It is indeed possible by editing the harvest components. For trees, there is a harvesting component wood, extra wood, and less wood BP. In those they havethe item it drops, the distance they respawn, and the time it takes to respawn. I believe you can make them children (need to make sure when I get home from work) and they need to be remapped in the primal game BP. I tested and it does work. I had trees and stones respawning in 2 min or less at a distance of roughly 20 meters. By the way, you need to start on a fresh map for the changes to take place if you are trying to do it for a saved ark.