The Woodcutting Instructor can be found in Dorpat (26,27) as well as in the Woodcutting Guild located in Moche (57,72). To access the Woodcutting Guild, a player must have 80 in woodcutting and have a Woodcutting Guild Permission (costing 98,000) in the players inventory.
When spoken too, the instructor will recite the below text.
"With woodcutting you can cut
trees and get different woods
that can be used to create items."
"To cut a tree you need to equip a
woodcutter's axe first and then
click on the Fir Tree."
Note from editor - Since I personally do not yet have 80 woodcutting required to enter the woodcutting guild, I cannot say whether the Woodcutting instructor in Moche says or offers anything different than the Instructor in Dorpat. If someone who is reading this does knows, you can update this page with said information and delete this note, or you can contact me with the info to make needed changes; thank you.