Forest red gum and pink bloodwood natural regeneration at 5 years old.

Trees ain’t trees

Regenerating native habitat is usually achieved using two basic methods, and they are not exclusive. A great result is often achieved by using both together.

  1. Planting saplings that either come from elsewhere or grown from seed on the property.
  2. Encouraging and nurturing natural regeneration.

Koala Gardens now has 8 years of regeneration work to observe and compare and during this time both strategies have been used.

Planting of species as tube stock is the only option when you need to add species to the property that do not currently exist. One thing it is important to consider when choosing species to introduce is what habitat and species are endemic to the area. Unfortunately, in the past, species have been planted outside of their native area, thinking that if they are Australian they are native. This is not always true.

Knowing what is endemic allows you to plant the habitat that will quickly assist the correct ecosystems to be re-established or repaired.

Natural regeneration

Regeneration needs to focus on entire ecosystems, rather than thinking in terms of creating plantations. This will mean considering the under-storey, mid-storey and top-storey with the flora, and considering the fauna that will be involved from insects through to the larger mammals, reptiles and birds.

Plantation thinking often results in mono-cultures or out-of-area plantings that don’t support the local fauna as well.

Row of saplings planted by hand in 2013

However, what has interested me more in my observations is two main areas of difference I have observed in how natural regeneration trees behave and grow, and in how the koalas behave in response to them.

In order to reproduce a tree will flower and these flowers must be pollinated to produce viable seed. There are a range of animals that assist this happening from fruit bats, to honeyeater birds to bees and other insects. In eucalyptus trees the seed is contained inside gum nuts which protect the seed until it is fully formed.

Each mature eucalyptus tree may release tens of thousands of seeds in a single year. Some of the seed falls to the ground around the parent tree, and some may be born on the wind to fall some distance away.

If conditions are right, there could be hundreds of young seedlings that result. They may be sparsely positioned or there may be clumps of saplings. Not every sapling is going to grow to maturity for many reasons. However, as they are growing, there are many benefits to growing in a community.

Naturally sown saplings generally grow at a slower rate than saplings grown in a nursery and planted as tube stock, and are often much closer to each other than deliberate plantings.

Area of natural regeneration – notice how close together each sapling is.

The next article will discuss the pros and cons of slower growth, and following articles will address community living of trees.

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