For those planning the urban forests
of the future, selecting appropriate species can be
challenging. For park and garden environments that
are characterised by high quality soil, ample soil vol-
umes, and plenty of space for crown development,
there is a diverse species palette available to choose
from. Indeed, in some cases, such locations can be
preferable to the tree's natural habitat which may
be highly competitive and on rather marginal land.
Conversely, paved environments provide some
of the most challenging conditions for tree devel-
opment in our towns and cities. Whilst a num-
ber of approaches exist to improve the plight of
trees in paved sites, it is not uncommon to see
trees thrust into diminutive planting pits, encap-
sulated by impervious paving, "gasping" for water
and air, barely clinging onto life. In fact, many
do not survive at all—instead becoming a buf-
fet for the saprotrophs or fodder for a chipper.
Trees that only just survive, and do not thrive,
provide few of the benefits that were ascribed
to the planting scheme by those that conceived
of it. Unfortunately, those "artistic impressions"
from the landscape architect—you know, the
ones with joyous couples skipping hand in hand
down an avenue as blossom falls like confetti,
or with young professionals earnestly discuss-
ing the next business venture in the dappled
shade of a birch—are more easily achieved
on the computer screen than in reality.
Of course, the reasons for this are complex.
They involve issues relating to the specification
of the rooting environment, economy, educa-
tion, practitioner expertise, plant quality, and
species selection, to name but a few. In this arti-
cle we do not have the opportunity to look at
all these factors, but we would like to explore
species selection in a little more detail.
Translating
Science to
Practice
By Drs. Andrew D. Hirons
and Henrik Sjöman
Andrew Hirons is a
Senior Lecturer in
Arboriculture and
Urban Forestry at
University Centre
Myerscough.
Henrik Sjöman is a
senior researcher
at the Swedish
University of
Agricultural Sciences
and Scientific Curator
at Gothenburg
Botanical Garden.
for
32 CityTREES
