Trees planted in urban areas are likely to be exposed to the air pollution produced by motor vehicles. Pollutants include sulphur dioxide and nitrogen dioxide which can contribute to lower rates of photosynthesis in trees, resulting in lower growth rates. Choosing trees tolerant to these chemicals can mitigate the harm done and increase their chances of survival.
The table below from Trees Built in the Environment categorises trees by tolerance to air pollutants.
Some tree species have more problems with pests and diseases than others. Make sure to check whether the tree species in question has any prominent pests or diseases. If so, choose another species or find a cultivar immune to the disease in question.
It is generally a good idea to have a variety of tree species on site so if any pests or diseases do infect a species, not all trees are affected.
Ideally use UK grown tree suppliers to minimise the chances of diseased stock infecting trees on site.
For further information on tree pests/diseases, refer to the links below: