An authority for arboricultural good practice, the Association delivers professional standards and guidance to industry and others, facilitating the responsible and competent management of trees.

The Royal Chartered body for forestry and arboricultural professionals providing support to members, guidance to the public, training and educational advice to students and professionals developing their career.

The world’s biggest group of professional arborists with over 20,000 members distributed throughout 38 ``Chapters`` across the 5 continents.

Econics is an approach to studying the dynamics and functioning of (complex and holarchically nested) ecological systems with the aim of deriving management solutions for natural resource-dependent socio-economic systems as a gateway towards sustainable development under global change.

The Green Infrastructure Partnership is a rapidly growing network of people and organisations that support the creation, enhancement and promotion of green infrastructure in the UK.

The United Nations Environment Programme (UNEP) is the leading global environmental authority that sets the global environmental agenda, and sustainable development within the United Nations system.