Board Thread:Questions and Answers/@comment-203.109.173.133-20130419215928/@comment-7486518-20130420174416

There is no way to reduce the cost of clearing trees. The cost of each tree (by name, not by shape) stays the same for everybody once you leave the first starting level of the island... I think prices range from 30k to 800k on the trees and from 7.5k-900k on the rocks... The Mushrooms are always low cost and fast though.

There is a thread on the Team Lava discussion forums that has mapped the "least expensive" expansions if you want to see it. I don't have the link available, maybe someone else does?

Either way, there's no trick or method to lower the cost... It's meant to be expensive so you feel forced to buy silver with Gold, which generally means you buy Gold with RL money.

Just be patient and save up the silver... Don't buy decorations and plant sparingly when you're trying to clear something expensive... When you get high enough level, and with enough dragons that earn well, you'll not have this problem much. =)