Woody Debris - Some Examples
- Category: Habitat Improvement
- Published: Wednesday, 22 December 2010 13:49
- Hits: 1806
A perfect barbel fishing swim (right). The overhanging trees and the woody debris in the water will attract barbel and chub. Underwater, the woody debris provides shelter and shade and can create a food hotspot which is why the fish love it. A certain amount of tree cover and woody debris is essential for a healthy fishery and to maintain the ecology and biodiversity of a river.
However, it has to be accepted that too much of a good thing can be a problem. Woody debris accumulating against structures such as bridges can cause a serious flood risk and may even cause damage or collapse. This is one place where woody debris is unwelcome and it is quite justified to expect it to be removed.
Nature usually provides a good supply of fallen trees to create woody debris and good barbel swims. In this case (below left), a willow has fallen into the river during a gale. This tree is just fine as it is, being firmly anchored to the bank and unlikely to move during floods. It is also alive and growing which helps to create new habitats for wildlife such as nesting birds.
Large woody debris such as (above right) this is a natural part of the river ecosystem. It may not look like it is doing much, but under the water, a lot is going on which results in major changes on the river bed.
(Left). Below this piece of large woody debris, you can see just how much effect a fallen tree has had on the river bed.
(Below). Although trees along the banks of rivers fall into the water after storms or by errosion for example.Woody debris can be put into the river to create new habitat for fishes, just so long as a few simple rules are followed. If done properly, woody debris will represent no flood risk and will provide esstnail shelter for fishes.
(Below). This tree has been firmly anchored and is not going anywhere. There is no risk of this providing a risk to bridges. This large piece of woody debris was created by felling tree and anchoring it to the bank. A living tree will survive and continue to grow, providing habitat for many species above and below water. Leaving the tree attached at the base will anchor it to the bank and ensure it carries on growing. Such extreme treatment may seem to be a bad way to treat a tree, but they soon recover and start growing again.
And finally, make sure you read up on woody debris before even planning anything and you must contact the EA and the land owner to agree any works to be carried out.