5.0 Species selection

Diversity in the urban forest

When discussing diversity in the urban forest two questions which are always asked are, which species should be planted and will species selected be available from the nursery when needed.

There are many publications and catalogues which offer advice and suggestions. The most recent, at the time of writing and certainly one of the most comprehensive, is the Trees and Design Action Group’s ‘Tree Species Selection for Green Infrastructure, A Guide for Specifiers,’ researched and authored by Dr Andrew Hirons and Dr Henrik Sjoman. This document, which is freely available as a download from the TDAG web site provides profiles for over 280 species supported with explanatory guidance. (www.tdag.org.uk).

Much can be learned from Dr. Sjöman’s thought provoking work. His research work has included a selection of natural habitats across the world which currently replicate, as far as is possible, the environmental conditions likely to be found in Scandinavian cities in the 2050’s as a result, of climate change.

‘The aim was to identify promising tree species and genotypes for urban environments in the CNE-region through dendrological studies in natural habitats.’ (Sjoman 2012)

In his doctoral thesis published in 2012 he lists tree species identified from case studies as specialists for warm dry habitats which have never been grown or grown to a limited extent, in the CNE-region. This list is reproduced below:

Carpinus orientalis

Carpinus turczaninowii

Celtis bungeana

Fraxinus chinensis

Morus mongolica

Ostrya japonica

Quercus aliena var acuteserrata

Quercus baronii

Quercus dalechampii

Quercus pubescens

Quercus wutaishanica

Sorbus folgneri

Syringa pekinensis

Ulmus glaucescens

Ulmus pumila