The Summer Cut at Woodwalton Fen

Tractor raking at Woodwalton Fen - Tristan Colaco, Natural England

This time of year is perhaps the busiest time of year at Woodwalton Fen. Natural England Reserve Warden, Tristan Colaco, explains the strategy behind vegetation cutting to manage essential nutrient levels and benefit wildlife.

This time of year (late summer into early autumn) is perhaps our busiest time of year at Woodwalton Fen as this is when we do most of our grassland management. This entails cutting the vegetation and removing the cut material. Different parts of the site are cut on different “rotations”; some being cut annually, others being left up to four years between cuts, and others still not being cut at all.

Different cutting rotations should provide a range of nutrient conditions across the site. Different plants grow best with different levels and ratios of particular nutrients in the soil, so with this strategy we hopefully maintain high floristic diversity for the site as a whole.

However, the nutrient situation is unfortunately not just that simple. Woodwalton Fen is a wetland fed by groundwater that comes into the site from the surrounding landscape. Water coming in can be nutrient enriched, potentially from fertilisers and sewage, and can thus be counterproductive to our on-site management work. This problem really emphasises the importance of acting on landscape scales for conservation; simply managing Woodwalton Fen alone is not enough - careful management of nutrient inputs to the surrounding area is also needed to ensure we don’t lose diversity on site. It's one of the reasons we're so excited about the potential the new Peatland Progress project holds for demonstrating how the wetland crops used in paludiculture can improve water quality to the site. 

Woodwalton Fen drone image

Woodwalton Fen drone image - Wildlife Trust BCN

Influencing nutrient conditions is not the only impact of our grassland management. By cutting different parts of the site on different rotations, we aim to maintain a variety of vegetation structures across the site. We also add finer variation by alternating the time of year different areas are cut. As with the nutrient conditions, different species will favour different vegetation structures (sometimes even the same species might prefer different vegetation structures at different times of the year, or even different times of the day), so by maintaining high structural diversity we hopefully maintain the right conditions for as many species as we can.

The diversity of vegetation structures that result from rotational cutting showing long and short grasses

The diversity of vegetation structures that result from rotational cutting - Tristan Colaco, Natural England

Normally, the majority of the cutting of our larger open grassland areas is done using our “Softrak”. This machine runs on large tracks, so has nice low ground pressure which is ideal on a soft wetland like Woodwalton Fen. The Softrak also gathers cut material as you are working, making the process of cutting and collecting the vegetation nice and easy. Unfortunately, some problems rendering the Softrak out of action for much of this year, has meant we have had to revert to a more traditional management method. This entails cutting the vegetation with a hay mower, raking the cut material into rows, and the gathering up of these rows using a tractor with hay forks. This three-step process takes more time than the single step process of using the Softrak, so we have been especially busy trying to keep on top of our management this year!

Softrak machine cutting at Woodwalton Fen - Katy Smith, Natural England

Cut vegetation raked into rows ready to be pushed off

Raking cut vegetation into rows ready to be pushed off - Tristan Colaco, Natural England

The vegetation alongside the ditches is managed by rotational cutting in much the same way as outlined above, with the same benefits to diversity in the ditchside vegetation. However, this ditchside grassland management has the added benefit of producing varied habitat within the ditches; some ditches being opened up to the sunshine, with others being left shaded. The Softrak isn't as suitable here, as the mower on this machine sits in line with the tracks so cannot cut vegetation right by the side of the ditches without driving in the ditch. This cutting is therefore always done using the three-step process mentioned in the previous paragraph. The mowers and rakes used can be offset to the side of the tractor, meaning that vegetation can be cut right by the side of the ditch without having to drive too close to the edge. Much safer for all involved!

If the weather is kind to us over the coming weeks, we hope to finish off our summer/autumn management work of fen cutting and brinking before the site becomes too wet! We are incredibly grateful to have our wonderful volunteers back on site to help. 

Tractor raking at Woodwalton Fen

Tractor raking at Woodwalton Fen - Tristan Colaco, Natural England

We hope that you'll continue to enjoy exploring the reserve as the seasons change. Please do share any photos or wildlife sightings from your visits.