Back in May, we shared the news about planting indigenous seedlings along the back fence. At the time, a reader responded with an astute observation. These plants might not be the best choice in the long run. For many trees, climate change could mean our local species wouldn’t grow to maturity.
What’s happening to Melbourne’s climate?
I’m going to assume those wild, crazy guys and gals at the CSIRO (and other scientific organisations) are correct with their predictions about global warming and climate change.
They’ve crunched the numbers and worked out that Melbourne is effectively on the move. We’re off to Adelaide, as far as our climate is concerned. If you’d like to know where Adelaide is going, check out Climate Change in Australia.
The weather bureau BOM provided a few numbers. Our summers are going to be about 2 degrees warmer (on average) with more days over 35 deg C and about half the amount of rain. Winters are also warmer with fewer days below 2 deg C but slightly more rain. On balance, Melbourne is going to be hotter and drier.
Impact on indigenous plants.
Since the climate is going to change significantly in a matter of decades rather than centuries (or longer), what we plant today may not survive and thrive in 50 years time. Should we be planting species, particularly long-lived trees, that are better suited for the future climate?
An article in Sanctuary magazine said that Melbourne City Council is investigating different species to purchase for their tree replacement program. Old stalwarts such as the Dutch elm could be replaced with the Queensland kauri. Given there are thousands of trees giving Melbourne its green, leafy appeal, this is an important decision that will affect the way the city looks in coming decades.
On a smaller scale, should we be doing the same thing in our garden? Are we better to plant trees from other Australian regions that will be suited for the predicted climate instead of indigenous trees that evolved in Melbourne’s previous climate?
The Community of Ringwood Indigenous Species Plant nursery (CRISP) magazine summarised some research which explained why eucalyptus trees struggled to adapt to hotter, drier climates. If a tree that lives in wetter conditions is exposed to extended periods of hot, dry weather it can develop embolisms which prevent water flow through the trunk when the rain returns. The condition eventually kills the tree. Eucalypts that evolved in drier conditions aren’t prone to embolisms because they have narrower vessels in their trunks.
Going for a variety of indigenous plants in our garden.
We’re going to hedge our bets with this garden. By planting a wide variety of indigenous trees, shrubs, ground covers, grasses, etc, we’d like to strike a balance. Not all of our plants will survive in the long term. However, hopefully enough will live on so that our indigenous fauna still have places to live. As we discover which plant species do well in the changing climate, we can plant more of them to replace the ones we lose.
By staying indigenous, we have the best chance of providing an outpost for the local nature reserve – Wombolano Park.
It just seems unfair to the native animals to replace indigenous plants with native ones and then assume the animals will be able to cope with the change. Our garden is off to Adelaide, hope you can come along for the ride!
How does your garden grow?
With a wetter than average Spring in Melbourne, the seedlings we planted in May have not only settled in, they’ve gone ahead in leaps and bounds.
The three canopy trees in May.
Now after 6 months, you you can hardly see the calf on the fence. Some of the shoots are at fence height.
The swamp paperbarks were just little sticks when they went in.
They’ve also done well, along with the grasses and shrubs that I’ve planted alongside them.
We’re on our way to a small urban forest.
Even the loganberry vines I transplanted to the back fence are enjoying the conditions. We’ll share whatever berries they produce with the birds. The main idea is to provide some food and cover along the fence line for the smaller birds/animals. There won’t be any interference from anyone climbing over the fence. Those vines have lots of sharp thorns!
New Year wish.
And so 2016 draws to a close. We’re looking forward to the New Year and its promise of big things happening with our project.