i like your method as i have found radiosondes in trees and had the same problem i have been using a long pole with a sharp razor blade on it but it's very hard to cut a cord hanging in the air with a blade. but your nichrome wire trick gives me idea of using a V of nichrome wire on my poles to touch the string or cord and have a battery pack with wire leads and a switch that will trigger the nichrome wire
You gives me an idea for Radiosonde. Just using CO2 laser, say 30W is sufficient. In the case radiosonde hang from the tree, fire laser and burn string. Easy. Not so easy carrying all that glass laser tube, water pump, water canister, battery, PSU converter (HV)...
Hey Tory, that's pretty cool. One question though; will the leads with special wire be left exposed like in your test simulation? If possible, it might be a good idea to put some type of protective covering over it so that if you crash into a tree, the wires aren't damaged by the branches, thus rendering it inoperative. Just a thought......