Maiden Erlegh Nature Reserve
Due to polution from agriculture and private gardens, especially nitrates, many lakes suffer from algal blooms. These not only look unsightly but can also be harmful to fish and other animals.
In order to maintain a high water quality in the lake, twice a year the Rangers and Water Bailiffs use a Christmas tree stuffing machine to produce large barley straw sausages which are then thrown into the lake where they sink. The barley straw works by releasing chemicals into the water as it rots which inhibits the development of algae.