Street trees
Species that are often used as street trees in Mediterranean-type climates.
This is a list of trees that have been used as street trees, it is not a recommended list, the reader must do their own research and investigate the planting site before choosing any species.
Some of the larger trees in this list may be better described as boulevard trees being too large for suburban streets.
There are many problems with street trees, from dropping leaves, flowers, fruit, and twigs to dropping branches, through to roots entering sewers and lifting paving, to even lifting building footings.
In horticultural school, to demonstrate the potential problems we may encounter selecting suitable species, we were given a description of an ideal no-problem street tree, it was 6 feet, 2m tall, had leaves and branches that didn’t fall off, with no flowers, and no roots!
But street trees have many advantages, from beautifying a street, fixing atmospheric carbon, providing shade and cooling the urban heat island effect, to creating a safer walking space as a buffer from vehicles, providing habitat for birds, animals, insects, and the all-important fungi and a connection to nature for us, and even increasing properties values.
Many of the following species are deciduous, even the subtropical Jacaranda drops its leaves in the dry season, and being deciduous is one of the reasons that they are widely planted in cities.
The particulate pollution in the air in cities collects on the surface of leaves and one way for the plant to rid itself of these particles is to drop its leaves and grow new leaves the following spring.
Deciduous trees often drop their leaves in response to shorter day lengths but generally even trees growing under artificial street lighting will drop leaves eventually, possibly in response to cold temperatures.
List of trees:
Betula pendula silver birch
Brachychiton populneus Kurrajong
Brachychiton rupestris Queensland bottle tree
Celtis australis Southern Nettle tree
Fraxinus angustifolia subsp. Oxycarpa ‘Raywoodi’ Claret Ash
Ginkgo biloba Maidenhair tree
Hymenosporum flavum Australian native frangipani
Jacaranda mimosifolia Jacaranda
Koelreuteria paniculata golden-rain tree
Lophostemon confertus syn. Tristania conferta Queensland box
Olea europaea olive
Platanus x acerifolia London plane
Podocarpus elatus brown pine or Illawarra plum
Pyrus ussuriensis Manchurian pear
Ulmus procera English Elm
syn. abbreviation of synonymous, meaning previously used plant name.
Betula pendula silver birch, a very popular graceful, deciduous tree, 20 to 50 feet, 6 to 15m high. Has attractive silver-white bark and leaves turn yellow before falling.
It will tolerate a wide range of conditions but does like adequate soil moisture. With age, they are susceptible to fungal diseases. In North America, it is susceptible to bronze birch borer attack when stressed. Originally from Europe.
Brachychiton populneus Kurrajong, a hardy upright tree, 20–50 feet, 6–15m, white spotted flowers in spring, then large seed pods.
Suitable for warm areas and tolerates limestone soil. From Australia, NSW, Qld, and Northern Territory.
Brachychiton rupestris Queensland bottle tree, 20 to 50 feet, 6 to 15m tall, an interesting tree with a swollen trunk, an adaptation to its original distribution in the dry inland areas of Queensland.
Celtis australis Southern Nettle tree, a deciduous tree from around the Mediterranean, 30–50 feet, 9–15m.
Flowers are inconspicuous in spring, with edible small brown berries. Identified by a toothed margin on leaves and downy underneath.
Fraxinus angustifolia subsp. Oxycarpa ‘Raywoodi’ Claret Ash, the species is originally from Europe but this garden hybrid occurred in Australia.
Its foliage turns a deep red claret wine color in autumn/fall and the leaves persist into winter.
A deciduous tree, 30 to 50 feet, 9 to 15m high, quick growing and will withstand hot conditions if sufficient soil water is available.
Ginkgo biloba Maidenhair tree has beautiful two-lobed leaves that turn a golden yellow in early autumn and persist on the tree well into winter, a trait referred to as marcescence (Lord, 1978).
Ginkgo biloba is also of taxonomic interest, it is the only remaining extant species of the Division of the Plant Kingdom Ginkgophyta that was prominent in the mid-Mesozoic (160–100 million years ago), I have heard them called dinosaur food trees. From southeast China.
Ginkgo, cycads, and conifers are commonly called gymnosperms, they produce ovules and pollen in cones. Most other trees are in the Division Magnoliophyta, are flowering plants, and commonly referred to as angiosperms, they produce seed within a fruit (Knox et al., 2014).
Hymenosporum flavum Australian native frangipani, 15 to 40 feet, 5 to 12m tall, a beautiful upright tree from Australia, NSW, and Queensland, prefers a warm aspect. Yellow-scented flowers in spring and summer.
Jacaranda mimosifolia is possibly one of the most beautiful trees with fern-like foliage and in summer a mass of lilac-blue flowers. Can grow up to 50 feet, 15 meters in height.
They are deciduous or can be semi-deciduous, and have thin grey-brown fissured bark, with fine fern-like opposite, bi-pinnate leaves.
The trees produce masses of drooping, showy blue or violet, bell-shaped flowers in panicles, which are usually terminal on the branch, and flowering lasts up to two months.
Originally from Argentina, Bolivia, and Paraguay.
Koelreuteria paniculata the golden-rain tree has large pinnate leaves and showy bright yellow flowers in summer. Its display of inflated bladder-like seed pods which dry to a golden color and gives it its common name (Lord, 1978). From China and Korea.
Lophostemon confertus syn. Tristania conferta Queensland box, 30 to 100 feet, 9 to 30m tall.
An Australian tree from the east coast of NSW and Queensland. Popular as a street tree in the more southern cities where it doesn’t get as tall.
Susceptible to frost when young, quite a drought-resistant tree once established.
Olea europaea the olive provides a high oil content and nutritious fruit and is very popular. The leaves of the olive also contain oils and it is very flammable. From the Mediterranean region, Middle East, Africa, Central Asia, and China.
Platanus x acerifolia, the London plane, believed to be a cross between P. orientalis and P. occidentalis is a majestic tree and probably the tree that is most tolerant of atmospheric pollution. It has been grown in London for over 200 years through the coal and anthracite burning years.
Podocarpus elatus, brown pine, or Illawarra plum. Can grow into a tall tree of 100 feet, 30m tall.
An Australian coastal tree from eastern New South Wales and eastern Queensland.
Attractive bark, unusual thick deep green leaves, and blue fruit.
Pyrus ussuriensis the ornamental Manchurian pear has a spring flush of white blossom and striking bronze leaves in autumn. From North and East China to Korea, Russian Far East to North Japan.
Ulmus procera English Elm. Deciduous trees, to 100 feet, 30m high, used to be widely planted but not so much now as it suckers. Suckers can have cork-type bark.
Also, trees have been decimated by Dutch elm disease in the northern hemisphere. From Europe to Central Asia and N. & NW. Iran, NW. Africa.
Ulmus parvifolia Chinese elm is a graceful tree and is resistant to Dutch elm disease.
Reference:
Lord, E. E. (1978). Shrubs and Trees for Australian Gardens (4th Ed.). Adelaide, S.A.: Lothian Publishing Co Pty Ltd. Book.
