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How to protect 120,000 trees

Last month our Tasmanian team undertook the massive challenge of re-planting dozens of hectares of grassy woodland. With the help of some bright blue skies (a mixed blessing if you keep reading) we are thrilled to tell you we have finally finished. After two months of hard labour we have successfully planted 120,000 young trees and built over 6000 cages to protect them.

Plants ready to be planted Plants ready to be planted

This is a defining step forward for the Tasmanian Midlands but we aren’t out of the woods yet, so to speak. Our juvenile forest still faces the issue of browsing by native and introduced animals. Tasmania has seen an explosion in the feral deer population who rub their horns on the young trees, smashing or ringbarking them before they are big enough to withstand it.

Where we had uncaged test sites, trees were heavily browsed and reduced to a few sticks poking out of the ground by large herds of deer. There is also a threat from possums that live in surrounding woodlands and feed on the new seedlings at night. In addition, farmers are understandably keen to graze their animals on the restored sites meaning they face a threat from sheep browsing.

Feral deer Feral deer

To counteract these risks our Tassie team have become expert cage builders, developing numerous cage designs to house the young trees while they grow:

  • For the University research trials, for which our trees were planted quite densely (800 stems/ha), we constructed a 2m high deer and possum proof fence around the entire 17-hectare paddock.
  • In other areas, where the paddocks were planted more widely (50 stems/ha), individual cages were constructed to house two trees in each. We planted two different Eucalyptus species with different environmental preferences in each cage. As would happen in naturally occurring woodlands, we expect one of the trees to dominate and the other tree to be outcompeted.
  • Within the same paddocks we also have put some larger 2 x 2m cages, which house 2 to 5 trees and 5 to 8 shrubs of different species. These cages are small enough to prevent deer jumping in but large enough to allow establishment of a group of trees and native understorey shrubs. These also provide nodes for future expansion.
  • In riparian areas we have constructed 6km of stock -proof fencing to exclude livestock 200m from the riverbank. There are few possums and wallaby and no deer along the Macquarie River so we don’t expect high browsing pressure. In addition these areas are prone to flooding and there is a  high risk of floodwaters pushing over individual cages and the trees within them.

Tree cage Tree cage

The issue we’re now facing is water. Those blue skies made the planting a lot more enjoyable than it could have been but rain is needed. We have had exceptionally dry conditions in the midlands for winter and spring, and the long-range forecast is not very promising.

The good news is that at the moment most of the young trees are looking well with some new green shoots, but even with all our hard work, the success of our grassy woodlands planting campaign will hang on the whim of the weather.

Time to cross your fingers please.

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Tasmanian team Tasmanian team

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