Peatland ‘time capsule’ reveals prehistoric woodland habitat & insects

An area of buried prehistoric woodland, plant and insect remains, has been discovered on land cared for by the National Trust on Exmoor as part of works by the South West Peatland Partnership to improve degrading peatlands across the South West.

The woodland and insect remains, dating between the Neolithic and Bronze Ages, were found preserved in the peat taken from an area on the Holnicote estate called Alderman’s Barrow Allotment, providing a snapshot of when and how the peat formed, as well as the kinds of species of plants and insects which lived in the landscape, many of which still live in similar wet woodland areas today. 

Remains from a prehistoric woodland floor composed of fragments of trunks, small branches and twigs were found to date from around 4,500 to 3,500 years ago during the late Neolithic and middle Bronze Age (2860–2570 Cal BC to 1400–1220 Cal BC). These fragments revealed the presence of tree species including alder and willow, with evidence of birch growing nearby indicated by seeds.

Bronze Age willow found in peatland at Alderman’s Barrow Allotment Credit National Trust Steve Haywood

Samples were taken at 5cm intervals to create a 1.5m deep sequence of peat, which was taken to a specialist lab at Wessex Archaeology in Salisbury to be analysed. Discoveries included over 100 fragments of Hydraena riparia beetles, a semi-aquatic beetle that flourishes in damp conditions that still exists today, and prehistoric samples of dung beetles, rove beetles, moss mites and water scavenger beetles. 

After careful removal and analysis, woodland remains from other parts of the site, like the segment of willow tree pictured, were found to date from as early as the beginning of the Neolithic (3940-3650 Cal BC).  Plant remains also recovered from the peat indicate that sedges and rushes were growing within this wet woodland habitat, whilst birch and oak were present in the wider surrounding landscape.

Phil Wright, SWPP Historic Environment Officer said, “Despite being thousands of years old, the fragments of wood look like they could have been buried yesterday, thanks to the way peat acts as a natural preserver. 

“Peat contains very little oxygen, which means that organic materials like wood can survive for thousands of years if the peat remains in good condition. Finding such well-preserved evidence for past woodland cover can help us to re-imagine the landscape in which people lived and constructed monuments thousands of years ago.

“The remains also have the potential to answer questions about contributing affects of climate change and woodland clearance to the decline of woodland in the later prehistoric period.” 

Perfectly preserved Bronze Age remains of wood being removed at Alderman’s Barrow Allotment

Works on this site included constructing leaky log dams to help slow the flow of water through the valley and to improve water quality. This higher, more stable water table within the peat will also help to reduce carbon emissions and to increase the resilience of the landscape to climate change as well as preserving archaeology.

The peatland restoration work will also allow the peat to continue its role preserving valuable archaeology and paleoenvironmental remains, which allow us to build an understanding of the past environment and our interactions with it over thousands of years.

The SWPP received funding from Natural England’s Nature for Climate Peatland Grant Scheme (NCPGS) in 2021, with match funding provided by South West Water, Duchy of Cornwall, National Trust and Cornwall Council for work across Exmoor, Dartmoor and Cornwall.

Kat Hopwood-Lewis, Senior Historic Environment Adviser for Peatlands at Natural England shared, “The Nature for Climate Peatland Grant funding is designed to protect archaeology during restoration work and we’re thrilled to see new discoveries that help us to better understand and restore our precious peatlands.’

Ed Treasure inspects archaeological samples found in the peat, Credit National Trust, Steve Haywood

Dr Ed Treasure, Senior Environmental Archaeologist at Wessex Archaeology, specialising in plant remains and wood explained, “These discoveries provide a unique and tangible way of connecting with Exmoor’s past, and they illustrate the changing nature of landscapes and reveal how this impressive landscape came to be.

“We can use this information to develop a 'baseline' for peatland restoration studies which can extend back centuries, if not millennia. This long-term view enables us to look beyond many of the significant changes in land-use practices in peatlands which occurred during the last few centuries.”

Microscope view of beetle wings (hydraeana riparia) found in the peat Credit: Sanders Aerts, Wessex Archaeology

As well as the Bronze Age barrow that gives the site its name, the remains of two prehistoric round houses are located within a few hundred metres of the restoration works. One of these, which was found during archaeological work in advance of the peatland restoration work, is terraced into the hillside overlooking the base of the valley where the woodland once stood. 

Basil Stow, Area Ranger at the National Trust said: “We're really excited about these findings.  It’s great to think that the discovery of the prehistoric insect and woodland remains provides an opportunity to understand the vegetation and the natural processes which helped establish this thriving wet, peaty, environment many thousands of years ago.

“Crucially, all of this information will help inform how we manage the landscape now and in the future.  During this phase of restoration work we have created larger areas of wetland pools with woody dams.”

An area of peatland restoration works one year after creation at Alderman’s Barrow Allotment

Jim Parry, Archaeologist for the National Trust said, “Peatlands are incredible environments that humans have used for thousands of years, their special properties helping preserve history under our feet.

“In helping to restore and protect peatlands and prevent them from cracking and eroding, we are helping to ensure that this valuable finite archive of history won’t crumble and wash away.  Climate change is threatening to destroy untold treasures buried in the UK as the soils that protect them dry out, so peatland conservation is vital for preserving our past as well as our future.”