What’s a forest worth?

David Lindenmayer has studied the Victorian Central Highlands flora and fauna for 35 years.

‘Most people in Melbourne know who runs around in tight shorts and kicks goals for Carlton or Collingwood but they have no idea where their water comes from.’ Professor David Lindenmayer

This is a story about science, but it’s also a story about wilful ignorance, a looming catastrophe, and, to run with the football reference, an ‘own goal’ on the part of government. It’s a story about Mountain Ash forests 90 minutes to the northeast of the MCG, but it could just as easily be about our forests here on the Far South Coast of NSW.

David Lindenmayer is Professor of Ecology and Conservation Biology at the ANU Fenner School of Environment and Society. He has published over 500 peer-reviewed scientific papers and 39 books, and won the Eureka Science Prize in 1998. With his team of 35 staff and students, he has worked in the Victorian Central Highlands collecting data sets on flora and fauna since 1983. Recently, Lindenmayer has used the System of Environmental-Economic Accounting (SEEA) to place a dollar value on the assets of these forests. SEEA is a framework used by the UN, World Bank and IMF to provide a comprehensive view of the interrelationships between the economy and the environment.

Lindenmayer spoke at a Bermagui Institute dinner at Bermagui Hotel on 15 August 2018. His subject: Earth, wind and fire (plus water, carbon and biodiversity).

The tallest flowering plants in the world

The Victorian Central Highlands forests comprise 90% of the water catchment for Melbourne, span 1.1 million hectares and are home to majestic stands of Mountain Ash trees—the tallest flowering plants in the world. Mountain Ash trees provide habitat, store carbon, affect local water yield and have a bearing on fire events.

About half of these forests have been clear-felled in the last 40 years.


Mountain Ash trees are integral to biodiversity. Lindenmayer’s team has measured these trees over 35 years and counted animals as they move in and out of hollows at dusk. The Leadbeater’s Possum (Victoria’s formal emblem), the Greater Glider, the Yellow-Belly Glider and the Common and Mountain Brushtail possums all rely on Mountain Ash hollows for safety and breeding.

Mountain Ash trees must have attained maturity (usually over 200 years) and generated hollows before they are likely to be occupied. But, says Lindenmayer, ‘Many of these big, old trees are collapsing, and collapsing rapidly’, due to a drying climate and thinning of the forest meaning less protection from wind.

Logging and fires remove more, and as Mountain Ash trees only set flower and reproduce when they’re old, young trees are not repopulating the forest. Old-growth forest used to account for 30-60% of the area. Now it’s about 1%.  Hollow-bearing trees are forecast to decline by a further 90% by 2035 with a ‘business as usual’ scenario. The International Union for Conservation of Nature, the organisation that reports on threatened and vulnerable species, has now started reporting threatened and vulnerable ecosystems—and Mountain Ash forests qualify as Critically Endangered.

The Central Highlands forests host an extraordinary diversity. ‘Almost none of the invertebrates in the forest have been described,’ says Lindenmayer, showing a slide of a new species of velvet worm. ‘If this was in the UK, you’d virtually know the first name of every insect.’


Mountain Ash forests store more carbon per hectare than any other forest studied in the world. On the other hand, the logging of Mountain Ash forest each year produces emissions equivalent to about one-third of the annual greenhouse emissions of Yallourn Power Station, either in high-intensity stand-regeneration fires or through accelerated decomposition. And if Melbourne Water’s desalination plant is brought online to replace water lost by logging the catchment (more on that later), that boosts emissions even more.

Water yield

Logging increases the proportion of young forest to artificially high levels. Lindenmayer likens young trees to his teenage kids, who ‘can empty the fridge in two days’. In their growth phase young Mountain Ashes grow about a metre a year—for 60 years. They soak up water, drying out the ground and emptying the creeks, then transpire so the moisture ends up in the atmosphere. An artificially high proportion of young trees has resulted in a 96% decrease in ‘wet plants’, like tree ferns, that need ground moisture.


It’s easy to see how Victoria has experienced three catastrophic fire events in the last 30 years. Logged landscapes are at increased risk of bushfire. Young forest burns at a much higher severity than old forest. 98% of the forest is now young, and it will carry an extra fire burden for 50 years each time it’s logged.

In 2014 Chris Taylor at the University of Melbourne studied forest areas that burned on Black Saturday in 2009 and found that the most severe fires, which consume the crowns of the trees, were most prominent in Mountain Ash trees aged between seven and 36 years of age, with a peak around 15 years. Crown fires were infrequent in older trees.

So what’s a forest worth?

We shouldn’t need to put our own arbitrary value on a forest. Forests have their own inherent value. But to state a case to government, dollar signs are needed. SEEA calculates the value of natural assets to the GDP of a region, state or nation. Lindenmayer’s SEEA study came up with the following asset dollar values for the Victorian Central Highlands Mountain Ash forests:

Agriculture: $312 million
Water: $310 million
Tourism: $260 million
Carbon abatement: $49 million
Plantation timber: $30 million
Native timber: $12 million

Ninety percent of Melbourne’s water supply comes from the Central Highlands. Young trees use water, old trees produce water. ‘As a catchment manager you’d want to keep the forest as old as possible,’ says Lindenmayer.

The Victorian government’s ‘own goals’

Logging started in the Victorian Central Highlands in about 1910. By 1924 there were 241 sawmills in an area roughly 60 x 80 kilometres. Since the 1970s there has been a shift from high intensity selective logging to clear-felling. Almost half of the forest has been clear-felled in the last 40 years.

For each hectare of forest that’s logged, 12 million litres of water is lost, per year. Logging in the Upper Thomson Catchment results in the loss of water equivalent to the consumption of 330,000 people – in a city which now has a population of five million.

Melbourne Water, forecasting shortfalls in supply, is already placing orders with the desalination plant, a more expensive water source which, in addition, raises carbon emissions and creates salt waste problems. But even at full capacity, the desal plant can only supply a third of Melbourne’s water needs.

In Victoria, 87% of felled trees go to pulp—ten trees are cut down for every saw log produced. It would be much the same here in SE NSW, where the Eden pulp mill claims to be using only waste timber for woodchips. ‘A very big tail wagging a very small dog,’ says Lindenmayer. And pulp can be made from plantation timber—in fact it’s preferable, as the plantation fibres are generally longer. For almost all uses, plantation timber can be substituted for native timber. And for carbon abatement purposes, it’s much better to source timber and paper products from plantations.

As for tourism, there are already about 3000 tourism-related jobs, ten times the logging jobs, in the Victorian Central Highlands—and that’s without any real tourism infrastructure. ‘If governments are serious about “jobs and growth”, about regional development, about the new economy, they need to start planning for infrastructure—walking tracks, access to waterfalls, aerial walkways … More, better, longer-lasting jobs result from tourism infrastructure, underpinned by the transition to nature-based economies,’ says Lindenmayer. Elsewhere, tourists travel huge distances to access the very experiences available in these Mountain Ash forests, only 90 minutes’ drive from Melbourne.

‘We are continuing to subsidise the employment of 300 people so we can scrub the water supply of 330,000,’ says Lindenmayer. This unprofitable industry also impedes tourism and reduces the capacity for valuable carbon abatement.

The acclaimed, dedicated and prolific scientist ended with a lament. ‘I’ve failed in the last 35 years to prosecute the case in a way to change policy for the better. My hope is that eventually we’ll work out a way to penetrate the psyche and ideology of our political masters to change how we view these natural assets so they’re of maximum public, economic, environmental and carbon value.’

7 thoughts on “What’s a forest worth?”

  1. Australia too a rich country with huge area and negligible population, yet they need to earn money from helpless , unselfish forests? Water can’t be substituted nor can be manufactured. Nature has gifted us forests so they can give us water, shade, cool the Earth…and you want to kill ‘God’s for a few dollars?
    Money is not everything. You may be rich but resources belong to all!
    Think dear Aussie’s intellectuals before axing a tree.

    1. Ah yes, I can see from your email address you’re from India, a denuded country if I ever saw one. God forbid Australia ends up the same.

  2. Well, the way I look at it, if we can not imagine it, it will not come to pass. Indeed, that is the only way anything has been materialised, I feel. Time? Well, again, what do we want and when do we want it…? I have my answer.

  3. Studies in other parts of the world show that healthy intact forest has a positive influence on rainfall further inland.
    Water from the desalination plant is pumped into the Cardinia

  4. Excellent piece, Jen. I know a bit about the state of play already, was at the talk, too, though had to gloss over some of it or be depressed for the morning.
    How does that Peter, Paul and Mary song? “when will they ever learn…?” About the size of it. for me.
    Having said that, I am trusting sense will prevail in the not too distant future.

    1. Oh Paul, you’re very trusting! You’d think that simple economics would turn their heads, but there’s no evidence of it so far.

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