Ancient Tree Hunt
- Campaign to record and map ancient and veteran trees. Includes information on ancient trees, interactive map of trees found and ability to add new records.
- http://www.ancient-tree-hunt.org.uk/

International Society of Arboriculture UK and Ireland Chapter
- Information about the society and membership, tree care advice and information on finding an ISA certified arborist.
- http://www.isa-arboriculture.org/

Consulting Arborist Society
- Lists members able to provide reports on various aspects of tree care. News and list of upcoming events organised by the society.
- http://www.consultingarboristsociety.co.uk/

Tree Aid
- UK based development charity supporting tree planting and reafforestation in rural Africa.
- http://www.treeaid.org.uk/

The Tree Register
- Charity recording Britain's largest trees. Information on measuring and reporting trees. The database of champion trees can be accessed by paid members.
- http://www.treeregister.org/

The Trees and Shrubs Website
- An interactive key to identifying 80 trees and shrubs commonly found in the UK and Ireland.
- http://www-saps.plantsci.cam.ac.uk/trees/index.htm

Trees for Cities
- Independent charity working with local communities on tree planting projects in urban areas.
- http://www.treesforcities.org/

Trees Are Good
- Extensive collection of tree care advice for the consumer, provided by the International Society of Arboriculture.
- http://www.treesaregood.org

Arbtalk
- Discussion forum aimed principally at those professionally involved in tree care.
- http://www.arbtalk.co.uk/

Tree-care.info
- Information on many aspects of tree care. Includes an advice forum and help finding a tree surgeon.
- http://www.tree-care.info

Quantified Tree Risk Assessment
- A probabilistic method of assessing the risk of harm posed by trees. Includes information on training and a directory of trained users.
- http://www.qtra.co.uk/

Trees and High Hedges
- Details of UK legislation, government guidance and policy relating to trees and hedges, from the Department for Communities and Local Government.
- http://www.communities.gov.uk/planningandbuilding/planning/treeshighhedges/

Edinburgh Centre for Tropical Forests
- Association of 5 organisations promoting sustainable development and forestry through co-ordinating research.
- http://www.ectf.co.uk/

Growing Citrus
- Tips and other information on the challenge of growing citrus trees.
- http://freespace.virgin.net/d.hardy/

British Trees
- Collection of pointers to information about British native trees and woodlands, with information on each of the 33 native tree species.
- http://www.british-trees.com/

Tree Advice Trust
- Independent charity offering expert advice by premium rate phone call. Tree damage alert bulletins available to download. Various other publications can be purchased.
- http://www.treehelp.info/

Institute of Chartered Foresters
- Details of the ICF's activities, list of members practising as consultants.
- http://www.charteredforesters.org/

Ancient Tree Forum
- Information on ecology, management and conservation of veteran trees. Includes a discussion forum.
- http://www.woodland-trust.org.uk/ancient-tree-forum/

The Woodland Trust
- Details of the Trust's woodlands and activities taking place in them, of their campaigns, publications and of how to get involved in protecting native woodland.
- http://www.woodland-trust.org.uk/