Tasmanian Times

The individual has always had to struggle to keep from being overwhelmed by the tribe. If you try it, you will be lonely often, and sometimes frightened. No price is too high for the privilege of owning yourself. ~ Friedrich Nietzsche

The individual has always had to struggle to keep from being overwhelmed by the tribe. If you try it, you will be lonely often, and sometimes frightened. No price is too high for the privilege of owning yourself. ~ Friedrich Nietzsche


Gingivitis – Boiling the Gum in Tasmania

*Pic: A gum tree on the boil (Rose Grant)

Boiled gum exuding from a dead tree (Rose Grant)

I have started to notice on my property here at Bentley in northern Tasmania a large number of dead trees having the sap running out of the trunks like blood from a wound and then turning the bark ginger in colour.

This is the colour of almost certain death … death by Gingivitis. It’s a well-known gum disease in humans and it’s now the name I am giving to the boiling of the gum in certain species of Tasmanian eucalypt.

The cause can be fairly and squarely laid at the door of climate change which caused a long and extremely hot spell of weather here in the summer of 2012/2013.

In trees recently felled a relationship can be established between record hot temperatures and the signs of the oozing sap. This is found by counting the tree rings as the tree has slowly bled to death.

Dr Tim Wardlaw (principal scientist, ecosystems services with Sustainable Timbers Tasmania, and researcher at the Office of the School of Natural Sciences University of Tasmania in the field of forestry pests, health and diseases) has stated that heat-stress is the cause in blue gum (Eucalyptus globulus) plantations.

“The reason we call it ‘ginger tree’ is the staining on the stem caused by gum bleeding out of large pockets of gum just underneath the bark.

“When we looked closely at those pockets, we found they were formed in the growth ring of the 2012 and ’13 growing season.

“That season was really notable because the summer months were much hotter than average, and they ended in a record breaking heat-wave in early March. It was really pronounced in the north of the state.

“Temperatures in Launceston were above 30 degrees for eight consecutive days … and that was double the previous average.

“In weather events like that, the trees respond by losing water really rapidly through their leaves.

“The trees become water stressed, and will shrink in response.

“I think that shrinkage is causing injury to the bit of the stem between the bark and the wood where the new wood cells are formed.

“That injury response is the production of those gum-veins and pockets we see, and red bleeding from the stem.

“In response to that stress the white gums are weakened, and are also attacked by insects and diseases that normally wouldn’t affect healthy trees.

“We’re seeing some trees dying, from wood-boring insects particularly, that have attacked the trees after the stress.”

Dr Wardlaw said the syndrome is not caused by insect attack, and it has nothing to do with fungal infections like myrtle rust or phytophthora root rot.

He said quite large areas of both native forests and blue gum plantations are affected.

The Liberal Party (the principal exponents of “Climate Change is Crap”) might like to consider this matter with some care.

Maybe the Gingivitis is the first real indicator of a serious underlying problem caused by climate change in Tasmania.

*John Hawkins was born and educated in England. He has lived in Tasmania for 13 years. He is the author of “Australian Silver 1800–1900” and “Thomas Cole and Victorian Clockmaking” and “The Hawkins Zoomorphic Collection” as well as “The Al Tajir Collection of Silver and Gold” and nearly 100 articles on the Australian Decorative Arts. He is a Past President and Life Member of The Australian Art & Antique Dealers Association. John has lived in Australia for 50 years and is 75 this year. In two of the world’s longest endurance marathons and in the only teams to ever complete these two events, he drove his four-in-hand team from Melbourne to Sydney in 1985 and from Sydney to Brisbane in 1988.

Author Credits: [show_post_categories parent="no" parentcategory="writers" show = "category" hyperlink="yes"]


  1. John Hawkins

    August 18, 2018 at 2:09 am

    Dear Rob,

    In the last 15 years we have planted over 100,000 trees at Bentley, and all to enhance the landscape for future generations. Roughly two thirds of those planted have taken.

    A large number have been bitten by the Gingivitis or eaten by hares or wallabies. The specimen trees in the drive planted for their trunk colours have been the hardest hit.

    It is very easy to cut the native trees down – all the finest blackwoods, a feature of the Bentley landscape until the early 60s, have gone, and most of the big Viminalis were logged for a pittance just before we arrived. These trees were worth a great deal more standing because then one does not have to replant at enormous cost to recreate a natural landscape.

    The last stand of Ovata on the valley floor on the property next door was scheduled for woodchip, but these magnificent trees were saved, thanks to local efforts, and the landscape enhanced and the value of the property greatly increased.

    Ovata seems to be unaffected so we are replacing those lost in the drive with Ovata.

    If you wish to visit, please contact the Editor who will give you my phone number.

    Always remember a thing, or place, of beauty is a joy forever.

  2. Rob Halton

    August 17, 2018 at 3:22 am

    John, I’m sorry to hear about the plight of your trees. Perhaps you could provide a picture of the stand. Is it intact with a natural canopy, or are these scattered across your property as feature trees which appear to be White Gums either E viminalis or Mountain White gums E darympleana?

    Do you know if your trees are actually surviving as natives, of may they have been planted in the past?

  3. phill Parsons

    August 15, 2018 at 12:27 pm

    Bushfires in winter, species decline across the natural range, pine beetle attack over huge areas, forest fires on an unprecedented scale.

    These are the mechanisms that change natural systems when the climate changes. Humans releasing CO2 into the atmosphere is increasing temperatures outside the tolerances of some species of plants.

    It will get worse even if we act now, and we must act now if we are to retain some semblance of the rules-based order on a habitable planet that we are all used to.

  4. MjF

    August 15, 2018 at 12:03 pm

    #8 … What do you recommend, Mr Incognito Forester, to assist the immediate situation ?

  5. Ted Mead

    August 15, 2018 at 12:27 am

    #7 … Another brain-dead comment from the dendrophobic master himself!

  6. MjF

    August 14, 2018 at 11:59 pm

    Clear-fell ’em Hawk, while they still got some chip value.
    Otherwise you only end up with dead perches for cockies and crows, and never ending falling limbs. Wouldn’t want one of them on your old scone.

  7. Andrew Ricketts

    August 14, 2018 at 10:30 pm

    Re #5 … Amusing – Josh in the one, not Tony, Trevor!
    Sure you were not commenting on post #4?

  8. TGC

    August 14, 2018 at 6:43 pm

    #1 … I knew it would be Tony Abbott’s fault.

  9. Clive Stott

    August 14, 2018 at 2:13 am

    Yes John, it is happening where I live too, but …
    Those who don’t want to see it are blind!

  10. Frank again

    August 13, 2018 at 10:26 pm

    As I have no control / influence on the above stated serious – very serious issues, may I suggest that if we wish to have shelter and hydrology, and yes, timber .. we should change the forest and land management practices to plant and support trees that are able to have a chance to grow.

    The midlands of Tasmania and the historic private farms have species growing well, but as they had only come with the early settlers from the United States, Europe or Asia, and are just seen as ornamental trees, they are mostly not managed for their many values. Fire protection, wind & sun, heat and rainstorms, for effective shelter of all, be that for people, livestock and wildlife.
    Carbon sequestration, wood values etc. etc.

  11. Ted Mead

    August 13, 2018 at 10:18 pm

    It’s definitely stress, caused most likely from heat and drought.

    White gums don’t have much insulation around the capillaries were the water is transferred. That’s why regnans suffer much greater in fire scenarios than well insulated species like obliqua or delagatensis.

    The summer of 2012-13 certainly took its toll on many trees, and it is claimed that many of the big old cider gums on the central plateau died through heat and dryness.

    The term ‘boiled’ has been used, and sap boil through fire and climate change is occurring everywhere.

  12. Andrew Ricketts

    August 13, 2018 at 2:00 pm

    White gums are dying in Tasmania, Southern Victoria and apparently also in the Eden Monaro Plateau.

    Last year when I visited the Otway Ranges (at Gellibrand) I noticed many trees in various stages of death.

    It is widespread. It is distressing for those who are concerned to see such lovely trees in their death throws.

    Keeping the canopy intact, increasing the shade and convincing Josh and the Liberals (Tony and Barnaby etc) may be a good thing.

    The Commonwealth has had a listing application for wet viminalis forest (to be listed as Critically Endangered) for a while now, but Josh has simply cut the Department’s resources. It’s criminal.

Leave a Reply

To Top