On a bed of moss on a large rock on a high knoll, below the summit of a steep, forested ridge, lies – prostrate and exposed – a slab of wood.
At first glance, it resembles a fence post, hewn roughly from the trunk of an old Black Cypress-pine. When buried upright, the thick slab would support a strong wire fence. But who would hew a post in such a remote place, and sacrifice their handiwork on a tall, granite boulder?
I pondered some ghostly wood chopper as I rested from my steep climb. Far below, a cow bellowed beside a rusty hayshed. A pair of eagles soared above, hunting for rabbits in the distant paddocks. Along the ridge, gaunt tree trunks tilted erratically; tall, dead cypress-pines, killed by drought.
As I relaxed, chewing into a juicy apple, I spied a shattered ruin of a cypress-pine to my left, its trunk twisted and broken limbs strewn widely. I knelt on the grass surrounded by the decaying shards of this grand old tree. One piece of which, resembling an old fence post, lay on top of a tall, moss-covered boulder.
My whimsical fence post was hewn, not by axe, sinew and sweat, but by 10,000 amperes of electrical current. The tree was killed and the slab was born in a lightning storm.
What about me?
Like many a weary hiker, I grinned triumphantly when I reached the knoll. I had made it, all the way to the top. But that blasted tree replaced my triumph with a hollow humility.
Imagine standing, huddling, cowering, on the ridge on that stormy night; soaked by the rain that extinguished the flames that blackened the shattered cypress-pine. I can conquer the forest on a good day; but it can spit me out, like an apple pip, on a bad one.
Yet, as Adam and Eve discovered, one bite of a juicy apple is all it takes to convert humility to a wild curiosity. So I bit again. What if I had stood on that rock on that stormy night, and the bolt of lightning chose not the old cypress-pine, but me?
Would I have exploded? Would my neck have twisted, my head have spun, and my limbs have been cast aside? If lightning can split firewood from a tall tree, would I have splattered the rocks like jello?
We have all heard stories of rare, luckless souls struck “out of the blue” by a bolt of lightning. Some die, some survive – many with terrible afflictions – and a few recover to be hit again and again according to urban legend.
Dallying in the sun, it dawned on me that I had never heard of a person being blown to bits when hit by lightning. Why not I wondered? Do our jiggly wet bodies absorb the shock? Do we wobble frightfully, exude a puff of smoke and – a millisecond later – lie resting in peace? All in one piece?
The day was too bright for morbid, dark thoughts, so I pulled on my backpack and strode up the ridge, down the gully, and along the dirt track to the car. At home, I vowed, I would ask the font of all knowledge, Google, to tell me everything it knew about lightning, trees and exploding people.
What Google knew
Google of course had much to say on the topic. As always, I learned that my search terms were chosen poorly. The best question isn’t “why do trees explode when humans do not?” but rather “why do trees explode when most things do not?”
Most objects don’t blow up when hit by lightning. Skyscrapers, cars, airplanes and cows all keep their act together. Buildings and vehicles typically remain in one piece unless a gas line or fuel tank is ruptured. Lightning rods protect church spires and office blocks.
Like water, lightning flows along a route of least resistance. When it hits a vehicle or plane, the metal exterior – a mobile Faraday cage – carries the current, leaving the occupants unharmed inside. It is far safer to sit in a car than to lie on the grass in a thunderstorm.
On those rare events when lightning directly strikes some ill-fated individual, much of the current is transmitted around the body, not through it, as the super-charged air creates a narrow band of conductive gas. The remainder of the charge enters the body and surges through the vascular system, where it often causes heart failure.
The dead heart
Unlike a human or a chocolate bar, the center of a healthy tree trunk isn’t soft and gooey. The heart of a healthy tree is dry and lifeless. Heartwood is dead wood.
A tree’s moist living cells are arranged in a narrow band just inside the bark, in the vascular system. This ring of cells contains the xylem – the long, tubular cells that pull water upwards, from the roots to the leaves – and the phloem, which carries carbohydrates (created by photosynthesis in the leaves) down to the roots.
The vascular system is where the watery sap flows. And, as everybody knows, electricity loves to travel through water.
If a tree trunk is wet by rain, the electrical charge may flow outside the trunk, rather than within. The lucky tree may remain undamaged. Commonly, the current surges through the vascular system. On entry, it super-heats the moisture in the cells, creating a boiling pillar of steam. The expanding steam – trapped between heartwood and bark – has nowhere to go, but out. Quickly. Explosively.
This is why trees explode. A tree trunk is an organic pipe bomb, ignited by the mother of all lighters and powered by boiling steam.
Spewing mud and guts
A lightning bolt may shoot down a narrow strip of cells and leave the bulk of the tree unharmed. The exploding cells tear off a thin strip of bark, leaving a surgical scar from the ground to the sky. Other bolts follow a wider course. Not all trees have a hard, dry heart. Old trees decompose, and the core of the trunk forms a dank hollow: “mud guts”, the timber cutters call them.
When lightning strikes a tree with a broken heart, it surges through the rotting core. The expanding column of steam blasts apart the outer trunk, tossing slabs of wood to the ground. Such a fate befell the old cypress-pine that I sat beside. The shattered stem spewed mud, guts and chunks of wood across the moss and rocks. A fast, loud end to a long, quiet life.
Let’s talk about you
Undoubtedly, you will now be comforted to have learned that – should you happen to stand on a stony knoll in a distant forest on a dark, wet night; and should you be smitten by 10,000 amperes of electricity – your body will not be blown to bits. If a search party finds you before the eagles do, your body may be repatriated; bruised, burnt, crinkled and veined. But you will die in one piece.
Unless of course, by a stroke of bad luck, the lightning slams into a mud-hearted pipe bomb beside you. In which case, shards of exploding wood, thicker than fence posts, shall pierce your torso and fling you up – like a lover in a Nick Cave ballad – atop a cold and wet, moss-covered boulder.
Where one sunny day a happy group of hikers – whistling “they call me the wild rose” – will clamber up the rocks, and recoil in shock, as they behold an exposed, prostrate figure beneath a decayed wooden stake; and they shall scream to their friends below, “oh my god, check this out, this is …”
Postscript (don’t worry, be happy)
According to Wikipedia, the world record for being hit by lightning belongs to the late Roy Sullivan, who was struck seven times between 1942 and 1977, while working as a ranger in Shenandoah National Park. And the lightning didn’t kill him. He died years later – at the ripe old age of 71 – after shooting himself in the stomach in a fit of “unrequited love”. Good luck or bad? You tell me. Either way, I hope I’m that passionate – and you are too – should we make it to 71.
recently in my area (moss vale, nsw) we have had numerous lightning events, some very close. Although I did not witness exploding people (now I know this doesn’t happen) I did find the tree the lightning hit. One day soon after the event I drove past a tree that appeared to have died all of a sudden. The back of this tree had the distinct marks of missing bark in a continuous spiraling line from top to base of the tree. This must have been a sight for motorists passing by! This sparked 😉 great interest in my home!
Thanks for sharing this info. Regards,
Hello Rus, thanks for writing in. It is always quite exciting to see where a lightning bolt hit isn’t it, the force is so great and the damage is so startling. I must admit I usually worry about bush fires being started when we have lightning storms near us, especially at this time of the year. Best wishes Ian
Interesting blog Ian, I posted on something similar back in 2007.
Hi Duncan, I wish I’d seen your post before I started this one – two bolts in the one place! Thanks for providing the link to your story. Cheers Ian
The distances that the slabs can travel are a great source of party stories where I come from. The longest distance (tale) conjured up so far is 400m from a local Ironbark species. Good party that one! We are sometimes unlucky enough to be caught out on horseback while mustering and two rules were drummed into us as children, (a) get off horse and get close to the ground away from trees and (b) never go near a fence. Thanks for your many and varied observations.
All the best, Dixie.
Hello Dixie, keeping away from wire fences is a great tip. There are some horrific articles on the web showing animal deaths beside fence lines, eg this link: http://www.telegraph.co.uk/news/worldnews/southamerica/uruguay/3249895/Fifty-two-cows-are-killed-after-lightning-hits-a-wire-fence.html. Thanks for taking the time to write a comment, best wishes Ian
Very interesting information and great pics, Ian. I lived on one property at Roma in SW Queensland which had a crazy number of lightning strikes. We would sometimes come across a dead cow that had been struck. Often they were lying next to fences. They seemed to have two burn spots, an entry and exit point (a leg) and the flesh would have a characteristic cooked rotting smell rather than the usual smell. Once when I was rushing to pen up some sheep during a storm, I was near a metal gate at the fence and felt a tingling all over my body. It certainly gave me a fright. Lightning struck a tree nearby shortly after. I’d never been concerned about lightning strikes until I lived there and saw the results!
Hi Jane, wow, that’s a pretty amazing experience. I never thought of Roma as being a place for living dangerously! I wonder how many farmers have similar experiences? I’m glad you escaped in one piece. 😊 Best wishes Ian
I’ve seen the aftereffects of trees and lightening. But not as personal as when a bolt hit and tore asunder my tall stately cottonwood tree near the pond. It was as if a giant a-bomb, mean and angry, took revenge on some unforgotten old war wound. It literally cleaved off half the tree and showered wooden shards everywhere. The neighbor saw it and hid under his bed (I’m not exaggerating).
I felt sad for the tree and the male Great Horned owl that daily used its top branch as a lookout. I spent the weekends of the next month finding shards of wood 200′ away from the tree.
I left what remained for owls and whatevers to make new homes in.
The GH owl decided to use the utility pole outside my bedroom windows and the satellite dish on the roof. We’re buddies.
Me; I insanely love lightening. If I go that route, so be it.
Hi Macrobe, wow, that must have been something to see. It sounds like the owl was lucky not to be sitting in the top of the tree at the time, or its time might have been up as well. Thanks very much for writing in and sharing your experiences. Best wishes Ian
I wonder if the tall tree (taller than all the others) being next to the pond containing water was an attractant and thus a conduit for the electricity. I also found two dead turtles floating in the pond the next day. Hmmm…….
My most memorable experience was while camping at Kinchega NP. We were calmly watching an electrical storm which seemed to be approaching from Broken Hill, before turning in for the night in a small tent. Then, a little while after, as they say, all hell broke loose with thunder booming around us and lightning flashing everywhere. We were pretty cowed in our sleeping bags, and while I knew that a car was safer it was obviously riskier to make a dash for it. At least we weren’t under trees. The next morning the only other campers there, who were two strapping guys from a country town emerged from their own little tent and commented ‘that it was a scary one last night’. It made us feel less like nervous city slickers. The sight of birds such as Rainbow Bee-eaters flinging themselves into puddles the next morning will also always stay with me.
On another note, I noticed when I was working in western Sydney Cumberland Plain Woodland remnants (over more than a decade), that of the Euc. apparently hit, and damaged or killed by lightening strikes, it was the Ironbarks that topped the score. They weren’t always the tallest trees in the area.
Hello Deb, I bet that experience was much more fun to describe after you got back home than it was at the time. We are starting to amass a great range of lightning tales here! Thanks for writing in, best wishes Ian
Fascinating Ian! Thanks.
Thank you M, I’m glad you liked it. Cheers Ian
Old cockies used to say wood from a tree stuck by lightning would not burn, (they probably wanted to pick up the wood for their own fire). I stumbled across your post while searching for info about tree hollows formed indirectly via fire ( Australian wildlife desperately needs more hollows) and found this http://vimeo.com/74284262 People are burning hollow trees for fun! We are so stupid. Maybe some well aimed lightning or falling hollow tree headed in the right direction could be useful.
Hello AL, the story about wood from trees hit by lightning not burning seems pretty widespread. I wonder where it started? Thanks for writing in, best wishes Ian
Lovely piece Ian thanks. Perhaps I should have encouraged…during an 8 year diversion in my career away from agricultural research, farming , environmental protection etc I worked at the Australia Council for the Arts. There I was pestered repeatedly by an American artist who wanted to create in Australia a “lightning farm” as an art work. He had done so in Florida “the lightning capital of the world”. Apparently several hundred kms south of Darwin we have the next most prolific site on the planet for lightning strikes (which he documented). He wished to build an array of metal conductors each many metres tall over an area of several hundred ha so people could regularly see lightning strikes. While it sounded funky to me I could not see how we could “get away” with it as we were being criticised at the time for some pretty eccentric art making so we gave it a pass…I did some years later see in Florida the work being done by US scientists aimed at understanding lightning strikes and their glassification of the Florida sands, amazing.
Hello Max, thanks for an amazing anecdote. Just think, instead of buying ‘Blue Poles’ we could have had the White Poles of lightning instead. Out of curiosity I just googled ‘Florida lightning farm’ and found this fascinating blog post that includes lots of artwork. I wonder if this was by the same artist? (You don’t have to answer that). Best wishes & thanks again, Ian http://bldgblog.blogspot.com.au/2013/08/lightning-farm.html
I remember one great bang that scared the wits out of me and scattered the sheep I was mustering. A large solitary Yellow Box on a ridgetop a few hundred metres away exploded with large shards scattered up to 50m metres or more. It raises another point – our few remaining paddock trees are very vulnerable to lightening as well as everything else.
Best wishes, Peter
Hi Peter, I bet that made you jump! Those big old paddock trees need all the help they can get given the number of pressures on them in many regions. Take care mustering! Best wishes Ian
Good story Ian. Over my years as a bush ecologist I have seen numerous exploded trees. One that stands out was a White Mahogany stringybark that had been blown up. It was standing amongst a lot of Spotted Gum smooth barks and stringybark fibres had penetrated up to a centimetre into nearby Spotted Gum’s bark making them look quite bristly. I pulled some bark fibres from another stringy and there was no way that I could push them any distance into the Spotted Gum bark. They must have hit with enormous velocity- just imagine what would happen to a human body!
BTW, nice blog.
Hi Biota, thanks for your recollection. I’d never thought of bark being blown into another tree, that’s pretty amazing. I’ll keep my eyes open for weird bristly tree trunks next time I see a tree split by lightning – I won’t be able to not do this now you’ve mentioned it 🙂 thanks again and best wishes Ian
Some other facts about lightning to consider for fire management.
1. The potential of a strike to be a “potential” fire starter is inversely proprtional to its intensity – high intensity strokes are blowing up trees!
2. Low intensity strokes are more likely to have a longer repeating stroke period, which means it can raise fine fuels to ignition point.
3. There is an increasing use of lightning detection systems in the wildfire industry in Australia.
4. There is a focus on positive polarity strokes as being potential fire starters
5. The breakdown of +ve / -ve polarity strokes is 20% / 80%, with 80% +ve & 20% -ve stroke being potential fire starters – which means that there is an equal number of both +ve and -ve potential fire starters
6. Detection systems have an intensity threshold level for successful detection of strokes, meaning that many potential fire starters go undetected
7. For fire investigators and insurers, the absence of a detected stroke is not proof of other ignition or damage causes.
Hello Peter, thanks very much for this, I had no idea that this information was available. I may email you soon to chase reports and papers on the topic, as it sounds like a great topic for another blog in the future. Thanks again and best wishes Ian
Really perfect Ian. Something really new added to my knowledge and definitely share it with our clients/customers for not staying under a tree during a thunderstorm. It means that a tree trunk wet by rain, has less chances of damage as compared with out other which are free from moisture.
Hi TC, thank for writing in. I must admit that I have never seen any stats on how much more likely (or less likely) it is that a wet tree will be damaged compared to a dry tree. The physics makes sense but it’s a pretty hard topic to monitor and experiment with, so the difference may perhaps be small. I don’t know. Either way, the old advice to never stand under a tree in a lightning storm is very compelling. The link in the post above to a story about the damage people suffer after being hit by lightning is very sobering. Thanks again and best wishes Ian