In the western highlands live the warlike Oelha tribes. The Oelha are infamous raiders left over from one of the hordes that ravaged the land generations ago. Oelha frequently steal cattle and attack outlying villages of the neighboring kingdoms or other clans. While being warlike and vicious the Oelha are also fine craftsmen and metal workers their lands are poor in metal. This means that most of the metals Oelha have go straight into the nobility and straight into swords. The Oelha need some sort of armor to be able to successfully raid further into their neighbors territory since they would come into contact with better arms and armor the further they travel. The Oelha's solution was to make armor out of the trees that surround their homes.
What I'm wondering is: would wooden armor cut into scales and sewn together be effective armor? Would wood be able to hold up against weapons common place in the Medieval High Period? Ex: long swords, long bow, pole axe, etc
Note: they have access to lots of oak trees