ClimbingArborist.com
Treemagineers blog
Rigging lab academy
Treetools (NZ) blog
International tree climbing championships
TreeBuzz forum
Arbtalk forum
RedBull branched out
Oregon University Tree ID tool
Arbor day foundation
Morton arboretum (US)
Westonbirt arboretum (UK)
The tree geek
International Society of Arboriculture
Arboriculture Australia
Tree care industry association
NZ Arboricultural association
European Arboricultural council
Arboricultural Association (UK)
Trees are Good
ANZI A300 Standards
ANZI Z133 Standards
BS 3998 (UK) Tree work standards