Bentley Priory Nature Trail
Post 19: You can now see that Summerhouse Lake is artificial, formed at the time of the Marquis of Abercorn by damming the valley of the Stanburn that falls away to the southeast. The lake and dam are maintained by the Environment Agency as a flood defence; at times of heavy rain, the lake can be allowed to fill up to the top of the dam then release the water slowly. The small tree by the post is an elm Ulmus procera. Elm leaves are often highly assymetic at the base (see illustration below). Dutch Elm Disease kills any plants that grow larger than these small trees here, but elm is still common as a woody shrub in this area of the reserve.

Coot, moorhen, mallard and mandarin duck breed on the lake in summer, along with Canada geese. Winter visitors include the small black and white tufted duck along with shoveler, goosander, pochard, gadwall, teal, dabchick and black headed gull.

From here, go over the stile and turn left along the track. Look out for Red Campion Silene dioica - there is a chance of seeing flowers all the way from March through October. The flowers have five petals, each deeply divided (see illustration below). Red Campion likes the richer clay soil in the south of the reserve.


Image: Elm leaves


Image: Red campion

To description for post 20

Click here to learn more about the Harrow Nature Conservation Forum including guided walks and conservation workdays.