Hi and welcome,
with a right click on destructible objects you can see their resistances (thresholds). If any of your weapon’s damage in one of the categories (sharp, blunt, pointed) is higher than the respective threshold, you can damage and destroy the object. So you might need a different weapon to cut down silverwood trees or vanadyte ore veins. The goblins are pretty tough in the beginning. If you can’t manage to kill them by yourself, try to team up with other players.
In the future, more playable regions will be unlocked. So there will be more spots to get those resources from.