To the southeast of Island Pool in the deer park of Dunham Massey in Cheshire is a group of burnt oaks. I came across them today on a New Year’s Day walk. At first I thought they might be due to a lightning strike, but further digging reveals they are the result of a bracken fire.
This first picture sets the scene of the small group of oaks, which have lost their tops at about the same height. Some have started to regrow crowns, but others are dead. You might be able to convince yourself that they got a fork each from a large lightning discharge, destroying their tops and (on closer inspection) leaving them as charred hollows. You can see lots of charring in the second picture. Lightning can also travel through the bark, burning and shattering as it goes.
These next six pictures are from two trees. The second large picture is a hole burnt right through the wall of the shell near ground level. In the fourth picture, the whole of the inside of the tree is charred. The bottom left and bottom right pictures are views up the charred hollows extending the full remaining height of each tree.
Naturally, there is a history of lightning strikes at Dunham Massey. John Boultbee painted “An oak tree struck by lightning in Dunham Park” in 1808. Other paintings of the deer park suggest it was denser than it is now, with something like a closed canopy of oak trees. In Boultbee’s painting there is not much evidence of burning, and instead the tree has just exploded when the lightning struck, leaving shards of pale wood strewn around. People are taking photos of very similar aftermaths around the world today.
So far, so plausible. But then it begins to break down. Another of the trees in the group looks just the same, but has no charring at all. Its hollow, rotted-out structure is the same, and it has a missing crown at the same height. That strongly suggests that the other trees were like this, and then set alight. It means that lightning can’t be explanation of the lost crowns, at least.
When I got home I had a look for anything online and the the National Trust website has an “ancient trees walk” at Dunham Massey which explains it:
Burnt, decayed, twisted, hollow, but still alive and healthy, the trees damaged in a past bracken fire show the tenacity of trees to survive.
The final three photos show another hollow but surviving oak in a different part of the deer park, and a big hollow branch on the ground. Finally a really cool den to the east of Island Pool.