1 00:00:01,840 --> 00:00:07,640 Speaker 1: Welcome to Brainstuff, a production of iHeartRadio, Hey brain Stuff 2 00:00:07,680 --> 00:00:11,680 Speaker 1: Lorn Vogel bomb here. Back in two thousand and eight, 3 00:00:11,760 --> 00:00:14,880 Speaker 1: a study proposed that the maximum height for a Douglas Fir, 4 00:00:15,280 --> 00:00:17,840 Speaker 1: one of the world's tallest types of trees, is right 5 00:00:17,880 --> 00:00:20,760 Speaker 1: about at four hundred and fifty three feet. That's one 6 00:00:20,840 --> 00:00:24,400 Speaker 1: hundred and thirty eight meters. But why is there a 7 00:00:24,480 --> 00:00:29,680 Speaker 1: specific limit. Trees are nature's skyscrapers, but as it turns out, 8 00:00:29,920 --> 00:00:33,520 Speaker 1: nature has hemmed them in. That's because trees can only 9 00:00:33,560 --> 00:00:39,040 Speaker 1: physically pull water so far up their trunks. The transporters 10 00:00:39,080 --> 00:00:42,200 Speaker 1: in question are a type of dead cells called tray kids, 11 00:00:42,520 --> 00:00:45,480 Speaker 1: with deep pits that help move water from one long, 12 00:00:45,520 --> 00:00:48,920 Speaker 1: skinny cell to the next. The diameter of these all 13 00:00:48,960 --> 00:00:52,960 Speaker 1: important pits shrinks as you ascend into a tree's upper reaches, 14 00:00:53,440 --> 00:00:57,720 Speaker 1: complicating water transport. Eventually, the flow of water reaching the 15 00:00:57,800 --> 00:01:01,200 Speaker 1: leaves and branches near the top dwindles or stops entirely, 16 00:01:01,600 --> 00:01:05,760 Speaker 1: and the struggling sections experience drought stress and they become 17 00:01:05,840 --> 00:01:10,080 Speaker 1: dehydrated and die, establishing a de facto maximum height for 18 00:01:10,200 --> 00:01:15,840 Speaker 1: that tree. Researchers think these progressively narrowing pits actually help 19 00:01:15,920 --> 00:01:20,000 Speaker 1: trees survive. A height poses the problem of air bubbles. 20 00:01:20,560 --> 00:01:23,200 Speaker 1: The taller the tree, the more likely it will develop 21 00:01:23,280 --> 00:01:26,560 Speaker 1: a xylum embolism, which is when air bubbles get in 22 00:01:26,720 --> 00:01:29,600 Speaker 1: and block the passage of water through the xylum, which 23 00:01:29,640 --> 00:01:31,800 Speaker 1: is the tissue that makes up a tree's vascular system 24 00:01:32,000 --> 00:01:34,679 Speaker 1: and allows it to transport water and minerals from the 25 00:01:34,760 --> 00:01:38,280 Speaker 1: roots to the rest of the plant. A xylum embolism 26 00:01:38,360 --> 00:01:41,160 Speaker 1: is similar to a human air embolism, in which air 27 00:01:41,319 --> 00:01:46,160 Speaker 1: enters the bloodstream and causes potentially severe complications. The trachid's 28 00:01:46,280 --> 00:01:48,520 Speaker 1: chain shape near the top of the tree to try 29 00:01:48,520 --> 00:01:51,920 Speaker 1: to prevent such air bubbles and withstand the increased pressure 30 00:01:52,280 --> 00:01:54,840 Speaker 1: of water being pulled three hundred feet up in the air, 31 00:01:55,520 --> 00:01:59,280 Speaker 1: but that protection comes at a price less water and 32 00:01:59,560 --> 00:02:02,400 Speaker 1: as the ree searchers suggest, a cap on how tall 33 00:02:02,440 --> 00:02:07,080 Speaker 1: trees can grow. Another tree height study positive the maximum 34 00:02:07,160 --> 00:02:10,120 Speaker 1: height of all trees at four hundred and twenty six 35 00:02:10,200 --> 00:02:12,480 Speaker 1: and a half feet or one hundred and thirty meters. 36 00:02:13,160 --> 00:02:16,799 Speaker 1: The study examined coast redwoods, currently the world's tallest trees, 37 00:02:17,160 --> 00:02:21,880 Speaker 1: and based projection on factors like existing weather conditions, photosynthesis levels, 38 00:02:22,000 --> 00:02:26,520 Speaker 1: water flow, and carbon dioxide levels. And not surprising. Health 39 00:02:26,560 --> 00:02:30,480 Speaker 1: factors like water flow and photosynthesis decreased in the higher 40 00:02:30,520 --> 00:02:34,400 Speaker 1: portions of the massive trees, while unhealthy factors like carbon 41 00:02:34,440 --> 00:02:39,240 Speaker 1: dioxide increased, But ultimately, as with the furs, it all 42 00:02:39,280 --> 00:02:43,720 Speaker 1: comes down to xylum. These redwoods pull water up through 43 00:02:43,720 --> 00:02:46,680 Speaker 1: their trunks as other trees do, although they can absorb 44 00:02:46,760 --> 00:02:49,080 Speaker 1: some water from the fog that often surrounds them in 45 00:02:49,120 --> 00:02:53,680 Speaker 1: their native California and Oregon environments. Before attaining their maximum height, 46 00:02:53,919 --> 00:02:56,680 Speaker 1: they shoot up about ten inches that's twenty five centimeters 47 00:02:56,720 --> 00:03:01,400 Speaker 1: every year. But of course, tree size is more than 48 00:03:01,520 --> 00:03:05,520 Speaker 1: just height. The world's heaviest and most voluminous tree is 49 00:03:05,680 --> 00:03:09,200 Speaker 1: General Sherman, a giant sequoia, one of two types of 50 00:03:09,200 --> 00:03:12,959 Speaker 1: redwood found in California, the other being the taller, skinnier 51 00:03:13,000 --> 00:03:16,960 Speaker 1: Coast redwood that we just mentioned. General Sherman is estimated 52 00:03:17,000 --> 00:03:20,320 Speaker 1: to weigh over six thousand tons and encompass fifty two 53 00:03:20,400 --> 00:03:24,080 Speaker 1: thousand cubic feet that's about one thousand, five hundred cubic meters. 54 00:03:25,080 --> 00:03:28,960 Speaker 1: Located in California's Sequoia National Park, General Sherman is two 55 00:03:29,080 --> 00:03:32,120 Speaker 1: hundred and seventy five feet tall that's eighty four meters 56 00:03:32,520 --> 00:03:36,320 Speaker 1: but it's not the world's tallest tree. That honor belongs 57 00:03:36,360 --> 00:03:39,640 Speaker 1: to a coast redwood named Hyperion, which clocks in at 58 00:03:39,680 --> 00:03:42,280 Speaker 1: three hundred and seventy nine feet tall that's one hundred 59 00:03:42,320 --> 00:03:46,240 Speaker 1: and fifteen meters. A general Sherman also isn't the world's 60 00:03:46,240 --> 00:03:49,200 Speaker 1: widest tree. It has a trunk circumference of one hundred 61 00:03:49,200 --> 00:03:51,920 Speaker 1: and two feet or thirty one meters, but it's beat 62 00:03:51,960 --> 00:03:55,560 Speaker 1: out by l Arbol de Tule in Wajaca, Mexico, which 63 00:03:55,600 --> 00:03:58,360 Speaker 1: has a maximum circumference of one hundred and seventy eight 64 00:03:58,400 --> 00:04:03,560 Speaker 1: feet or fifty four meters. So there are different ways 65 00:04:03,600 --> 00:04:06,560 Speaker 1: of considering tree size, just as there are various ways 66 00:04:06,600 --> 00:04:09,840 Speaker 1: of considering what might be the world's largest living organism. 67 00:04:10,640 --> 00:04:14,240 Speaker 1: Some scientists consider massive reefs like Australia's Great Barrier reef, 68 00:04:14,280 --> 00:04:18,440 Speaker 1: to be giant singular organisms. There are also huge fungi 69 00:04:18,480 --> 00:04:21,440 Speaker 1: out there, such as a fungus discovered in Washington State 70 00:04:21,640 --> 00:04:25,560 Speaker 1: that spans one five hundred acres that's six hundred hectares. 71 00:04:27,200 --> 00:04:30,120 Speaker 1: But we are talking about trees here, and the world's 72 00:04:30,160 --> 00:04:34,240 Speaker 1: most massive living organism may be one group of quaking 73 00:04:34,360 --> 00:04:38,000 Speaker 1: aspen trees located in the mountains of Utah and nicknamed 74 00:04:38,200 --> 00:04:43,040 Speaker 1: Pando Latin for I spread. A Pando is considered one 75 00:04:43,160 --> 00:04:46,080 Speaker 1: organism because the trees in the group share an identical 76 00:04:46,120 --> 00:04:51,600 Speaker 1: genetic code and a common interconnected root system. The Pando 77 00:04:51,720 --> 00:04:54,760 Speaker 1: trees are basically clones of one another, and new trees 78 00:04:54,800 --> 00:04:57,040 Speaker 1: are made as stems spread out as far as one 79 00:04:57,080 --> 00:04:59,359 Speaker 1: hundred feet or thirty meters from the base of the 80 00:04:59,400 --> 00:05:04,400 Speaker 1: original tree and then periodically take root, creating new genetically identical, 81 00:05:04,640 --> 00:05:09,960 Speaker 1: interconnected trees. The process, known as vegetative reproduction, is also 82 00:05:10,040 --> 00:05:15,279 Speaker 1: how strawberries and many other plants reproduce. Pando is made 83 00:05:15,320 --> 00:05:18,160 Speaker 1: up of some forty seven thousand trees spread across one 84 00:05:18,200 --> 00:05:21,640 Speaker 1: hundred acres or forty hectors, and maybe up to eighty 85 00:05:21,720 --> 00:05:25,679 Speaker 1: thousand years old, but in testament to the massive size 86 00:05:25,720 --> 00:05:29,679 Speaker 1: of California's redwoods, this batch of forty seven thousand trees 87 00:05:29,960 --> 00:05:33,600 Speaker 1: weighs only about six thousand, six hundred tons, only a 88 00:05:33,600 --> 00:05:41,240 Speaker 1: little bit more in total than General Sherman. Today's episode 89 00:05:41,279 --> 00:05:43,600 Speaker 1: is based on the article how Tall can a Tree Grow? 90 00:05:43,720 --> 00:05:47,240 Speaker 1: On HowStuffWorks dot com, written by Jacob Silverman. Brainstuff is 91 00:05:47,240 --> 00:05:49,800 Speaker 1: production by Heart Radio in partnership with Hostiff Works dot 92 00:05:49,800 --> 00:05:52,919 Speaker 1: com and is produced by Tyler Klang. Four more podcasts 93 00:05:52,920 --> 00:05:56,120 Speaker 1: from my Heart Radio. Visit the iHeartRadio app, Apple Podcasts, 94 00:05:56,240 --> 00:06:02,360 Speaker 1: or wherever you listen to your favorite shows.