Sunday, January 8, 2012

The Australian Pine

Recently, I asked  Martin,  an Australian friend of mine to write in his blog about how Australian Pines might be used here in the Bahamas.  The Australian Pines, or "Casuarinas"  have the reputation of being "invasive plants", rather unmanageable and growing everywhere, with and without permission, thus being largely viewed in the Bahamas and in Florida as giant weeds.

He replied with some very thoughtful commentary.  Here is what he said:

Thank you, Martin, for your thoughtful remarks.

Let's see if we can't get some additional good ideas about how to manage and use these pines from both sides of the world.


  1. Hi Martin - Thank you so much to you and Mary for starting this enlightening discussion. As Mary said, who knows where this may lead.

    My knowledge base is in human/animal zoology/physiology. I am fairly ignorant about the Causarinas, aside from than what's been shared with me by locals in around 300 days there, plus what I've read about the erosion problems they lead to in our local paper, The Abaconian.

    One reason "immigrant may be bad" is their shallow root system, relative to some preferred, indigenous flora. Another is their very rapid rate of growth. I've made a trip to my home there every 2-3 months for the past 6 years, and am amazed at how quickly they spread (airborne) and proliferate. They can easily reach 6' height in < 8 months, and of course compete for water and nutrients with local flora.

    Each time I arrive, I remove each and every one from my property. This Christmas holiday I removed all of them on the beach side of the road for about 0.25 km to the East of my border. Even 6" trunk Causarinas can be easily felled with a machete as they are soft pines. And 6' tall trees can be often be pulled from sand by hand due to their shallow surface roots.

    Your point about "thinning" is well taken, as their roots and trunks certainly do provide barriers to erosion vs. the major tidal surge from severe storms.

    They are certainly not attractive plants (at least to me), unlike the other major Abaco invasive, the Hawaiian Seagrape. I similarly remove them from my property each trip, except on the my borders until I find more time to deal with them there.

    One last point/question that someone may know or research: It may be another reason not to "throw them all in a pile and burn them". A local told me that when burned green, they emit a toxic smoke, and regaled me with tales of deaths from persons dancing around Causarina beach fires from toxic smoke.

    Thanks again for the discussion.

    Kind regards,
    John W. (Jack) Bowers

  2. Thanks for the comments Jack.

    Good luck with the weeding! With some of the invasive stuff on our property it is possible that underground buds can grow after the main part has been pulled up. That is dealt with by cutting the stems off and dabbing the surface with herbicide (being careful about safety with nasty poisons).

    The reference to the smoke being poisonous is not something I have heard before and I'll look into it.


  3. I have started a little research into the smoke issue but will have to wait until my expert returns from vacation. However this paper seems quite sanguine about the use of fire as a control mechanism with no mention of poisonous smoke. However the range of chemicals they mention - some rather nasty - suggests they might have quite a high risk-tolerance!


  4. Several years back I listened to a lecture by an entomologist named Doug Tallamy who explained that one of the reasons that non-native plants proliferate and become invasive the way that they do is because the insects and birds native to the area are not eating the seeds of the Casurina trees. The food supply is often alien to them.
    There has been discussion in Florida of importing insects that eat Casurina seeds as a way of slowing down its growth. This is in the testing stage. And we all know that imported non-native insects can also bring new problems. It will take considerable testing before they proceed with such a plan. Here is an article written in 2008 summarizing research goals:

  5. Thanks Mary & Martin for the additional info. Back to the puns: Mary Martin played the original Peter Pan. Never had the pleasure of meeting her, but had dinner with Mary Martin's son, Larry Hagman & his wife Maj, 4 out of 5 nights in Louisville at the Transplant Games in 2006. He is quite bright, spry & quite a character.
    Perhaps we can call Mary & Martin's initiative "The Peter Pan Project"? Or, perhaps not ;-)

  6. G'day folks

    My experts on matters arboreal have returned to Greening Australia from their vacations and both have advised that they have never heard of Casuarina smoke being poisonous. One commented that in our bad bushfires of 2003 many Casuarinas were burnt and if there were poisons in the smoke it would have been reported.

    So I would put that down to an littoral legend (and perhaps contemplate what else was being smoked around the beach fire)!


    1. Thanks, Martin, for your reply. I have never learned of anything poisonous about Casuarina smoke either. We have burned Casuarina wood without a problem for several years now. My husband cuts it up and stacks it. It is excellent firewood.