There are environmental benefits for bunds as well as improving the aesthetic of your woodland.
Contour bunds are a form of microcatchment technique. Bunds can be used to reduce water pollution and address flood risk by controlling water levels which aids habitat creation and restoration. Some areas of South East England are flat and designing bunds into the landscape of your woodland will change the appearance of your land. This will create a beautiful design and a unique style to your woodland.
Most likely, earth bunds will require planning consent, unless it is part of an existing approved landscape scheme.
Spacing of bunds depends on the slope, the steeper the slope, the closer the contour bunds can be. For environmental benefits, bunds height is usually around 20-40cm, but this can vary depending on the slope and your desired style.