The exact reason why Gerim was 'chosen' is because he was not very well-liked. He had a habit of taking shortcuts. Shortcuts that never worked out and often had a dangerous side to them, and worst yet, those he worked with consistently took the blame. So why would Gerim take any different route to solve his village's problems? 

Merthild's elders told Gerim to venture into the forest's center. There he would find a shaman that had in the past advised the region's city Mirtheu to prosperity. So they hoped he would do the same for Merthild. If not, maybe the shaman could point him towards someone who could. 

Gerim, being Gerim, had other plans. He didn't want some "useless" sage advice, hell, he didn't even want to help his village. He just wanted to be rich. Plus the forest's center was weeks away, while the forest's edge was but a few days. A few days of travel towards the forest's edge would be all it would take to get to an elderly blacksmith.  A blacksmith that was rumoured to be able to forge a blade that could slay any beast. "Surely a blacksmith of his repute could forge an axe to cut the Emerald trees," Gerim thought and using the axe he planned to become wealthy. Wealthy from selling the lumber of the Emerald Trees.