Eric Sturman is one of the most eloquent and passionate landscape architects and horticulturists you’re likely to meet.
Through his work with WaterUps and previously with a large Sydney council Sturman has worked closely with local government and communities that want to green their public spaces.
- See Eric Sturman take the stage at Urban Greening on 28 July at UTS, Sydney
He understands the challenges and the motivations of keeping public spaces green but also the costs and he’s not averse to some thought-provoking observations about how to green urban spaces effectively – and what many people might unintentionally be getting wrong.
For example, trees sweat. And that planting native trees is not necessarily the best option in a heating climate.
Many native and European tree varieties in heatwave conditions stay functional by evaporating large quantities of water.
But some eucalyptus trees can’t survive extreme heat, because they adapted to retain moisture in droughts and therefore cannot “sweat” effectively to cool down – especially if they don’t have access to water, Sturman says.
So it’s not as simple as whacking some seedlings in the ground and watching them grow. You’ll need the experience and the know-how on plant species, placement and grow times. You’ll need an effective and dedicated irrigation system. You’ll need punctual timing when it comes to planting, watering, fertilising and pruning.
And you’ll also need a bigger budget than you might think.
The NSW Government’s Greening our City plan, for example, aims to increase the tree canopy and green cover across Greater Sydney by planting one million trees by the end of 2022. It is part of a broader commitment to plant five million trees by 2030 – but programs like this, Sturman says, need to be handled with care.
“It seems to be the easiest thing for governments to say, ‘we’re gonna plant a million trees’ you know, as a big environmental contribution. Now, a couple of problems with that. Is it a biodiverse solution, or is it the same species of trees?”
The investment therefore needs to be proverbially bubble-wrapped and managed with the eyes of a mother hawk – by someone who knows what they’re doing, and knows when to water what plant. As a friend told him it’s a constant job to plant and water. Miss a couple of days in a heat wave and all the investment in people hours could be lost.
“It’s called hydraulic failure,” Stuman says. That’s when the plant is unable to move water from its roots to its leaves, and according to a study by the University of Sydney it is almost universally present when trees die during droughts.
So that’s a big red flag of improper maintenance if your tree is not being cared for properly – you may as well pour your cash down the drain.
“It dies from there, and we get full necrosis or full death of the tree.
“We’re really putting a lot of hope in the fact that each one of these trees is going to grow from the little seedling that the government gives us, to a big beautiful canopy in 30 years time giving us all of this shade.”
So that long–term investment into the health, wellbeing, and urban temperature of an environment is an investment which, like any, needs proper attention.
Built environment professionals might see that urban greening is all the rage and think that it’s as easy as whacking some trees in the ground and watching them grow – think again.
That is just a taste of Eric Sturman’s thoughts on Urban Greening. His expertise in horticulture and landscape architecture will be available in full to delegates of the event on July 28, and to Fifth Estate members. Click here to learn more.