Specifiers (Hirons and Sjöman 2018), we have
determined a four-level qualitative scale (Tolerant,
Moderately Tolerant, Moderately Sensitive, and
Sensitive) that is underpinned by trait data wher-
ever possible. This is then used to help inform
recommendations for the "use potential" of a spe-
cies. For example, a key criteria for species recom-
mended for paved environments is that they must
be tolerant or moderately tolerant to drought.
As well as providing information on the drought
tolerance of species, we provide informa-
tion on shade and waterlogging tolerance,
ornamental qualities, tree and crown charac-
teristics, and known species-specific issues.
Please go to the Trees & Design Action Group
website (www.tdag.org.uk) if you are inter-
ested in this free guidance (Figure 3).
It is critical to note that the selection of appro-
priate species is only one element of successful
tree establishment. Designing high-quality rooting
environments, procuring excellent plant mate-
rial, and sound arboricultural practices are also
required if trees are to establish and thrive in our
urban landscapes (Hirons and Percival 2012).
If any readers are interested in discussing this
work further, please feel free to contact Dr.
Andrew Hirons: ahirons@myerscough.ac.uk.
Recommended Viewing
Selecting Species for a Better Urban Landscape
With Drs Andy Hirons and Henrik Sjöman
Citations:
Bartlett, M.K., Scoffoni, C., Sack, L. (2012a) The
Determinants of Leaf Turgor Loss Point and Prediction
of Drought Tolerance of Species and Biomes: A
Global Meta-analysis. Ecology Letters, 15, 393-405.
Bartlett, M. K., Scoffoni, C., Ardy, R., Zhang, Y., Sun,
S., Cao, K., Sack, L. (2012b) Rapid Determination
of Comparative Drought Tolerance Traits: Using
an Osmometer to Predict Turgor Loss Point.
Methods in Ecology and Evolution, 3, 880-888.
Hirons, A.D. and Percival, G.C. (2012) Fundamentals
of Tree Establishment: A Review. In: Johnston,
M. and Percival, G. (eds.) Proceedings of the
Urban Trees Research Conference, 'Trees, People
and the Built Environment'. Held in Birmingham,
13-14 April 2011. Forestry Commission. 51-62.
Hirons, A.D. and Thomas, P.A. (2018) Applied
Tree Biology. Wiley-Blackwell. Oxford, UK.
Hirons, A.D. and Sjöman, H. (2018) Tree
Selection for Green Infrastructure: A Guide for
Specifiers. Trees & Design Action Group.
Sjöman, H., Hirons, A.D., Bassuk, N.L. (2015)
Urban Forest Resilience through Tree Selection—
Variation in Drought Tolerance in Acer. Urban
Forestry and Urban Greening 14: 858-865.
Acknowledgements
This work is kindly supported by the Hyland
R. Johns Research Grant (TREE Fund),
Fund4Trees, and NERC (NE/N017773/1).
36 CityTREES
