Apply for trees: Woodland Trust (they've been very helpful to me)
Buy trees and supplies: Alba Trees (they've been very helpful to me)
Volunteering: Trees for Life (join a group for a week to plant & learn)
Friends of the River Almond Walkway (easy way to get involved)
Friends of Cammo (easy way to get involved)
Central Scotland Green Network Trust
Community Woodland
Permission to plant: North Lanarkshire Countryside Ranger Service (they've been very helpful to me)
Other: Reforesting Scotland
Scotland's Environmental and Rural Services
Scottish Natural Heritage