Trees of stone
The petrifying world of ancient forests and why it’s wise to look, but never touch.
The petrifying world of ancient forests and why it might be wise to look but never touch.
HERE ARE SOME amazing facts about petrified wood. It used to be wood; it’s now stone. When it was a living tree, diplodocus and brachiosaurus might have munched its leaves. And it can curse thieves.
First, the alchemy, or perimineralization as it’s properly known. When a tree dies it normally rots fast, unless it’s buried in sediment where the lack of oxygen inhibits decay. As water seeps into the wood, it deposits minerals which replace the tree’s slowly disintegrating cells over millions of years, to form a cast so detailed it shows bark, knots, grain and growth rings. Different minerals tint the stone different colours and it can be mistaken for the wood it once was – until you try to lift it.
Walk the coast path east of Lulworth in Dorset and you’ll discover the Fossil Forest. Here the remains of gymnosperm trees perch on a cliff ledge, although in the Jurassic when they were growing
this would have been a swamp on the edge of a warm lagoon. Rings like stone doughnuts are moulds of where the cypress-like trees stood 140 million years ago, while coffin-shaped casts show where others fell, some still holding pieces of now petrified tree. In Glasgow’s Victoria Park there’s a Fossil Grove with 11 petrified stumps of extinct lepidodendrons from a 325-million-year-old forest. Petrified wood has been unearthed at quarries on the Isle of Portland and Brymbo near Wrexham. And out on the Ardmeanach Peninsula on the Isle of Mull is MacCulloch’s Fossil Tree ( left). Named for the man who identified it in 1811, its trunk slices up the cliff like an ancient woodcut. Much of it is an imprint in the basalt that buried it 60 million years ago, but some fossil tree in the lower reaches has survived the years and the souvenir hunters.
And those who pilfer the wood may be cursed by it, or that’s the story at Arizona’s Petrified Forest National Park. Beguiled by the jewelled mineral hues of its 225-million-yearold trees, some visitors tuck a piece in a pocket, trouser leg, or even bra. And then, sometimes, a little later, they send it back in the mail with a letter. ‘ Upon returning home we first found that my step mother had kidney failure,’ wrote one person. ‘ Then our dog died, our central air conditioning went out and our freezer. I had a really close call in having a bad auto accident, our truck broke down needing major repairs, our cat was killed and last night close by our home a gas well blew out a cap. Please take these pieces back before we have any more bad luck.’ Sorry in Texas wrote ‘ The final straw was when I stepped thru the ceiling of our new house. That’s when I told my wife. I’ve had enough. I’m sending it back.’ And some return their fragments because they can’t stand the guilt: ‘ They are beautiful but I can’t enjoy them. They weigh like a ton of bricks on my conscience.’ Unfortunately, the rocks’ origin cannot be verified and they cannot be returned to the park. Instead, they’re put on what the rangers call a ‘conscience pile’ and there’s no record of whether luck improves for the penitent thieves, but we’re thinking these ancient tree-stones are best left where they are.
WALK HERE: Download a wild walk to the fossil tree on Mull’s Ardmeanach Peninsula from www.lfto.com/bonusroutes, where you can also find a walk from Lulworth past the Fossil Forest. It enters the Lulworth Ranges: check they’re open at www.gov.uk/government/publications/lulworth -firing-notice. Steps to the forest are under repair after a landslip but you can see it from above.