Here are some links you may find interesting.

Botanical gardens and Arboreta

Arboretum de Villardebelle — www.pinetum.org

Societies

The British Conifer Society — www.britishconifersociety.org.uk

Northern Nut Growers Association, Inc. — www.nutgrowing.org

Other Online Data Sources

Trees for the Future — www.plant-tree.org

Enviropedia — www.enviropedia.org.uk

Gymnosperm Database — www.conifers.org

Oaks of Bialowieża — www.deby.bialowieza.pl

Pálmaliget — www.palmaligetetmagyarorszagnak.com

The Tree Register — www.tree-register.org

Places of Peace and Power — www.sacredsites.com

Treemail — www.treemail.hu

Nemzetközi Dendrológiai Alapítvány — www.dendrologia.eu