Building green cities involves a huge change for the trees in terms of the habitat that they will have to adapt to, compared to what they would normally enjoy in rural conditions.
Trees are forestry plants. As soon as we forget this simple fact we are likely to make mistakes when planting them in town and city environments.
A tree in a woodland forest has near perfect conditions; Sheltered microclimate, rich fertile soil with an abundance of nutrients and humus, uncompacted leaf mould, rich rooting volume with plenty of moisture and pore space.
Now spare a thought for the tree in the town. A harsh paved surround increasing microclimate temperatures and reflected glare, exposure to wind, de-icing salt and gratuitous vandalism. Below ground an equally hostile environment of compacted soils, lack of quality rootable volume, competition for space with multiple utilities and if the tree does manage to spread its root system someone will mutilate it, through trenching or pavement reinstatement.
With these factors in mind, we can begin the process of successfully integrating trees in built up areas. By protecting them above and below ground, managing and providing for delicate root systems, we can as far as possible recreate optimum conditions for our trees to establish.
We cannot recreate entirely the conditions trees enjoy in woodlands but we can go a huge distance in improving their chances of thriving in challenging conditions by using tree literate design accompanied with the correct sustainable development strategy.