Collapses

[anfieldman]

Changing outside the UBSS hut the other night I was looking at all the trees there and it got me wondering if trees are sometimes responsible for the collapses in of caves.
After all, they are responsible for house subsidence on occassions.
Any evidence of this?
:-\

 

[cap n chris]

Lack of fitness is surely the main cause of collapses underground.

 

[darkplaces]

I would have thought trees and plants etc tie the soil together and stop collapses/landslides and slow down erosion etc.

For example, above a rather 'muddy hole' somewhere not too far a tree is sitting basically holding the roof together with nothing else but roots.

 

[graham]

They could well be part of a process that would lead to a collapse anyway. That is, the formation of a collapse doline could be speeded up by tree roots assisting in widening fractures above the (soon to be) collapse feature, allowing freeze/thaw to take place more rapidly, etc.

Having said that, the situation that DP describes does exist. Hunter's Hole, for example is an example of an upwardly eroding aven that is roofed by little more than tree roots & soil.

 

[Pitlamp]

Darkplaces - I apologise if this seems pedantic but trees ARE plants. Lots of people (including TV presenters who should be better informed) use the expression "trees and plants" but they are classified in the same kingdom by biologists.

 

[Dep]

I can think of many local exmaple of shallow working that have tree roots grwoing through.
These do seem to hold things together but also open up cracks in rocks to allow water through, gradually widening these cracks.
The problem arises when the tree dies and the roots rot away - all that remains is an open crack full of slippery clay fines - perfect conditions for collapses.

On balance I wdl say trees roots ae neither good nor bad as far as collapses and stability are concerned - but can certainly be a factor in shallow systems.

 

[darkplaces]

SO if you line graphed a collapse with plant life involved it might draw like a regulated lamp in that its stable/horizontal for a period with rapid decline to the end were as without plant life the its more of a evenly declining line from top/left to bottom/right.

How cool is that, graphs without stats!

 

[T pot 1]

Only one entrance exposed by a tree that i have ever seen was back in in the eighties when the famous gales brought chaos to the UK. A huge birch tree was blown over exposing a hole no bigger than a dinner plate with a collapse feature below it
The collapse was into old mine workings, the shaft which was some sixty feet deep had been under the tree for approx 150 years (dated after counting the rings of the tree when it was chainsawed into logs) but was not the original way in, miners pick marks were found which indicated that it was mined from below.
As an aside i named the mine Birch Fell but because of my arboreal ineptitude Dave Arvescough took the piss out of me in the pages of Descent pointing out that the tree was a BEECH tree so i had to rename the mine to everyones amusement

T pot

PS before anyone says owt the name for counting the rings in trees is dendochronology

 

[Peter Burgess]

dendrochronology.

 

[wormster]

dendrochronology.

YAY the original pedant is back.

 

[Slug]

dendrochronology.

YAY the original pedant is back.
/quote]

Walked into that one didn't You Pete.

 

[Peter Burgess]

dendrochronology.

YAY the original pedant is back.

Walked into that one didn't You Pete.

Well, the temptation was overwhelming.

PS before anyone says owt