If you want a clean & green sustainable neighbourhood, then planting more trees & plants is a no brainer. But what should we plant?

When it comes to tree planting, there are different sustainable outcomes, which are sometimes at odds with each other, I'll run each strategy and the pros and cons of each, and I’ll leave you to make your own decision about what's best:

Plant indigenous trees: Create a strong urban ecology
The benefits of this are pretty obvious, indigenous trees can make a significant difference to the local urban ecology by supporting insect, frog and bird populations.

A single large tree can act to double the habitat of a bird of prey, like a Powerful Owl for example, by providing a ‘stop-over’ in the city on-route from one hunting area in, lets say; the Grampians, to another one, like Wilson’s Prom.

Two local streets are a good contrasting example of this: Most afternoons I ride south down Dight Street (on the right, with the orange line) to pick up my daughter from childcare. Dight Street is planted with an avenue of an exotic tree, Chinese Elm I think. On the way home I travel north up Campbell Street (green line), which is planted with a native species (C. ficifolia I think).

Anyway, Dight Street is always silent, with some pigeons and doves flying around – while a few meters away Campbell Street is fabulously full of activity and birdsong.

Indigenous trees are adapted to local soil, are drought tolerant and are naturally disease resistant. They also help to give us a better emotional connection to and understanding of the natural environment we live in.

Here's a list of trees indigenous to Collingwood (and the City of Yarra)

Plant Deciduous Exotic trees: Reduce green house emissions
Most Australian trees are evergreen, with a couple of exceptions – like the Illawarra Flame tree, which is not much good because it looses its leaves in summer, or the White Cedar (Melia azedarach) which is another beautiful street tree. Anyway, neither is indigenous.

The benefit of planting deciduous trees, is that they provide shade in summer, but let warm sunshine through in winter. This makes a big difference to the heating load in our neighbourhood in winter, and in turn to our energy use, and green house emissions.

We could try to minimise the effect by planting indigenous trees with nice open canopies – but they’re still going to cast shade.

It is possible to select exotic deciduous trees with are relatively drought tolerant, but of course they’re never going to be quite so well adapted to the soil conditions.

Plant Fruit Trees: Food without food miles
The argument here is that locally planted food crops can provide us all with fresh fruit and veg that can supplement our store bought food to decrease the overall food miles of our diets, and in turn reduce green house gas emissions.

It’s a nice concept too, I like the idea of wandering out onto the street in the afternoon to pick a fresh apple straight off the tree, or maybe a nice ripe lemon for my gin and tonic in summer.

Like planting indigenous trees, there is an argument that growing and harvesting our own food can help our understand of natural systems. It would certainly be great for the kids.

On the downside - few fruit trees are drought tolerate, and they're often susceptible to disease. I'm not sure how organic farming practices would work in an urban environments? Although we could reduce water use from mains by using harvested rainwater and storm water.

Also, and maybe this is a little alarmist, but plants can very efficiently extract toxins from the soil by phytoextraction, these contaminants are then present in the plant material. So if you don't want a Sleeping Beauty experience, you'd want to make sure there was no serious contaminates in the soil before eating your apples.

Fruit trees tend to be small, so they won't have have as much visual impact as other trees, and they also require a lot more maintenance - of the trees themselves, picking the fruit and/or cleaning rotting fruit off the pavement.

Ideally you would have a local community group, like the people who have plots in the community garden, to manage the trees and other plants. We could have a neighbourhood orchard! The success of the 'orchard' would probably also depend on how popular the actual fruit produced was; how good it tasted.