Taxodium distichum and Nyssa aquatica, the two dominant species of bottomland hardwood forests. Congaree National Park, South Carolina
The United States: a hotspot of diversity for relict trees

The eastern and western coasts of the United States have played a particularly important role as climatic refugia for plants during cold phases throughout the Cenozoic. Nowadays, these regions share some of the rarest relict trees with Asia and the Caucasus (e.g. Gleditsia, Liquidambar, Castanea). The United States are also very important for the Juglandaceae family, with approximately 11 species of Carya distributed along the East Coast and 6 species of Juglans along the West Coast. Thus, it became essential for the Zelkova-Team to enhance the general knowledge and understanding of relict trees and in particular of members of the Juglandaceae family coming from the New World. Therefore, an expedition was organized in the USA in October 2016 with the great help and collaboration of the Arnold Arboretum of the Harvard University.

Fruits of Pterocarya rhoifolia, Royal Botanic Garden Edinburgh
Royal Botanic Garden Edinburgh – the paradise of Pterocarya researchers

Understanding the ecology of a species requires expeditions to its country of origin and visiting its wild populations. However, field explorations are often cost- and time-consuming, especially when lacking a solid background on the species that we want to study. The Royal Botanic Garden in Edinburgh (UK) offers a unique alternative and allows studying different species of the genus Pterocarya found in its ex-situ collections. 2016 we have visited the garden twice and been able to observe the most important criteria of differentiation between the species (especially terminal buds, leaflet and nuts) and bring back numerous pictures and knowledge, which will be very helpful for future expeditions in wild populations of Pterocarya in Asia. We would like to thank warmly Peter Brownless of the Royal Botanic Garden of Edinburgh for his precious help and advice.

Alfaroa williamsii
Juglandaceae of Neotropis: Alfaroa and Oreomunnea

In April 2016 our Zelkova-team organized a scientific expedition to Costa Rica in order to explore and collect iconographic material of poorly known Juglandaceae of Neotropis. Costa Rica is center of species diversity for two genera of this family: Alfaroa (minimum 4 species) and Oreomunnea (2 species). They are typical elements of mountain forests and are growing often accompanied by some other trees belonging to temperate families and genera (e.g., Quercus, Alnus, etc.)

Pupils planting their tree
Ex situ plantation of Zelkova abelicea with primary school of Skine-Fourne (Crete)

As part of the Zelkova abelicea conservation project, an ex situ plantation was established in the Levka Ori with the involvement of the Municipality of Platanias, the Forest Directorate of Chania (FDC), the Mediterranean Agronomic Institute of Chania (MAICh) and the local Primary school of Skine-Fourne.

Exploring Cuc Phuong National Park, Vietnam

Pterocarya tonkinensis has the most southern distribution among the species of the genus - it occurs in riparian forests of Southern China, Laos and Vietnam. An expedition was held in 2015 in order to find and investigate this fascinating tree in Vietnam in collaboration with the Vietnam National University of Forestry in Hanoi.


Our research and conservation activities

  1. Basic and applied research on relict, rare and/or threatened woody species (biogeography, conservation biology, phylogeny, phylogeography, population genetics, population structure, dendrochronology, etc.).
  2. Conservation actions (in situ and ex situ conservation), action plans and conservation status assessments.
  3. Capacity building (teaching, internships, exchange of students and young scientists, etc.).
  4. Public awareness and outreach (exhibitions, books, workshops, etc.).
  5. Iconographic collections (scientific photography, scientific drawings, etc.)

Zelkova abelicea

Zelkova sicula

Conservation biogeography of Pterocarya & Juglandaceae

Relict and threatened woody species of Azerbaijan

Relict trees of China, Taiwan, Vietnam, South Korea and Japan

Local conservation & research projects, exhibitions, discoveries.