Lumberjacking is useful (as far as combat is concerned) only for swordsmanship while using axes.
Abilities
Lumberjacks receive a Damage Increase when they wield certain weapons. The formula is Lumberjack skill ÷ 5 (plus 10% if Lumberjacking is equal to or greater than 100). At GM Lumberjacking, there is a 5% chance for a Lumberjacking damage bonus of 100% from base weapon damage.
The following axe weapons and the artifacts based on those items impart the damage bonus:
Axe (Standard)
Battle Axe
Double Axe
Executioner's Axe
Large Battle Axe
Two Handed Axe
Ornate Axe
Hatchet