Which Trees To Plant At Inverell, NSW, To Cope With Predicted Climate Change?

Persian Silk tree, Albizia julibrissin, Bingara.
Persian Silk tree, Albizia julibrissin, Bingara.

Dear Jerry, I want to plant shade trees on my 25 acre property at Inverell, NSW. Can you offer suggestions for the changing climate? I’m not sure the deciduous trees planted by many around here will be appropriate for our future climate“.

Answer: “I can only suggest the following list as ‘climate change winners’ up to 2040. In other words, for one human generation. So much depends on what society does about reducing greenhouse emissions – we only have twelve years to slash emissions in order to avoid catastrophic climate change. For longer term success, I would review the progress of your new trees ten years after planting“.

Jerry Coleby-Williams RHS, Dip. Hort. (Kew), NEBSM
Director, Seed Saver’s Network
Patron, National Toxics Network
Patron, Householder’s Options for Protecting the Environment
2nd February 2019


Question: “Dear Jerry, I want to plant shade trees on my 25 acre property at Inverell, NSW. Can you offer suggestions for the changing climate? I’m not sure the deciduous trees planted by many around here will be appropriate for our future climate. I would love to plant a couple of London plane trees. What are your thoughts? I have many indigenous Eucalyptus on my property and land for wildlife habitat, so I don’t feel bad about planting a few non natives.

 Kind regards, Jane B.

Reply: Dear Jane,

Broad-leaved Bottle tree, Brachychiton australis, near Aramac.
Broad-leaved Bottle tree, Brachychiton australis, near Aramac.

I strongly advise against planting any kind of Platanus, aka plane trees. Despite being admirably suited to your changing climate, this genus  sheds huge quantities of irritating hairs and their spring pollen drop is dramatic and highly allergenic. Europe has studied the negative impact these trees have on public health in urban areas for forty years, but Australia has no comparable research. For years I lived with the vegetable pollution dumped by three of the largest trees in NSW. I would not wish this on anyone. I reported on the health risks of pollinosis associated with Platanus in a story with Gardening Australia made with an allergen expert at Westmead Hospital when I was living in Sydney.

Tree wistaria, Bolusanthus speciosus, Monto.
Tree wistaria, Bolusanthus speciosus, Monto.

Predictions for climate change tend to focus on hotter weather lasting for longer periods and briefer, heavier, more unseasonal rainfall. But you also need to add in to the stress factors the chance of occasional frost. I’ve had five frosts in my frost-free district since 2003, and while -0.5C is a minor frost, damage can be significant if you plant frost-intolerant species.

There’s also a significantly increased risk of hail storm and bushfire intensity and frequency in eastern Australia. Bushfire season is no longer seasonal – it has become an all year round risk.

Adding in those factors into your existing dry temperate climate zone – which falls within the Kamilaroi traditional lands – you currently can hope for (in a good year) for 800mm annual rainfall, long, hot summers and cool winters. That’s a little bit wetter than present day Madrid (Spain).

Climate modelling is evolving and becoming more precise. In 2003, the Australian Greenhouse Office predicted our climate to 2050. At the same time the CSIRO predicted the urban heat island effect would double by 2050.

But in 2013, climate scientists announced our climate has already changed much faster than expected. This year, climate scientists have said the speed of change has further accelerated. The UN recently warned the world has twelve years to dramatically cut fossil fuel emissions to limit runaway global warming, that is warming which occurs whatever society does.

Queensland Lacebark, Brachychiton discolor.
Queensland Lacebark, Brachychiton discolor.

It is my belief as a conservationist and a gardener who has been actively gardening with climate change for forty years, that the world in general and Australia in particular, will delay cutting greenhouse emissions and therefore ensuring catastrophic climate change will occur.

Factoring all this together, I can only suggest the following as ‘climate change winners’ up to 2040. In other words, for one human generation.

For longer term success, I would review the progress of these trees ten years after planting.

It’s hard to imagine that fifty percent of animals have died since the 1970’s, but recent catastrophic fish kills in the Murray-Darling Basin demonstrates that while a natural system appears to cope with ongoing change, once a tipping point has passed things change dramatically.

Jelly palm, Butia capitata, Goondiwindi.
Jelly palm, Butia capitata, Goondiwindi.

All life on Earth is now experimental. Thanks to a lack of Australian political climate leadership, we grow crops and plant gardens in uncharted climate territory. If this is the future of gardening, then we must embrace experimental tree planting for shade, food, fodder and biodiversity.

Personally speaking, I do not believe the future is a predetermined destination, it is a consequence of the small, everyday choices each one of us makes. That’s why I founded Bellis in 2003.

Happy tree planting!

Native species
Araucaria cunninghamiana;
Atalaya hemiglauca;
Brachychiton australis, B. bidwillii, B. populneus, B. discolor, B. rupestris (all briefly deciduous);
Eucalyptus argophloia;
Eucalyptus melanophloia;
Eucalyptus melliodora;
E. tereticornis;
Geijera parvifolia;
Grevillea robusta (briefly deciduous in late winter – spring);
Syzygium australe, S. luehmannii (latter is unaffected by sap-sucking psyllid if you wish to plant a good looking hedge);

Robinia pseudoacacia 'Inermis', Bingara.
Robinia pseudoacacia ‘Inermis’, Bingara.

Exotic species
Albizia julibrissin;
Bolusanthus speciosus;
Butia capitata;
Citharexylum montividense (briefly deciduous in late winter – spring);
Cupressus arizonica;
Ficus carica (winter deciduous);
Fraxinus oxycarpa (winter deciduous);
Handroanthus chrysanthus (still being sold under the old, redundant name of Tabebuia chrysanthus. Briefly deciduous during winter to spring);
Liriodendron tulipifera (winter deciduous);
Liquidambar styraciflua (winter deciduous);
Olea europaea
Phoenix canariensis, P. sylvestris (latter accepts semi-saline irrigation water);
Phytolacca dioica;
Pistacia vera (winter deciduous);
Quercus suber;
Robinia pseudoacacia (winter deciduous);

Kind regards

Jerry Coleby-Williams
Founder of Bellis, Brisbane’s award-winning, affordable sustainable house and garden
Director, Seed Saver’s Network
Patron, National Toxics Network
Patron, Householder’s Options for Protecting the Environment
2nd February 2019

Fallen leaves of fiddle-wood, Citharexylum montividense, near Mt Crosby.
Fallen leaves of fiddle-wood, Citharexylum montividense, near Mt Crosby.

 

2 Comments Add yours

  1. Danielle Wheeler says:

    Thanks so much for this email Jerry! I am a local Councillor on Hawkesbury City Council. I am trying to get Council to adopt a policy to increase urban tree canopy, which you’d think would be a no-brainer given how hot its been in Richmond and Windsor this summer. Alas, it seems like its all too hard for staff. Your list of trees is really useful.

    Also really useful is the information about Plane trees and their health impacts. We have several trees planted in Windsor Mall and they are a bloody nuisance. I’d love to have them replaced and your comments have now given me a great starting point.

    Thanks again for all your work. It really is appreciated
    Kind regards
    Danielle Wheeler

    Sent from my iPad

    1. Dear Danielle,

      When I was living in Sydney I assisted the community group ‘No More Plane Trees’ with information from Westmead Hospital. For a similar deciduous ‘look’ to plane trees but without the negative health impacts or the costs involved in restricting their ultimate, enormous size, I recommend planting tulip tree (Liriodendron tulipifera) instead. There’s some examples of mature tulip trees growing in Liverpool Street opposite Hyde Park, Sydney City.

      In terms of cost/ benefit analysis with regard to the benefits of maintaining good tree cover in an urban environment, I strongly advise looking at what the City of Boulder, Colorado, has done. It’s a state of the art analysis which has appeal to finance managers and plant lovers alike.

      Kind regards,

      Jerry

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