Dr Greg Moore has spent close to 40 years spreading the word about the “vital functions” of trees. But many of us have been slow to take his message on board and now he says Australia’s shrinking canopy cover is obvious.
He says that given Australia’s exposure to the effects of climate change, you would think we would be leading the game.
“But they are further ahead on these matters in North America and Europe… and I am genuinely amazed at how China is planting incredible numbers of trees.”
Moore was principal of Burnley College for 20 years and still teaches in arboriculture there, and has been the chair of the National Trust’s Register of Significant Trees for the past 20 years. He has also been the chair of Treenet for the past 12 years. He says that as a society we have failed to comprehend the extent to which trees can change our lives.
He puts much of the blame on home owners, who have fewer trees than in the past because of smaller gardens and concerns about mess and other “problems”. In contrast, local governments have “in general been good” at increasing the green canopy of public open space.
But planting more trees in public spaces is not enough to improve the livability and sustainability of urban environments.
“People have to understand this is really quite a serious issue. There is ample evidence that if you have green and leafy streets and open spaces people tend to be healthier and live longer.”
Moore will speak about the importance of planting trees in our home gardens next week for the Australian Plants Society, Keilor Plains Group. While the focus will be on Australian natives, which, Moore says, are “under-appreciated”, he encourages people to plant whatever tree takes their fancy. Small gardens can handle trees up to 10 metres high, while taller specimens can be used in bigger gardens.
“If you are looking at what tree to grow, the answer is really simple. Ask yourself what you want the tree to do – be evergreen, deciduous, have a particular bark, foliage, fruits and so on … walk around your local area and see which trees are performing well.”
For the best results, he encourages people to plant no larger than 15-centimetre-pot seedlings. “They are good value, will grow into the soil and, if you treat them well, will outperform bigger trees over a three- to five-year period.”
For a 15-centimetre-pot seedling, he says the hole doesn’t have to be deeper than the rootball but should be at least 50 centimetres wide. Don’t amend the soil, don’t add fertilisers, but do mulch (with an organic, mixed-particle mulch, such as a hard woodchip) to a depth of 75 to 100 millimetres. If using automatic irrigation, install it below the mulch. Moore also strongly recommends formative pruning, such as removing a co-dominant stem or crossing branches.
Appropriate tree selection and good plant management will, he says, reduce the time it takes to reap the benefits, including shade, water absorption, wind reduction, air quality and improvements to your own physical and mental health.
Moore would like to see local governments mandate that householders retain a certain amount of private open space where they can plant “largish” trees. He says this needn’t come at the expense of increasing urban density if we “change our mindset and follow the English and European model” and build up rather than out.
“We are just custodians of the environment we inherit … we have benefited from people in urban areas who, 100 and 150 years ago, planted trees … and we have to think about the environment we are leaving for future generations,” he says.
By losing rather than gaining trees, Moore warns, “we will pay in every way”.
Moore speaks on Strategic Tree Selection for Climate Change at 8pm on May 5 at the Raleigh Road Activity Centre, 54 Raleigh Road, Maribyrnong.