Walking the tightrope of establishing trees next to rivers in dry landscapes

Establishing new trees is no easy business, especially among dry Australian landscapes and river banks that risk flooding. Since planting 121,000 seedlings across 480ha of the Tasmanian Midlands last year we have held our collective breaths and waited to see if our infant trees would sink or swim. We are pleased to announce that since September the progress of our trees has been successful, with some putting on 35cm plus of new growth.

It has been a dry winter and spring (only 380mm of rain in 2014 compared with a long term annual average of 550mm). This has made everyone understandably nervous. We considered watering but the complex logistics and high cost made it impossible, so we got ready to replant if the cohort was killed by drought. Thankfully the clouds eventually broke, and the gentle soaking rain may have saved our trees for this year.

We’re also thankful that the dry season has saved our sites from the usual winter flood on the Macquarie River. They can easily turn the water from a steady trickle to a turbid highway one kilometre wide. We carefully chose species that can tolerate getting their feet wet and now they are getting big enough now to survive flooding.

Keeping out the animals

Not surprisingly the best growth can be found in the 17ha site within the animal proof fence. Resembling a maximum-security facility, the fence is a 2.1m high mesh and electric perimeter, which serves to protect the trees from the most harmful browsing animals.

We understand that wallaby, fallow deer and wombats are not the kind of animals that usually strike fear into hearts – but for new seedlings they are like a pack of hungry lions surrounding a fallen antelope. The fence has proved effective at keeping out these ferocious browsers but has failed to stop the white cockatoos who occasionally infiltrate the site and snip the seedlings to access the sugary sap inside. Just take a look at the broken stem above.

In the Northern Midlands of Tasmania we have plans to completely restore both sides of the river bank that makes up part of the 21km riparian connection between the Eastern Tiers and Macquarie Tier.  We have planted eight kilometres of river bank to date, and are in the process of signing agreements with adjacent landholders so we can complete restoration on both sides of the river for the full length on the connection.

The future

Things are moving along steadily but our current budget will not stretch to complete the entire project. We’re hopeful that the Federal Government’s upcoming 20 Million Trees program will give the project a financial boost, plus we’re on the lookout for other funding sources. If you’d like to chip in to our work every dollar helps, and we always welcome opportunities to form fresh partnerships.

For a more detailed progress report on the Tasmanian Midlands restoration take a look at this great ABC TV news clip.

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