Saturday 7 March 2015

Clearing the river bank

I was able to put some time and effort into clearing unwanted trees from the river bank at the Turnditch orchard. The purpose of the clearance is to give some light for willow. We intend to plant the willow as woven spiling to protect the river bank from further erosion. This part of the River Ecclesbourne is prone to scour after the bridges in the fast flowing winter spate. 

We are initially removing some large hawthorn bushes which are overgrown, tangled and threatening to fall over into the river. We cannot simply fell the bushes as the weight of the top growth would cause them to topple into the river and make recovery much more difficult. Even directional felling cuts would not guarantee a safe or convenient fall of the bush. These bushes are about 20 ft (6 metres) tall and probably weigh about one tonne. They each have several upright trunks clustered around a root.

To achieve safe removal we're using cable winches to apply tension from the best direction. Once the trunk is under tension using a chainsaw we apply a partial felling cut, but not enough to fell that section of the bush. We then retire to the winch and increase the tension until the trunk disentangles from the top growth and falls. Using the winch we pull that section of the bush to a safe place where we can cut off branches then cut up the trunk. We are using an indirect pull from a cable winch and steel wire. The direction of the pull is set up using a snatch block pulley anchored to a convenient place.

We are delivering a coppice type cut to the hawthorn. It should allow them to regrow, but this time the process will be managed!

View of indirect winch set up.
Indirect winch arrangement

The snatch block anchored to old gate post:
Snatch black anchoring
The cable winch:
Cable winch anchored to ash tree
Applying tension to the bush:
Apply tension prior to cutting

The next step will be to remove half a dozen small Elm trees on the river bank. I noticed last year there were badly wilting which suggests they have Dutch Elm Disease. We'll burn the wood on site to prevent any further spread of this tree disease.