Monday, December 21, 2015

How To Choose A Street Tree - Part 3


Tolerance of pruning

In some locations (eg CBDs) the trees will be manipulated significantly to produce the exact canopy size and shape desired for the specific location. This means the species chosen will need to be able to tolerate regular pruning without causing a significant reduction in the tree's lifespan or structural integrity.

Form

The natural growth habit of the tree needs to be considered. Generally, single-trunked trees with relatively upright form and medium density canopies will be ideal in urban streets. Other features of the tree such as flower colour, trunk appearance and leaf colour should also be taken into consideration but are not usually a major consideration for urban street tree selection where the emphasis is more on the tree's ability to withstand the relatively tough conditions.

Scale

There is a need in most streets to create a more human scale if the street is to be a pleasant place to be. This usually requires a degree of "enclosure" and is most often achieved by street trees. For a satisfying amount of enclosure the ratio of horizontal to vertical should be no more than about 2:1. Any greater than this and the street will still feel too "open".

Tolerance of climate change

Although there is still uncertainty regarding the magnitude and timing of climate change impacts, it is prudent to select trees that are going to be tolerant of a generally drying trend here in Perth, Western Australia.

Availability

Finally, it's important to ensure that the species chosen is readily available in commercial numbers so that replacement trees can be readily sourced.

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