1 00:00:14,680 --> 00:00:16,600 {\an8}The biggest living thing 2 00:00:16,600 --> 00:00:19,360 {\an8}that exists on this planet is a plant... 3 00:00:21,240 --> 00:00:24,000 ..like this giant sequoia tree in California. 4 00:00:27,720 --> 00:00:31,760 Plants, whether they are enormous, like this one, 5 00:00:31,760 --> 00:00:35,360 or microscopic, are the basis of all life, 6 00:00:35,360 --> 00:00:37,680 including ourselves. 7 00:00:37,680 --> 00:00:41,920 We depend upon them for every mouthful of food that we eat 8 00:00:41,920 --> 00:00:45,040 and every lung full of air that we breathe. 9 00:00:48,600 --> 00:00:51,760 Plants flourish in remarkable ways, 10 00:00:51,760 --> 00:00:54,040 yet, for the most part, 11 00:00:54,040 --> 00:00:58,240 the secrets of their world have been hidden from us... 12 00:00:58,240 --> 00:01:00,040 ..until now. 13 00:01:06,800 --> 00:01:12,120 Now we have new ground-breaking technology that enables us 14 00:01:12,120 --> 00:01:15,240 to enter their extraordinary world 15 00:01:15,240 --> 00:01:17,680 and see their lives from their perspective. 16 00:01:25,560 --> 00:01:29,920 This series will reveal the extraordinary 17 00:01:29,920 --> 00:01:32,240 and dramatic ways in which plants behave... 18 00:01:38,280 --> 00:01:41,360 ..and we will explore the challenges demanded by 19 00:01:41,360 --> 00:01:43,960 the very different landscapes in which they live. 20 00:01:48,320 --> 00:01:49,880 The tropics. 21 00:01:51,320 --> 00:01:53,680 The richest and most competitive place 22 00:01:53,680 --> 00:01:55,080 in which to survive. 23 00:01:58,480 --> 00:02:00,240 The bizarre water world... 24 00:02:03,920 --> 00:02:07,520 ..where giants fight ferocious battles, 25 00:02:07,520 --> 00:02:10,440 and plants eat animals alive. 26 00:02:12,760 --> 00:02:14,520 Deserts... 27 00:02:14,520 --> 00:02:16,240 Agh! 28 00:02:17,200 --> 00:02:19,560 A world of extremes. 29 00:02:24,200 --> 00:02:26,200 Seasonal lands... 30 00:02:28,760 --> 00:02:33,160 ..where survival depends on precision timing. 31 00:02:34,320 --> 00:02:36,960 And everywhere, we will explore the critical 32 00:02:36,960 --> 00:02:41,840 and intimate relationships between plants and animals, 33 00:02:41,840 --> 00:02:43,400 including ourselves. 34 00:02:47,240 --> 00:02:51,680 Join me in a world that takes you by surprise... 35 00:02:59,960 --> 00:03:02,680 ..and see our planet as never before... 36 00:03:08,440 --> 00:03:11,040 ..from the plants' perspective. 37 00:03:12,480 --> 00:03:15,280 This is The Green Planet. 38 00:03:59,520 --> 00:04:03,240 I'm in Costa Rica, in the heart of a rainforest, 39 00:04:03,240 --> 00:04:07,160 the richest and most dynamic environment on Earth. 40 00:04:08,160 --> 00:04:11,160 Rainforests only cover a very small proportion 41 00:04:11,160 --> 00:04:12,640 of the Earth's surface, 42 00:04:12,640 --> 00:04:15,520 yet they contain over half of all known 43 00:04:15,520 --> 00:04:18,560 species of animals and plants. 44 00:04:20,800 --> 00:04:26,360 Up here, the forest's canopy is bathed by life-giving sunlight. 45 00:04:31,360 --> 00:04:33,480 The branches of the great trees 46 00:04:33,480 --> 00:04:36,080 carry rich, flourishing sky gardens... 47 00:04:42,680 --> 00:04:46,440 ..home to countless different kinds of beautiful plants. 48 00:04:50,120 --> 00:04:54,520 Each species has evolved its own exquisite solution 49 00:04:54,520 --> 00:04:56,880 to the challenges of survival. 50 00:05:02,040 --> 00:05:05,560 This forest world may look peaceful, 51 00:05:05,560 --> 00:05:07,960 timeless and unchanging, 52 00:05:07,960 --> 00:05:12,120 but that is far from the truth. 53 00:05:12,120 --> 00:05:14,360 This is a battlefield. 54 00:05:19,560 --> 00:05:22,920 Throughout this forest, plants are competing ferociously 55 00:05:22,920 --> 00:05:26,280 with one another to claim the light. 56 00:05:28,920 --> 00:05:33,040 The battle is at its fiercest on the forest floor... 57 00:05:37,520 --> 00:05:40,280 ..where only 2% of the sunlight filters through. 58 00:05:42,800 --> 00:05:45,560 Plants here have to bide their time. 59 00:05:51,120 --> 00:05:55,600 Their opportunity comes when an old tree dies. 60 00:06:00,120 --> 00:06:03,360 When that happens, sunlight floods the forest floor 61 00:06:03,360 --> 00:06:06,320 for the first time in perhaps 100 years. 62 00:06:26,240 --> 00:06:29,040 The seedling's wait is over. 63 00:06:33,000 --> 00:06:35,600 It must now race skywards 64 00:06:35,600 --> 00:06:37,840 and claim a place in the canopy. 65 00:06:39,480 --> 00:06:41,640 But it's not alone. 66 00:06:45,480 --> 00:06:47,840 Rivals are everywhere, 67 00:06:47,840 --> 00:06:50,240 each with its own survival strategy. 68 00:07:03,800 --> 00:07:06,560 Some plants, like this monstera, 69 00:07:06,560 --> 00:07:10,040 stretch out divided leaves to collect what light they can. 70 00:07:17,320 --> 00:07:21,840 This vine is groping blindly around with its tendrils. 71 00:07:25,840 --> 00:07:29,760 It attempts to reach the light by hitching a ride. 72 00:07:32,880 --> 00:07:36,000 Its tendrils are highly sensitive to touch. 73 00:07:41,560 --> 00:07:45,280 And a suitable target is in range. 74 00:07:51,560 --> 00:07:52,920 Got it! 75 00:08:13,080 --> 00:08:14,920 The vine tightens its grip 76 00:08:14,920 --> 00:08:18,040 and begins to haul itself upwards. 77 00:08:22,040 --> 00:08:24,240 But it's now overtaken 78 00:08:24,240 --> 00:08:27,640 by the forest's fastest-growing tree. 79 00:08:30,800 --> 00:08:32,400 A young balsa. 80 00:08:36,160 --> 00:08:39,600 Its giant leaves are already 40cm across 81 00:08:39,600 --> 00:08:43,080 and are stealing the light from its rivals below. 82 00:08:45,000 --> 00:08:47,680 But the balsa's battle is not yet won. 83 00:08:49,000 --> 00:08:52,920 Other, different vines are lying in wait. 84 00:09:03,720 --> 00:09:08,720 Each is armed with dozens of claw-like hooks. 85 00:09:11,760 --> 00:09:15,320 If just one hook gets a grip, 86 00:09:15,320 --> 00:09:18,320 the vine will be able to smother its victim. 87 00:09:51,520 --> 00:09:57,400 But the balsa is defended by a shield of slippery hairs. 88 00:10:02,000 --> 00:10:05,080 The vine's hooks just can't get a hold. 89 00:10:08,520 --> 00:10:11,120 The balsa brushes them aside... 90 00:10:11,120 --> 00:10:13,840 ..and continues to rush skywards... 91 00:10:21,600 --> 00:10:24,280 ..leaving the losers in its shadow 92 00:10:24,280 --> 00:10:26,080 to fight among themselves. 93 00:10:30,480 --> 00:10:33,560 This balsa has won its battle for the light. 94 00:10:39,600 --> 00:10:42,360 And it's done so in a little over a year. 95 00:10:45,480 --> 00:10:48,960 Most trees would have grown an inch or so in that time, 96 00:10:48,960 --> 00:10:53,520 but this one is already 30 feet - 10 metres - tall. 97 00:10:59,280 --> 00:11:01,240 Balsas owe their success 98 00:11:01,240 --> 00:11:03,880 to the special character of their wood. 99 00:11:05,680 --> 00:11:09,000 If this section of tree trunk came from a hardwood tree, 100 00:11:09,000 --> 00:11:10,720 it would be really quite heavy. 101 00:11:10,720 --> 00:11:12,080 But as it is, 102 00:11:12,080 --> 00:11:13,720 it's from balsa, 103 00:11:13,720 --> 00:11:17,000 and it's really very light, 104 00:11:17,000 --> 00:11:20,040 and that's because of its internal structure. 105 00:11:23,280 --> 00:11:26,880 Under the microscope, balsawood looks like a honeycomb. 106 00:11:28,960 --> 00:11:31,480 It contains more air than wood, 107 00:11:31,480 --> 00:11:34,800 so, not only can it grow very fast, 108 00:11:34,800 --> 00:11:38,840 but it gets the maximum height for minimum weight. 109 00:11:40,640 --> 00:11:43,760 But fast growth needs something else. 110 00:11:43,760 --> 00:11:45,360 Fuel... 111 00:11:45,360 --> 00:11:47,360 ..and lots of it. 112 00:11:57,400 --> 00:12:00,480 That fuel is created in a plant's leaves, 113 00:12:00,480 --> 00:12:02,400 as they soak up the sun. 114 00:12:13,640 --> 00:12:16,600 It's a process called photosynthesis... 115 00:12:19,120 --> 00:12:24,760 ..a chemical reaction that is the basis of all life on Earth. 116 00:12:30,480 --> 00:12:34,520 Leaves are covered by thousands of microscopic pores 117 00:12:34,520 --> 00:12:36,360 called stomata. 118 00:12:37,880 --> 00:12:41,760 When open, they extract carbon dioxide from the air, 119 00:12:41,760 --> 00:12:43,880 and, using energy from the sun, 120 00:12:43,880 --> 00:12:47,800 combine it with nutrients to build the plant's tissues. 121 00:12:51,480 --> 00:12:55,920 And critically for us, the process releases the oxygen 122 00:12:55,920 --> 00:13:00,360 that we and all animals need in order to breathe. 123 00:13:11,320 --> 00:13:14,720 But for plants, there is a downside. 124 00:13:14,720 --> 00:13:18,240 These precious, energy-packed leaves attract predators... 125 00:13:20,880 --> 00:13:22,360 ..in every shape... 126 00:13:23,880 --> 00:13:25,080 ..size... 127 00:13:27,120 --> 00:13:29,360 ..and agility. 128 00:13:41,840 --> 00:13:45,800 A sloth can only move slowly, 129 00:13:45,800 --> 00:13:49,440 but you don't need speed to gather leaves, 130 00:13:49,440 --> 00:13:51,600 and it eats nothing else. 131 00:14:10,280 --> 00:14:13,840 The plants here are under constant attack 132 00:14:13,840 --> 00:14:17,040 from all kinds of leaf-eaters, 133 00:14:17,040 --> 00:14:20,920 but the most voracious by far is hardly ever seen. 134 00:14:22,800 --> 00:14:27,400 It consumes 50,000 leaves every day. 135 00:14:27,400 --> 00:14:30,640 It's created this great clearing in the forest... 136 00:14:32,000 --> 00:14:34,600 ..and it lives just beneath my feet. 137 00:14:43,160 --> 00:14:45,840 It's called leucoagaricus. 138 00:14:48,760 --> 00:14:50,840 It's neither animal nor plant. 139 00:14:53,360 --> 00:14:54,840 It's a fungus. 140 00:14:56,800 --> 00:15:00,040 It lives five metres underground, 141 00:15:00,040 --> 00:15:02,400 far from the leaves that it devours. 142 00:15:06,400 --> 00:15:07,920 To get them, 143 00:15:07,920 --> 00:15:11,320 it employs the best leaf-gatherers in the tropics. 144 00:15:17,640 --> 00:15:19,280 Leafcutter ants. 145 00:15:25,280 --> 00:15:28,720 Millions of them provide the fungus with its food, 146 00:15:28,720 --> 00:15:32,760 and in return, the fungus cultivates tiny mushrooms 147 00:15:32,760 --> 00:15:34,440 as food for the ants. 148 00:15:40,280 --> 00:15:43,200 The fungus releases chemical signals 149 00:15:43,200 --> 00:15:46,880 that tell the worker ants what type of leaf it wants to eat. 150 00:15:49,640 --> 00:15:54,000 Scouts are sent out with the latest orders. 151 00:16:01,000 --> 00:16:03,880 Worker ants will travel hundreds of metres 152 00:16:03,880 --> 00:16:05,360 to find the right kind. 153 00:16:08,440 --> 00:16:12,000 Today's crop is being taken from a young bixa tree. 154 00:16:15,680 --> 00:16:19,040 Just a few years old and still battling to reach the canopy, 155 00:16:19,040 --> 00:16:21,560 it can ill afford to lose any of its leaves. 156 00:16:40,160 --> 00:16:44,120 Between them, the ants can demolish a large leaf 157 00:16:44,120 --> 00:16:45,680 in a matter of minutes. 158 00:16:51,360 --> 00:16:55,440 The sound of cutting attracts more ants. 159 00:17:07,360 --> 00:17:10,880 Now the pieces are carried back to the underground fungus. 160 00:17:18,440 --> 00:17:21,800 The ants can run at speeds of two metres a minute. 161 00:17:26,520 --> 00:17:30,040 And each can carry a load ten times its own weight. 162 00:17:44,760 --> 00:17:47,600 It's a river of leaves across the jungle floor... 163 00:17:50,480 --> 00:17:54,400 ..part of a vast network that extends for miles 164 00:17:54,400 --> 00:17:55,760 through the forest. 165 00:18:04,800 --> 00:18:06,440 To avoid congestion, 166 00:18:06,440 --> 00:18:09,400 worker ants dig trenches around obstacles. 167 00:18:37,600 --> 00:18:40,360 Thousands of pieces are delivered every hour 168 00:18:40,360 --> 00:18:42,000 to the waiting fungus. 169 00:18:54,440 --> 00:18:57,200 Fed by such a continuous supply, 170 00:18:57,200 --> 00:18:59,120 the fungus grows rapidly, 171 00:18:59,120 --> 00:19:01,880 filling the chambers in which it lives... 172 00:19:04,800 --> 00:19:08,200 ..so, the ants excavate more space. 173 00:19:12,080 --> 00:19:14,800 It seems that the fungus has the upper hand... 174 00:19:17,040 --> 00:19:20,560 ..and the bixa tree will not survive. 175 00:19:25,680 --> 00:19:27,480 But it fights back... 176 00:19:30,080 --> 00:19:32,800 ..using chemical warfare. 177 00:19:35,280 --> 00:19:38,920 The bixa tree floods its leaves with toxins 178 00:19:38,920 --> 00:19:42,080 that could kill the distant fungus. 179 00:19:43,680 --> 00:19:47,480 As the ants carry the fragments back, they are themselves 180 00:19:47,480 --> 00:19:50,080 poisoning the fungus on the tree's behalf. 181 00:19:56,000 --> 00:19:58,000 It's a long-distance attack. 182 00:20:05,640 --> 00:20:09,080 As the poison takes effect, the ants sense 183 00:20:09,080 --> 00:20:11,040 that their fungus is weakening... 184 00:20:21,960 --> 00:20:24,400 ..and they respond to its signals 185 00:20:24,400 --> 00:20:27,400 by changing to another source of leaves. 186 00:20:32,080 --> 00:20:34,560 So, the plant's chemical response 187 00:20:34,560 --> 00:20:40,640 forces the ants to constantly switch from tree to tree. 188 00:20:44,960 --> 00:20:47,680 Strike and counterstrike. 189 00:20:50,720 --> 00:20:54,840 And that ensures that enough leaves remain uneaten 190 00:20:54,840 --> 00:20:57,320 for each tree to recover. 191 00:21:13,240 --> 00:21:15,600 Once a plant becomes adult, 192 00:21:15,600 --> 00:21:17,640 it can switch its energies 193 00:21:17,640 --> 00:21:20,400 from growth to reproduction. 194 00:21:26,120 --> 00:21:30,400 The tropical forests of the Americas stretch from Mexico 195 00:21:30,400 --> 00:21:32,400 to the southern reaches of the Amazon. 196 00:21:33,680 --> 00:21:39,960 They contain more than 100,000 different species of plants, 197 00:21:39,960 --> 00:21:43,600 each with its own particular survival strategy. 198 00:21:45,880 --> 00:21:50,520 One species that has adopted a grow-fast lifestyle 199 00:21:50,520 --> 00:21:53,840 flourishes throughout this vast region. 200 00:21:56,480 --> 00:21:57,920 The balsa. 201 00:21:59,720 --> 00:22:02,880 But it has to pay a high price for doing so. 202 00:22:02,880 --> 00:22:05,720 The lightweight wood that enables it 203 00:22:05,720 --> 00:22:08,400 to grow at such speed is not strong 204 00:22:08,400 --> 00:22:10,240 and is easily broken. 205 00:22:11,960 --> 00:22:15,120 Few balsas live longer than 20 years. 206 00:22:17,320 --> 00:22:20,680 This one is approaching the end of its brief life, 207 00:22:20,680 --> 00:22:24,720 so, the time has come for it to reproduce. 208 00:22:30,680 --> 00:22:34,520 It has used a huge amount of energy to produce 209 00:22:34,520 --> 00:22:37,800 some of the most extravagant flowers in the forest, 210 00:22:37,800 --> 00:22:39,720 in immense numbers. 211 00:22:48,640 --> 00:22:52,120 Each is the size of a human hand. 212 00:22:57,600 --> 00:22:59,400 As night falls, 213 00:22:59,400 --> 00:23:01,640 the tree prepares an enticing treat. 214 00:23:10,120 --> 00:23:13,000 This is a kinkajou, 215 00:23:13,000 --> 00:23:15,480 a kind of fruit-eating racoon. 216 00:23:20,760 --> 00:23:24,400 Each flower is filled with huge quantities 217 00:23:24,400 --> 00:23:27,120 of exceptionally rich nectar, 218 00:23:27,120 --> 00:23:28,960 supercharged with sugar. 219 00:23:37,640 --> 00:23:39,840 Irresistible! 220 00:23:48,040 --> 00:23:50,800 The kinkajous drink so greedily 221 00:23:50,800 --> 00:23:54,000 that they get pollen all over their faces. 222 00:23:56,640 --> 00:23:59,560 So, as they move from tree to tree, 223 00:23:59,560 --> 00:24:01,640 they carry pollen with them. 224 00:24:09,080 --> 00:24:12,240 But the balsa leaves little to chance. 225 00:24:13,240 --> 00:24:15,960 The nectar might appear to have run out, 226 00:24:15,960 --> 00:24:18,280 but this is just the first round. 227 00:24:19,400 --> 00:24:23,160 Now the balsa refills its flowers, 228 00:24:23,160 --> 00:24:27,160 enticing the kinkajous back to repeat the process... 229 00:24:27,160 --> 00:24:28,920 ..seven times a night. 230 00:24:31,080 --> 00:24:33,280 Pollination is complete. 231 00:24:37,720 --> 00:24:41,200 And the kinkajous - they also get well served, 232 00:24:41,200 --> 00:24:44,720 with over 100 pints of nectar in just a few weeks. 233 00:24:49,600 --> 00:24:53,800 Both plant and animal do well out of this arrangement. 234 00:24:56,480 --> 00:25:00,880 But in the tropical world, that isn't always so. 235 00:25:06,480 --> 00:25:07,880 Borneo. 236 00:25:12,800 --> 00:25:16,160 Here, on the slopes of Mount Kinabalu, 237 00:25:16,160 --> 00:25:19,200 live plants that eat animals 238 00:25:19,200 --> 00:25:22,200 using pitcher-shaped leaves full of water. 239 00:25:31,600 --> 00:25:35,080 Insects are attracted by the expectation of nectar, 240 00:25:35,080 --> 00:25:37,680 but tumble into the pitcher, 241 00:25:37,680 --> 00:25:40,840 where they are drowned and absorbed. 242 00:25:46,000 --> 00:25:48,480 On the lower slopes of the mountain, 243 00:25:48,480 --> 00:25:51,240 a plant grows that has no leaves at all. 244 00:25:52,760 --> 00:25:54,400 Or even a stem. 245 00:25:56,760 --> 00:25:59,760 All that can be seen is this - 246 00:25:59,760 --> 00:26:01,080 a bud. 247 00:26:08,360 --> 00:26:10,160 It is a parasite. 248 00:26:18,280 --> 00:26:23,400 The rest of its body lies within the tissues of a liana, 249 00:26:23,400 --> 00:26:25,120 on which it feeds. 250 00:26:29,520 --> 00:26:31,600 After about five years, 251 00:26:31,600 --> 00:26:36,280 the bud finally opens into a monstrous flower. 252 00:26:38,680 --> 00:26:43,120 It now has only a day or so in which to be pollinated 253 00:26:43,120 --> 00:26:45,280 before it starts to wither. 254 00:26:47,560 --> 00:26:50,400 Its petals are the colour of blood. 255 00:26:52,640 --> 00:26:55,480 Their surface is tough and warty. 256 00:27:01,160 --> 00:27:03,000 It appears to have fur. 257 00:27:06,520 --> 00:27:08,760 Even whiskers and teeth. 258 00:27:14,040 --> 00:27:17,240 At first sight, it might be mistaken for a dead animal. 259 00:27:19,920 --> 00:27:23,520 This is rafflesia, the corpse flower. 260 00:27:28,640 --> 00:27:31,800 A metre across, it's the world's biggest flower. 261 00:27:35,880 --> 00:27:37,640 And this one is a male. 262 00:27:41,160 --> 00:27:45,320 From its centre comes the pungent odour of death. 263 00:27:53,200 --> 00:27:56,880 It's a scent that might not appeal to every animal. 264 00:28:03,000 --> 00:28:05,720 But it's very attractive to carrion flies. 265 00:28:08,600 --> 00:28:11,120 They lay their eggs on rotting flesh. 266 00:28:24,560 --> 00:28:28,120 The scent lures the fly deep into the flower 267 00:28:28,120 --> 00:28:30,000 in search of meat. 268 00:28:36,080 --> 00:28:38,960 The fly finds nothing. 269 00:28:38,960 --> 00:28:43,160 The rafflesia, however, has the fly exactly where it wants it. 270 00:28:47,640 --> 00:28:50,280 It's stuck pollen to the fly's back. 271 00:29:03,200 --> 00:29:06,560 If this male rafflesia's strategy is to work, 272 00:29:06,560 --> 00:29:09,560 the fly carrying its pollen must now visit 273 00:29:09,560 --> 00:29:11,160 a female corpse flower... 274 00:29:16,120 --> 00:29:17,920 ..such as this one. 275 00:29:29,000 --> 00:29:30,400 Success! 276 00:29:47,560 --> 00:29:51,280 Once pollinated, plants are able to produce seeds, 277 00:29:51,280 --> 00:29:53,320 the next generation, 278 00:29:53,320 --> 00:29:57,160 but once again, there are animals all over the forest 279 00:29:57,160 --> 00:29:59,400 that are eager to make a meal of them. 280 00:30:15,240 --> 00:30:17,720 The Malay Archipelago, 281 00:30:17,720 --> 00:30:21,080 a vast tropical world of 1,000 islands. 282 00:30:29,880 --> 00:30:33,080 It's home to giants - 283 00:30:33,080 --> 00:30:35,640 the tallest trees in the tropics, 284 00:30:35,640 --> 00:30:38,360 many of which live for centuries. 285 00:30:43,640 --> 00:30:46,760 They produce seeds in enormous numbers, 286 00:30:46,760 --> 00:30:49,320 but only do so when the time is right. 287 00:30:53,120 --> 00:30:56,520 This individual hasn't produced a single seed 288 00:30:56,520 --> 00:30:58,360 for nearly a decade, 289 00:30:58,360 --> 00:31:01,640 but in the last weeks, it has become festooned 290 00:31:01,640 --> 00:31:03,640 with more than 10,000 of them. 291 00:31:08,120 --> 00:31:11,640 Each seed has the potential to produce a giant, 292 00:31:11,640 --> 00:31:13,360 like its parent. 293 00:31:20,600 --> 00:31:22,480 But success will depend... 294 00:31:24,200 --> 00:31:25,680 ..on timing. 295 00:31:39,520 --> 00:31:41,360 Seed-hunters are gathering. 296 00:31:45,440 --> 00:31:47,000 Bearded pigs. 297 00:31:55,280 --> 00:31:59,040 But these seeds have been produced by a dipterocarp... 298 00:32:01,960 --> 00:32:04,400 ..trees that create the tropical world's 299 00:32:04,400 --> 00:32:06,080 largest seed nursery. 300 00:32:12,600 --> 00:32:14,720 After years of waiting, 301 00:32:14,720 --> 00:32:18,080 thousands upon thousands of individual dipterocarps 302 00:32:18,080 --> 00:32:21,240 have synchronised to produce the next generation, 303 00:32:21,240 --> 00:32:23,320 all at exactly the same time. 304 00:32:42,320 --> 00:32:46,080 And now these seeds will face the dangers below together. 305 00:33:32,640 --> 00:33:36,760 By releasing billions of seeds all at the same time, 306 00:33:36,760 --> 00:33:40,080 they swamp the pigs and any other animals 307 00:33:40,080 --> 00:33:42,360 with more than they could possibly eat. 308 00:34:03,960 --> 00:34:09,080 And that buys time for some of the seeds to take root 309 00:34:09,080 --> 00:34:10,920 and sprout. 310 00:34:36,560 --> 00:34:39,920 The tree's strategy has worked. 311 00:34:39,920 --> 00:34:44,040 But a seedling will have to overcome many more dangers 312 00:34:44,040 --> 00:34:47,560 over the years if it, too, is to become a giant. 313 00:34:54,200 --> 00:34:57,200 And there are many ways in a tropical forest 314 00:34:57,200 --> 00:34:59,720 by which a tree's life can be ended 315 00:34:59,720 --> 00:35:02,080 before it reaches its prime. 316 00:35:06,440 --> 00:35:08,760 The northernmost tip of Australia. 317 00:35:12,480 --> 00:35:15,960 This is the world's most ancient rainforest. 318 00:35:33,640 --> 00:35:36,400 Battles between animals and plants 319 00:35:36,400 --> 00:35:40,240 have raged here for 180 million years. 320 00:35:47,400 --> 00:35:51,240 So, the plants have had time to develop effective defences. 321 00:35:53,960 --> 00:35:56,880 This is a poison arrow tree, 322 00:35:56,880 --> 00:36:00,360 one of the tropical world's most heavily defended plants. 323 00:36:04,280 --> 00:36:06,840 Its trunk is tall and slippery 324 00:36:06,840 --> 00:36:08,760 and exudes a poisonous sap. 325 00:36:13,960 --> 00:36:16,600 It appears to be almost invulnerable. 326 00:36:22,920 --> 00:36:24,600 But even so, 327 00:36:24,600 --> 00:36:27,760 just as this individual reaches maturity, 328 00:36:27,760 --> 00:36:29,960 its life has become endangered. 329 00:36:35,640 --> 00:36:37,400 Each monsoon season, 330 00:36:37,400 --> 00:36:40,080 it is invaded from above. 331 00:36:46,480 --> 00:36:49,560 It attracts hundreds of shining starlings. 332 00:36:53,240 --> 00:36:57,280 Its immense smooth trunk makes its high branches above 333 00:36:57,280 --> 00:36:59,800 a safe place to nest, 334 00:36:59,800 --> 00:37:01,440 but over the years, 335 00:37:01,440 --> 00:37:04,000 this has created a major problem for the tree. 336 00:37:09,160 --> 00:37:12,120 After feeding, the starlings return to the nest 337 00:37:12,120 --> 00:37:14,280 to digest their food, 338 00:37:14,280 --> 00:37:16,880 with inevitable consequences. 339 00:37:22,160 --> 00:37:23,600 Every year, 340 00:37:23,600 --> 00:37:27,720 they produce almost a quarter of a ton of droppings. 341 00:37:30,880 --> 00:37:33,160 The toxic chemicals they contain 342 00:37:33,160 --> 00:37:36,440 create a dead zone that completely surrounds the tree. 343 00:37:44,160 --> 00:37:47,200 The toxins are absorbed by its roots 344 00:37:47,200 --> 00:37:50,600 and travel up through the trunk and into every leaf. 345 00:38:06,080 --> 00:38:08,880 Branch by branch, 346 00:38:08,880 --> 00:38:11,480 the tree is slowly dying. 347 00:38:14,600 --> 00:38:17,920 It has become a victim of its own success. 348 00:38:19,840 --> 00:38:21,520 It has been poisoned. 349 00:38:29,120 --> 00:38:31,600 Now a new battle begins... 350 00:38:34,080 --> 00:38:36,800 ..one to claim the tree's dead body 351 00:38:36,800 --> 00:38:40,320 and the vast amount of nutrients that it contains. 352 00:38:42,040 --> 00:38:45,120 It's a battle that is fought throughout the natural world... 353 00:38:46,400 --> 00:38:48,480 ..involving a group of organisms 354 00:38:48,480 --> 00:38:49,960 that we rarely notice. 355 00:38:52,560 --> 00:38:56,160 Here, on the floor of a tropical rainforest, 356 00:38:56,160 --> 00:38:58,960 it's dark, it's humid 357 00:38:58,960 --> 00:39:00,640 and it's hot - 358 00:39:00,640 --> 00:39:04,040 ideal conditions for fungi. 359 00:39:04,040 --> 00:39:07,920 We normally think of fungi as things like this. 360 00:39:07,920 --> 00:39:10,320 Mushrooms of one kind or another. 361 00:39:10,320 --> 00:39:12,760 But these are just the fruiting bodies. 362 00:39:15,440 --> 00:39:17,920 They exist for most of the time 363 00:39:17,920 --> 00:39:20,520 hidden in the leaf litter and the earth 364 00:39:20,520 --> 00:39:22,840 as a network of fine white threads. 365 00:39:25,160 --> 00:39:29,720 The threads of competing fungi envelop their victim's body, 366 00:39:29,720 --> 00:39:33,440 releasing enzymes which digest the tree's tissues 367 00:39:33,440 --> 00:39:35,960 and unlock the nutrients within. 368 00:39:38,600 --> 00:39:42,120 There a million or so different species of fungi 369 00:39:42,120 --> 00:39:44,400 in the tropics. 370 00:39:44,400 --> 00:39:47,640 Some feed on dead plants. 371 00:39:47,640 --> 00:39:49,400 Others eat them alive. 372 00:39:51,000 --> 00:39:55,480 And some reveal their existence in an eerily beautiful way. 373 00:40:05,640 --> 00:40:07,840 In Africa, in the Congo, 374 00:40:07,840 --> 00:40:10,760 this is known as chimpanzee fire. 375 00:40:16,520 --> 00:40:19,480 The mysterious bioluminescent glow 376 00:40:19,480 --> 00:40:23,120 becomes brighter as the fungus digests the tree. 377 00:40:28,560 --> 00:40:30,800 When fungi have fed sufficiently, 378 00:40:30,800 --> 00:40:33,240 they develop their reproductive organs. 379 00:41:02,600 --> 00:41:06,720 Each can produce literally billions of spores... 380 00:41:09,000 --> 00:41:10,560 ..the tiny particles 381 00:41:10,560 --> 00:41:12,800 that carry the species' genetic blueprint. 382 00:41:15,800 --> 00:41:17,720 Each spore like this 383 00:41:17,720 --> 00:41:20,240 has the potential to kill a tree. 384 00:41:43,240 --> 00:41:45,000 The spores are so light 385 00:41:45,000 --> 00:41:47,680 they can be carried by the slightest air currents. 386 00:41:57,280 --> 00:41:59,120 At least a billion 387 00:41:59,120 --> 00:42:02,080 float above every square metre of rainforest. 388 00:42:12,040 --> 00:42:15,200 Recently, it has been discovered that these spores 389 00:42:15,200 --> 00:42:18,600 do far more than just bring death and decay. 390 00:42:21,000 --> 00:42:24,440 They are, in fact, at the very centre 391 00:42:24,440 --> 00:42:27,040 of the rainforest's life support system. 392 00:42:35,240 --> 00:42:36,960 High in the humid air, 393 00:42:36,960 --> 00:42:39,840 the spores combine with molecules of water. 394 00:42:53,720 --> 00:42:56,640 Gradually, they collect into droplets, 395 00:42:56,640 --> 00:42:59,840 which, when they are heavy enough, fall... 396 00:43:02,280 --> 00:43:03,760 ..as rain. 397 00:43:43,000 --> 00:43:46,880 Over two-and-a-half metres of rain falls every year 398 00:43:46,880 --> 00:43:48,680 in a rainforest. 399 00:43:56,000 --> 00:43:59,440 And in the centre of almost every raindrop, 400 00:43:59,440 --> 00:44:01,200 there is a fungal spore. 401 00:44:16,680 --> 00:44:19,800 The world's rainforests are the richest 402 00:44:19,800 --> 00:44:22,960 and most dynamic environments on Earth, 403 00:44:22,960 --> 00:44:26,840 built on complex connections and relationships. 404 00:44:30,680 --> 00:44:32,640 But these connections, 405 00:44:32,640 --> 00:44:35,280 competitive or collaborative, 406 00:44:35,280 --> 00:44:37,840 are now becoming increasingly fragile. 407 00:44:53,800 --> 00:44:58,080 When Charles Darwin was exploring the tropical world 408 00:44:58,080 --> 00:45:00,320 nearly 200 years ago, 409 00:45:00,320 --> 00:45:03,480 he wrote this in his diary. 410 00:45:03,480 --> 00:45:08,200 "Among the scenes which are deeply impressed on my mind, 411 00:45:08,200 --> 00:45:11,520 "none exceed in sublimity 412 00:45:11,520 --> 00:45:16,840 "the primeval forests undefaced by the hand of man." 413 00:45:18,520 --> 00:45:21,440 He would struggle to find such a place today. 414 00:45:36,520 --> 00:45:41,080 Today, 70% of all the world's rainforest plants 415 00:45:41,080 --> 00:45:44,320 grow within a mile of a road or a clearing 416 00:45:44,320 --> 00:45:47,520 that we have cut into the forest... 417 00:45:50,920 --> 00:45:54,120 ..and this is creating new battlefields 418 00:45:54,120 --> 00:45:55,840 in the tropical world. 419 00:45:58,080 --> 00:46:01,640 Alien armies of identical cultivated plants 420 00:46:01,640 --> 00:46:05,480 now stand where thousands of different species once grew. 421 00:46:14,400 --> 00:46:17,640 We have planted vast regiments of crops 422 00:46:17,640 --> 00:46:20,160 in order to provide ourselves 423 00:46:20,160 --> 00:46:22,360 with food and other commodities... 424 00:46:24,400 --> 00:46:27,000 ..and the ancient forest has been reduced 425 00:46:27,000 --> 00:46:29,720 to ever fewer isolated fragments. 426 00:46:34,360 --> 00:46:36,240 All, however, is not lost. 427 00:46:37,880 --> 00:46:40,880 The fragments can still be sanctuaries, 428 00:46:40,880 --> 00:46:44,080 keeping alive the intimate relationships within them. 429 00:46:46,520 --> 00:46:49,600 Their size is nonetheless critical. 430 00:46:59,040 --> 00:47:01,960 This is the seven-hour flower. 431 00:47:13,360 --> 00:47:17,040 This plant produces its flowers at night. 432 00:47:17,040 --> 00:47:19,800 They open about six o'clock, 433 00:47:19,800 --> 00:47:24,440 and each blossom only lasts that night. 434 00:47:24,440 --> 00:47:27,080 It opens for about seven hours 435 00:47:27,080 --> 00:47:29,520 and then it dies. 436 00:47:29,520 --> 00:47:32,120 But during that time, it provides food 437 00:47:32,120 --> 00:47:33,840 for one particular animal. 438 00:47:35,200 --> 00:47:36,760 A bat. 439 00:47:36,760 --> 00:47:38,160 And here it is! 440 00:47:56,800 --> 00:47:59,840 During the seven-hour flower's flowering season... 441 00:48:01,520 --> 00:48:04,880 ..Underwood's bat feeds almost exclusively on its nectar. 442 00:48:07,040 --> 00:48:09,680 It is the plant's primary pollinator. 443 00:48:14,160 --> 00:48:16,280 It might seem that this is 444 00:48:16,280 --> 00:48:19,200 a fairly evenly balanced relationship, 445 00:48:19,200 --> 00:48:20,560 but not so. 446 00:48:21,880 --> 00:48:26,120 The bat likes this nectar because it's sweet, 447 00:48:26,120 --> 00:48:29,520 but it's not very nourishing. 448 00:48:29,520 --> 00:48:32,480 So the bat must visit hundreds of flowers a night... 449 00:48:35,400 --> 00:48:37,600 ..and it pollinates them as if feeds. 450 00:48:45,400 --> 00:48:48,880 But if a patch of forest becomes too small, 451 00:48:48,880 --> 00:48:50,680 with too few flowers, 452 00:48:50,680 --> 00:48:52,800 the bats will disappear, 453 00:48:52,800 --> 00:48:56,280 and without the bats, the flowers can't reproduce 454 00:48:56,280 --> 00:48:57,920 and will soon die out. 455 00:49:00,400 --> 00:49:02,120 The partnership is broken. 456 00:49:12,560 --> 00:49:17,040 Life in the forest depends on countless close relationships, 457 00:49:17,040 --> 00:49:19,800 but they are increasingly under threat 458 00:49:19,800 --> 00:49:23,440 as forests become more fragmented. 459 00:49:23,440 --> 00:49:24,920 The solution, of course, 460 00:49:24,920 --> 00:49:27,640 is to join these remaining fragments together again. 461 00:49:28,880 --> 00:49:32,000 30 years ago, I came to this exact spot. 462 00:49:33,840 --> 00:49:35,720 This land belonged to 463 00:49:35,720 --> 00:49:37,840 a scientific research establishment 464 00:49:37,840 --> 00:49:41,520 and it was covered with grass being grazed by cattle. 465 00:49:41,520 --> 00:49:44,520 The scientists got rid of the cattle 466 00:49:44,520 --> 00:49:47,800 and allowed nature to take its course. 467 00:49:47,800 --> 00:49:49,560 Just look at it now! 468 00:49:58,920 --> 00:50:01,880 This new forest has become a bridge 469 00:50:01,880 --> 00:50:04,840 that connects several fragments, 470 00:50:04,840 --> 00:50:09,280 allowing plants and animals to both renew old connections 471 00:50:09,280 --> 00:50:11,120 and create fresh ones. 472 00:50:22,840 --> 00:50:26,320 Of course, we urgently need to protect 473 00:50:26,320 --> 00:50:28,480 what healthy forests still remain. 474 00:50:33,040 --> 00:50:34,640 But looking forward, 475 00:50:34,640 --> 00:50:38,000 we must take what may well be our last chance 476 00:50:38,000 --> 00:50:40,520 to re-establish the lost rainforest... 477 00:50:44,320 --> 00:50:48,120 ..and help the tropical world to heal itself. 478 00:50:50,960 --> 00:50:55,480 It will take the co-operation of nations around the world, 479 00:50:55,480 --> 00:50:58,760 but it is the only way in which we'll be able to 480 00:50:58,760 --> 00:51:02,240 preserve the treasures of the tropical rainforest 481 00:51:02,240 --> 00:51:04,560 for future generations. 482 00:51:04,560 --> 00:51:06,600 And with it, 483 00:51:06,600 --> 00:51:10,200 ultimately protect all life on this, 484 00:51:10,200 --> 00:51:13,000 our green planet. 485 00:51:29,120 --> 00:51:32,840 The aim of The Green Planet team was to take the viewer 486 00:51:32,840 --> 00:51:35,640 into the world of plants, so that it could be seen 487 00:51:35,640 --> 00:51:37,400 from the plants' perspective 488 00:51:37,400 --> 00:51:39,600 in a way that had not been possible till now. 489 00:51:41,840 --> 00:51:45,040 That meant developing an entirely new camera system. 490 00:51:51,560 --> 00:51:54,440 And this is the game-changer - 491 00:51:54,440 --> 00:51:57,480 a specially designed robot camera 492 00:51:57,480 --> 00:52:00,120 that we affectionately call "the Triffid". 493 00:52:05,080 --> 00:52:08,240 The Triffid started life in the garage of an American 494 00:52:08,240 --> 00:52:11,040 ex-military engineer, Chris Field. 495 00:52:11,040 --> 00:52:12,520 I'd seen quite a few of these 496 00:52:12,520 --> 00:52:14,720 Planet Earth style documentaries, 497 00:52:14,720 --> 00:52:16,520 and they always absolutely blew my mind, 498 00:52:16,520 --> 00:52:19,840 especially the botanic time-lapse really spoke to me. 499 00:52:19,840 --> 00:52:22,760 In his spare time, Chris spent a decade 500 00:52:22,760 --> 00:52:25,240 building elaborate motion-controlled 501 00:52:25,240 --> 00:52:27,400 time-lapse camera rigs 502 00:52:27,400 --> 00:52:30,960 and teaching himself how to film plants. 503 00:52:30,960 --> 00:52:34,840 Plants often behave like animals in so many ways, 504 00:52:34,840 --> 00:52:37,480 and being able to see it through time-lapse is one thing 505 00:52:37,480 --> 00:52:40,720 but using the motion-control brings you into that timescale. 506 00:52:45,480 --> 00:52:47,560 We could really see the potential 507 00:52:47,560 --> 00:52:49,560 in how we could use this sort of movement 508 00:52:49,560 --> 00:52:51,560 to bring plants alive 509 00:52:51,560 --> 00:52:54,040 and film them in the same way that we film animals. 510 00:52:56,320 --> 00:52:58,240 Soon, Chris joins the team 511 00:52:58,240 --> 00:53:00,840 in a quiet corner of the Devon countryside 512 00:53:00,840 --> 00:53:03,800 and the robot army begins to take shape. 513 00:53:05,560 --> 00:53:08,080 After 40 years of filming time-lapse, 514 00:53:08,080 --> 00:53:11,440 these rigs have opened up a whole new world for us. 515 00:53:12,720 --> 00:53:15,840 So, it'll be like hovering around something 516 00:53:15,840 --> 00:53:18,520 with a drone or helicopter, but in a time-lapse speed. 517 00:53:20,600 --> 00:53:24,040 The holy grail for us is being able to take this technology 518 00:53:24,040 --> 00:53:27,400 out into the wild, try and get the same sorts of dynamic moves 519 00:53:27,400 --> 00:53:30,120 in some of the most extreme environments in the world. 520 00:53:32,800 --> 00:53:34,280 So, what we needed to do 521 00:53:34,280 --> 00:53:37,240 was to develop this technology even further. 522 00:53:37,240 --> 00:53:39,760 Six months later, the Triffid is born... 523 00:53:42,520 --> 00:53:47,400 ..and with slight trepidation, they hand me the controls. 524 00:53:47,400 --> 00:53:50,360 That makes it go away. 525 00:53:50,360 --> 00:53:53,160 And this makes it come back. 526 00:53:53,160 --> 00:53:55,760 And this sends it up. 527 00:53:59,240 --> 00:54:00,440 Ooh! 528 00:54:01,680 --> 00:54:04,440 I think I'd better hand it over to the experts. 529 00:54:06,520 --> 00:54:09,080 Now it's time to put this new member of the team 530 00:54:09,080 --> 00:54:10,800 properly through its paces. 531 00:54:13,480 --> 00:54:16,280 The aim here is for Ollie to find a target, aim for it 532 00:54:16,280 --> 00:54:18,720 and fly through it, as if he is a tiny fly 533 00:54:18,720 --> 00:54:21,120 going through a hole in a leaf. 534 00:54:21,120 --> 00:54:23,360 Easier said than done. 535 00:54:23,360 --> 00:54:25,600 Oops! I'm trying to find a target. 536 00:54:27,320 --> 00:54:31,240 Whether the kit's going to stand up to that sort of use 537 00:54:31,240 --> 00:54:34,040 and the abuse that we throw at most pieces of kit 538 00:54:34,040 --> 00:54:35,600 has yet to be seen. 539 00:54:35,600 --> 00:54:39,160 In the studio, it seems to be working pretty well. 540 00:54:39,160 --> 00:54:41,760 But this is only a dress rehearsal. 541 00:54:41,760 --> 00:54:44,400 It's time for the Triffid to face the challenges 542 00:54:44,400 --> 00:54:46,840 of the Costa Rican rainforest, 543 00:54:46,840 --> 00:54:48,760 and leafcutter ants. 544 00:54:55,400 --> 00:54:58,720 We want to film their journey all the way 545 00:54:58,720 --> 00:55:02,200 down the trunk and along this buttress root 546 00:55:02,200 --> 00:55:03,680 and down to their nest. 547 00:55:05,400 --> 00:55:07,720 The team and the Triffid need several days 548 00:55:07,720 --> 00:55:09,200 of dry weather, 549 00:55:09,200 --> 00:55:11,800 but a storm can hit at any moment... 550 00:55:13,000 --> 00:55:15,560 ..and rain is one thing the Triffid does not like. 551 00:55:17,920 --> 00:55:20,160 The conditions that we're working in now 552 00:55:20,160 --> 00:55:22,720 are a little bit more challenging than the studio. 553 00:55:24,520 --> 00:55:27,080 All the ground is really bumpy. 554 00:55:27,080 --> 00:55:29,080 We've got loads of plants in the way. 555 00:55:29,080 --> 00:55:31,360 I know we're making a series about plants, 556 00:55:31,360 --> 00:55:33,920 but sometimes they're a complete pain in the neck! 557 00:55:36,080 --> 00:55:38,520 The Triffid needs to be programmed 558 00:55:38,520 --> 00:55:42,320 to capture images from 7,000 different camera positions 559 00:55:42,320 --> 00:55:43,640 on the ants' trail. 560 00:55:46,120 --> 00:55:48,280 Just one drop of rain on the lens, 561 00:55:48,280 --> 00:55:49,480 or a wobble, 562 00:55:49,480 --> 00:55:52,680 and the whole process will have to start again. 563 00:55:52,680 --> 00:55:55,560 I think this is when we're going to find out 564 00:55:55,560 --> 00:55:58,080 if our ambition outweighs our ability. 565 00:56:01,800 --> 00:56:04,120 For the crew, the ambition is certainly high. 566 00:56:07,640 --> 00:56:10,480 Fortunately, it's all down to the Triffid now. 567 00:56:20,320 --> 00:56:23,560 We've been filming the ants with the Triffid 568 00:56:23,560 --> 00:56:27,240 for eight days now, and we're on our third set-up. 569 00:56:27,240 --> 00:56:29,240 It's pretty slow going. 570 00:56:30,320 --> 00:56:33,480 While the Triffid seems to be handling the pressure well, 571 00:56:33,480 --> 00:56:37,200 for the crew, trying to take a tree's-eye view of ants 572 00:56:37,200 --> 00:56:39,520 is turning into a bit of a nightmare. 573 00:56:41,400 --> 00:56:45,520 Wake up, film ants, go to sleep, dream of ants. 574 00:56:45,520 --> 00:56:48,640 Wake up, film ants, sleep, dream of ants. 575 00:56:48,640 --> 00:56:50,400 Wake up, film ants, 576 00:56:50,400 --> 00:56:53,120 go to sleep, dream of ants. 577 00:56:56,360 --> 00:56:58,160 After two weeks in the jungle, 578 00:56:58,160 --> 00:57:01,320 ambition and ability finally come together, 579 00:57:01,320 --> 00:57:03,600 for the Triffid, at least. 580 00:57:03,600 --> 00:57:06,240 Thousands of individual images 581 00:57:06,240 --> 00:57:08,680 creating a single extraordinary time-lapse... 582 00:57:11,560 --> 00:57:14,000 ..one that follows a river of leaves 583 00:57:14,000 --> 00:57:16,840 across the jungle floor from a unique perspective. 584 00:57:21,920 --> 00:57:24,600 For the Triffid, this was just the beginning. 585 00:57:27,200 --> 00:57:29,080 Take a bow, Triffid. 586 00:57:34,920 --> 00:57:37,840 Next time on The Green Planet... 587 00:57:37,840 --> 00:57:40,600 ..the wonder of water worlds... 588 00:57:42,960 --> 00:57:45,240 ..where plants hunt... 589 00:57:46,920 --> 00:57:48,560 ..go on the move... 590 00:57:49,920 --> 00:57:51,040 ..fight... 591 00:57:52,720 --> 00:57:54,920 ..and create the air we breathe. 592 00:57:57,920 --> 00:58:01,360 The Open University have produced a poster 593 00:58:01,360 --> 00:58:06,040 that explores the vital role that plants have for our planet. 594 00:58:06,040 --> 00:58:08,200 To order your free copy, call... 595 00:58:12,120 --> 00:58:13,480 ..or go to... 596 00:58:18,000 --> 00:58:20,800 ..and follow the links to The Open University.