with the price of steel being pritty low these arn't too harsh for skillups. i personaly just recently finished skilling up smithing and have 8 stacks of steel sitting around.. was holding on in hopes of steel ging back up. dosn't look like it is. so. i got use out of em :D
walnut ~600 a log chance of HQ50%
so average ~300 a lumberx2 =600 steel is 2.5k a peace. and they NPC for 600. so you lose 2.5... ouch
on the bright side. you don't have to camp the AH for phenox feathers and don't have to try mythic poles to only fail 90% of the time and get burned there. needless to say. its not a bad bridge item