1 00:00:36,800 --> 00:00:42,540 The relationship between plants and humans is extraordinary. 2 00:00:45,300 --> 00:00:48,020 We've been adapting to each other 3 00:00:48,020 --> 00:00:50,980 for as long as we've been on the planet. 4 00:00:53,620 --> 00:00:58,100 We rely upon plants for almost everything. 5 00:00:58,100 --> 00:01:03,180 The air we breathe, the water we drink, the food we eat, 6 00:01:03,180 --> 00:01:05,580 much of the clothes we wear, 7 00:01:05,580 --> 00:01:10,340 in some parts of the world, the very buildings in which we live. 8 00:01:10,340 --> 00:01:13,340 But that relationship is now changing. 9 00:01:16,300 --> 00:01:21,860 How it changes next will shape the future of our green planet. 10 00:01:36,460 --> 00:01:40,260 Some plants have the ability to live alongside us... 11 00:01:43,420 --> 00:01:47,820 ..even when we make it extremely difficult for them to do so. 12 00:01:50,980 --> 00:01:55,780 This is Piccadilly Circus in the heart of London. 13 00:01:55,780 --> 00:02:01,260 It would be difficult to imagine a more hostile place for a plant. 14 00:02:03,860 --> 00:02:08,620 And yet, even here, plants will find a way. 15 00:02:19,780 --> 00:02:24,460 Plants like this may seem to follow us wherever we go. 16 00:02:28,140 --> 00:02:31,260 We call them, perhaps a little unkindly, 17 00:02:31,260 --> 00:02:32,740 weeds. 18 00:02:36,820 --> 00:02:40,180 In fact, these plants are pioneers, 19 00:02:40,180 --> 00:02:45,180 the ones that are most able to take advantage of new habitats, 20 00:02:45,180 --> 00:02:47,500 even very harsh ones. 21 00:02:52,460 --> 00:02:56,180 This wall is at least 100 years old. 22 00:02:56,180 --> 00:03:01,420 It's like a sheer cliff face with no sign of soil, 23 00:03:01,420 --> 00:03:05,260 and yet this ivy-leaved toadflax thrives here. 24 00:03:06,700 --> 00:03:08,100 How? 25 00:03:09,740 --> 00:03:13,780 The plant grows towards the light with its flowers facing outwards 26 00:03:13,780 --> 00:03:15,980 to attract pollinators. 27 00:03:17,540 --> 00:03:20,020 But once they've succeeded in doing that 28 00:03:20,020 --> 00:03:22,740 and the seed pods start to develop, 29 00:03:22,740 --> 00:03:23,900 its behaviour changes. 30 00:03:25,980 --> 00:03:31,020 For now, the pods turn and grow away from the light, 31 00:03:31,020 --> 00:03:34,100 seeking the darkest place they can find. 32 00:03:34,100 --> 00:03:37,220 A crevice, perhaps, like this one. 33 00:03:43,660 --> 00:03:46,260 It's all the toadflax needs. 34 00:03:46,260 --> 00:03:50,540 It can now germinate and start to produce a new plant. 35 00:04:08,220 --> 00:04:11,460 Other pioneers have a different strategy. 36 00:04:11,460 --> 00:04:18,580 They instead distribute their seeds far and wide in great numbers. 37 00:04:18,580 --> 00:04:22,860 Sow thistles are masters of this trick. 38 00:04:22,860 --> 00:04:27,300 Each of its seeds is equipped with a tiny downy parachute, 39 00:04:27,300 --> 00:04:29,940 which will catch the slightest breeze. 40 00:04:32,020 --> 00:04:35,420 And they can travel extraordinary distances. 41 00:04:36,900 --> 00:04:39,260 They can rise a mile high in the sky 42 00:04:39,260 --> 00:04:43,980 and reach places hundreds of miles away from the parent plant. 43 00:04:48,020 --> 00:04:51,820 The seeds only need to find the tiniest chink 44 00:04:51,820 --> 00:04:53,700 and they can take hold. 45 00:04:58,420 --> 00:05:01,820 We barely notice many of these plant invaders. 46 00:05:04,500 --> 00:05:07,060 But here in the heart of Hong Kong, 47 00:05:07,060 --> 00:05:12,180 strangler fig seeds that landed on a stone wall generations ago, 48 00:05:12,180 --> 00:05:17,260 have spread their flexible branching roots far and wide. 49 00:05:22,020 --> 00:05:23,980 They can be anchored so firmly 50 00:05:23,980 --> 00:05:27,180 that they become a part of the city's architecture. 51 00:05:31,300 --> 00:05:34,420 This is perhaps the ultimate weed. 52 00:05:38,860 --> 00:05:42,700 But there are places where the extraordinary abilities of fig trees 53 00:05:42,700 --> 00:05:47,100 have created a very different relationship with human beings. 54 00:06:01,980 --> 00:06:05,980 Meghalaya in north-east India, 55 00:06:05,980 --> 00:06:10,700 a high altitude plateau riven by dizzyingly steep valleys. 56 00:06:15,380 --> 00:06:18,420 It's home to the Khasi people... 57 00:06:21,100 --> 00:06:25,260 ..who've learned how to use the remarkable properties of fig trees 58 00:06:25,260 --> 00:06:28,180 to help them live in such difficult country. 59 00:06:32,820 --> 00:06:38,540 As in Hong Kong, the tree's numerous roots anchor it firmly, 60 00:06:38,540 --> 00:06:40,940 here to steep mountainsides. 61 00:06:43,660 --> 00:06:48,580 These roots can grow up to 2.5cm a day. 62 00:06:48,580 --> 00:06:51,140 They are unusually strong, 63 00:06:51,140 --> 00:06:55,580 flexible, and can develop into a multitude of shapes. 64 00:06:58,340 --> 00:07:01,820 The Khasi persuade them to provide them with stairs. 65 00:07:08,140 --> 00:07:12,260 The monsoon season brings a seemingly insurmountable challenge 66 00:07:12,260 --> 00:07:14,300 for Khasi communities. 67 00:07:18,980 --> 00:07:23,540 This is the wettest place in the world. 68 00:07:23,540 --> 00:07:27,100 Nearly 30cm of rain can fall in a day. 69 00:07:37,700 --> 00:07:39,980 Rivers become lethal torrents, 70 00:07:39,980 --> 00:07:42,580 dividing communities from each other. 71 00:07:44,180 --> 00:07:47,620 This is when the relationship between fig trees and the Khasi 72 00:07:47,620 --> 00:07:49,500 becomes most important. 73 00:07:52,940 --> 00:07:56,580 They deliberately plant fig trees near the rivers. 74 00:07:56,580 --> 00:08:00,860 When they're mature enough to have developed many hanging roots, 75 00:08:00,860 --> 00:08:04,460 Shining Star Kongthaw begins working with them. 76 00:08:25,300 --> 00:08:28,420 He guides the roots through bamboo tubes 77 00:08:28,420 --> 00:08:31,860 that are pointed towards the opposite river bank. 78 00:08:50,380 --> 00:08:54,460 These strands will combine as they grow, sharing nutrients 79 00:08:54,460 --> 00:08:59,420 and resources and becoming stronger than a lone strand could ever be. 80 00:09:27,540 --> 00:09:33,300 As the years pass, the growing roots become a living bridge. 81 00:09:52,140 --> 00:09:56,380 As they grow, they become ever stronger and more stable. 82 00:10:20,980 --> 00:10:25,340 This unusual relationship has allowed the people here to thrive 83 00:10:25,340 --> 00:10:28,700 in an otherwise challenging landscape. 84 00:10:44,700 --> 00:10:48,940 But there are plants that have found a deeper partnership with us, 85 00:10:48,940 --> 00:10:53,340 and in doing so, have changed landscapes across the globe. 86 00:10:56,740 --> 00:10:59,500 It began over 10,000 years ago, 87 00:10:59,500 --> 00:11:02,620 with plants that we found especially good to eat. 88 00:11:05,660 --> 00:11:09,780 At first, this relationship created challenges of its own. 89 00:11:11,140 --> 00:11:13,860 Many of the ancestral grasses, 90 00:11:13,860 --> 00:11:16,220 like these wild oats from Israel, 91 00:11:16,220 --> 00:11:19,780 have a trick to ensure that their seeds are planted 92 00:11:19,780 --> 00:11:21,300 in the perfect place. 93 00:11:22,500 --> 00:11:29,260 Each seed head, at the top, carries two long bristles called awns, 94 00:11:29,260 --> 00:11:32,580 and when a seed drops to the ground, 95 00:11:32,580 --> 00:11:36,260 these awns do something truly extraordinary... 96 00:12:14,620 --> 00:12:18,580 ..they walk. 97 00:12:22,460 --> 00:12:26,100 The awns twist as they dry out during the day, 98 00:12:26,100 --> 00:12:28,340 and then when they get wet... 99 00:12:30,780 --> 00:12:32,980 ..they untwist. 100 00:12:35,420 --> 00:12:37,860 Tiny hairs grip on to the ground, 101 00:12:37,860 --> 00:12:41,100 keeping the individual moving forward. 102 00:12:47,660 --> 00:12:51,340 In this way, the seeds work their way along the ground 103 00:12:51,340 --> 00:12:54,940 until eventually they find a rock to hide under 104 00:12:54,940 --> 00:12:56,780 or a crack to drill in to. 105 00:13:03,380 --> 00:13:05,980 This adaptation is useful for the plant, 106 00:13:05,980 --> 00:13:08,940 but not for us. 107 00:13:08,940 --> 00:13:12,420 It's hard to collect seeds when they drop off and walk away. 108 00:13:14,500 --> 00:13:20,020 So our ancestors selected plants whose seeds don't drop off, 109 00:13:20,020 --> 00:13:22,060 don't have legs 110 00:13:22,060 --> 00:13:24,180 and don't bury themselves out of reach. 111 00:13:28,060 --> 00:13:31,380 They also selected those individuals which put their energy 112 00:13:31,380 --> 00:13:33,820 into developing much larger seeds. 113 00:13:36,580 --> 00:13:42,380 Close relationships like this have developed all over the world, 114 00:13:42,380 --> 00:13:46,180 producing the plants that are now our crops. 115 00:13:50,940 --> 00:13:54,220 This may seem a poor deal from the point of view of plants, 116 00:13:54,220 --> 00:13:55,660 but not so. 117 00:13:55,660 --> 00:13:58,100 We eat their seeds, 118 00:13:58,100 --> 00:14:03,060 but in return, we cherish and cultivate them, 119 00:14:03,060 --> 00:14:06,820 and now they are widespread and far more abundant 120 00:14:06,820 --> 00:14:08,740 than their wild ancestors. 121 00:14:14,380 --> 00:14:20,700 You might call this a bargain between ourselves and plants, 122 00:14:20,700 --> 00:14:24,300 and over the years, it's proved extraordinarily powerful. 123 00:14:34,060 --> 00:14:39,740 In the beginning, the bargain operated on a small scale. 124 00:14:48,300 --> 00:14:54,780 Plant, tend and harvest by hand in small patches. 125 00:14:59,380 --> 00:15:02,300 Over time, these plants produced more food, 126 00:15:02,300 --> 00:15:04,540 increasingly efficiently... 127 00:15:10,420 --> 00:15:13,460 ..and the partnerships became more exclusive. 128 00:15:17,340 --> 00:15:22,620 We started doing more and more for a small number of chosen species. 129 00:15:30,780 --> 00:15:36,020 These few persuaded us to eliminate their competitors, 130 00:15:36,020 --> 00:15:38,860 cure their diseases, 131 00:15:38,860 --> 00:15:42,900 poison their enemies, 132 00:15:42,900 --> 00:15:45,980 and keep them well-watered, 133 00:15:45,980 --> 00:15:49,420 even when other species faced drought. 134 00:15:51,260 --> 00:15:54,100 Fewer and fewer plant species, 135 00:15:54,100 --> 00:15:56,140 like soy, wheat and rice, 136 00:15:56,140 --> 00:15:58,540 now occupy more and more land. 137 00:16:00,660 --> 00:16:03,860 And so now whole landscapes are dominated 138 00:16:03,860 --> 00:16:05,860 by a single species of plant. 139 00:16:09,540 --> 00:16:12,180 A monoculture. 140 00:16:17,100 --> 00:16:21,100 This is the Central Valley of California, 141 00:16:21,100 --> 00:16:24,180 the biggest orchard in the world. 142 00:16:25,580 --> 00:16:30,860 A million acres of just one type of tree, 143 00:16:30,860 --> 00:16:32,540 almonds. 144 00:16:40,820 --> 00:16:43,260 Each flower, if it's fertilised by pollen 145 00:16:43,260 --> 00:16:46,020 from a different almond tree, 146 00:16:46,020 --> 00:16:48,620 will produce an almond nut. 147 00:17:01,340 --> 00:17:05,300 The flowers, patterns and scent have evolved to attract insects 148 00:17:05,300 --> 00:17:09,100 and bribe them to do that job for them. 149 00:17:09,100 --> 00:17:11,780 The pollen doesn't have to move far, 150 00:17:11,780 --> 00:17:14,820 it just needs to reach a neighbouring tree. 151 00:17:18,620 --> 00:17:23,140 There are about 20,000 flowers on each tree... 152 00:17:27,340 --> 00:17:30,980 ..and 140 million trees. 153 00:17:33,900 --> 00:17:38,700 That is billions of flowers all calling out at once. 154 00:17:42,780 --> 00:17:46,460 But here, the beauty of the blossom is wasted. 155 00:17:46,460 --> 00:17:48,700 To make way for these almond trees, 156 00:17:48,700 --> 00:17:51,300 the land was, in effect, wiped clean. 157 00:17:55,020 --> 00:17:59,660 Countless wild species of plants and animals were removed, 158 00:17:59,660 --> 00:18:02,020 including, critically, pollinators. 159 00:18:05,020 --> 00:18:09,180 So now the flowers need help, and lots of it. 160 00:18:12,180 --> 00:18:14,220 ENGINE REVS 161 00:18:20,740 --> 00:18:22,580 MACHINERY WHIRS 162 00:18:39,620 --> 00:18:41,660 LOUD BUZZING 163 00:18:43,220 --> 00:18:47,820 40 billion honeybees... 164 00:18:47,820 --> 00:18:51,420 ..trucked in from all over the United States. 165 00:18:58,780 --> 00:19:02,180 The orchard is only in bloom for a few weeks, 166 00:19:02,180 --> 00:19:06,340 so the almonds need the bees to get to work immediately. 167 00:19:22,500 --> 00:19:25,340 Each bee can visit thousands of blossoms a day. 168 00:19:28,860 --> 00:19:32,140 And while they take most of the pollen they collect back 169 00:19:32,140 --> 00:19:37,660 to the hive, they also drop some pollen at each stop. 170 00:19:37,660 --> 00:19:39,380 And, so, with luck, 171 00:19:39,380 --> 00:19:42,220 the flowers are all eventually fertilised. 172 00:19:45,060 --> 00:19:48,100 Day after day, the process is repeated. 173 00:20:02,060 --> 00:20:04,260 Flower after flower. 174 00:20:09,660 --> 00:20:12,060 Tree after tree. 175 00:20:31,420 --> 00:20:34,020 By the time the petals fall, 176 00:20:34,020 --> 00:20:38,380 2.5 trillion flowers have been successfully pollinated 177 00:20:38,380 --> 00:20:42,460 and will now grow in to 2.5 trillion almonds. 178 00:20:44,980 --> 00:20:49,460 This type of intensive, streamlined agriculture 179 00:20:49,460 --> 00:20:52,660 produces amazingly high yields. 180 00:20:56,740 --> 00:20:59,380 But monocultures are fragile. 181 00:21:00,780 --> 00:21:04,500 While they can function effectively when conditions remain stable, 182 00:21:04,500 --> 00:21:09,580 it only takes a small change to create catastrophe. 183 00:21:23,100 --> 00:21:26,780 Lodgepole pine, 184 00:21:26,780 --> 00:21:31,860 a very valuable timber tree grown extensively in western Canada. 185 00:21:34,980 --> 00:21:38,580 Millions of acres of the same species, 186 00:21:38,580 --> 00:21:41,660 all the same age and the same size. 187 00:21:44,500 --> 00:21:48,780 For centuries, lodgepole forests have lived in a natural balance 188 00:21:48,780 --> 00:21:50,580 with their enemies, 189 00:21:50,580 --> 00:21:54,020 including this one, 190 00:21:54,020 --> 00:21:55,700 the mountain pine beetle. 191 00:22:00,140 --> 00:22:04,660 In summer, female beetles start hunting for a suitable nursery 192 00:22:04,660 --> 00:22:06,820 in which to lay their eggs. 193 00:22:14,380 --> 00:22:18,300 The ideal site is a mature lodgepole pine 194 00:22:18,300 --> 00:22:21,860 with bark thick enough to feed a female's brood 195 00:22:21,860 --> 00:22:24,980 and, critically, to protect them from the bitter cold 196 00:22:24,980 --> 00:22:26,540 of the coming winter. 197 00:22:32,660 --> 00:22:36,300 Once under the bark, she tunnels upwards... 198 00:22:39,980 --> 00:22:42,180 ..laying her eggs as she goes. 199 00:22:47,020 --> 00:22:51,540 A single female beetle can lay 100 eggs in a season. 200 00:23:07,460 --> 00:23:09,220 When the larvae hatch, 201 00:23:09,220 --> 00:23:12,540 they grow by feeding on the inside of the bark. 202 00:23:14,860 --> 00:23:19,340 As they do, they damage the channels that transport water and nutrients 203 00:23:19,340 --> 00:23:21,380 between the roots and needles. 204 00:23:35,180 --> 00:23:37,820 For centuries, the freezing northern winters 205 00:23:37,820 --> 00:23:39,860 killed the majority of larvae, 206 00:23:39,860 --> 00:23:42,700 so tree and beetle remained in balance. 207 00:23:44,220 --> 00:23:48,380 But now, with the climate changing, the winters aren't cold enough 208 00:23:48,380 --> 00:23:50,620 to control the beetle numbers. 209 00:23:53,780 --> 00:23:58,820 Needles turning red are a sure sign that the trees are dying. 210 00:24:07,540 --> 00:24:11,380 The beetle plague spreads like wildfire across a landscape 211 00:24:11,380 --> 00:24:15,620 covered by a monoculture of similarly vulnerable trees. 212 00:24:19,020 --> 00:24:22,140 Since the first mass outbreak 40 years ago, 213 00:24:22,140 --> 00:24:25,780 trillions of trees in North America have been killed 214 00:24:25,780 --> 00:24:27,980 by the mountain pine beetle. 215 00:24:33,940 --> 00:24:38,180 Loss of plant diversity makes any habitat more vulnerable 216 00:24:38,180 --> 00:24:39,900 to changing conditions. 217 00:24:42,340 --> 00:24:44,980 Now, with climate changing so fast, 218 00:24:44,980 --> 00:24:49,140 we are losing plant diversity just when we need it the most. 219 00:24:51,660 --> 00:24:56,340 Two out of five plants are now facing extinction. 220 00:24:58,020 --> 00:25:04,300 Of course, the loss of any one species is in itself a tragedy, 221 00:25:04,300 --> 00:25:10,420 but such a loss erodes the stability of a whole ecosystem, 222 00:25:10,420 --> 00:25:13,940 and that should be of great concern for all of us. 223 00:25:17,980 --> 00:25:23,980 We need an insurance policy, a hedge against extinction. 224 00:25:27,260 --> 00:25:30,340 This is Kew's Millennium Seed Bank. 225 00:25:33,420 --> 00:25:38,700 Packets of seeds arrive here from all over the world. 226 00:25:38,700 --> 00:25:42,980 These are from a relative of the yucca plant, 227 00:25:42,980 --> 00:25:47,420 which grows in central Mexico on the slopes of volcanoes, 228 00:25:47,420 --> 00:25:49,660 and nowhere else. 229 00:25:52,940 --> 00:25:57,820 Most of the seeds are from plants that are threatened. 230 00:25:57,820 --> 00:26:02,300 Some indeed, have gone extinct since their seeds arrived here. 231 00:26:02,300 --> 00:26:06,500 But here, at least, those seeds are safe. 232 00:26:09,220 --> 00:26:13,140 When they arrive, they're processed 233 00:26:13,140 --> 00:26:16,100 and sealed in to airtight jars. 234 00:26:18,540 --> 00:26:22,980 Seeds are then brought underground to be stored in a vault, 235 00:26:22,980 --> 00:26:26,220 like this one, at -20C. 236 00:26:32,540 --> 00:26:35,620 Since the bank was founded, 237 00:26:35,620 --> 00:26:39,940 two billion seeds from 40,000 different species 238 00:26:39,940 --> 00:26:42,900 have been brought and stored here. 239 00:26:51,300 --> 00:26:56,180 Because a seed contains everything it needs to start a new plant, 240 00:26:56,180 --> 00:27:01,180 each and every one of them represents a little grain of hope... 241 00:27:16,220 --> 00:27:20,900 ..hope that one day we will make it possible for the seeds 242 00:27:20,900 --> 00:27:24,140 of these rarities to grow in the wild once again. 243 00:27:29,460 --> 00:27:33,900 The seed bank certainly gives us options when a species becomes rare 244 00:27:33,900 --> 00:27:36,380 or even extinct. 245 00:27:42,020 --> 00:27:45,020 But around the world, people are trying ways to keep 246 00:27:45,020 --> 00:27:48,900 natural plant populations healthy where they should be, 247 00:27:48,900 --> 00:27:50,740 in the wild. 248 00:27:59,860 --> 00:28:01,660 Hawaii. 249 00:28:04,940 --> 00:28:07,980 90% of the plant species here 250 00:28:07,980 --> 00:28:10,860 are found nowhere else in the world. 251 00:28:15,940 --> 00:28:21,140 Many are threatened by a plant invader called Miconia. 252 00:28:25,100 --> 00:28:30,140 It was brought to the island of Maui in the '70s as an ornamental plant. 253 00:28:31,340 --> 00:28:33,020 In its native Mexico, 254 00:28:33,020 --> 00:28:36,460 it grows in balance with a rich variety of predators, 255 00:28:36,460 --> 00:28:38,260 competitors and diseases. 256 00:28:45,620 --> 00:28:49,220 It grows taller than most native Hawaiian vegetation, 257 00:28:49,220 --> 00:28:51,500 and little can grow beneath it. 258 00:29:01,180 --> 00:29:04,860 On the island of Maui, with nothing to keep it in check, 259 00:29:04,860 --> 00:29:07,300 it creates a stifling monoculture. 260 00:29:10,540 --> 00:29:13,340 Miconia, it would appear, 261 00:29:13,340 --> 00:29:15,660 is doing very well for itself. 262 00:29:19,540 --> 00:29:22,380 But today it's under attack. 263 00:29:28,780 --> 00:29:33,900 On level ground, a single dedicated team can keep Miconia in check. 264 00:29:42,100 --> 00:29:46,100 But unfortunately, this plant can spread to places impossible 265 00:29:46,100 --> 00:29:48,140 for people to reach on foot. 266 00:29:54,620 --> 00:30:00,060 Just one plant can produce around ten million seeds a year, 267 00:30:00,060 --> 00:30:02,780 enough to cover this entire landscape. 268 00:30:05,820 --> 00:30:08,660 With so much at stake, the team have come up 269 00:30:08,660 --> 00:30:11,300 with an extraordinary plan. 270 00:30:55,820 --> 00:31:00,660 It's too dangerous to land here, 271 00:31:00,660 --> 00:31:03,100 but they don't need to. 272 00:31:10,100 --> 00:31:14,260 A marksman with great skill can shoot the Miconia 273 00:31:14,260 --> 00:31:18,540 with paint balls full of herbicide. 274 00:31:22,260 --> 00:31:25,460 A perfect shot is one that hits the stem, 275 00:31:25,460 --> 00:31:29,620 so ensuring that the herbicide spreads throughout the plant. 276 00:31:42,900 --> 00:31:45,980 The method is so precise 277 00:31:45,980 --> 00:31:48,740 that with careful flying and accurate aim, 278 00:31:48,740 --> 00:31:53,500 they can kill the intruders without damaging any wild plants. 279 00:32:25,620 --> 00:32:29,980 Destroying alien invaders is not the only way to help 280 00:32:29,980 --> 00:32:31,660 the native plants here. 281 00:32:39,780 --> 00:32:44,180 This is Waikamoi Preserve, the last surviving fragment 282 00:32:44,180 --> 00:32:47,740 of a high-altitude Hawaiian rainforest, 283 00:32:47,740 --> 00:32:51,140 and home to one of the world's rarest plants. 284 00:32:54,460 --> 00:32:56,020 Holokea. 285 00:32:59,100 --> 00:33:02,940 There are only 57 fully-grown individuals left in the wild. 286 00:33:07,620 --> 00:33:11,060 Their peculiar flowers evolved to suit the beak 287 00:33:11,060 --> 00:33:13,900 of a bird found only in Hawaii, 288 00:33:13,900 --> 00:33:15,260 the 'i'iwi. 289 00:33:17,980 --> 00:33:20,700 The bird is now so rare itself that, today, 290 00:33:20,700 --> 00:33:24,300 these partners seldom, if ever, meet. 291 00:33:26,500 --> 00:33:31,980 So the chances of holokea getting pollinated are very slim. 292 00:33:33,540 --> 00:33:37,900 But a strange new partnership might just save it. 293 00:33:39,100 --> 00:33:46,620 I look at losing a plant as flying in a plane and taking a screw out 294 00:33:46,620 --> 00:33:51,260 and, yeah, the plane will fly and you might be able to take a couple 295 00:33:51,260 --> 00:33:53,340 of screws out and keep flying, 296 00:33:53,340 --> 00:33:56,180 but eventually you're going to crash. 297 00:34:07,100 --> 00:34:13,420 Hank knows where to find every one of the last 57 plants, 298 00:34:13,420 --> 00:34:17,500 and he returns every year to act as their pollinator. 299 00:34:18,940 --> 00:34:25,020 We have to step in and play that role as pollinator or matchmaker. 300 00:34:34,100 --> 00:34:37,500 Hank collects the pollen from the male flower 301 00:34:37,500 --> 00:34:41,460 and dusts it onto a female flower of a different plant. 302 00:34:44,300 --> 00:34:47,140 He's currently their life support, 303 00:34:47,140 --> 00:34:50,820 but his goal is for holokea to thrive without him. 304 00:34:52,100 --> 00:34:58,140 So, before he leaves, he plays the call of the 'i'iwi bird. 305 00:34:58,140 --> 00:35:03,580 'I'IWI BIRD CALLS 306 00:35:11,300 --> 00:35:14,740 Hank hopes the sound will attract the living birds, 307 00:35:14,740 --> 00:35:19,060 and if they come, that they will reconnect with the last holokea 308 00:35:19,060 --> 00:35:22,900 and rekindle their vital relationship. 309 00:35:34,300 --> 00:35:40,140 I believe all species are important 310 00:35:40,140 --> 00:35:43,780 and I believe we have a duty to act. 311 00:35:49,940 --> 00:35:54,460 We need to act, not only in the wild places, 312 00:35:54,460 --> 00:35:57,420 but even in those where we live 313 00:35:57,420 --> 00:35:59,540 and where we farm. 314 00:36:04,980 --> 00:36:06,580 Like much of the world, 315 00:36:06,580 --> 00:36:10,020 Kenya is losing thousands of native trees annually. 316 00:36:10,020 --> 00:36:13,460 Ones that local people rely on for so much, 317 00:36:13,460 --> 00:36:15,420 especially fuel. 318 00:36:18,820 --> 00:36:22,820 But here, people have come up with an ingenious way to reverse 319 00:36:22,820 --> 00:36:25,660 some of that loss around them. 320 00:36:33,820 --> 00:36:36,860 At a factory in the outskirts of Nairobi, 321 00:36:36,860 --> 00:36:40,900 workers collect and sort waste charcoal dust. 322 00:36:45,980 --> 00:36:52,060 Seeds of carefully selected native trees are mixed with the dust. 323 00:36:55,140 --> 00:36:59,580 This carbon coat will protect the seeds from hungry animals 324 00:36:59,580 --> 00:37:01,620 until the rains arrive. 325 00:37:11,300 --> 00:37:13,820 These are seed balls. 326 00:37:28,220 --> 00:37:30,660 In the village of Kibwezi, 327 00:37:30,660 --> 00:37:33,620 acacia trees are becoming scarce, 328 00:37:33,620 --> 00:37:37,580 cut down by previous generations to make charcoal. 329 00:37:58,780 --> 00:38:04,780 But the students at this school make forest restoration child's play. 330 00:38:23,060 --> 00:38:25,900 The nutrients in the dissolving char dust 331 00:38:25,900 --> 00:38:28,740 will give each little seed a good start. 332 00:38:35,420 --> 00:38:38,900 If only a handful of these seeds grow into a tree, 333 00:38:38,900 --> 00:38:42,140 the effort has been well worth it. 334 00:38:42,140 --> 00:38:48,060 Every mature acacia tree can itself produce thousands of seeds a year. 335 00:38:52,700 --> 00:38:57,940 13 million seed balls have been distributed in Kenya alone... 336 00:39:01,580 --> 00:39:04,700 ..and the methods by which they're dispersed... 337 00:39:07,780 --> 00:39:10,180 ..are ever more inventive, 338 00:39:10,180 --> 00:39:11,420 to say the least. 339 00:39:25,580 --> 00:39:29,300 This technique is being repeated around the globe. 340 00:39:29,300 --> 00:39:30,980 Seed-ball-making workshop. 341 00:39:32,980 --> 00:39:37,260 People are choosing seeds of local native plants, 342 00:39:37,260 --> 00:39:40,460 giving them a little initial help 343 00:39:40,460 --> 00:39:43,900 and bringing some wild plants back into the world around them. 344 00:39:49,540 --> 00:39:54,300 But is it possible, even in our most extreme monocultures, 345 00:39:54,300 --> 00:39:58,380 to invite a bit of wildness in 346 00:39:58,380 --> 00:40:02,260 and, with it, a bit of resilience? 347 00:40:05,300 --> 00:40:10,180 I have two different kinds of forage growing in my orchard. 348 00:40:10,180 --> 00:40:15,700 The yellow that you see behind me is a variety of different mustards. 349 00:40:15,700 --> 00:40:17,460 And then after the bloom, 350 00:40:17,460 --> 00:40:20,060 we're going to see some clover blossom. 351 00:40:22,340 --> 00:40:25,980 This mix of plants means the bees can feed 352 00:40:25,980 --> 00:40:30,460 before and after the brief almond bloom. 353 00:40:30,460 --> 00:40:34,900 And they also get a more balanced, healthier diet. 354 00:40:34,900 --> 00:40:39,020 In the meantime, it's going to provide habitat for all sorts 355 00:40:39,020 --> 00:40:42,020 of insects and the bees, and probably some rabbits. 356 00:40:43,820 --> 00:40:48,700 It's a step towards establishing a better, more stable system. 357 00:40:50,340 --> 00:40:52,340 It's about finding balance. 358 00:40:52,340 --> 00:40:53,980 That's what we're trying to do here. 359 00:40:53,980 --> 00:40:55,460 Find a balance. 360 00:40:59,300 --> 00:41:04,940 Can humanity globally find a new balance between wild plants 361 00:41:04,940 --> 00:41:07,180 and those we have domesticated? 362 00:41:11,100 --> 00:41:15,060 Around half the usable land on Earth is taken up by agriculture. 363 00:41:16,500 --> 00:41:18,780 Do we really need that much? 364 00:41:19,980 --> 00:41:22,100 Maybe not. 365 00:41:23,260 --> 00:41:30,540 It's a remarkable fact, but around 80% of all cultivated land 366 00:41:30,540 --> 00:41:35,340 is used for raising livestock for us to eat. 367 00:41:37,500 --> 00:41:41,580 Raising animals can be a sustainable way to create food, 368 00:41:41,580 --> 00:41:45,180 but in many places, plants can produce the same amount 369 00:41:45,180 --> 00:41:49,340 of protein on a fraction of the land that animals need. 370 00:41:52,860 --> 00:41:56,300 What could it mean for wild plants if the global balance 371 00:41:56,300 --> 00:41:59,300 between plant-eating and meat-eating shifted? 372 00:42:02,060 --> 00:42:06,340 It may sound odd, but the more plants we eat, 373 00:42:06,340 --> 00:42:10,780 the more space there will be for wild plants. 374 00:42:14,140 --> 00:42:19,380 Remarkably, it's possible to restock even highly degraded land 375 00:42:19,380 --> 00:42:20,700 with wild plants. 376 00:42:27,620 --> 00:42:32,580 In Brazil, the needs of cattle ranching drive most deforestation. 377 00:42:39,780 --> 00:42:43,900 30 years ago, the owners of one former cattle ranch 378 00:42:43,900 --> 00:42:48,060 wanted to restore their land to the Atlantic rainforest 379 00:42:48,060 --> 00:42:50,380 that once covered it. 380 00:42:52,260 --> 00:42:54,860 They had no idea if it could be done... 381 00:42:56,260 --> 00:42:58,980 ..the land was so bare and eroded. 382 00:43:01,620 --> 00:43:03,900 But they were determined to try. 383 00:43:06,020 --> 00:43:09,980 First, they cleared the introduced African cattle grasses, 384 00:43:09,980 --> 00:43:13,340 invasive plants that outcompete most of the native plants. 385 00:43:21,700 --> 00:43:25,740 The grasses were replaced by seedlings grown from seeds 386 00:43:25,740 --> 00:43:29,340 gathered in nearby remnants of Atlantic rainforest. 387 00:43:38,340 --> 00:43:42,140 The Earth Institute, or Instituto Terra, 388 00:43:42,140 --> 00:43:44,140 as the ranch is known now, 389 00:43:44,140 --> 00:43:48,940 was encouraged by early success and expanded its scope and ambition. 390 00:44:07,180 --> 00:44:12,140 In five years, trees covered the land again, 391 00:44:12,140 --> 00:44:14,060 and within ten, 392 00:44:14,060 --> 00:44:16,500 it was clear something remarkable was happening. 393 00:44:37,460 --> 00:44:42,660 When rain falls, it now no longer simply runs off the land, 394 00:44:42,660 --> 00:44:44,140 leaving it parched. 395 00:44:48,220 --> 00:44:51,020 Instead, it clings to the plants, 396 00:44:51,020 --> 00:44:53,500 to every root, stem and leaf... 397 00:44:55,340 --> 00:44:58,780 ..and then slowly filters to the forest floor. 398 00:45:01,860 --> 00:45:06,260 ..and, so, previously dry streams burst into life 399 00:45:06,260 --> 00:45:08,580 for the first time in decades. 400 00:45:14,140 --> 00:45:17,460 The Institute never introduced animals or plants 401 00:45:17,460 --> 00:45:18,980 other than the trees. 402 00:45:25,180 --> 00:45:27,620 The animals came back on their own. 403 00:45:30,260 --> 00:45:32,900 Small ones came first. 404 00:45:49,700 --> 00:45:52,380 And then, very recently, 405 00:45:52,380 --> 00:45:56,460 camera traps left in the forest captured images 406 00:45:56,460 --> 00:45:59,100 beyond the hopes of everyone involved. 407 00:46:03,060 --> 00:46:06,020 A maned wolf, 408 00:46:06,020 --> 00:46:11,020 an animal that is being driven from its native habitat by deforestation, 409 00:46:11,020 --> 00:46:14,300 drawn to its favourite plant, 410 00:46:14,300 --> 00:46:16,940 the wolf fruit tree. 411 00:46:20,220 --> 00:46:21,620 Not only that... 412 00:46:21,620 --> 00:46:24,700 YAPS 413 00:46:26,900 --> 00:46:29,140 ..a puma... 414 00:46:31,820 --> 00:46:33,420 ..with cubs! 415 00:46:42,580 --> 00:46:47,660 The arrival of these precious top predators and their young 416 00:46:47,660 --> 00:46:52,100 shows what can happen when we make space for wild plants. 417 00:46:57,980 --> 00:47:00,060 We have, for centuries, 418 00:47:00,060 --> 00:47:04,700 robbed wild plants of the space and time they need to thrive. 419 00:47:06,780 --> 00:47:10,980 That has certainly not been to their benefit. 420 00:47:12,100 --> 00:47:15,900 Nor, ultimately, is it to ours. 421 00:47:20,660 --> 00:47:25,020 Our relationship with plants has changed throughout history, 422 00:47:25,020 --> 00:47:27,540 and now it must change again. 423 00:47:27,540 --> 00:47:30,740 Whether it's what we eat and cultivate 424 00:47:30,740 --> 00:47:33,060 or whether it's what we like, 425 00:47:33,060 --> 00:47:38,620 we must now work with plants and make the world a little greener, 426 00:47:38,620 --> 00:47:40,060 a little wilder. 427 00:47:48,380 --> 00:47:53,100 If we do this, our future will be healthier 428 00:47:53,100 --> 00:47:55,740 and safer 429 00:47:55,740 --> 00:47:59,020 and, in my experience, at any rate, happier. 430 00:47:59,020 --> 00:48:01,100 Plants are, after all, 431 00:48:01,100 --> 00:48:04,380 our most ancient allies, and, together, 432 00:48:04,380 --> 00:48:07,060 we can make this an even greener planet. 433 00:48:21,460 --> 00:48:23,620 Throughout the Human episode, 434 00:48:23,620 --> 00:48:25,740 the Green Planet crew sought 435 00:48:25,740 --> 00:48:29,580 to capture the lives of plants confronted with the human world. 436 00:48:31,420 --> 00:48:34,860 But they also heard the stories of people deeply connected 437 00:48:34,860 --> 00:48:36,900 to the plants around them... 438 00:48:40,020 --> 00:48:44,140 ..such as those at the front line of the battle to save Hawaii's native 439 00:48:44,140 --> 00:48:47,540 endangered plants from invasive species. 440 00:48:48,940 --> 00:48:50,980 If we don't get a handle on Miconia, 441 00:48:50,980 --> 00:48:55,620 we could lose everything that makes Hawaii special and unique. 442 00:48:57,780 --> 00:49:01,100 But before the Green Planet team could start work, 443 00:49:01,100 --> 00:49:05,380 they had to undertake some rigorous preparation. 444 00:49:05,380 --> 00:49:08,020 We're going into somewhere that has very... 445 00:49:08,020 --> 00:49:09,660 It's a very sensitive ecosystem. 446 00:49:09,660 --> 00:49:12,340 They're trying to protect it from invasives. 447 00:49:12,340 --> 00:49:16,140 Filming in a place so ravaged by invasive species 448 00:49:16,140 --> 00:49:19,780 meant they had to be 100% sure that they were not spreading 449 00:49:19,780 --> 00:49:23,820 any non-native stowaways themselves. 450 00:49:23,820 --> 00:49:27,580 They had to scrub and disinfect every item of equipment. 451 00:49:31,380 --> 00:49:34,700 With kit clean, the team first focus on filming 452 00:49:34,700 --> 00:49:36,660 the rare holokea plant... 453 00:49:41,100 --> 00:49:43,740 ..accessible only on foot. 454 00:49:49,940 --> 00:49:55,460 There are a few pristine areas like this left in Hawaii, 455 00:49:55,460 --> 00:50:00,820 only 40% of the land still has native vegetation, 456 00:50:00,820 --> 00:50:05,500 most of it wiped out by invasive species like Miconia. 457 00:50:10,980 --> 00:50:16,060 Next on the list was to film the team waging war on Miconia, 458 00:50:16,060 --> 00:50:18,660 known locally as the purple plague. 459 00:50:20,740 --> 00:50:22,940 For crew member Aja, 460 00:50:22,940 --> 00:50:25,020 the work is not just a physical battle 461 00:50:25,020 --> 00:50:28,020 against this invasive species, 462 00:50:28,020 --> 00:50:30,260 it's deeply personal. 463 00:50:30,260 --> 00:50:32,100 I've been to the pristine areas, 464 00:50:32,100 --> 00:50:35,180 so I know what it looks like and feels like, 465 00:50:35,180 --> 00:50:37,180 you know, to be in the presence 466 00:50:37,180 --> 00:50:40,620 of all that mana and spirituality. 467 00:50:44,500 --> 00:50:46,340 Those aren't just plants. 468 00:50:48,140 --> 00:50:51,060 Those are ancestors' spirits, you know? 469 00:50:51,060 --> 00:50:55,060 Controlling these invasive plants is a relentless job, 470 00:50:55,060 --> 00:50:59,380 and Aja is not just doing this for native Hawaiian ecosystems, 471 00:50:59,380 --> 00:51:02,580 but also to protect her ancestral relationship 472 00:51:02,580 --> 00:51:04,620 to this fragile landscape. 473 00:51:05,820 --> 00:51:08,260 So, going through this, it feels good to hack 'em 474 00:51:08,260 --> 00:51:09,500 and pull them out and be like, 475 00:51:09,500 --> 00:51:11,140 "Yeah, OK, take that!" You know? 476 00:51:11,140 --> 00:51:14,180 We can sort of fight back. 477 00:51:14,180 --> 00:51:19,860 Aja's fierce passion to protect these native forests is evident, 478 00:51:19,860 --> 00:51:22,700 but the purple plague has spread to places 479 00:51:22,700 --> 00:51:24,740 Aja could never reach on foot. 480 00:51:26,980 --> 00:51:30,260 Taking to the sky is the only way to reach the front line 481 00:51:30,260 --> 00:51:32,420 of this battleground. 482 00:51:34,580 --> 00:51:38,340 With only enough fuel to stay airborne for two hours, 483 00:51:38,340 --> 00:51:42,380 the window for capturing this aerial battle is uncomfortably small. 484 00:51:44,220 --> 00:51:47,660 We have one day of doing the heli operations. 485 00:51:47,660 --> 00:51:49,700 The weather could completely mess us up 486 00:51:49,700 --> 00:51:51,980 if we get a system that comes in, 487 00:51:51,980 --> 00:51:56,340 heli to heli is always dangerous and difficult. 488 00:51:56,340 --> 00:51:59,860 This flight is not just tense for Liz, 489 00:51:59,860 --> 00:52:02,300 for plant sniper Brooke Mahnken, 490 00:52:02,300 --> 00:52:05,340 these short flights represent his only opportunity 491 00:52:05,340 --> 00:52:07,540 to hold back the invasion. 492 00:52:07,540 --> 00:52:11,980 Miconia left unchecked can be terribly damaging. 493 00:52:11,980 --> 00:52:14,620 The potential for one seeding plant, 494 00:52:14,620 --> 00:52:17,020 if it were to get far away from the population, 495 00:52:17,020 --> 00:52:19,780 reach maturity and put seeds out, 496 00:52:19,780 --> 00:52:22,820 then it's starting a whole new infestation. 497 00:52:22,820 --> 00:52:25,620 And once it occupies that entire area, 498 00:52:25,620 --> 00:52:27,980 then it's completely wiped it out. 499 00:52:31,780 --> 00:52:36,180 The helicopter is really important because you can fly in extreme 500 00:52:36,180 --> 00:52:39,060 terrain with these, like, 1,000ft cliffs 501 00:52:39,060 --> 00:52:40,700 and find Miconia that... 502 00:52:40,700 --> 00:52:43,980 There would be no other way to get to these plants. 503 00:52:45,340 --> 00:52:48,860 The Miconia team are used to the aerial challenges 504 00:52:48,860 --> 00:52:51,660 of this battle, but for producer Liz, 505 00:52:51,660 --> 00:52:54,300 the pre-fight talk from the helicopter pilot 506 00:52:54,300 --> 00:52:56,900 brings home the lengths that this team go to 507 00:52:56,900 --> 00:52:59,060 in order to complete their work. 508 00:52:59,060 --> 00:53:01,420 So, you're just going to be in the back here 509 00:53:01,420 --> 00:53:03,500 and it's a hurricane in the back seat, 510 00:53:03,500 --> 00:53:06,300 literally a hurricane, so nothing loose, 511 00:53:06,300 --> 00:53:09,260 you don't want to put an arm ahead, a leg or a hand out 512 00:53:09,260 --> 00:53:11,140 cos it's going to blow behind you 513 00:53:11,140 --> 00:53:13,300 and you don't want to stick your head out 514 00:53:13,300 --> 00:53:15,620 because if the headset comes off, 515 00:53:15,620 --> 00:53:19,460 then it's into the tail rotor and then it's bye-bye, Maui. 516 00:53:19,460 --> 00:53:21,380 Pre-flight checks completed, 517 00:53:21,380 --> 00:53:24,180 the clock is now ticking to get into the air. 518 00:53:28,220 --> 00:53:30,260 This matters so much to everyone here. 519 00:53:30,260 --> 00:53:32,820 I definitely feel the pressure to get this right. 520 00:53:39,940 --> 00:53:42,620 INDISTINCT SPEECH 521 00:53:50,780 --> 00:53:53,380 To get within shooting distance of the plants, 522 00:53:53,380 --> 00:53:56,740 the helicopter pilot must carefully manoeuvre in 523 00:53:56,740 --> 00:53:59,260 to one of the area's deepest canyons. 524 00:54:00,940 --> 00:54:03,180 See the light-coloured rock? Yep. 525 00:54:03,180 --> 00:54:05,580 Follow that up, to the right. 526 00:54:05,580 --> 00:54:07,940 You see it? 527 00:54:07,940 --> 00:54:10,140 The target is in sight. 528 00:54:10,140 --> 00:54:11,380 Oh, yeah. There it is. 529 00:54:14,900 --> 00:54:18,180 OK, I'm live and ready. 530 00:54:18,180 --> 00:54:21,060 With high winds gusting up from the waterfall, 531 00:54:21,060 --> 00:54:23,980 getting into position is tricky enough in one helicopter, 532 00:54:23,980 --> 00:54:25,380 let alone two. 533 00:54:26,740 --> 00:54:29,900 To give Brooke the best chance of hitting the Miconia, 534 00:54:29,900 --> 00:54:33,620 the pilot must get him within 20 metres of the plant 535 00:54:33,620 --> 00:54:35,540 and ideally at eye-level. 536 00:54:35,540 --> 00:54:38,900 Any missed shot threatens to become friendly fire, 537 00:54:38,900 --> 00:54:42,180 harming the species he aims to protect. 538 00:54:42,180 --> 00:54:44,020 Ready? Yeah. Here we go. 539 00:54:47,180 --> 00:54:49,500 Brooke must strike the stem of the plant 540 00:54:49,500 --> 00:54:52,660 to have the best chance of completely killing it. 541 00:54:54,740 --> 00:54:57,580 Whoa! My God, nice fire! 542 00:55:05,380 --> 00:55:08,380 Yeah, worked really, really well. Thanks, guys. 543 00:55:09,540 --> 00:55:13,340 This has been a successful mission for both teams. 544 00:55:13,340 --> 00:55:16,340 The pilot's skills and Brooke's sharp shooting 545 00:55:16,340 --> 00:55:18,740 has saved another patch of forest, 546 00:55:18,740 --> 00:55:21,340 and Liz is relieved that she has the shots 547 00:55:21,340 --> 00:55:24,060 she needs to do the story justice. 548 00:55:24,060 --> 00:55:26,860 It's over. It's over. 549 00:55:26,860 --> 00:55:29,140 It just looked amazing. 550 00:55:29,140 --> 00:55:31,300 Yeah, it looks good. 551 00:55:31,300 --> 00:55:33,380 It looks good. 552 00:55:33,380 --> 00:55:36,820 For Brooke and Aja, however, their work doesn't stop. 553 00:55:36,820 --> 00:55:40,660 Just holding back the tide of invasive species in Hawaii 554 00:55:40,660 --> 00:55:43,740 is more than a lifetime's work. 555 00:55:43,740 --> 00:55:46,740 But Aja believes that her fight is worthwhile. 556 00:55:46,740 --> 00:55:49,940 Everything we do is for the next generation, 557 00:55:49,940 --> 00:55:51,980 just like our ancestors and kupuna. 558 00:55:51,980 --> 00:55:56,260 It wasn't for them, it was for the next generation. 559 00:55:56,260 --> 00:55:59,540 And just to have my kids go into areas, like, where they can see 560 00:55:59,540 --> 00:56:01,340 there are still natives, 561 00:56:01,340 --> 00:56:06,020 where we don't have to go through all this invasive vegetation. 562 00:56:10,740 --> 00:56:13,940 You know, it's not just my responsibility, 563 00:56:13,940 --> 00:56:15,980 it's everyone's responsibility. 564 00:56:19,340 --> 00:56:22,100 You know, the Earth takes care of us, so we have to do the same, 565 00:56:22,100 --> 00:56:24,660 we can't just let it go by. 566 00:56:28,180 --> 00:56:30,340 We've got to take care, too. 567 00:56:38,220 --> 00:56:41,620 The Open University had produced a poster 568 00:56:41,620 --> 00:56:46,260 that explores the vital role that plants have for our planet. 569 00:56:46,260 --> 00:56:52,460 To order your free copy, call... 570 00:56:52,460 --> 00:56:55,140 or go to... 571 00:56:57,860 --> 00:56:59,500 ..and follow the links 572 00:56:59,500 --> 00:57:00,660 to the Open University.