Don't know if it's a matter of not being able to, but rather a matter of knowing where the nodes are. You don't get the ability to detect nodes unless you're within 5 levels of them, as pointed out above. (1-5 for lv 5 nodes, 6-10 for lv 10 nodes, etc.)

Personally I didn't try gathering from something much higher than me, but I imagine the chance for success would be pretty low, given you don't have the gear that would be available when you're actually capable of detecting the nodes.