologists, advisers and practitioners coming together in the National Forest. We weren’t the usual clientele for the Deer Barn, which usually hosts weddings or kids for the adventure park (although some of us had to resist the temptation of the huge bouncy slide). The aim: to share knowledge around integrating more natural processes into woodland creation practice, and all made possible by a collaboration between the Woodland Trust conservation training programme, the TreE PlaNat research project and the National Forest.

This two-day knowledge exchange and training event aimed to: 

• disseminate the latest evidence from the TreE PlaNat (and other relevant) research projects 

• enable practitioners and advisers to network and share knowledge, and  

• develop the latest in a series of woodland creation training events run by the Woodland Trust across the UK

Learning from Simon Greenhouse (National Forest Company) at Yoxall Park Farm (photo: Elisa Fuentes-Montemayor)

More complex structure = better for nature

We kicked off hearing from Elisa Fuentes-Montemayor, TreE PlaNat’s principal investigator, about the learnings from the long-term natural experiment, WrEN, or “Woodland creation and Ecological Networks” which has been running since 2013. This project has set up a replicated chronology of woodland creation sites in Scotland and England and has carried out numerous field surveys on these sites over time.  ​

The WrEN project has given us a great understanding about how planted woodland creation sites develop over time. We know that habitat development is slow, and that it takes from 80-160 years for characteristics similar to that of an ancient woodland to develop. Most sites also show a significant lack of natural regeneration in the understory. In terms of biodiversity outcomes, creating new woodland adjacent to existing ones (i.e. close proximity) is really beneficial for several taxa including moths, small mammals and plants. We also know that more complex woodland habitat structure (e.g. gaps, fallen trees, variety of tree sizes) is associated with greater abundance and/or diversity in many taxa. 

Can natural processes create more structural complexity than planting alone?

So, we know a decent amount about planted woodlands - that they can lack some of the features of a ‘good’ habitat, and that it takes a long time for these features to develop. Because of the urgency of the nature and climate crises, there’s therefore a lot of interest in (and expectations of) natural processes such as natural regeneration and natural colonisation, to help us meet national creation targets. It’s often assumed that these processes will create woodlands with more complex structure (therefore benefiting biodiversity) and be more resilient than planted woodlands. 
 
However, as highlighted by Kevin Watts on the day, to date there’s been a limited evidence base for the outcomes of woodland created via natural processes, because of a small number of studies, highly variable results & possible survivorship bias, where results are only reported when they’re positive (i.e. where natural colonisation successfully resulted in a new woodland). We have some limited knowledge about what to expect from recent research (see Bauld et al. 2023), but research gaps remain, and TreE PlaNat has been aiming to fill some of these.  
 
Laura Braunholtz talked the group through some early results from the ecology work package of the project, where new woodland creation sites created by planting, natural colonisation, and a hybrid of the two have been compared. Structure came through as an important variant between the three methods, and often correlated with biodiversity measures. Planted sites were predominantly uniform, while higher ‘gappiness’ in hybrid sites with a mixture of planting and natural colonisation was associated with higher floral species richness and moth species riches & abundance. 
 
If you’re keen to find out more, take a look at Laura’s blog https://www.wren-project.com/tree-planat-blog/notes-from-the-field, Thiago & Sam’s blog on structural measurements of the field sites using LiDAR https://www.wren-project.com/tree-planat-blog/lasering-trees-for-science-how-we-use-lidar-technology-to-understand-woodland-ecology and the ecology webinar https://www.youtube.com/watch?v=cAN-ylzGgWE.  ​

Assessing potential for natural processes

After hearing from the research team, we hopped on a minibus to visit a new site for the National Forest where they’re undertaking woodland creation in collaboration with the landowner. After a tour from Simon Greenhouse participants were split into groups and asked to assess the site for it’s potential to accommodate natural processes. Factors to assess for included: 

• The wider landscape 

• Seed source 

• Current land use 

• Soil type 

• Vegetation 

• Existing colonisation 

• Herbivory pressure ​

Woodland edge provides potential seed sources for natural colonisation at Yoxall Park Farm (photo: Hayley Wood)

Designing woodland communities

On day two, the groups took pre-prepared woodland creation designs for the site and discussed the appropriate woodland communities (species composition) and method choices for the site, making use of the Woodland Trust Tree Species Handbook. ​

Four common trajectories for natural processes

We finished by discussing four possible trajectories for natural colonisation sites that have been highlighted in work by Forest Research. We explored how natural processes might result in: 

1. A woodland community similar to source woodland 
2. Unpalatable vegetation (e.g. bracken, bramble) dominating 
3. A single tree or shrub species dominating 
4. Very few trees establishing at all 

 
The groups had valuable discussions about how to respond in each of these situations. A recurring theme was that good monitoring and adaptive management are essential to respond appropriately, but that these are currently hard to do in practice due to time, resource and guidance limitations. ​

It's not over yet!

Oak seedling in grassland at Yoxall Park Farm (photo: Elisa Fuentes-Montemayor)

Our two days in the inspiring National Forest landscape (which during the event, celebrated reaching 25% woodland cover https://www.nationalforest.org/whats-new/news/sustainable-success-celebrating-our-landmark-achievement-of-25-forest-cover) were positive and collaborative, and there was appetite for more. This year there will be two further training events “Working with natural processes for woodland creation” via a partnership with Natural England: 13/14 (Yorkshire) and 21/22 May (Surrey). 

​As we enter the new year, TreE PlaNat is wrapping up – so take a look at our existing resources, keep an eye out for upcoming ones (e.g. some simple monitoring guidance to support land managers – sign up to our mailing list here), have a look at the Woodland Trust’s suite of Woodland Creation guidance, and reach out to Hayley Wood ([email protected]) if you’re working in a woodland advisory capacity and you’re interested in coming along to the this year’s training events. 

Big thanks to Heather and Simon at the National Forest for hosting us.​