WEBVTT 00:00:00.680 --> 00:00:03.200 Imagine you're walking through a forest. 00:00:03.960 --> 00:00:07.096 I'm guessing you're thinking of a collection of trees, 00:00:07.120 --> 00:00:09.856 what we foresters call a stand, 00:00:09.880 --> 00:00:12.520 with their rugged stems and their beautiful crowns. 00:00:13.360 --> 00:00:15.920 Yes, trees are the foundation of forests, 00:00:16.480 --> 00:00:18.960 but a forest is much more than what you see, 00:00:19.560 --> 00:00:23.240 and today I want to change the way you think about forests. 00:00:23.880 --> 00:00:27.256 You see, underground there is this other world, 00:00:27.280 --> 00:00:30.336 a world of infinite biological pathways 00:00:30.360 --> 00:00:33.776 that connect trees and allow them to communicate 00:00:33.800 --> 00:00:37.280 and allow the forest to behave as though it's a single organism. 00:00:38.040 --> 00:00:40.760 It might remind you of a sort of intelligence. NOTE Paragraph 00:00:41.600 --> 00:00:43.256 How do I know this? 00:00:43.280 --> 00:00:44.520 Here's my story. 00:00:45.560 --> 00:00:47.720 I grew up in the forests of British Columbia. 00:00:49.080 --> 00:00:52.256 I used to lay on the forest floor and stare up at the tree crowns. 00:00:52.280 --> 00:00:53.520 They were giants. 00:00:54.320 --> 00:00:55.896 My grandfather was a giant, too. 00:00:55.920 --> 00:00:57.376 He was a horse logger, 00:00:57.400 --> 00:01:00.960 and he used to selectively cut cedar poles from the inland rainforest. 00:01:01.760 --> 00:01:05.736 Grandpa taught me about the quiet and cohesive ways of the woods, 00:01:05.760 --> 00:01:08.160 and how my family was knit into it. 00:01:09.080 --> 00:01:11.216 So I followed in grandpa's footsteps. NOTE Paragraph 00:01:11.240 --> 00:01:13.800 He and I had this curiosity about forests, 00:01:14.800 --> 00:01:16.936 and my first big "aha" moment 00:01:16.960 --> 00:01:18.840 was at the outhouse by our lake. 00:01:19.640 --> 00:01:22.760 Our poor dog Jigs had slipped and fallen into the pit. 00:01:24.080 --> 00:01:27.216 So grandpa ran up with his shovel to rescue the poor dog. 00:01:27.240 --> 00:01:29.480 He was down there, swimming in the muck. 00:01:31.000 --> 00:01:33.696 But as grandpa dug through that forest floor, 00:01:33.720 --> 00:01:36.336 I became fascinated with the roots, 00:01:36.360 --> 00:01:39.456 and under that, what I learned later was the white mycelium 00:01:39.480 --> 00:01:42.560 and under that the red and yellow mineral horizons. 00:01:43.240 --> 00:01:46.416 Eventually, grandpa and I rescued the poor dog, 00:01:46.440 --> 00:01:48.776 but it was at that moment that I realized 00:01:48.800 --> 00:01:51.376 that that palette of roots and soil 00:01:51.400 --> 00:01:53.840 was really the foundation of the forest. NOTE Paragraph 00:01:54.640 --> 00:01:56.040 And I wanted to know more. 00:01:56.680 --> 00:01:58.400 So I studied forestry. 00:01:59.440 --> 00:02:03.056 But soon I found myself working alongside the powerful people 00:02:03.080 --> 00:02:04.960 in charge of the commercial harvest. 00:02:05.960 --> 00:02:08.536 The extent of the clear-cutting 00:02:08.560 --> 00:02:09.816 was alarming, 00:02:09.840 --> 00:02:13.000 and I soon found myself conflicted by my part in it. 00:02:13.600 --> 00:02:18.696 Not only that, the spraying and hacking of the aspens and birches 00:02:18.720 --> 00:02:23.016 to make way for the more commercially valuable planted pines and firs 00:02:23.040 --> 00:02:24.240 was astounding. 00:02:25.040 --> 00:02:28.760 It seemed that nothing could stop this relentless industrial machine. NOTE Paragraph 00:02:29.640 --> 00:02:31.040 So I went back to school, 00:02:32.360 --> 00:02:34.320 and I studied my other world. 00:02:35.480 --> 00:02:39.736 You see, scientists had just discovered in the laboratory in vitro 00:02:39.760 --> 00:02:41.896 that one pine seedling root 00:02:41.920 --> 00:02:45.320 could transmit carbon to another pine seedling root. 00:02:46.160 --> 00:02:47.936 But this was in the laboratory, 00:02:47.960 --> 00:02:51.016 and I wondered, could this happen in real forests? 00:02:51.040 --> 00:02:52.240 I thought yes. 00:02:53.120 --> 00:02:57.080 Trees in real forests might also share information below ground. 00:02:58.120 --> 00:02:59.896 But this was really controversial, 00:02:59.920 --> 00:03:02.536 and some people thought I was crazy, 00:03:02.560 --> 00:03:05.616 and I had a really hard time getting research funding. 00:03:05.640 --> 00:03:07.080 But I persevered, 00:03:08.200 --> 00:03:12.056 and I eventually conducted some experiments deep in the forest, 00:03:12.080 --> 00:03:13.480 25 years ago. 00:03:14.120 --> 00:03:17.016 I grew 80 replicates of three species: 00:03:17.040 --> 00:03:20.216 paper birch, Douglas fir, and western red cedar. 00:03:20.240 --> 00:03:24.296 I figured the birch and the fir would be connected in a belowground web, 00:03:24.320 --> 00:03:25.576 but not the cedar. 00:03:25.600 --> 00:03:27.120 It was in its own other world. 00:03:28.440 --> 00:03:30.296 And I gathered my apparatus, 00:03:30.320 --> 00:03:33.496 and I had no money, so I had to do it on the cheap. 00:03:33.520 --> 00:03:35.136 So I went to Canadian Tire -- NOTE Paragraph 00:03:35.160 --> 00:03:36.576 (Laughter) NOTE Paragraph 00:03:36.600 --> 00:03:40.016 and I bought some plastic bags and duct tape and shade cloth, 00:03:40.040 --> 00:03:43.280 a timer, a paper suit, a respirator. 00:03:44.160 --> 00:03:47.336 And then I borrowed some high-tech stuff from my university: 00:03:47.360 --> 00:03:51.976 a Geiger counter, a scintillation counter, a mass spectrometer, microscopes. 00:03:52.000 --> 00:03:54.456 And then I got some really dangerous stuff: 00:03:54.480 --> 00:03:59.256 syringes full of radioactive carbon-14 carbon dioxide gas 00:03:59.280 --> 00:04:01.296 and some high pressure bottles 00:04:01.320 --> 00:04:04.840 of the stable isotope carbon-13 carbon dioxide gas. 00:04:05.560 --> 00:04:07.136 But I was legally permitted. NOTE Paragraph 00:04:07.160 --> 00:04:08.856 (Laughter) NOTE Paragraph 00:04:08.880 --> 00:04:10.480 Oh, and I forgot some stuff, 00:04:11.080 --> 00:04:12.800 important stuff: the bug spray, 00:04:13.600 --> 00:04:16.440 the bear spray, the filters for my respirator. 00:04:17.160 --> 00:04:18.360 Oh well. NOTE Paragraph 00:04:19.560 --> 00:04:22.336 The first day of the experiment, we got out to our plot 00:04:22.360 --> 00:04:25.160 and a grizzly bear and her cub chased us off. 00:04:25.920 --> 00:04:27.440 And I had no bear spray. 00:04:29.120 --> 00:04:32.296 But you know, this is how forest research in Canada goes. NOTE Paragraph 00:04:32.320 --> 00:04:33.776 (Laughter) NOTE Paragraph 00:04:33.800 --> 00:04:35.336 So I came back the next day, 00:04:35.360 --> 00:04:37.616 and mama grizzly and her cub were gone. 00:04:37.640 --> 00:04:39.656 So this time, we really got started, 00:04:39.680 --> 00:04:42.456 and I pulled on my white paper suit, 00:04:42.480 --> 00:04:44.320 I put on my respirator, 00:04:46.160 --> 00:04:47.376 and then 00:04:47.400 --> 00:04:49.680 I put the plastic bags over my trees. 00:04:51.080 --> 00:04:53.176 I got my giant syringes, 00:04:53.200 --> 00:04:54.856 and I injected the bags 00:04:54.880 --> 00:04:58.296 with my tracer isotope carbon dioxide gases, 00:04:58.320 --> 00:04:59.536 first the birch. 00:04:59.560 --> 00:05:02.536 I injected carbon-14, the radioactive gas, 00:05:02.560 --> 00:05:04.136 into the bag of birch. 00:05:04.160 --> 00:05:05.416 And then for fir, 00:05:05.440 --> 00:05:09.256 I injected the stable isotope carbon-13 carbon dioxide gas. 00:05:09.280 --> 00:05:11.016 I used two isotopes, 00:05:11.040 --> 00:05:12.296 because I was wondering 00:05:12.320 --> 00:05:16.160 whether there was two-way communication going on between these species. 00:05:17.640 --> 00:05:20.216 I got to the final bag, 00:05:20.240 --> 00:05:21.736 the 80th replicate, 00:05:21.760 --> 00:05:24.176 and all of a sudden mama grizzly showed up again. 00:05:24.200 --> 00:05:25.616 And she started to chase me, 00:05:25.640 --> 00:05:28.056 and I had my syringes above my head, 00:05:28.080 --> 00:05:31.016 and I was swatting the mosquitos, and I jumped into the truck, 00:05:31.040 --> 00:05:32.256 and I thought, 00:05:32.280 --> 00:05:34.016 "This is why people do lab studies." NOTE Paragraph 00:05:34.040 --> 00:05:35.480 (Laughter) NOTE Paragraph 00:05:37.120 --> 00:05:38.616 I waited an hour. 00:05:38.640 --> 00:05:40.256 I figured it would take this long 00:05:40.280 --> 00:05:43.056 for the trees to suck up the CO2 through photosynthesis, 00:05:43.080 --> 00:05:46.216 turn it into sugars, send it down into their roots, 00:05:46.240 --> 00:05:48.936 and maybe, I hypothesized, 00:05:48.960 --> 00:05:51.760 shuttle that carbon belowground to their neighbors. 00:05:52.920 --> 00:05:54.776 After the hour was up, 00:05:54.800 --> 00:05:56.376 I rolled down my window, 00:05:56.400 --> 00:05:58.000 and I checked for mama grizzly. 00:05:58.600 --> 00:06:01.000 Oh good, she's over there eating her huckleberries. 00:06:01.720 --> 00:06:04.336 So I got out of the truck and I got to work. 00:06:04.360 --> 00:06:08.256 I went to my first bag with the birch. I pulled the bag off. 00:06:08.280 --> 00:06:10.600 I ran my Geiger counter over its leaves. 00:06:11.280 --> 00:06:12.480 Kkhh! 00:06:13.400 --> 00:06:14.616 Perfect. 00:06:14.640 --> 00:06:17.576 The birch had taken up the radioactive gas. 00:06:17.600 --> 00:06:19.176 Then the moment of truth. 00:06:19.200 --> 00:06:20.720 I went over to the fir tree. 00:06:21.320 --> 00:06:23.096 I pulled off its bag. 00:06:23.120 --> 00:06:25.456 I ran the Geiger counter up its needles, 00:06:25.480 --> 00:06:27.680 and I heard the most beautiful sound. 00:06:28.440 --> 00:06:29.640 Kkhh! 00:06:30.760 --> 00:06:33.496 It was the sound of birch talking to fir, 00:06:33.520 --> 00:06:36.976 and birch was saying, "Hey, can I help you?" 00:06:37.000 --> 00:06:40.616 And fir was saying, "Yeah, can you send me some of your carbon? 00:06:40.640 --> 00:06:43.040 Because somebody threw a shade cloth over me." 00:06:44.360 --> 00:06:48.056 I went up to cedar, and I ran the Geiger counter over its leaves, 00:06:48.080 --> 00:06:49.600 and as I suspected, 00:06:50.520 --> 00:06:51.760 silence. 00:06:52.560 --> 00:06:54.776 Cedar was in its own world. 00:06:54.800 --> 00:06:58.760 It was not connected into the web interlinking birch and fir. NOTE Paragraph 00:06:59.840 --> 00:07:01.120 I was so excited, 00:07:02.000 --> 00:07:05.976 I ran from plot to plot and I checked all 80 replicates. 00:07:06.000 --> 00:07:08.136 The evidence was clear. 00:07:08.160 --> 00:07:11.096 The C-13 and C-14 was showing me 00:07:11.120 --> 00:07:15.240 that paper birch and Douglas fir were in a lively two-way conversation. 00:07:15.960 --> 00:07:17.816 It turns out at that time of the year, 00:07:17.840 --> 00:07:19.056 in the summer, 00:07:19.080 --> 00:07:22.736 that birch was sending more carbon to fir than fir was sending back to birch, 00:07:22.760 --> 00:07:25.056 especially when the fir was shaded. 00:07:25.080 --> 00:07:28.056 And then in later experiments, we found the opposite, 00:07:28.080 --> 00:07:31.616 that fir was sending more carbon to birch than birch was sending to fir, 00:07:31.640 --> 00:07:35.280 and this was because the fir was still growing while the birch was leafless. 00:07:35.880 --> 00:07:38.536 So it turns out the two species were interdependent, 00:07:38.560 --> 00:07:39.840 like yin and yang. NOTE Paragraph 00:07:40.960 --> 00:07:43.936 And at that moment, everything came into focus for me. 00:07:43.960 --> 00:07:46.216 I knew I had found something big, 00:07:46.240 --> 00:07:50.976 something that would change the way we look at how trees interact in forests, 00:07:51.000 --> 00:07:53.016 from not just competitors 00:07:53.040 --> 00:07:54.720 but to cooperators. 00:07:55.800 --> 00:07:58.256 And I had found solid evidence 00:07:58.280 --> 00:08:01.656 of this massive belowground communications network, 00:08:01.680 --> 00:08:02.920 the other world. NOTE Paragraph 00:08:03.960 --> 00:08:05.856 Now, I truly hoped and believed 00:08:05.880 --> 00:08:09.496 that my discovery would change how we practice forestry, 00:08:09.520 --> 00:08:11.296 from clear-cutting and herbiciding 00:08:11.320 --> 00:08:14.256 to more holistic and sustainable methods, 00:08:14.280 --> 00:08:17.496 methods that were less expensive and more practical. 00:08:17.520 --> 00:08:18.760 What was I thinking? 00:08:19.920 --> 00:08:21.200 I'll come back to that. NOTE Paragraph 00:08:23.760 --> 00:08:27.600 So how do we do science in complex systems like forests? 00:08:28.720 --> 00:08:32.056 Well, as forest scientists, we have to do our research in the forests, 00:08:32.080 --> 00:08:34.096 and that's really tough, as I've shown you. 00:08:34.120 --> 00:08:37.360 And we have to be really good at running from bears. 00:08:38.760 --> 00:08:40.336 But mostly, we have to persevere 00:08:40.360 --> 00:08:43.256 in spite of all the stuff stacked against us. 00:08:43.280 --> 00:08:45.896 And we have to follow our intuition and our experiences 00:08:45.920 --> 00:08:48.056 and ask really good questions. 00:08:48.080 --> 00:08:51.256 And then we've got to gather our data and then go verify. 00:08:51.280 --> 00:08:56.440 For me, I've conducted and published hundreds of experiments in the forest. 00:08:57.080 --> 00:09:01.080 Some of my oldest experimental plantations are now over 30 years old. 00:09:02.040 --> 00:09:03.456 You can check them out. 00:09:03.480 --> 00:09:05.280 That's how forest science works. NOTE Paragraph 00:09:06.200 --> 00:09:08.536 So now I want to talk about the science. 00:09:08.560 --> 00:09:11.616 How were paper birch and Douglas fir communicating? 00:09:11.640 --> 00:09:16.136 Well, it turns out they were conversing not only in the language of carbon 00:09:16.160 --> 00:09:19.176 but also nitrogen and phosphorus 00:09:19.200 --> 00:09:23.936 and water and defense signals and allele chemicals and hormones -- 00:09:23.960 --> 00:09:25.160 information. 00:09:26.160 --> 00:09:29.336 And you know, I have to tell you, before me, scientists had thought 00:09:29.360 --> 00:09:32.936 that this belowground mutualistic symbiosis called a mycorrhiza 00:09:32.960 --> 00:09:34.456 was involved. 00:09:34.480 --> 00:09:37.560 Mycorrhiza literally means "fungus root." 00:09:38.360 --> 00:09:42.256 You see their reproductive organs when you walk through the forest. 00:09:42.280 --> 00:09:44.096 They're the mushrooms. 00:09:44.120 --> 00:09:47.136 The mushrooms, though, are just the tip of the iceberg, 00:09:47.160 --> 00:09:51.416 because coming out of those stems are fungal threads that form a mycelium, 00:09:51.440 --> 00:09:54.136 and that mycelium infects and colonizes the roots 00:09:54.160 --> 00:09:56.296 of all the trees and plants. 00:09:56.320 --> 00:09:58.976 And where the fungal cells interact with the root cells, 00:09:59.000 --> 00:10:01.776 there's a trade of carbon for nutrients, 00:10:01.800 --> 00:10:04.856 and that fungus gets those nutrients by growing through the soil 00:10:04.880 --> 00:10:06.880 and coating every soil particle. 00:10:07.840 --> 00:10:12.136 The web is so dense that there can be hundreds of kilometers of mycelium 00:10:12.160 --> 00:10:13.720 under a single footstep. 00:10:14.720 --> 00:10:19.520 And not only that, that mycelium connects different individuals in the forest, 00:10:20.320 --> 00:10:25.936 individuals not only of the same species but between species, like birch and fir, 00:10:25.960 --> 00:10:28.280 and it works kind of like the Internet. NOTE Paragraph 00:10:29.760 --> 00:10:31.656 You see, like all networks, 00:10:31.680 --> 00:10:34.496 mycorrhizal networks have nodes and links. 00:10:34.520 --> 00:10:38.576 We made this map by examining the short sequences of DNA 00:10:38.600 --> 00:10:44.096 of every tree and every fungal individual in a patch of Douglas fir forest. 00:10:44.120 --> 00:10:47.936 In this picture, the circles represent the Douglas fir, or the nodes, 00:10:47.960 --> 00:10:52.080 and the lines represent the interlinking fungal highways, or the links. NOTE Paragraph 00:10:53.120 --> 00:10:57.456 The biggest, darkest nodes are the busiest nodes. 00:10:57.480 --> 00:10:59.416 We call those hub trees, 00:10:59.440 --> 00:11:01.856 or more fondly, mother trees, 00:11:01.880 --> 00:11:06.496 because it turns out that those hub trees nurture their young, 00:11:06.520 --> 00:11:09.056 the ones growing in the understory. 00:11:09.080 --> 00:11:11.216 And if you can see those yellow dots, 00:11:11.240 --> 00:11:14.536 those are the young seedlings that have established within the network 00:11:14.560 --> 00:11:15.800 of the old mother trees. 00:11:16.400 --> 00:11:20.600 In a single forest, a mother tree can be connected to hundreds of other trees. 00:11:21.800 --> 00:11:24.096 And using our isotope tracers, 00:11:24.120 --> 00:11:25.616 we have found that mother trees 00:11:25.640 --> 00:11:28.576 will send their excess carbon through the mycorrhizal network 00:11:28.600 --> 00:11:30.536 to the understory seedlings, 00:11:30.560 --> 00:11:33.696 and we've associated this with increased seedling survival 00:11:33.720 --> 00:11:34.960 by four times. NOTE Paragraph 00:11:35.880 --> 00:11:39.096 Now, we know we all favor our own children, 00:11:39.120 --> 00:11:42.360 and I wondered, could Douglas fir recognize its own kin, 00:11:43.760 --> 00:11:45.760 like mama grizzly and her cub? 00:11:46.560 --> 00:11:48.376 So we set about an experiment, 00:11:48.400 --> 00:11:52.296 and we grew mother trees with kin and stranger's seedlings. 00:11:52.320 --> 00:11:55.216 And it turns out they do recognize their kin. 00:11:55.240 --> 00:12:00.216 Mother trees colonize their kin with bigger mycorrhizal networks. 00:12:00.240 --> 00:12:02.656 They send them more carbon below ground. 00:12:02.680 --> 00:12:05.256 They even reduce their own root competition 00:12:05.280 --> 00:12:08.136 to make elbow room for their kids. 00:12:08.160 --> 00:12:11.816 When mother trees are injured or dying, 00:12:11.840 --> 00:12:16.360 they also send messages of wisdom on to the next generation of seedlings. 00:12:17.120 --> 00:12:18.656 So we've used isotope tracing 00:12:18.680 --> 00:12:21.256 to trace carbon moving from an injured mother tree 00:12:21.280 --> 00:12:23.616 down her trunk into the mycorrhizal network 00:12:23.640 --> 00:12:25.640 and into her neighboring seedlings, 00:12:26.640 --> 00:12:29.416 not only carbon but also defense signals. 00:12:29.440 --> 00:12:31.256 And these two compounds 00:12:31.280 --> 00:12:35.376 have increased the resistance of those seedlings to future stresses. 00:12:35.400 --> 00:12:36.680 So trees talk. NOTE Paragraph 00:12:38.560 --> 00:12:40.576 (Applause) NOTE Paragraph 00:12:40.600 --> 00:12:41.800 Thank you. NOTE Paragraph 00:12:45.440 --> 00:12:47.736 Through back and forth conversations, 00:12:47.760 --> 00:12:50.440 they increase the resilience of the whole community. 00:12:51.360 --> 00:12:54.256 It probably reminds you of our own social communities, 00:12:54.280 --> 00:12:55.856 and our families, 00:12:55.880 --> 00:12:57.261 well, at least some families. NOTE Paragraph 00:12:57.285 --> 00:12:59.496 (Laughter) NOTE Paragraph 00:12:59.520 --> 00:13:01.425 So let's come back to the initial point. 00:13:02.480 --> 00:13:04.936 Forests aren't simply collections of trees, 00:13:04.960 --> 00:13:08.496 they're complex systems with hubs and networks 00:13:08.520 --> 00:13:12.016 that overlap and connect trees and allow them to communicate, 00:13:12.040 --> 00:13:15.816 and they provide avenues for feedbacks and adaptation, 00:13:15.840 --> 00:13:18.256 and this makes the forest resilient. 00:13:18.280 --> 00:13:22.656 That's because there are many hub trees and many overlapping networks. 00:13:22.680 --> 00:13:24.656 But they're also vulnerable, 00:13:24.680 --> 00:13:27.560 vulnerable not only to natural disturbances 00:13:28.200 --> 00:13:31.896 like bark beetles that preferentially attack big old trees 00:13:31.920 --> 00:13:34.360 but high-grade logging and clear-cut logging. 00:13:35.240 --> 00:13:38.056 You see, you can take out one or two hub trees, 00:13:38.080 --> 00:13:39.800 but there comes a tipping point, 00:13:40.920 --> 00:13:43.856 because hub trees are not unlike rivets in an airplane. 00:13:43.880 --> 00:13:47.416 You can take out one or two and the plane still flies, 00:13:47.440 --> 00:13:49.016 but you take out one too many, 00:13:49.040 --> 00:13:51.656 or maybe that one holding on the wings, 00:13:51.680 --> 00:13:53.520 and the whole system collapses. NOTE Paragraph 00:13:55.000 --> 00:13:57.896 So now how are you thinking about forests? Differently? NOTE Paragraph 00:13:57.920 --> 00:13:59.136 (Audience) Yes. NOTE Paragraph 00:13:59.160 --> 00:14:00.360 Cool. 00:14:01.040 --> 00:14:02.240 I'm glad. NOTE Paragraph 00:14:02.920 --> 00:14:06.776 So, remember I said earlier that I hoped that my research, 00:14:06.800 --> 00:14:10.176 my discoveries would change the way we practice forestry. 00:14:10.200 --> 00:14:14.320 Well, I want to take a check on that 30 years later here in western Canada. NOTE Paragraph 00:14:22.840 --> 00:14:25.376 This is about 100 kilometers to the west of us, 00:14:25.400 --> 00:14:27.760 just on the border of Banff National Park. 00:14:29.120 --> 00:14:30.560 That's a lot of clear-cuts. 00:14:31.020 --> 00:14:32.460 It's not so pristine. 00:14:33.980 --> 00:14:39.036 In 2014, the World Resources Institute reported that Canada in the past decade 00:14:39.060 --> 00:14:42.660 has had the highest forest disturbance rate of any country worldwide, 00:14:43.620 --> 00:14:45.340 and I bet you thought it was Brazil. 00:14:47.140 --> 00:14:50.676 In Canada, it's 3.6 percent per year. 00:14:50.700 --> 00:14:54.620 Now, by my estimation, that's about four times the rate that is sustainable. NOTE Paragraph 00:14:57.100 --> 00:15:01.436 Now, massive disturbance at this scale is known to affect hydrological cycles, 00:15:01.460 --> 00:15:03.436 degrade wildlife habitat, 00:15:03.460 --> 00:15:06.356 and emit greenhouse gases back into the atmosphere, 00:15:06.380 --> 00:15:09.300 which creates more disturbance and more tree diebacks. NOTE Paragraph 00:15:11.300 --> 00:15:14.276 Not only that, we're continuing to plant one or two species 00:15:14.300 --> 00:15:16.260 and weed out the aspens and birches. 00:15:17.260 --> 00:15:19.836 These simplified forests lack complexity, 00:15:19.860 --> 00:15:23.276 and they're really vulnerable to infections and bugs. 00:15:23.300 --> 00:15:25.196 And as climate changes, 00:15:25.220 --> 00:15:27.500 this is creating a perfect storm 00:15:29.420 --> 00:15:32.996 for extreme events, like the massive mountain pine beetle outbreak 00:15:33.020 --> 00:15:35.060 that just swept across North America, 00:15:35.820 --> 00:15:39.140 or that megafire in the last couple months in Alberta. NOTE Paragraph 00:15:40.980 --> 00:15:43.300 So I want to come back to my final question: 00:15:44.980 --> 00:15:46.756 instead of weakening our forests, 00:15:46.780 --> 00:15:50.340 how can we reinforce them and help them deal with climate change? 00:15:51.700 --> 00:15:55.716 Well, you know, the great thing about forests as complex systems 00:15:55.740 --> 00:15:58.780 is they have enormous capacity to self-heal. 00:15:59.700 --> 00:16:01.116 In our recent experiments, 00:16:01.140 --> 00:16:04.596 we found with patch-cutting and retention of hub trees 00:16:04.620 --> 00:16:08.756 and regeneration to a diversity of species and genes and genotypes 00:16:08.780 --> 00:16:12.620 that these mycorrhizal networks, they recover really rapidly. 00:16:13.940 --> 00:16:18.276 So with this in mind, I want to leave you with four simple solutions. 00:16:18.300 --> 00:16:21.660 And we can't kid ourselves that these are too complicated to act on. NOTE Paragraph 00:16:23.180 --> 00:16:26.380 First, we all need to get out in the forest. 00:16:27.500 --> 00:16:32.036 We need to reestablish local involvement in our own forests. 00:16:32.060 --> 00:16:33.676 You see, most of our forests now 00:16:33.700 --> 00:16:36.916 are managed using a one-size-fits-all approach, 00:16:36.940 --> 00:16:41.300 but good forest stewardship requires knowledge of local conditions. NOTE Paragraph 00:16:42.420 --> 00:16:46.100 Second, we need to save our old-growth forests. 00:16:47.020 --> 00:16:52.740 These are the repositories of genes and mother trees and mycorrhizal networks. 00:16:54.620 --> 00:16:56.876 So this means less cutting. 00:16:56.900 --> 00:16:58.940 I don't mean no cutting, but less cutting. NOTE Paragraph 00:16:59.980 --> 00:17:02.635 And third, when we do cut, 00:17:02.660 --> 00:17:04.460 we need to save the legacies, 00:17:05.180 --> 00:17:06.716 the mother trees and networks, 00:17:06.740 --> 00:17:08.875 and the wood, the genes, 00:17:08.900 --> 00:17:12.796 so they can pass their wisdom onto the next generation of trees 00:17:12.819 --> 00:17:15.940 so they can withstand the future stresses coming down the road. 00:17:16.620 --> 00:17:18.700 We need to be conservationists. NOTE Paragraph 00:17:19.819 --> 00:17:22.539 And finally, fourthly and finally, 00:17:23.340 --> 00:17:26.796 we need to regenerate our forests with a diversity of species 00:17:26.820 --> 00:17:29.036 and genotypes and structures 00:17:29.060 --> 00:17:31.820 by planting and allowing natural regeneration. 00:17:32.620 --> 00:17:35.516 We have to give Mother Nature the tools she needs 00:17:35.540 --> 00:17:38.260 to use her intelligence to self-heal. 00:17:39.180 --> 00:17:42.236 And we need to remember that forests aren't just a bunch of trees 00:17:42.260 --> 00:17:43.516 competing with each other, 00:17:43.540 --> 00:17:45.460 they're supercooperators. NOTE Paragraph 00:17:46.700 --> 00:17:48.356 So back to Jigs. 00:17:48.380 --> 00:17:52.836 Jigs's fall into the outhouse showed me this other world, 00:17:52.860 --> 00:17:55.556 and it changed my view of forests. 00:17:55.580 --> 00:17:58.916 I hope today to have changed how you think about forests. NOTE Paragraph 00:17:58.940 --> 00:18:00.196 Thank you. NOTE Paragraph 00:18:00.220 --> 00:18:05.997 (Applause)