Decades ago, RSPB Blean woods would have been a part of a hectic timber industry, fuelled by wars and the need for ships. The priority was not its spectacular wildlife, peaceful woodland walks, or its resilience to any changes in climate, but simply the speed of which timber could be grown and extracted from site.
The priorities have now changed drastically. Rides and coppice plots are partially cleared on a rotational basis to maintain a variety of ages within the woodland flora, with timber sales from these practices helping to fund the conservation of the woodland. However, remnants of the more intensive management of the past remain, and one of those remnants is the straightening of our wonderful Sarre Penn, the largest watercourse that runs through the centre of the wood.
The natural course of the Sarre Penn, and that of many other streams, is a charming series of meanders where the watercourse winds and wiggles its way through the landscape. You can still see the Sarre Penn doing this, particularly on the eastern side of the site. However, certain sections that may have been problematically wet during timber harvesting have been artificially straightened, leaving the historical meanders ‘high and dry’ and the watercourse looking more like a roman road. This was done to accelerate drainage and remove water from site as quickly as possible.
Figure 1 On the left you can see the natural shape of the Sarre Penn as it enters our woodland, and then how it suddenly becomes extremely straight after crossing a footpath. The light blue lines represent the old, natural route.
One of the most exciting aspects of our project is to reconnect these historic meanders to the main channel, using only materials from the woodland and kickstarting natural processes to make this happen. Wood and brash is being used to block the straightened sections of the watercourse, while the entrances to the meanders that have been blocked off with earth are being reinstated. It is hoped that in time, water that is backed up by our new dams will be forced the long way around the meander, gradually eroding the historical route back to its former glory.
Our contractors have only just got started, but the results so far are already promising! Some meanders are already filling up with water after heavy rain, and the dams are doing a fabulous job of holding water back.
Figure 2 One of the first dams to be installed, and it's already raising the water level!
As well as aesthetically pleasing, this work will also help create a more resilient woodland in the face of climate change. With drier springs and summers expected, the dams and meanders will help hold water from high rainfall events in our woodland for longer and reconnect the natural floodplain, providing wildlife with the damper conditions it needs to survive and thrive.