we use winches, ropes, cables, pulley blocks etc - for tricky trees - we couldn't manage in our wood without them (we don't have access to tractors or other machinery - so we have to do everything by hand - unless you know what you are doing, attacking the leaners with the chainsaw out might not be your safest option
my old dad is a bit of an expert in the use of ropes, pulleys and winches etc - (and with leaning / snagged up trees) and i am sure he would be happy to talk through / show you the basics of using this sort of kit and how to tackle troublesome trees - if you fancy a day trip out to hampshire - just let me know -