Instructions
Speak with the Green Gremlin who hangs out in front of the crow̵7;s nest. He will tell you that he can fix the crow̵7;s nest as long as you have the scrap metal.
Give the Green Gremlin the scrap metal he needs. Leave Ventureland and come back so that he can complete repairs. Simply exiting the zone and re-loading it is enough to see the repairs finished.
Ride the lift at the crow̵7;s nest into the trees. Run to the farthest tree to the right, and help Oswald zap it. Go to the tree to the far left, and help Oswald again. Zap the middle tree, and use thinner on the top to find one more zap spot.
Collect the treasure at the base of the crow̵7;s nest when it opens.