The Heart of the Forest: A conversation with David Lindenmayer

David Lindenmayer is a forest of a man. A world-leading expert in biodiversity conservation and natural resource management, he’s published forty-eight books and more than 800 peer-reviewed scientific papers. He’s a professor of ecology and conservation biology at the Australian National University’s Fenner School of Environment and Society, an Officer of the Order of Australia, and a fellow of both the Australian Academy of Science and the Ecological Society of America.

Public accolades and global renown mean little in the forests of Victoria’s Central Highlands, on the lands of the Gunaikurnai, Taungurung and Wurundjeri Peoples. These forests cover over 710,000 hectares and are home to some of the tallest trees on Earth – mountain ash (Eucalyptus regnans). Some, still living, are over ninety metres (the height of a twenty-five-storey building). Others, long ago turned into timber, were reputedly more than 120 metres tall.

Here, in these old, old forests, it’s more important to be able to recognise the songs of superb lyrebirds, passed down from fathers to sons over decades; to know the biggest and oldest trees by name; to replicate the warning call of the critically endangered Leadbeater’s possum (zit-zit-zit), have one land on your head in alarm, wee on your watchband and have the scent stay with you for years. Here, amid the tallest trees; amid the noise of the harvesting machines a few valleys beyond; amid the wonder and devastation, it’s most important to observe, listen, feel.

When David Lindenmayer speaks of these forests – globally and nationally significant for their biodiversity and conservation value – his words come from the forest itself, a place he’s spent forty years recording, monitoring and studying. When he suggests there needs to be an extended reserve system – the Great Forest National Park – to protect the remaining forests in the Central Highlands, his words come from long-term research projects documenting the impacts of industrial logging and fire on the region’s ecology and biodiversity.

When the forest speaks through a man like David Lindenmayer, we’d do well to listen.

Georgina Reid: David, I’ve got so many questions. You’ve done so much, and there’s so much we could talk about. Let’s start with your childhood and how, specifically, you learnt to see and observe landscapes.

David Lindenmayer. Photo: Sammy Hawker

David Lindenmayer: My parents were from Queensland. My mother was a concert pianist, from a little mining town called Mount Morgan. She went to Queensland Conservatorium. There aren’t many concert pianists who come from a town like that. She always thought that education was an important part of making your way in the world.

Both my parents went to the University of Queensland at a time when less than one per cent of the population went to university – everybody had this idea that it was a silly thing to do. There was this terminology, ‘Bill’s nobody’s fool … he’s not educated, but he’s still nobody’s fool’. I used to hear that all the time in the mid to late 1960s when I went there for holidays.

My parents used to do these epic car journeys from Melbourne to Queensland. They took days. And there was no music, no DVDs, no videos. The only thing to do was to look out the window. That’s when I started looking at landscapes and thinking about how places work. I’m still like that.

GR: Even now!?

DL: Yeah, I get great pleasure from walking and looking. You can look at a place and see where it’s been burnt and where it hasn’t, where the different tree species are, the different shapes of the canopies, how the topography fits together …

GR: You’ve spent nearly forty years looking, walking and thinking in the forests of the Victorian Central Highlands. How did you get there and what’s kept you there for so long?

DL: I started in July 1983, working for a very bright, very innovative scientist called Andrew Smith. Andrew had done his PhD there, working at a site that had Leadbeater’s possum on it. He got a grant to identify its habitat requirements across the whole forest environment.

In a forest, no species occurs everywhere all the time. The idea was to try to work out where Leadbeater’s possum occurred and why. And what the effect was of disturbing the forest, through logging or fire, or both. I never thought like that until I started to work for Andrew.

The first three months were full-on – every single day putting out traps, catching animals, walking through the forest. It rained the entire time and by the end of the second month, everything was mouldy, including my sleeping bag.

When it’s wet down there, there are literally millions of leeches everywhere. For the first day, you don’t realise. Then you come out of the forest, jump in the shower and you’ve got this black necklace on, and you think, what the hell is that?

I thought, there’s no way I’m going to be able to do this for a year. It’s amazing what human beings get used to.

After a while, I started to appreciate what an incredible place it was. Even though I live in Canberra now, one of my favourite things is to go to those forests, count birds and have that quiet time. The more you get to know a place, the more you want to know, and the more you resonate with how amazing it is.

GR: Is there one particular place that calls you back?

DL: Yeah. O’Shannassy water catchment has never been logged. It’s got a special atmosphere. You don’t have all the log trucks, the people on their motorbikes and all the other crap that goes on. It’s where I do some of my best thinking.

I take my son there, and he walks up and down the tracks while I walk into the forest and listen for birds for fifteen, twenty minutes. It’s cathedral-like – the resonance of the calls between the massive trees gives a sense of amphitheatre you don’t get elsewhere.

GR: For someone like you, who’s spent your life researching forests and being embedded in them, I guess it comes down to relationship with a place as much as numbers and statistics?

DL: Yeah, it’s more than numbers. There’s an excitement in numbers because you don’t know what the intensive research is going to bring until you work with a statistician, and they pull out some of the results. But in the O’Shannassy forest, there’s a strong sense of place. I’ll hear a superb lyrebird running through a string of calls, and I know it’s either the same male bird I’ve been hearing for years, or its son. The sons learn the calls from their fathers. There’s a couple of places where I know that that bird’s going to be calling. It’s been the same since July 1983. I have bird plots from then.

GR: How long do lyrebirds live?

DL: We think for about twenty years, so it’s likely to be that bird’s son. That string of calls it makes, you know they have to be closely related to be able to sing that same set of songs in the same order.

They add others – in some places you’ll hear lyrebirds mimicking harvesting machines. I’ve heard them calling out ‘cooee’ as well, which is kind of fun.

GR: That’s horrible – the lyrebirds imitating the harvester. I think you’ve said that the forests of the Victorian Central Highlands are the best-known forest ecosystems in Australia, if not the world. Is that right?

DL: Among the best. The American Pacific Northwest forests have had a lot more work done on them. There are more forest ecologists in little towns like Corvallis in Oregon, than there’s ever been in the entire history of Australian forest ecology.

There’s very few people working in forest ecology in Australia now. It’s very different to the 1980s and 1990s.

GR: There’s an urgency in telling the stories of what’s happening in native forests – why they’re important and need protection. But you’re saying that there’s not many forest ecologists anymore. Which means this knowledge is held by fewer people, and therefore the stories of these places are being told by fewer people. What’s happening?

DL: For the last ten or fifteen years, there’s been a pronounced effort to prosecute a strong anti-environment case. That’s meant lots of young people who might otherwise have come into environmental science and management have done other things because they couldn’t see a pathway.

A lot of forest ecologists probably started doing forestry degrees. That’s how I ended up in this space, before discovering forest ecology was more engaging than cutting the forest down and growing it again.

As a profession, forestry is on the nose. There’s no university in Australia that has a viable forestry school. This means the typical pathway to attract people into forest ecology has evaporated.

GR: What do you mean by ‘on the nose’?

DL: Forestry has run violently to the right and has become ultraconservative. It’s forgotten the other things it should be. It’s forgotten about landscape restoration, revegetation, mine site rehabilitation, urban forests, plantations. It’s focused on native forest logging, which the vast majority of Australians don’t want.

GR: You’re right. I guess forestry is not a very attractive term for anyone interested in caring for trees.

DL: Over the last ten years, I’ve graduated more PhD students than forestry has graduated undergraduate foresters. Our forestry schools are extinct … The same problem’s occurring in North America and parts of Europe. People are more interested in conserving forests than chopping them down.

GR: We need to stop logging native forests, this is clear, but there’s demand for paper products, building materials etc. What does a sustainable forestry framework look like to you?

DL: Because of the legacy of the last fifty, sixty years of intensive industrial forestry, we’ve lost the ability to structure the industry in a way that could be sustainable. What we need to do now is source our timber products from plantations. The greenhouse gas emissions from producing plantation timber are much lower, and the conversion to wood products from plantations is higher – there’s much less waste. Native forests are worth way more standing than they are turned into woodchips and paper pulp.

We need to exit native forest logging as soon as we can if we’re serious about tackling our carbon emissions problem. Two of the biggest carbon abatement projects in south-eastern Australia would be taking the industry out of the native forest in Victoria and south-eastern New South Wales. If you were to do that in Victoria tomorrow, that would be the equivalent of 730,000 cars off the road. And in New South Wales, it would be the biggest carbon abatement project by an order of magnitude.

 The reality is that serious attempts to do emissions reduction and carbon capture have to involve forests.

GR: It seems so obvious. But what’s the problem?

DL: The unions. Governments are, in some states, running to the union’s agenda. In Victoria, that’s the clear case and in New South Wales it’s also pretty bad.

There’s only a few forestry companies, but they have powerful lobbyists. Once you put industry in bed with unions, you’re done. The only thing that will change this is if there’s a serious methodology for long-term carbon storage in forests. If that happens, you’ll have big business interested.

There’s a huge amount of potential revenue for states that would come from long-term carbon storage in forests, far more than they lose from the native forest sector at the moment.

GR: So, stopping native forest logging is a win-win for business and the environment except that there’s a few people yelling loudly?

DL: Yeah. But those people can readily transition to other employment in the plantation sector as elite firefighters, doing regeneration of forests, all sorts of stuff.

Industrial logging on a hilltop near Warburton. Wurundjeri Country. Photo: Sarah Rees. From The Great Forest, by David Lindenmayer. 2021, Allen & Unwin.
Cool temperate rainforest on Wurundjeri Country. Photo: Sarah Rees. From The Great Forest, by David Lindenmayer. 2021, Allen & Unwin.

 GR: Can you speak to the Great Forest National Park vision and why you’ve been championing it for as long as you have?

DL: There’s several angles. First, there’s the science on biodiversity, which indicates quite clearly that we need a greatly extended national park. Most of the populations of threatened species are not viable in the current reserve system. The area of protected forest needs to be much larger.

The second thing is that the economics indicate that the value of the forest for water and carbon way exceeds the value for woodchips. Economically, it’s stupid what’s going on.

The third thing is we’ve discovered that the more forest is logged, the more it’s likely to burn, and burn at high severity. There’s a really nasty feedback between human disturbance created by logging and natural disturbance associated with wildfire.

The vision, then, is an area that would have many more economic benefits, as well as biodiversity and environmental benefits, than what’s happening at the moment.

GR: The native forest that’s being clear-felled in the Central Highlands is not old growth, but regrowth. Maybe eighty, ninety years old. It’s an ecosystem, not a plantation, is that right?

DL: That’s correct. Most of it regrew from a big fire in 1939. It’s a natural forest that would normally be disturbed by fire about once every 150 years.

That’s very different to a plantation where you normally have an exotic tree species such as Pinus radiata or Tasmanian blue gum. These days, most plantations are established on former cleared grazing land. You put it in, fertilise it, and then after about ten to fifteen years, you thin it the first time, take out every third row of trees. And then you thin it a second time, at about twenty years. You clear-fell it in twenty-five. And start again. It’s a crop, but instead of growing it and harvesting it every year, you’ve got a cycle that goes through twenty-five years.

Plantations have very little biodiversity, high wood volumes and low waste. A parallel project to our work in Victoria is a study at Tumut, west of Canberra, focusing on the biodiversity, water and other values of plantations. About eighty-eight per cent of all the sawn timber that gets produced in south-eastern Australia already comes from plantations, mostly Pinus radiata. Plantations produce a lot less logging slash or debris, have a much higher conversion of timber, and can produce newsprint and other paper. There’s really no need to be logging native forests anymore.

GR: How much has already been cleared and what is planned in the Central Highlands?

DL: About fifty per cent has been clear-felled in the last thirty years. About twenty per cent of it is in water catchments and won’t be available for logging. The remaining twenty to thirty per cent will be cut in the coming ten to twenty years. The Victorian Government say they’re going to exit the industry in ten years, but I think that’s rubbish. There is no hard evidence the industry will actually cease.

When you cut a forest down, after about a year all the logging slash – the tree heads, lateral branches, understorey, bark and ground cover – dries out. Then you burn it, and burn about half of the biomass. That becomes a deep bed of ash and you parachute-in seeds collected from the cut-down trees and regrow your crop. After about twenty years, most people can’t tell the difference between a place that’s been logged and one that hasn’t.

But if you know what you’re looking at, you can see a forest that’s been highly simplified by the logging process. If you work through a natural forest on a cutting cycle of about fifty to sixty years, after about three to four of those cycles, the forest is highly simplified. Many elements of the biodiversity that should be there are missing. Some of the key plants, many of the animals. The forest becomes very fire prone. Then you need to think okay, if it’s employing lots of people and there’s lots of money involved, that’s the price we have to pay for a wealthy industry.

But in fact, native forest logging loses large amounts of money for the state, both in New South Wales and Victoria. And you’re not producing high quality timber from it. You’re producing almost all paper pulp and woodchips.

If so much of the forest is going into woodchips and paper pulp, do you need to cut down native forest in the first place?

 GR: It seems like a no-brainer …

DL: A complete no-brainer, yep. The Victorian Government’s forestry policy is one of the most stupid policies in natural resource management. Why would you keep pushing a loss-making industry that employs just a few hundred people whilst screwing over the water supply, boosting carbon emissions, and making places more fire prone?

Half the time I go to Victoria, it feels like I need to take a bucket of sand with me so people can stick their heads in it when I’m there.

GR: I bet you’re popular!

DL: Well, I’m old and grey and grumpy, and I don’t care anymore. If a policy is stupid, you may as well tell everyone about it until it changes.

Wollert, or Leadbeater’s possum on Wurundjeri Country. Photo: Steven Kuiter. From The Great Forest, by David Lindenmayer. 2021, Allen & Unwin.

GR: You’ve been working with Leadbeater’s possum for so long, it’s still critically endangered, and the greater glider has just been listed as endangered.

DL: It’s been uplisted. Yeah.

GR: You’re in this space, you’re watching these forests disappear and species shrink, and you obviously care deeply about them. How do you hold all of that?

DL: Because I know it’s the right thing to do. If it takes me another thirty years to fight to have it changed, then I’ll do that. It’s the right thing to do by climate, by biodiversity, by generations of younger Australians who have been let down by my generation.

It would be immoral to have this kind of knowledge and not do something about it. I love the forest and know there’s hope for it to recover. We just need to have some sensible policy, because at the moment, it’s disgraceful. And people should know about it.

GR: Do you consider yourself an activist or do you have to be a scientist first?

DL: I’ve struggled with this for a large part of my career. You can spend thousands of hours writing a scientific paper and three other people might read it. Nobody else will understand it because of the way you have to write it. And yet, the taxpayers support you to do that science.

If you’ve got an intimate knowledge about something and you don’t communicate it, I think that’s morally irresponsible.

In 2009, I was giving a public seminar after the Black Saturday fires. Somebody from the audience called out, ‘If it wasn’t for you greenies, none of this would have happened, the forest wouldn’t have burnt, all those people wouldn’t have died, shame on you.’

My response to that statement was: ‘You’re implying that if we were to log these forests, they wouldn’t be likely to burn as severely and we would save lives. That’s an interesting proposition, we should explore that.’

Later on that year, we published a paper where we looked at that. And we found that in drier forests, there’s some evidence that suggests some kinds of logging can reduce fire risk. But in wetter forests and rainforests and wet temperate forests, it’s the other way around.

I got a letter from the head of one of the paper industry lobby groups saying, ‘You shouldn’t say this stuff, it’s making our members feel bad about themselves.’ The letter was leaked to the media by the industry, and when I was questioned, I said, ‘If I have knowledge about the relationship between the age of a forest and how flammable it is, then it’s incumbent on me to tell people. It may affect their lives.’

If you know the relationships between logging and fire; if you know the importance of forests for carbon storage; if you know that biodiversity’s declining, then you damn well need to say it. If some people brand that as being an activist, then frankly, I don’t care.

GR: Have you always been like this, or is it you being grumpy and old?

DL: It’s called irritable male syndrome [laughs]. And it’s partly because environment policies have been so appalling for the last decade or so. We’re now seeing the outcomes of that.

GR: Something that’s interesting with your work is how much of it is long-term. There’s so much in our world that’s about the quick grab, the three-year election cycle. These long-term projects you work on, do they give you a different perspective? You know, you have to think like a tree in a way.

DL: Yeah, you do. It gives you a kind of tenacity, and a perspective you don’t normally get from a snapshot. It’s humbling, because the things you thought you knew are more complicated than you realised. Perspectives that you might have had twenty years ago become different. You have to acknowledge that sometimes you’re savagely wrong.

One of the reasons long-term work is so exciting, especially in a hyper-variable place like Australia, is that things change and you discover new things as a consequence.

For example, as more and more of the landscape is being logged around our long-term monitoring sites in the Central Highlands – where we re-count animals year after year – we’re seeing cumulative and incremental effects on local species, which you don’t get from a single snapshot.

Old growth mountain ash with snow and lichens on Gunaikurnai Country. Photo: Chris Taylor. From The Great Forest, by David Lindenmayer. 2021, Allen & Unwin.

GR: The place I’m most at home on the entire planet is probably the landscape I grew up on. It has a very strong pull on me. Where’s your heart landscape?

DL: Being in the forest is very spiritual for me, though I’m not religious. I love the mountain ash forest. But I also love the High Country. One of the things I love is being out on my cross-country skis. To ski beyond Charlotte Pass to where I got married – there’s a little snow meadow there. But the problem when I do those kinds of things is my mind is going with ideas. I’ve got to travel with my little yellow waterproof book.

I’ve got a real passion for this country. My son, he’s a wanderer, and said, ‘The great thing about wandering around the bush in Australia is there’s still so many animals calling.’ Yesterday, we would have heard about fifty or sixty things. I was trying to help him assemble the calls.

GR: That’s the thing isn’t it, you write in the introduction to your book that there’s so much beauty and wonder still present. It’s important that we see it, that we don’t think it’s all lost or broken. It’s still there.

DL: Yes, absolutely. The world is still a beautiful place and it’s still worth conserving. And there are lots of good people working hard to make a difference. I’ve had a wonderful life and I want other people and other people’s kids and their grandkids to be able to have those same experiences or something similar, and help contribute to keeping it as a beautiful place.

GR: As you say, the more curious you are, the more you see. It’s a virtuous cycle. I have to ask, what things do you write in your yellow book? Ideas for experiments? Poetry?

DL: No, no poetry, I write ideas. For example, we were recently doing a film on big trees, so I was out in the forest measuring the circumference of a special tree we call the elephant tree because it’s got these buttresses that look like elephant feet. We put the diameter tape around it, it’s 13.7 metres. I thought, hang on, the last time I measured it was in 1992 because we were measuring all the trees possums had nested in. Then, it was 12.9 metres. The tree had put on 0.8 or 0.9 of a metre in the last thirty years.

I had to get my little yellow book out while they were messing around with camera gear. I was thinking, I know of about 200 or 250 big trees like this that we’ve measured. That means that there’s an opportunity to look at the change in the diameters of these big trees, over this time. Which means that there’s probably a model for the relationship between tree diameter starting size, ending size, all sorts of stuff. And that triggers a whole set of ideas. Okay, oh shit, I’ve gotta get back out into the forest. Next time I’m in the forest, I need to do that.

GR: What a great job you have.

DL: Well, not if you ask my kids. They always say, ‘Oh, Dad, you’ve got ADHD, why can’t you just sit on a beach?’ I can’t do that.  

David Lindenmayer. Photo: Sammy Hawker