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Two Possums, One Tree and Two Humans

Tony and Liz Cavanagh

This is the story of the long battle between two possums (a mother and her offspring) which seemed bent on eating every leaf off one of our favourite trees and the determination of two humans, bordering on obsession, to defeat them. The battleground was a stately white cedar tree (Melia azedarach) over 20 years old which was already suffering stress from the drought and seemed destined never to provide a shade canopy for us over summer.

The humans triumphed in the end but we still have a grudging admiration for those possums and their determination and persistence.

Melia azedarach is a rarity in the native plant world, one of the few non-tropical deciduous Australian plants. It loses its leaves over autumn and winter and bursts into new leaf in spring.

November 2005     December 2006
Left: The melia in November 2005. Right: The Same tree in December 2006.

We planted one on the north side of our house to provide summer shade for our outdoor table and lounge room; being deciduous, it lets the winter sun through. In past years, it has a full canopy by November but in 2006, hardly any leaves were evident by mid December and they seemed to disappear over night. Then one night about midnight we found the cause.

Two heavy-footed possums thumped over our metal deck roof and then proceeded to climb the Melia and munch all of the new leaves.

One of the culprits     Typical possum damage
Left: One of the culprits. Right: Typical possum damage, bark stripped, new shoots eaten off.

The fact that the fruits (and I believe the leaves also) are supposed to be poisonous didn't deter them and when we tried to chase them out of the tree, they just moved to higher branches. Drastic action was called for. Female human had seen plastic possum guards in the Geelong Botanic Gardens so male human decided to copy and wrapped the three main trunks in 50 cm wide "rings" of Laserlite-type smooth plastic sheeting to prevent them climbing the tree. Two nights later, both possums were back so Mark II action involved extending the rings to 100 cm width. But, yes you've guessed it, they were back again in a few days - more gnashing of teeth and threats from male human about possums which didn't know when to give up!

Possum protector Mark II    Possum protector Mark III
   Definitely possum unfriendly!
Left: Possum protector Mark II. Right top: Possum protector Mark III. Right bottom: Definitely possum unfriendly!

The problem was twofold. No one could tell us how high a possum can jump upwards (eg. were they simply leaping from the base of the tree up over the 1 metre strips) and secondly, we weren't able to observe how they got into the tree, ie. which branches they were using (they weren't able to jump from the table or patio beams).

One night when we heard the tell-tale thumping on the roof, we managed to turn the outside lights on in time to observe the younger one calmly jump from the base of the trunk along the branch I suspected they were using. This was not vertical but at an angle of about 70o to the ground and the possum simply "bounced" itself off the middle of the plastic rings and caught the trunk above it. "Right" says male human, "a couple of discs above the plastic rings will give you a headache if you try that trick again."

Female human, always one for recycling, suggested old garbage bin lids and male human proceeded to cut and fit them, holding them in place with 75 mm nails. And just to make things more difficult, similar nails were partly driven into the base of the trunk at the spot the possums launched themselves from.

A week went by and both humans thought "we've stopped them this time" and new shoots began to appear on branch ends. The one night, female human heard a crash and turned on the lights just in time to see mother possum high-tailing it from the tree. From long experience and complete lack of trust of possums, she went to inspect the tree by torchlight and yes, you've guessed it again, there was junior up in the branches! He was made completely unwelcome by being sprayed with strong jets of water until he fled the scene but male human was apoplectic by this stage and couldn't wait for morning to see if he could work out how junior possum had managed it. Sure enough, there were tell-tale bits of possum hair on the nails at the base of the trunk and interestingly, hairs on the edge of the rubbish bin lid.

Possum protector Mark IV    Possum hairs on the lid edge
   Victory to the humans
Left: Possum protector Mark IV. Right top: Possum hairs on the lid edge. Right bottom: Victory to the humans

This possum had worked out how to spring both upwards, and outwards about 15 cm, to catch onto the edge of the lid and haul itself on to the top, after which it was a breeze. Human male said lots of things about animal intelligence as he manufactured Mark IV modification which consisted of a sheet of thick plastic on the underside of the lid, projecting about 30 cm out all around, to prevent such acrobatics.

Mother possum was simply too heavy to copy junior and this was the crash we had heard as she hit the lid.

And so far, touch wood, it works and the tree is healthy and covered with new growth.

There is a lesson in all this and it seems to be, never underestimate the cunning and intelligence of a determined possum. We certainly learned a lot, spending more than $50.00 and putting up with hours of frustration in an effort to stop two "dumb" animals. I sometimes wonder just who is dumb!

Two months later.....

There certainly is a lesson - don't brag too soon either! Junior possum has had two months to practice jumping and managed to circumvent all of the barriers by leaping 2.5 metres from the top of our patio beams across to the closest branches, now that the tree is all leafy and green.

Male human now has the task of cutting off the offending branches (about 4 metres up in the air), or perhaps spiking the top of the beams, or both, and rising to the next challenge, which is bound to come!


Well, come it did with a vengeance.

Taken by torchlight at 11 pm
Possum protector Mark V
Top: Taken by torchlight at 11 pm.
Bottom: Possum protector Mark V.

The low point was reached on the night of the 12th of April when we found three possums in the tree! The third, which we christened sub junior, was apparently the next generation, also being taught bad habits. A period of intense frustration followed for the humans, for not only had all possums circumvented all the human barriers but they had changed their tactics. No longer did they thump over the roof but managed it silently so we never knew when they would visit the tree. They even took to walking to the tree on the ground and two of them received a shock when they saw human female sewing one night in the room close to the tree, just as they were about to attack it again.

There were two possibilities -

  • either they had managed to scramble up the plastic sheeting and pull themselves over the rubbish bin lids, or
  • they were still able to leap from the roof or patio beams onto suitable leafy branches.

Mark V protector involved adding further strips of sheeting to prevent them being able to gain any sort of grip of the wood of the trunk, with another sheet angled out hopefully to stop any jumping, and the angle changed on the rubbish bin lid on the branch which now seemed to be their main entry path.

Two nights later, suspicious noises on the roof prompted male human to turn on the outside lights and venture outside just in time to see junior take a running jump from the edge of the roof and leap slightly upwards about 1.7 m to another branch which had not been pruned. A couple of judiciously-placed sawcuts ensured that he was in for a nasty surprise the next time he tried the leap!

Two nights later, the branch was on the ground and we heard scratching at the tree. Not deterred in the slightest by his rapid descent to the ground when the branch broke, junior was scrabbling at the plastic sheeting and succeeded in again pulling himself up over the barriers and into the branches. Unfortunately, the main vertical trunk of the tree hid how he had managed it from the view of the humans so Mark VI protector was built to try to prevent him gaining access to the gap between the two main trunks.

Possum protector Mark VI    Junior and sub junior enjoying the melia leaves
Left: Possum protector Mark VI. Right: Junior and sub junior enjoying the melia leaves.

This consisted of two sheets of stiff plastic attached to either side of the gap and extra nails added to the base of the trunk but we had forgotten how far an agile possum can reach when standing on its hind legs. Several nights later, an inspection of the tree showed the sheeting pushed out as if they had used it as a step and both junior and sub junior happily eating melia leaves.

In desperation, Mark VII was devised, along the same lines as Mark IV (ie. fitting a horizontal plastic sheet around the trunk to prevent upward progress).

Who knows whether this will work but judging from previous acute lack of success, the possums will probably use it as a convenient platform on which to rest before an energetic night of stripping the melia tree.

Finally, below is a last picture of one of the trio which has given us so much frustration over so many months.

Possum protector Mark VII    Aren't I cute?
Left: Possum protector Mark VII. Right: Aren't I cute? How could anyone dislike me?

On a more serious note, I do have some information on that vexed question of just how far a possum can jump. If you are interested please contact me.

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Australian Plants online - 2007
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