Seven Billion Burnt Trees

Horrific statistics ricochet around the world, sparked by the Australian bushfires. Half a billion animals, now likely to be closer to a billion. Millions of acres, thousands of homes, 33 human lives. I follow these, I feel these, and a voice in the back of my head asks ‘how many trees, how many shrubs? How many plants?’

I can’t help but feel a sense of incomprehension. Why is the impact of fires on plants not making the news; rarely the subject of fundraising campaigns; not being spoken of as anything other than habitat or hazard? Why, when nothing exists without plants, does our society continue to choose not to pay serious attention to their existence?

I dig around online, trying to find statistics of trees per hectare of different vegetation types so I can get some kind of idea of numbers affected. I don’t really understand why this is important for me to find out, but for some reason, it is. The numbers are elusive, like the news stories.

I call Brett Summerell, Director of Research and Chief Botanist at the Royal Botanic Garden Sydney, and it’s the first question I ask him. He tells me he’s been trying to work it out too. His rough estimate is, he says, somewhere between three and seven billion. Maybe more, maybe less. Seven thousand times one million. And more, again, of shrubs, climbers, groundcovers, fungi, moss; the microscopic and the magnificent. These are quantities hard to fathom, hard to imagine, hard to feel.

We meet in mid January. I want to find out what’s happening, what might happen, and what’s been lost. I want news of the plants.

GR: I keep thinking about what to do right now. Sitting and watching and waiting, or doing something, and if so, what?!  From a scientific perspective, where do you start?
BS: It’s a really interesting question.  A lot of it will be at this stage will be sitting and waiting.

We’re working with National Parks and also within the Department of Environment, to try to get a reasonable handle on what part of the natural vegetation in New South Wales has been impacted by the fires. We will be able to map that against fire intensity. This will help us get an idea of where we’ve had lower intensity burns, where we’ve had higher intensity burns, and then we can start to look at how this might have impacted the plant ecosystems in those areas.

We’ve got pretty good vegetation maps and there’s a lot of existing plot data, so we can look at the data before and after the fire and see what the impact is – what’s responding, what’s regenerating and how it all fits together.

We’ve got a focus at the moment on threatened species, and that’s probably too narrow. I think we need to broaden it to looking at what we call ‘narrow range endemic species’. This is a species that might only occur in one place – they have a restricted range and may not necessarily have been what we call threatened in the past, but now there’s the potential they may have been burnt out as a result of the fires.

Essentially, we need to get out into the bush and just see what’s coming up, what’s happening, so we can start to understand that. It’s a huge job because of the scale of the fires. It will need to be enormously collaborative, too, because no one organization is going to be able to get across all of the affected areas, so we’ll need to talk, to be working with each other and sharing data so that we can all start to get a better idea of where things are at.

GR: I’m interested in the relationship between you and your team of around 50 scientists at the Royal Botanic Garden Sydney and the broader ecosystem of land management in NSW. How do you fit in? How do you work with National Parks?
BS: We have a good on-the-ground relationship with National Parks. We’ve worked together really closely for a long time now. Our data in the herbarium and our plant identification service are really important for them and are used regularly. Here, in the plant clinic, we do a lot of Phytophthora mapping (Phytophthora is a plant pathogen which causes dieback in many native species, with the potential to cause widespread ecosystem damage and extinction) and provide information to National Parks on management of that.

Our seed banking and collecting team work really closely with National Parks and also with NSW Government programs like Saving Our Species.

There’s an enormous desire to do something to help wildlife, which is great, but the best way to help wildlife is for them to have an ecosystem that they can function in. That’s plants.

Brett SUmmerell

GR: Is there a relationship between the living collection here at the gardens in Sydney and at Mount Annan, and the potential work that might be happening with the response to the NSW bushfires? What’s the interplay there?
BS: This is a really important point. Within our living collections team, we’ve got really skilled, professional horticulturists who can get anything to grow.

For example, we’ve just done some work on a little plant called Lenwebbia. It’s in the Myrtaceae family, like Eucalyptus, and it’s very susceptible to myrtle rust.  We’re trying to build up its numbers, so we collected some pretty scrappy cuttings from Lamington National Park and now have the team in the nursery at Mount Annan propagating it. We’ll get plants growing, build up numbers, and then hopefully we will have the ability to supplement populations or learn ways in which we can control the disease, things like that.

The team at Mount Annan, particularly in the nursery, are really important for that sort of conservation work. They can grow anything! And obviously, it’s even more important now.

Nursery at the Australian Botanic Garden, Mount Annan.

GR: It’s a common perception that Australian native plants are adapted to fire so, you know, ‘the bush is fine, it will come back, don’t worry about it’. Can you speak a little to this point?
BS: In some places, that’s exactly right, the plants will survive because they’re adapted to responding to fire. 

But in some of the fires, particularly on the South Coast, temperatures were incredibly intense – no vegetation is adapted to survive in those sorts of conditions.  So, you will see areas which will almost be like a sterilization event. 

…the fire may stimulate species we haven’t seen for a long time to germinate, grow and produce seed, which we’ll then be able to collect and put in the seed bank.

Brett SUmmerell

There’ll be areas with no vegetation response because the fire has just been too intense and too hot. There’ll be other areas where the fire has come through fairly quickly. In these places you may still see a few green leaves in the canopy, but the understory has been burnt out. Here you’ll see eucalypts responding with epicormic growth and grass trees shooting up pretty quickly.  And if you get a rain event, hopefully then you’ll see lots of things germinating because the fire and the smoke stimulates everything to grow.

Rainforests are not adapted to fire at all.  There’s probably likely to be a fair bit of damage in those sorts of ecosystems.

GR: What happens with those?  Do you just leave them and see what happens, or do you replant – trying to re-establish the pre-fire ecosystem?
BS: There will be bits of all of those sorts of things.  If areas have died out, you need to look at what you do in terms of restoring those ecosystems – you can either leave it and it’ll take a long period of time to re-establish and they may get invaded by sclerophyll species that are better adapted to fire or we may have to do an intervention.

GR: That leads to interesting questions.
BS: It does.

And questions will be where do we go, what do we do, how do we prioritize? 

I think we should be looking at opportunities to ramp up what we’re doing in terms of seed collecting and seed banking because that will be an effective way to make sure that we’ve got diversity in the seed bank as an insurance policy.  Given the expectation that this sort of event is probably more likely to happen more frequently.

Seed collection records at Plant Bank, at the Australian Botanic Garden, Mount Annan

GR: What questions are coming up for you personally now? Not necessarily maybe as scientist, but just personally, what’s coming up?
BS: Once you start to hear what’s happened to different bits of work that we’ve been doing, you know, they got burnt out or at different places that we’ve been working in that have been impacted, that’s quite depressing and you sort of think ‘we’re going back to square one’.

But then, when you get an event like this, it does highlight the importance of the work that we do.  So, in a weird way it’s sort of reassuring to have the realization that actually, ‘oh, yeah, this is important, isn’t it?’

GR: There’s something in that realization in that that’s quite energizing and focusing, I imagine.
BS: That’s right.  And it’s a validation of decisions we’ve made, particularly over the last 10 years, to have a stronger focus on plant conservation. This has been a deliberate decision across the whole of the Botanic Gardens community – to move away from the traditional areas of botany, which is still critically important, and to have a more active role in plant conservation.

So, when you see events like the fires, you can say that this, really, is the reason for our existence.

Seed Vault at PlantBank, at the Australian Botanic Garden, Mount Annan

GR: What about PlantBank, the Royal Botanic Garden’s seed bank? I know you have around 65% of threatened species of NSW contained within it. At times like this it must be so necessary and important?
BS: Over the last five years we had a really strong focus on trying to get threatened species and rare species into the seed bank. And now, after the fires, we’re wondering whether we’ll get back out into the field and discover that the only currently existing germplasm of species A, B or C is actually in the seed bank, or maybe in the gardens. This could well be the case.

GR: It’s hard to see a silver lining at times like this. Can you tell me something good?!
BS: Well, one positive that may arise in some fire affected areas is that the fire may stimulate species we haven’t seen for a long time to germinate, grow and produce seed, which we’ll then be able to collect and put in the seed bank. This has happened after previous fires.

There may be great opportunities to collect seed from a whole bunch of species we have not seen for ages. 

The other thing is, if 2020 has better rainfall than the previous couple of years, we may see a spectacular spring, with lots of species flowering that we haven’t seen for a while, and in abundance. Fingers crossed.

GR: One of the amazing, and heartening, things in the wake of the bushfires was seeing all the fundraising taking place. But I kept looking to see who was raising money for the plants, the trees, and I couldn’t actually find any organisations doing this. It seems like plants are, more often than not, the invisible ones. This worries me because it means less funding, less attention, less resources. And yet, they’re the foundation of all life.

BS: Yes. There’s been an enormously big focus on animals, you see all the images in the media. There’s an enormous desire to do something to help wildlife, which is great, but the best way to help wildlife is for them to have an ecosystem that they can function in. That’s plants.

Some Statistics

(From NSW Government Wildlife and Conservation Bushfire Recovery: Immediate Response Report, Jan. 2020)

More than 90% of the recorded range of 46 threatened plant species has been fire affected.

53% of heathlands in New South Wales have been impacted by the fires. The native plant species in these ecosystems are highly adapted to fire.

41% of wet sclerophyll forests have been impacted by the fires. The trees in these ecosystems are generally adapted to fire but the moist understory habitat can be more fire sensitive.

35% of rainforests in New South Wales have been impacted by the fires. These types of ecosystems are sensitive to fire and may require more support for recovery.

While more than 80% of the Greater Blue Mountains World Heritage Area has been fire-affected, only 7% experienced high fire intensity burns.

54% of the Gondwana Rainforests World Heritage Area has been fire affected.

37% of NSW National Parks have been fire affected.

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