This is the second progress report on two field trials with fence posts at SP’s test site in Borås, Sweden. The tests started in 1997 and 2006. The aim of the tests was to comparethe performance of posts of “traditional” materials, such as untreated, fine-textured(narrow growth rings) Norway spruce (Picea abies) and Scots pine (Pinus sylvestris) aswell as spruce posts with charred butt end or butt end immersed in a wood tar productwith preservative-treated posts, Nordic wood preservation class NTR A.

Both trials were inspected in 2016 and the conclusions reported in the first progress reportwere further confirmed, namely

Preservative-treated material, NTR class A, performs far better than untreated posts, irrespective of material, and posts of “traditional” material.

Charred butt end has not improved the durability properties at all in this trial and was the same as for untreated material.

The service life of the “traditional” materials was in general from a few years upto between 5 and 10 years. Favorable exposure conditions may give a somewhat longer service life.

“Traditional” materials cannot be regarded as realistic alternatives topreservative-treated posts, NTR A class A, even with very low expectations onservice life and cost-effectiveness.