The Problem with Biodiversity Offsets

I recently received a brochure explaining how developers wishing to clear native vegetation can either purchase and protect land with the same biodiversity values or purchase appropriate biodiversity credits from an accredited third party. 

Most conservationists oppose offsets unless the proposed development is absolutely necessary, and the destruction cannot be avoided. The reason being that, while the amount of land under conservation will increase over time with off-setting, there will always be a net loss of biodiversity overall. However, off-setting may force developers to seriously consider lower impact alternatives at the outset.

The brochure also featured an image of an old-growth eucalypt with a hollow branch to emphasise the importance of tree hollows in conservation. It also had the commonly seen cavity at its base, hollowed out and charred by successive bushfires.

It takes more than 150 years for eucalypts to grow and develop even small hollows and most will be logged long before they reach 50. Many of the remaining old-growth trees have likely survived because they were already too old and defective when their forest was first logged.

However, when the smaller surrounding trees are removed, those old trees are left unsupported and exposed to the elements, leading to high attrition rates from storm damage. Many can be seen with the upper portion of the tree missing and the ground beneath littered with broken branches.

Butt damage in older trees is common, and while machinery is often to blame, bushfires, and the prolonged burning of dead limbs lying against the trunk can have the effect of killing the tissues in that part of the living tree, leaving it vulnerable to future fire.

The drought conditions that led to the catastrophic 2019 bushfires were such that millions of defective old-growth trees were lost, and we must do everything possible to avoid a repetition.

However, while all governments promised to take the bushfire threat seriously, the recent Hill End fires proved that they have a long way to go to fulfil that promise.

John Edwards