When hedging is not practical, e.g. as in the case of an ancient woodbank, boundary, and a physical barrier is required, then a post and barbed wire fence can provide a useful approach.
Unfortunately after a while the posts will tend to rot through at ground level even when these are made from nominally durable timber like Western Red Cedar. The reason for this is very simple.
Posts are made from fairly small diameter straight pole trees which will contain a minimal amount of durable heartwood and a high proportion of perishable sapwood. The fence post above was sawn through at the neck to determine just how well the post stood up in service.
The untreated rotten end was then split along its length to determine what was happening inside the post.
This revealed that the relatively juvenille heartwood of western red cedar is durable with the outer sap wood visibly perished.
I have found that untreated cedar posts will last for between 5 - 10 years in the ground before they break off at ground level. This length of service is insufficient especially if KM of fence are involved.
Rather than repeat this eco friendly approach I have decided to trial using home made treated posts where the bottom 2.5 - 3 ft of the posts are soaked and painted with creosote. Creosote is quite a nasty material and is no longer available for the general public to buy in small 1 gallon / 5 litre cans at the garden centre or hardware store for domestic use, however contractors & agricultural / forestry persons engaged in larger scale work can still buy 25 litre drums and use same provided they follow the clear personal health & safety guidelines.
The above ground portion of the fence post does not need to be treated and in any event this part of the post will need to be grasped to hold and drive same into its final position and secure the wire to the posts using staples.
The ends of the fence post (0 - 12") can be stood in an old oil can and allowed to soak up creosote whilst the upper (12" - 36") can be treated using a paint brush. The posts should then be left for several days on top of an old pallet so that any surface creosote is absorbed into the wood.
I have found that untreated larch & hand split oak posts can last for decades in the ground and so when these timbers along with split chestnut are available then they should be the first choice for fence posts.
Chilterns
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