GROUNDED Live - 2026: Dave Watson - Mistletoe Magic

Welcome to a new season of GROUNDED Live. This season features presentations recorded at GROUNDED Festival 2026, held over two memorable days on Yan Yan Gurt West Farm in Victoria, Australia. Each episode captures the ideas, stories and practical knowledge shared by the farmers, researchers, chefs, practitioners and thinkers who came together to explore healthier landscapes, healthier food systems and healthier communities.

In this entertaining presentation, ecologist Dave Watson challenges one of nature's most misunderstood plants. Mistletoe is often dismissed as a pest, but Dave reveals the remarkable role it plays in supporting biodiversity, healthy ecosystems and thriving landscapes. It's a fascinating reminder that nature's smallest players can have an outsized impact. 

GROUNDED Festival is a cross between a farming conference and a food festival, held on a different farm each year. Every festival is unique, celebrating the people, landscapes and food of its host region through an inspiring line-up of speakers, local producers and hands-on learning.

With multiple stages running concurrently, GROUNDED brings together science and technology, ancient wisdom and fresh thinking. It provides a respectful place for lively discussion, an audience as interesting as the speakers, and an excellent menu of local food, drinks and music, all on a beautiful, regeneratively managed farm.

Each year, we record many of the presentations and make them freely available as the GROUNDED Live podcast. We hope you enjoy the conversations.

Thanks for listening, and if you enjoy this episode, we'd love to welcome you to a future GROUNDED Festival.

Transcript

SPEAKER_10 0:56

Okay, welcome to the Blackwood Tent for our next session. This has been an awesome tent for those who've just arrived. My name's Kate Myrams. I'm a dairy farmer east of Melbourne, near Mafra in Gippsland. And we've been farming there for 22 years, and the last six years we've been really serious about regenerative agriculture, which has led me to do um, you know, a little bit of speaking and unbelievably got this gear, and I'm so stoked to to be able to be uh hosting this tent today. So yeah. Um this next presentation is about mistletoe, and I just want to share a little tiny story about my relationship to mistletoe. I grew up between Eden and Bombarda in New South Wales in the Toowomba Valley, and during the 90s, when I was young and impressionable, we had a lot of drought, and a lot of the monuments of our landscape, the ancient trees, the 300, 400, 500-year-old box trees, were dying, and they had mistletoe in them. And my dad taught us to shoot the mistletoe out of the trees to try and save the trees, and we thought this was a reasonable drought job compared to the other shooting jobs on. So, you know, that's my early impression of mistletoe, and so I'm so delighted to actually learn the reality of the power of mistletoe in our landscape. So, with that, I would like to introduce Professor David Watson, who's based at Charles Stewart University's Gubbel Institute. Dave's an ecologist with a particular fascination for mistletoe. And I'm just going to let him tell us a little bit about how he got to this place in his career, and then I think Dave would like to run this as fairly interactional. So normally we'll let him talk for a bit, but feel free to put your hand up, we'll bring a microphone to you, and we'd love you to share where you're coming from before you um give us your question. So thanks. Over to you, Dave.

SPEAKER_01 2:55

Lovely. Thanks, Kate. Uh lovely to be here. Thanks for coming along. Um, and just want to acknowledge here we're on uh Eastern Ma country. Uh fabulous uh welcome to country this morning with uh smoking ceremony involving exocarpus, which is a cousin of mistletoes. It's a much more discreet parasite that does its parasitism below ground where you can't see what's going on. Um so I'm I live and work on Waragery Country, and as Kate mentioned, I'm a program lead for all environmental science at the Galbali Institute. Galbali is a oragery word gifted to us by Uncle Stan Grant, um the father of the journalist Stan Grant, who's also um one of my colleagues. Um it's part of a phrase Galbali Nurembang, which is a oragery phrase meaning to understand country. Um, but understand in in oragery language means not just understand country um from afar, but to understand your place in it as and your part of it. Uh there's that reciprocity uh in that in that in that uh in that language. Um and it's an important part of what we do at my university, uh, and just acknowledging that um that we're on unceded land here, and what I'm gonna tell you about now is is very much a Western science perspective, but a lot of this stuff has been nutted out by traditional scholars, the first scientists um around this place for a for a very long time before we got here. So, what we're gonna do, just just to let you know what that what the journey is gonna look like, uh I'm just gonna give you a quick rundown on who I am and how I came to be the mistletoe man, which is a weird, you know, handle. Um uh, and then just run through um a few a few bits and pieces about mistletoes, bust a few myths, including the the big bad parasite that you've got to shoot off, because otherwise, you know, dead trees. We'll we'll sort that out early on. Um, and then I'll just give you a bit of a bit of an understanding um about what I've learned in the 30 years I've been studying these plants. So I'm gonna speak for around half an hour. Uh it's about a year's work per minute. Okay, so this is not this is not quaffing, you know, talk. This isn't just knock it back and have another have another swig. This is whiskey. This is we're gonna be sipping, this is distilled stuff, okay? This is this is strong stuff, so it's good you're sitting down. Um, early in my training, uh I was doing work looking at habitat fragmentation um and how it affects biodiversity, how it affects um wildlife in particular. Um so when you take woodland, a forest that used to be continuous, wall to wall, and chop it up, um bit of farm here, a bit of a city there, um schools development, uh broadacre cropping, whatever it is, and leave little pockets of vegetation behind, what happens? What happens to those little pockets and why do some of them support more species than others? It's an open question that many people are still very interested in in working out to sort of broker those win-wins in our agricultural landscape. So it's not just production or biodiversity, it's both. So when I was doing that work in the western in in in Western Victoria in the Wimera, um that's when I first really got to pay attention to mistletoe. And all these weird desert birds, all these inland species were only in a few of these sites, and they were only in those sites where there was lots of mistletoe. It's like, eh, well, that's interesting. Filed that away. Then moved to the States, spent a lot of time climbing up mountains in southern Mexico, looking at cloud forests, an ancient fragmented landscape, a landscape that was fragmented in the last ice age. So the fragments of forest I was studying had been fragmented 30,000 years ago, and gave us a real window into how our landscapes that we've um adjusted here are going to function long after we are gone. And there was mistletoe there too. If you wanted to see hummingbirds, if you wanted to see cool tannages, if you wanted to see weird mammals, just camp under a mistletoe and just pay attention, and there's just all sorts of stuff going on. So I filed that away, so finished the PhD and thought, okay, I really need to pay a bit more attention to this to this mistletoe caper. So sat in the library for a year, read three, three and a half thousand papers, everything that had ever been written about the ecological interactions involving mistletoe, just slurped it all up and realized that there was a few things going on there that people hadn't really acknowledged before. It was a real powerhouse when it comes to diversity. If you're looking at two otherwise comparable areas, that area with more mistletoe has just a lot more stuff going on. Way more biodiversity, more birds, more mammals, all sorts of things. And we didn't really know why. So it's like, okay, well, I guess I better sort that out. I guess we better find out why. So published a few papers about this stuff saying, look, it it seems to fulfill all the criteria of what ecologists call a keystone, an ecological keystone. One of many species, but one that seems to punch well above its weight. It really has a disproportionate impact on what's going on in terms of what we see in the environment. So I did what all ecologists try to do to really answer, uh definitively answer a question. I did an experiment, a big experiment. So I'm I'm I'm I'm based just uh at the Aubrey campus of Charles Dirt Uni. So just up the road uh is uh town of Holbrook, that's a submarine town for those of you Hume Highway uh commuters, um, and so worked in around the Holebrook area on farms. Uh the Holbrook Land Care Network is a is a wonderful um uh NRM group that I'm now on the on the board of. Um and I worked with a whole lot of farmers, mostly sheep farmers and cattle producers in the area. Forty chunks of grassy boxwood land was was when that was my study system. So we you're talking Blakely's Blakely's red gum, white box country, a bit of yellow box, a bit of red box on the ridges, just to orient you. Spent a year looking at who was who in all these chunks of bush, so I had a pretty good idea of what sort of background biodiversity was going on, and then removed every single mistletoe plant from half of those woodlands. If it's so bloody important, take it away and let's see what happens. So a non-trivial logistical exercise, 45 tons worth of work, all with hand tools and cherry pickers. Teams of volunteers put on a lot of barbecues to keep them happy. Within three years we lost a third of our birds. Theatrical pause. Within three years, the only thing we did in these treatment woodlands was just chop away the mistletoe from the canopy, let it fall, and then for the the control woodlands, the woodlands where we left the mistletoe alone, we cut random branches from random trees just to rough up the trees a bit to mimic the disturbance we were doing, but leave the mistletoes alone. Those diversity went up in the sites where we left them alone and left the mistletoes where they were. We lost a third of our species of birds within three years of removing mistletoes. It's like, well, I was expecting some sort of response. Not that big, not that quick, not that clear cut. Okay, so had a good look at, okay, so let's have a look at the data. And we know a fair bit about mistletoes, and so I thought, okay, like I'm they're pollinated by birds, and just I should have done this before, sorry. If you're thinking, what's this bastard on about? This is mistletoe, okay? So I've sort of jumped ahead of myself, but yeah, we'll get there. So um it's a parasitic plant. Um and it grows on on if you can think of an Australian tree, it's probably got its own mistletoes. So this is drooping mistletoe, it's a it's a it's a eucalyptus parasite, it looks like eucalypts. There's um there's mistletoes that latch onto she oaks. They're a dead ringer for she oaks, they've got long skinny leaves. There's there's mistletoes on colitris, there's mistletoes on acacias, there's mistletoes on mangroves, there's mistletoes on hacheas, there's mistletoes on most Australian groups of trees you can think of. Um, interesting group of plants did this study, found a huge change in diversity, and really wanted to know more what was what was driving this. And so went back and did some homework. It's like, okay, so what interactions do we know about that might be explaining this? So they're bird pollinated, they've got showy flowers like a banksia, like a bottle brush, um, and because they're parasitic, they flower whenever they want to flower. A banksia can only flower when it's got enough water, enough nutrients, enough goodies to give it away as free carbs as a bribe to say, come and get my sweet treats. And while you're there, just move my move my pollen around if you if you don't mind. Um, mistletoes flower when no other plants flower to maximise pollination vegetation. So in the arid zone, middle of summer, fry an egg on the bloody bottom of your ute, mistletoes are flowering. They're the one shop open in town. In the middle of winter, in temperate forests, where nothing else is flowering, mistletoes have flowers available. So I thought, okay, maybe, in my big experiment, maybe it's all nectar feeders that dropped out. Nope, nectar feeders were unchanged between the sites with and without mistletoes. So, hmm, okay. Well, what else could it be?

SPEAKER_10 11:44

Fruit.

SPEAKER_01 11:45

Mistletoes are basically the only fleshy fruit available in many woodlands in southern Australia and a very reliable fruit source in all the desert ecosystems where they where they live. Indigenous Australians have been snacking on mistletoe fruit for a very, very long time. Tasty stuff, full of amino acids. If you're stuck on a desert island, you will thrive eating nothing other than mistletoe fruit. All 11 essential amino acids are in mistletoe fruit pulp. There's fat, there's carbs, good gear. So looked at the fruit, the fruit eaters. There's not that many fruit eaters in Southern Australia where we were doing our work. No difference. It's like, okay, well, what is the difference between the sites with and without mistletoe? It's insectivores. It's it's it's the it's the it's the birds that eat insects, specifically the birds that eat insects on the woodland floor. It's like, that's nothing to do with mistletoe. Mistletoe's this thing up in the trees, and I got these bloody babblers and robins and chuffs and and and whistlers and tree creepers just dropping out completely when I remove the mistletoe, and they're they're doing their foraging down there. What's going on? So I needed to do more work, more experimentation. And we looked at litter. Leaf litter specifically. You would know that eucalypts um and and and most of our native plants, they're misers. They've grown up in very, very poor soils, they've got a hard life, they grow leaves, they defend those leaves with nasty toxins to stop herbivores eating them, they hang on to those leaves for a very long time, defending them with tannins to make them stronger, and then when they drop them, they withdraw all the nutrients from those leaves, those hard fought nutrients, back into the plant, put waste products into the leaf, drop it, you're dead to me. Mistletoes didn't read those textbooks. They don't do any of those things. Remember, they're parasites, they're freeloaders. They didn't work hard to get those nutrients, they just slurped it out of the gum tree. It's like just drop my leaf, grow some more. Mistletoe leaves, as they drop them, had exactly the same nutrient profile as a living, breathing leaf on the mistletoe, full of goodies, and the way they withdraw nutrient uh the way they withdraw water from their host is to maintain very high concentrations of cations in their tissues. There's more phosphorus in real terms, like weight for weight, grams. There's more phosphorus in a little basketball-sized mistletoe tree than than in an entire gum tree above and below ground. They're full of the stuff. Calcium, potassium, molybdenum, iron, copper, all these elements that are rare in Australian soils, mistletoes are chock, chock full of. So when they drop their leaves, their leaves are full of those goodies. It's like crack for woodland soils. Things go bananas with a little spritz of mistletoe litter. Microbial communities, especially fungal communities, are really limited by a lot of these cations. They'd love to grow big and strong and prosper and gobble up all this carbon in the soil, but they're limited by phosphorus. They're limited by potassium. There's just not enough of some element to get them going. Add a mistletoe to the canopy of a tree, you've completely changed the nutrient availability of that entire woodland. So more mistletoes equals more cations equals activated humus. Decomposition rates triple, insects move in, and that's where the insectivores come in. It's like, yeah, it's a pretty freaking complicated story. But that's what you get when you start mucking with systems. That you you adjust things and you learn a heck of a lot that you never thought of before. So my understanding of mistletoes, it's a bit like if you take if you just take the imaginary network of interactions in a woodland, I've just taken one of those hubs, one of those organisms, in this case mistletoe, and pulled. And pulled and pulled and pulled and pulled and pulled hard and been able to visualize and quantify all those connections that we didn't even know existed through that one that one organism. You could do the same thing with bats, with spiders, with fungi. You know, pick your your your your your spirit organism, yank on that hard enough, and you'll realize just how interconnected our systems are. So running with that, I've learned a heck of a lot about the way woodlands actually function. Because as an ecologist, it's not good enough just to just to study patterns, just to go, hmm, that's interesting, and then move on. Because we're dealing with a landscape, with many landscapes that need help. Um and if you want to manage a landscape um, you know, efficiently and effectively, it really helps to know how things work because then you know what levers are available for you to pull on. And at places like this, it's certainly talks I've been to already, function, function, function always crops up. If you're a farmer, you want to know how to how to how to tweak functionality in your system towards those things you care about, towards those things that you make money from. My interest is not in making money. I'm an ecologist, it's a foreign concept to us. My interest is in learning more about the way the world works. Um, and so mistletoes have certainly uh allowed me um to do a lot of that. Um just want to touch on a few other things that I've sort of skipped over. Um get to the management thing now because many people are concerned about this. Mistletoes are parasites. And the P word you don't generally mention in polite company. Uh, because if your kids have parasites, they're no longer welcome to daycare. You know, they need to stay home. Um and so I think mistletoes have copped a lot of flack from from many. Your your parents, uh uh by far the majority. Um if it's a parasite, you need to get rid of it. It's it's it's by definition bad. Parasites are as bad as predators. It's not good or bad, it's just a way of being. There are more species of parasite on Earth than non-parasite. You're in the exception. You're not a parasite. Well, some of you might be, I don't know. Um But parasitism is uh is a legitimate way of making a living. Now you watch an Attenborough documentary, you see tigers going about their business, you think, how dare you, Mr. Tiger, beating up those poor little innocent deers. You don't do that. That's just a tiger doing what a tiger does. And so parasites do the same thing. They just do it in a subtle way, without necessarily consuming the entire organism. They just take a little bit and then and then keep going. So I think mistletoes have popped a heck of a lot of flack because of the P word, because of the parasites. We start assuming they're bad and then go from there. But what we now know, there's 97 species of mistletoe in Australia described. There's three more we're about to describe, so we're gonna get to a century. So compared to England, you know, not just crap at cricket, crap at mistletoes. They've got one. One, one mistletoe. It's like, come on, they're not even trying. So there's a lot of them. There's a hundred species of mistletoe that we know of in Australia. Um, they're everywhere except Tasmania. They used to be in Tasmania, but they're not anymore. Um another thing, many people assume that they're introduced. It's like, well, there's blackberries, and they're terrible, and they're from England. And there's sparrows, and they're no good, and they're from bloody Europe. And then there's this mistletoe that's killing our trees, and it must be from Europe because there's mistletoe in Europe. It's a different thing. So our mistletoes are completely different to mistletoes around the world. Every single mistletoe is a native plant. They were here before Australia split off from Gondwana land, so they're Aussie, Aussie as. They're as Australian as kangaroos and wattles and emus. Another misconception is that they they necessarily kill trees, and I just want to tackle that head on. Um, and this is the thing you hear about with parasites generally, the parasites are bad and they they they they knock around their hosts. If a parasite kills its host, that's literally biting the hand that feeds it. I mean, if mistletoes kill trees, that way of being a plant would have died out a very long time ago. So it's a dance. It's a dance they do through evolutionary time. Mistletoes, as a group, we're talking sort of 45 million years, 50 million years or something ages. Quite a while. Okay, they're not Johnny Cum Laties, they've been doing this for quite a while. So mistletoes in Australia certainly are effectively water parasites. They're green plants. They're not one of those weird, ghostly things that takes all their goodies from um from fungi or from or from plants. They're green plants, they photosynthesize, they pay the bills, but they don't have a root system. Instead, they take the water that they need from their host and whatever nutrients are dissolved in that water. So they're hemiparasites, is the technical term for them. You only really get into trouble as a tree when you're struggling to pay the bills in terms of your water balance. If it's thirsty and you're trying and trying and trying to find the water you need, and it's getting drier and drier and drier, and you've got some mistletoes in your canopy, that's not a good situation. Mistletoes aren't helping. Nick Reed, uh, University of New England, um, back in the 90s, did a whole bunch of experiments where many landholders on sheep properties that were very worried about their trees dying from dieback and they need their trees for shading their livestock. He did some experiments and removed mistletoes from individual trees. It's like, okay, let's see. Let's see if mistletoes are contributing to tree health. Pruned away all mistletoes from single trees, followed them through time, no difference in mortality. If the tree's dying, it's dying anyway. You can zip off the mistletoes, you can feel better about yourself, sleep better at night, you haven't made a lick of difference. It's a symptom, not a cause. If a tree is struggling to pay the bills in terms of its water, the mistletoes are already dying. They need regular supply of high volume water. If they're succulent plants. On a hot day, grab a sprig a mistletoe foliage, it's cold to the touch. We'll revisit that at the end about microclimate, because that's we're just discovering stuff about that, and it's it boggles my mind. Where am I going with this? Quite alright. Maybe just answer it, you know? It's always knocking. Yes, Dave. Yep, mistletoes. Now's not a good time. Um so the effects on trees is is a serious one. Farmers care about trees. I love it when farmers call me up and say, Are you the bastard that says mistletoes a good thing? Because I've got a few things to tell you. I I start with a very positive frame of mind because, mate, talking to a farmer who cares about trees on their property, that's a nice conversation to have. We already share a heck of a lot of values. The trick to understanding mistletoes on trees on farms is to pull back a bit. Don't worry about mistletoe for a sec, and just think about the context around that tree and what's changed in the life of that tree. That tree grew up around France, had lots of buddies within reach. They're all gone now. It's a tree out in the middle of a paddock by itself. The normal things that keep mistletoes from being everywhere, the reason why you didn't wade through mistletoes from between where you slept tonight and your position right now, there's a heck of a lot of things that want to eat mistletoe. All those nutrients I mentioned, all those cations, herbivores go out of their way to eat mistletoe. The great apes around the planet, the top three foliage species in the diet of every single great ape includes the mistletoe. They love the stuff. It's full of goodies. Had a PhD student working on brush tail possums. The brush tail possum will go through three manigums to get to a fourth manigum with mistletoe in it, and the only thing they'll eat is the mistletoe foliage. It's not defended, it's got none of those nasty eucalyptus oils in it, it's not spiky, it's not leathery, it's got a whole lot of water in it, and it's got all those cations that don't just um uh uh boost nutrient availability in the soil, it uh it fulfills the nutrient balance that herbivores need. So, in an intact woodland, that tree that's currently sitting out with no friends had a connected canopy, possums would come through it, they'd gobble up mistletoes. There's 17 species of butterfly in Australia, the only thing their larvae eat is mistletoe foliage. Those butterflies will fly around the landscape, sniffing at mistletoes, lay their eggs on the foliage. Those hungry, hungry caterpillars will defoliate an entire mistletoe plant in the time it takes them to pupate. But the butterflies, they're broad nectar feeders, they don't really care where they get their nectar from. What have we done to the landscape around those trees? We've either grazed out or cleared those nectar-bearing shrubs that the butterflies depend on as food plants. The last element is fire. Mistletoes have no defences against fire. They've got no storage organs, they've got no roots. A defoliated mistletoe is dead. If it has no leaves, it can't pay the bills. It's good night Irene. So think of that tree in the woodland. Understory plants with nectar, well, they're not there anymore. Connected canopy with hungry, uh, hungry possums, they're not there anymore either. And the occasional fires that would come through and clean out the whole canopy, that's not there anymore either. And so no wonder there's a heck of a lot of mistletoe there. So if you're worried, if you're worried, if you're losing sleep over this, that you've got mistletoes knocking out the big trees on your place, firstly don't be worried. There's other things to worry about. Just cross that one off the list. To make a difference, think about those three things I mentioned. The hungry mouths. What can you do to increase nectar availability in the understory of your place where butterflies frolic? Possums, do you see brushtail possums when you're out rabbit shooting or knocking off foxes at night? If not, they're probably gone from the landscape. Probably because they're missing out on the hollows they need for homes. Chuck some nest boxes up, possums will say thank you very much, and they'll work for free, knocking off mistletoes. And then fire. Fire is a very contested topic. I'm not giving you license to just burn up the place. But think about fire as a management tool, not just for all sorts of reasons you'd be thinking about cool burns anyway, but realize that that's a very effective way to reset the canopy, emulating the natural um fire cycles that many woodlands would have, where a fire would come through now and then and clear out the canopy of mistletoes. Those three things will take care of mistletoes on your property in almost all situations. But if you disagree violently, fantastic. Let's have a chat and let's let's explore more and and and see what we can do about about optimizing that balance at your place. Just a few things I want to close on, and then I really want to open it up to what you want to know about, because as you probably realised, I actually can talk under wet concrete about mistletoe, so I want to make sure this is relevant for you. So you've come here, I want to answer your questions directly. Mistletoes don't regulate their water use. Just like they throw down their litter full of goodies because they didn't work hard to get it, their pores are always open. They didn't work hard to get that moisture. Their guard cells, if you remember high school biology, there's little pores on leaves that weep out water vapor and gases. Um there's two cells around that called guard cells, like pillows. When they're rigid, um they open up. When they're flaccid, they close up. That's how plants regulate water use. Mistletoe guard cells don't open and close. They're always open. It's like a tap you can't turn off. It is always dripping. That's why mistletoes need a high volume of water, because they're using it and getting rid of it. But from a microclimate point of view, in a hot, dry environment, that dripping tap, that's a cool guardi safe, up in the canopy. It's six degrees cooler than the rest of the canopy. It's 15 degrees cooler than ambient air. If you want to find an owl on a stinking hot day, look at mistletoes. Owls aren't dumb. They find the coolest part of the landscape to sit in, and what is that? It's an hexocarpus, it's a cherry ballard, also a parasite, or it's a mistletoe. Koalas do the same thing. They're not eating it. They're just nestling down going, pretty warm today, eh? This'll do. I can survive this. So we're learning more and more now about how mistletoes are affecting microclimate, not just within the canopy, but the entire canopy. Colleagues at uh Western Sydney University have looked at whole canopy microclimate of eucalyptus with and without mistletoes. Huge differences at the at the tree scale. And so I'm now working with the City of Melbourne. Melbourne is a big city, and they're worried about urban heat island effects, about hot days, cities getting hotter and hotter and hotter. They've got all these ghastly plane trees there, um, but they want to make them better. So they've worked with me, and we're putting mistletoes in the plain trees. So we stopped traffic, we got cherry pickers up there, stuck a bunch of sticky seeds and a bunch of canopies, and we've now done the first successful reintroduction of mistletoes on plane trees in the city of Melbourne. So when you're next there, looking for a latte, look up, you'll see little blobs in the trees. We put them there. Uh and we learned during that, we really found just how important uh the whole possum thing is. Because you know those possum colours you see on trees, the perspex shield to stop possums frolicking up in there. The only trees where mistletoes really came away were the trees, the plain trees that had those perspexed shields. Um because it was enemy-free space. If possums were, and that's why we had to do this work, because there's so many eaves, there's so many camellias, there's so many fruit trees in Melbourne. The possums are just like they're in Fat City. Everything they want is right there. And so you're never gonna get mistletoes establishing it unless you give them a helping hand. I'm gonna stop there. I would entertain any questions. Thank you very much.

SPEAKER_10 29:43

Beautiful day, thank you. We've got heaps and heaps of questions. I'm gonna start this side because this is the side where the microphone is up the in the middle there. Thank you. If you wouldn't mind just uh telling us your name and where you're from.

SPEAKER_08 29:56

Okay, and Samantha, Jules, and I've got property up near Bendigo, a place called Sedgwick. And I have a forest which I've had a natural person come through and says you know, a naturalist, a a person who studies flora, flora prism, and they said I have the best forest in all of the forests around Bendigo, which is pretty extraordinary. And I don't do anything to it, which he said is what I should keep doing. Because I was going to put some boxes in for sugar gliders for the powerful owls, and he said, No, look, we've got all these natural holes, and some of the trees are 500 years old and like amazing things which I didn't know about. So my question was, because I am surrounded by Buttersbridge Forest, is the the two things, one, is the mistletoe that I can see in the odd tree, are they likely to spread into the forest and will that balance itself out? Because I don't seem to do anything to the forest around me either. Um, although he did point out my forest was better than across the fence, which I can't quite see why, but I can't really see what I'm looking at. Um, and the other question is why are not more mistletoes throughout the forest? Is that because there are so many animals eating it?

SPEAKER_01 31:07

Okay, so first party question. You very rarely need to need to do any active management. Mistletoes move around pretty well, uh, but it's actually fascinating. The main agent of mistletoe dispersal across Australia is the mistletoe bird. It's well named, it's a little jolly, it's like you need four for a taco. I mean, they're minuscule. Uh but they're an Asian species. They've only been in Australia for about a million years. So they're a Johnny Cum lately. They weren't the original co-evolved partner of mistletoes. That was mostly honey eaters, including honey eaters that have long since gone. Um, but birds will find them, they've got very clear search images. They can just scan a canopy and go, right there, tasty, tasty snacks, and just go straight to it, munch, munch, munch, and move around. Mistletoe birds aren't the agents that establish new infections because they they only eat mistletoe fruit. So they go from mistletoe to mistletoe to mistletoe. Whereas things like Oreoles, where you are in Bendigo, silver eyes, Oreoles, a few of the honey eaters, they've got a broader diet. So they eat mistletoes as part of a much wider diet. So they'll have a bit of mistletoe lunch at your place and then go over there to see a man about some termites, and while they're there, drop off a little present. So you don't have to worry about it. They're going to move around just fine. The patterns you're seeing about big changes in occurrence, almost certainly that's because of herbivores. There's a lot of insects, not just the caterpillars I mentioned, there's a lot of insects that eat mistletoes. Um, ringtails, not so much, but brush saaltums, they they literally cross the road to get to a mistletoe. They love the stuff. So if there's if there's decent numbers of brush tail fossums around, you can struggle to find a single mistletoe. They're there, but they get gobbled up every night, and they're these munted little little little bonsai things. Um, yeah, so probably natural enemies, probably herbivores are explaining that that patchiness you've observed.

SPEAKER_07 32:55

Okay, another question. Jill. Uh hi, Jill Sandbrook. Hello.

SPEAKER_01 32:59

Old Brook.

SPEAKER_07 33:00

Yeah, hi David. Um, how can you transplant mistletoe? And is it uh something that farmers can do to improve biodiversity?

SPEAKER_01 33:08

Great. So you can't transplant the actual plant. It is bolted on. It is literally, it's wood to wood, it's connected. Um the only way you can move them around is by seeds. So we've done a beautiful uh booklet that you can you can download for free from the interwebs. Um it's called It's a BirdLife Australia publication. It's called I think the mistletoe planting guide, mistletoe, but if you Google mistletoe planting bird life, you'll get straight there. It's literally a step-by-step process about what you need to do as a farmer to get mistletoe going at your place. It's easy. I mean you could do you could plant 50 mistletoes in an hour. Um, the issue is getting access to ripe fruit. Um, and and what you want, it's like getting avocados from the from the supermarket. You've got to give them the squeeze test. There's a few ripe ones on here. It wants to be yielding. You want to give it a bit of a squeeze and feel a bit of give, uh like a lychee. Uh if it's hard, it's not ripe. But harvest some seeds where you can find them. Uh, and if you're really serious, you might need to net a few low plants to get there before the the seed dispersing birds get them. Um, but uh harvest them with the stalk intact and they'll stay in a ziploc bag in your fridge for weeks. We've we've we've had three months with no change in viability. But ideally, um, fresh seed uh from around your neck of the woods and then just squeeze it out where you want a mistletoe to grow. You want pencil thin branch or thinner underside of the branch so the dew accumulates there and rehydrates the growing little dude, and in a well-lit area, because it's a photosynthetically active seed. It's a naked seed, it's a green seed, so it needs to be somewhere sunny to power its own germination. So pencil thick, underside, well lit, and you get about 10% success rate. So you want two mistletoes, plant 20 seeds.

SPEAKER_10 35:00

On the surface or cut the surface to allow it.

SPEAKER_01 35:03

Do not cut the surface. That's ungodly. No, no. Just wipe it on, be the bird. Just just glue in the seed will stick to the underside of the fruit. Millions of years of evolution went into that adhesive. It's j whenever that whenever ripe fruit is available is the right season. Um but think about hungry, hungry mouths. Think about isolated trees where where you're less likely to get possums coming, because if you if you put seeds in areas where possums are frolicking, you've done a bit of work and you'll never see the the reward because it'll just get gobbled up by by possums. Well, they are because the wallabies have taken the low ones. That's because there's hungry mouths downstairs. So camels, well, depending on where you are, cows, cows, cows will I mean so when we're in doing the cherry picker work, it it's already, you know, a brown trousers moment when you're up there in a high wind. And then you've got 30 angers saying, Where's my mistletoe? It's like, oh, just one of the time, ladies. It's it's conf yeah, a lot of things eat mistletoe.

SPEAKER_10 36:06

Okay, our next question up there.

SPEAKER_05 36:08

Thank you. Um Yeah, hi, I'm Chelsea from Mount Tulbiwon and Mora Murakoop. Um I was just curious as to why you um gave us you methods of if you wanted to get rid of mistletoe, why you would, because I really love it now more. Thank you.

SPEAKER_01 36:26

There's farmers in the audience who who are gonna come at me with that question, so it's an efficient way to answer those questions without without them necessarily putting a hand up and saying, Well, I'm wanting to get rid of it. So it's educating them discreetly.

SPEAKER_05 36:39

Okay. Thank you.

SPEAKER_01 36:43

Exhibit A.

SPEAKER_04 36:47

It's good gear. I don't want to get rid of it, but we have it from the New England Tablands, Glenn and Chapman. And it's on our yellow box trees, which is in sort of and it's they're not necessarily isolated trees. And it it's it it's quite thick, and take I can show you a video of stuff later. It's quite thick, so I want to be other we're trying to work out what we do to to manage it because it's actually the bigger mature trees that it's actually affecting. And I suppose just to clarify what you're saying, if those trees, if it appears that they are dying from a mistletoe, they're dying not because of it, but because of something else.

SPEAKER_01 37:26

And that's work from New England, so from your neck of the woods, so it's directly applicable.

SPEAKER_04 37:31

But that's what I'm trying to work out because we've got a whole stack of regenerating trees in those landscapes. But it's yeah, I I I'm trying to work out what the balance is and what we've done in that balance. Because we live in a that we we farm a valley that was naturally clear with the yellow box in that valley. And and we know that from the history of when they first brought sheep into that area, it was all just groved in, they weren't actually clearing country to to graze it. Right. To have shepherds' huts and things.

SPEAKER_10 37:59

So can I just uh add a clarification there? So what you're trying to ask, Glenn, is if you've got a tree that is dying, even though you accept the mistletoe may not be the cause of that, is it a first aid option to remove the mistletoe from that tree to maybe help that tree to survive in the longer term?

SPEAKER_04 38:16

Yeah, like I've got some video here I can show people that that tree is probably 60 to 80 percent mistletoe.

SPEAKER_01 38:22

Okay, so let me dive in here. A rule of thumb is about 30%. If if 30% or less of your canopy, your tree's canopy, if you just visualize it, like block out a third, if it's a third or less, no worries, mate. No worries. More than that, you might you might have a problem. And if it's a tree you care about for all sorts of reasons, I've got no problem at all with you getting your your rifle out, getting up getting a cherry picker, doing whatever you want to do to clear it off. It will, it will make more water available to that tree almost instantly. Take photos. Take photos before, during, and after, and and you judge for yourself if it made a difference. Compare the one that you've mucked around with to that one over there that you didn't do anything to. Trees come and go. We're a short-lived organism. Trees are not. They invest heavily in storage, in architecture. Um, that they have good years and bad years. Mistletoes come, mistletoes go. They're live fast, die young plants. An old mistletoe is 12 years old. An old yellow box, what, 600, 600, 700? Easy. So um take photos with dates so you can keep track of this yourself. But as in terms of first date, it's it's a it's a good analogy to make. I've got no problem at all with you having a having a crack at this, but understand um it might make you feel better, feel better. It's not actually gonna make much of a difference in the long term for that tree's viability. Yeah, bingo. It is. And if you want to see hooded robins, if you want to you know spend the morning frolicking with babblers, that's where you go. Because that's where they will go, because it's cockroach heaven, because they're gobbling up those nutrients that are otherwise hard to find in that landscape. Indeed. Another thing you can consider, and I'm not saying this lightly, because it depends on your situation, if there's a way of excluding stock from camping directly beneath those trees, you will be doing those trees a massive favour. Okay. Happy days. Oh, lovely. Okay. Take photos and convince yourself that it's not a problem. Perfect.

SPEAKER_10 41:21

We'll take a question over here on the side. Oh, sorry, Vince is next to the first one.

SPEAKER_03 41:25

Sorry, just really quickly, the probably have almost asked and answered, but talking about areas where there's um dry sorry, Vince from Bullies Crossing on the Lochman River in New Zealand. Uh where there's dry sclerophyll forests, so think of 100% canopy cover, as opposed to areas that are more open where you've got you know 20 or 30 percent canopy cover, you traditional boxcom, grassy woodland type density, and you seem to see more mistletoe in that than you do in the forest per se. Is that a actually uh just a blind perception or is that the truth? And then just following on, you were talking about someone said Jezebel butterflies, which are prevalent in January, February, March type thing, but they need flowering plants, which include your visarias and a couple of gums that flower at the time of the year. You put those in there, you get Jezebel butterflies, and that's a control on mistletoe. But the more you talk about the more you're answering your own question. This is this is this is a self-correcting problem. And how did the indigenous people use these because if they're so 11 amino acids, did they eat them? Did they eat the just the fruit or did they eat the flowers or so um about this is an interview?

SPEAKER_01 42:32

About the uh the the canopy density thing is a fascinating one. So mistletoes need high light environments. Um I've done some work with macadamia growers that get very shirty because they get because and it's a native plant, it's the only native commercially grown horticultural plant in Australia. And there's a whole bunch of mistletoes that have that infect them. And so when you plant a whole lot of these tasty, tasty hosts and irrigate them and fertilize them and prune their canopies to maximise yields so all the light comes in, you have a mistletoe problem and it's your fault. I mean, you you laid the table. So um light is definitely a factor for mistletoe growth and establishment. So a tree that's open growing has far more light than a tree surrounded by friends in a shaded woodland situation. Um, but there's also a detectability thing. It's easier for you to see a mistletoe in an isolated tree because you can skylight it, whereas a mistletoe in a woodland, it's a busier uh environment. And with the with the the the possum thing, even if mistletoes are there, they get pruned. So when we were doing the experimental removal, we scoped out all the trees with mistletoes in them, got their cherry picker there. Okay, there's three in this tree, up you go, you're 14 metres off the ground. Oh, well, I took care of the three big ones. There's 12 other ones that we didn't see from the ground, just little ones that were hiding behind branches. Um, so it's we're very terrestrial in in our outlook. Um, and if you can get up into the tree, you realize it's actually a bit of a different story. Um, indigenous use of mistletoes. Um I've been privileged enough to work with many First Nations people talking about parasitic plants. Kwandong, uh, an exocarpus, uh, and in Tanunga, uh Noitia, the West Australian Christmas tree, they are amongst the most culturally important plants on the continent to First Nations people. They're right up there for all sorts of reasons. Mistletoes, there's many indigenous words for mistletoes. It's an important plant as a snack. It's not a staple from all the knowledge that's been shared with me. Um, but there's a lot of stories around it as well. Because of those weird flowering patterns I mentioned, there's lots of women's stories around when they flower and what that has to do with childbirth, with there's many stories about mistletoes. So um, but what's fascinating, and this is around the world, not just in Australia, no indigenous stories about mistletoes pay any heed to the fact that they're parasitic. They use the same modifiers as a vine or an epiphyte. It's a plant, it's a different plant growing on that plant, but there's there's no relevance attached to the fact that it's a parasite. It's just that's just it's it's it's a different thing growing in a bigger thing. Which is which is fascinating.

SPEAKER_09 45:13

Uh so I'm Jan Ratcliffe from Forest. Um I was just wondering what they do to plants. If they're littering nutrients on the forest floor, is that really good for planting?

SPEAKER_01 45:25

Yeah, so we've looked at that. Um, and annuals really benefit from this. So annuals including weeds. So things like uh St. John's wart can be go bananas under under an infected tree, whereas there's just not enough nutrients for them to get away under an uninfected tree. So, yes, you do see an effect on annual plants. Um, more complicated um uh interactions I've only looked at in WA for root parasitic things, so for Kondong, sandalwoods, and exocarpus, and there's huge effects. You get basically these nurseries around these large parasitic shrubs where you get deep, deep litter beds, you get really cakey uh humus, very active mycorrhizal uh hyphal networks, um, and all sorts of things you just can't find elsewhere are growing there in abundance. Um, and I think that's partly a scale thing because a large Kwandong is much bigger than the biggest mistletoe. Um, so and and you you do see a lens of productivity. So directly underneath the mistletoe, you can see it. It stains the soil rusty with all the iron in the tissue. I can show you pictures. And then as you walk away, you get a gradient. No one's done those studies to look at plant diversity down that gradient and just how far do you need to go away from a mistletoe to see no effect. Um, but I think most of the effects you see on plants is mediated by microbial activity in the soil, especially fungi. Um, but no one's looked at bacteria. There's been some work done on mycorrhizal fungi and mistletoes in North America in a completely different system, showing huge, huge uh influence of mistletoe activity on mycorrhizal fungi diversity and abundance. None of that work's been done in Australia, and no one's done any work on bacterial diversity, but there's ways to do it. So we need human cloning to get to the point where there's five Dave's and like one Dave can do that stuff.

SPEAKER_09 47:13

You just need to inspire a few more Dave.

SPEAKER_01 47:16

You're all infected. You are part of that.

SPEAKER_09 47:19

You didn't.

SPEAKER_01 47:20

You didn't know that. No, no, no. See, I snuck it in there. So now you've got to go and spread the good word.

SPEAKER_10 47:25

It's on the skinny underside, apparently. Am I allowed to ask one more hopefully short question? Oh, yes, and then the gentleman just hanging onto the rail.

SPEAKER_09 47:32

Um, so with the cherry ballarts, there's a place in Barwandowns which has got the most sickly looking eucalypts there. It's just it's just a little bit of woodland in the town, so it's not an ideal location. And it's absolutely full of cherry ballarts. I've never seen so many there. You know, they're the they're the most common plant there. Do those two things go together? Are they are they possibly exceeding the tree capacity? Quite possibly, and cleansing burn would be my Yeah, I don't think it'd be popular with the Navy.

SPEAKER_01 48:06

Yeah, well that's that's that's what it means. And that's the issue with many urban remnants, and even like pockets of bush on farms where a fire is just not an option in terms of infrastructure loss or whatever. Um and again you've isolated this this little bit of an ecosystem from all those other elements that kept it that way, and you wonder why it turns turns up its toes. So I think every Australian ecosystem needs fire at a particular frequency, and you know, first the first Australians got onto that pretty early, um, and we've got a lot of catching up to do. A lot. Um and yeah, so Exocarpus there there's a bit written about exocarpus and fire, and Greg Mule is just behind you in that in a hat. Talk to that guy. He's forgotten more about hexacarpus than I know. So talk to him.

SPEAKER_10 48:51

And Greg, you've got the next question.

SPEAKER_00 48:54

Um Is water the limiting factor in mistletoes, or are they like sucking nutrients out until they've got enough buffer and then they just shed everything else?

SPEAKER_01 49:04

In Australian systems, every everything I've done and all the work I depend on by others, especially physiologists, it's exclusively water. They're water parasites. Um whereas in Africa, different story. So you see a really interesting pattern where you get much more mistletoes on trees growing on all on old termite mounds because those are lenses of productivity of missing nutrients, and those are the limiting factors in those soils. But here, most of the patterns you see, like roadside, roadside trees full of mistletoe, that's because the road sheds a lot more water than the bush just over there. So they've got wetter feet, they've got more spare, more spare water, they can pay the bills and still have a few mistletoes without without without issue. And then with drought, you see that a drought comes through an area, mistletoes curl up their toes.

SPEAKER_02 49:50

Hi David. Uh Tony Mike from Torma. Um, thank you for studying this thing that that um everybody's got um issues with. Isn't it funny how we as humans identify important things and then stuff up what it actually means until someone like you studies it? Um So I was just wondering a bit the same, if we're driving somewhere or and we see mistletoe, what's that telling us? What's that telling us about that landscape or why is it there?

SPEAKER_01 50:22

That's the beauty of it. It's telling you 101 things because it's connected to so many different things. It's telling you that a bird crapped there at some point. It's telling you it's telling you that that tree has spare resources and that's doing quite well for itself. It's telling you the possums either don't go there or there's other things nearby that are better. Um it's telling you that the litter, that the the the the soil directly beneath that tree has more available nutrients than a stone's throwaway. So just it it gets you tapped into that really fine-scale heterogeneity. You look look at a woodland and go, oh yeah, it's it's all the same. It's not the same. It's a it's a really complicated mosaic, like the like the surface of the ocean. And this just gives you a little window into that complexity.

SPEAKER_06 51:11

Okay, hey, I'm Evelyn from Kangaroo Valley in New South Wales, and just with all your questions, um so I was wondering when you were taking all those samples off your initial study, um, where did you place all of those mistletoe and did you find any kind of increase in uh you know, um, I don't know, whether improve the soil where you put it?

SPEAKER_01 51:39

Uh when we did the initial experiment, I didn't want to change the nutrient balance of the system. I just wanted to to change mistletoe occurrence. So we just left it where it fell. So we didn't take it away. Um and uh as I said, all except I think two, two of these blocks which were on travelling stock reserves, almost all that all of them were on working farms. And so depending on what the farmers were doing, there might have been livestock and might have had access to that place at that time or a little bit later, or not at all. So some of those mistletoes I know were gobbled up that day, the day they fell. Others, uh, when I went for repeat visits, you could see the quiet decomposition of that clump in situ where we dropped it. You could still see the soil marks on it. Um we didn't do any of the soil work because we didn't know that at that stage. Um, so we were just stumbling along, doing our best, working stuff out, paying attention. Um, we did the only work on mistletoe litter um a few years after that that that study was initiated. So, retrospect, beautiful thing. We would have taken all sorts of soil samples before and after. I wasn't even thinking about below ground um factors when we when we set up that experiment.

SPEAKER_06 52:45

So I'm just gonna follow that because um because what uh we find in Tony and stuff on different types of farms that are trying to regenerate themselves is that they'll find certain types of um like fireweed will come up. And so um you can grab all that fireweed and create a ferment and then you re- remineralise that. So the concept would be perhaps in this instance with this gentleman where he has all of this. Definitely you could grab all that, ferment it, and then re-dilute it and put it back on those.

SPEAKER_01 53:16

You can make amazing I've I've talked to permaculture dudes about this, and you can make amazing teas from mistletoes that just just full of goodies. Exactly. Yes. Back for more. Excellent.

SPEAKER_07 53:34

I am now. Um you just said every Australian landscape needs fires. Does that include like rotationally grazed country that is hopefully improving? Or is that uh just a wide statement?

SPEAKER_01 53:48

So I was talking about native ecosystems and I was extending that to tropical rainforests, wet, steamy places that you think a fire could never carry. There's still there's still a presence of fire in those systems. A completely modified system like I'm standing within, you wouldn't carry a fire. Um so no, I was I was talking about native ecosystems, not not modified ones. Um and but I'm sure there's people here today that can tell you about about fire in pastoral in cropping um situations and and pros and cons. I'm not that little black duck.

SPEAKER_04 54:19

Jill Jill Samuel over here um I don't I haven't found any um data or information on this, but when we came out of the 2019-2020 drought and we had all the eastern east coast fires up to New England, those next two seasons we had phenomenal native grass growth after we'd been all smoking. So I have a theory that those grasses were stimulated by the bushfires that were associated, not they weren't over our country, but the smoke came across really quite thick. And so we had um kangaroo grass and silky broom top and plume grass and stuff where I was grabbing bunches of it with my hand and cutting it off and selling it at the markets. It was so thick after that, and then over the last few years it's dropped off again. So I haven't found any science.

SPEAKER_01 55:24

So the closest thing I know that that uh that addresses that are Peter Vatusek's work on uh on dust. So there's particulates in smoke. Uh there's volatiles, there's gases, but there's particulates as well. And so if you get smoke and then rain, a lot of those things come down. And so Peter Vatusek uh looked at Hawaiian forests and and tried to work out how are they getting all their nutrients because there's a lot of stuff that's just they're not getting from the soil we've looked. It's from Gobi Desert Dust. There's enough, enough fine particulate stuff moving in global weather systems that that gives them just enough selenium, just enough whatever it is, to pay the bills. So I don't doubt that that smoke is a very important uh factor for a lot of that stuff. Good good point.

SPEAKER_10 56:07

Thank you. Thank you, everyone, for um your participation here. Please join me in thanking Dave for his amazing work.