Trees: 10, Concrete: 0
February 15, 2016 2:38 PM   Subscribe

The term APHERCOTROPISM refers to the response an organism makes as it grows to overcome an obstacle in its way.
Or, how to convince tree roots to make 90 degree turns.
posted by jeather (15 comments total) 25 users marked this as a favorite
 
A little sad that trees have to do this, but a lot of awesome that they can, and do. Thanks for the link, the word, and the mindset.
posted by datawrangler at 2:45 PM on February 15, 2016


As a professor in college was fond of saying, nature bats last.
posted by filthy light thief at 3:01 PM on February 15, 2016 [1 favorite]


Trees are the best.
posted by turbid dahlia at 3:28 PM on February 15, 2016


Guy Clarke used to tell a story when he was introducing "L.A. Freeway" about how he lived in a garage apartment in LA where the only nature he and Susanna could see out their window was a lone scraggly grapefruit tree, which he used to stare at while writing songs and trying to become an LA hitmaker. Then one day he came outside to discover the landlord cutting down the tree and when he protested the landlord pointed to how the roots were destroying the concrete driveway.

As he tells it they packed the car and headed back to Texas that week.
posted by spitbull at 3:31 PM on February 15, 2016 [5 favorites]


Am I wrong that the "90 degree turn" article seems to get it backwards, imagining the roots bursting up through cracks in the concrete where, to my eye, it looks more like they're desperately trying to slither down?
posted by nobody at 3:44 PM on February 15, 2016


I believe 90 degrees refers to the horrifying replication of the spaces between the bricks.

Nightmarish pictures. I'll not sleep well tonight.
posted by tilde at 3:48 PM on February 15, 2016 [1 favorite]


We've got a tree a little bit too close to our foundations... Do not remind me again of tree vs concrete :)
posted by coust at 4:51 PM on February 15, 2016


nobody: "Am I wrong that the "90 degree turn" article seems to get it backwards, imagining the roots bursting up through cracks in the concrete where, to my eye, it looks more like they're desperately trying to slither down?"

Trees are amazing, and roots are cool and unfortunately mostly overlooked. I mean, they're pretty goddamn hard to see unless they're like these, of course. Roots are both pipelines and structural elements; imagine each root coming off of the trunk as a watershed, carrying liquid and minerals into the tree from far reaches. Roots can extend tremendous distances from tree trunks, and in the majority of cases don't grow very deep at all (like, in most temperate areas less than 2 feet deep and the majority of functional roots are right up in the organic layer on top). But the roots closest to the tree function to anchor and buttress; all of these trees in the photos are tropical, and tropical trees tend to grow shallow but sometimes giant buttresses as architectural elements to increase the footprint and stability of the trees on thin or soft soils. Most temperate trees also have buttress, but they also use a wider variety of tension and compression roots going deeper right in the vicinity of the trunk, in the "root plate" that works to actually hold the trees in the soil; the roots past the plate are just carrying water, so to speak.
So the roots in these photos are extending outward like pipelines and branching smaller, more ephemeral roots down, searching for soil to exploit in the only directions they can. While many trees tend to grow more superficial roots, even deeper-rooted trees will burst through to the surface if soils are compacted enough and the pressure is less in the upward direction. Roots grow and expand and will push out wherever they can; if the weak spot is in concrete, then the pressure from the growth will break it.

coust: "We've got a tree a little bit too close to our foundations... Do not remind me again of tree vs concrete :)"

Sometimes it's the pressure of roots pushing against foundations, but sometimes it's just weakness in foundations combined with increased subsidence and expansion as trees pull moisture too efficiently from the soil.

blah blah i like trees
posted by Red Loop at 5:10 PM on February 15, 2016 [16 favorites]


Sometimes it's the pressure of roots pushing against foundations, but sometimes it's just weakness in foundations combined with increased subsidence and expansion as trees pull moisture too efficiently from the soil

I've been told the roots won't crack it but they'll definitely make any crack appearing for other reasons worse. I love trees too, we have to decide what to do with it (just got the house). Inspector was like 'this has to go' architect friend I showed a pic of the yard had the same 'kill it' comment. If we ever have to dig to redo the French drain it's probably a goner also. But I really like the shade it gives...
posted by coust at 6:20 PM on February 15, 2016


On College Street in Toronto, in 1988, five year old Yusef sees a tree growing through a chain link fence and says, "Trees are the bravest. They can't run away." Mouths of babes and all that.
posted by sic friat crustulum at 2:55 AM on February 16, 2016 [2 favorites]


A little sad that trees have to do this, but a lot of awesome that they can, and do.

This is how trees deal with rocks in the natural environment. They just see these as really odd flat rocks.

As a professor in college was fond of saying, nature bats last.

And while it doesn't often hit for power, it will positively wreck you with walks and bloop singles.

Never forget the time factor. The push a root gives is very small. When it pushes for decades, though, that ends up being a lot of energy applied. Trees aren't very long on power, but power isn't everything.

Power is, naturally, energy over time. Gridiron football players tend to be very powerful -- very high energy output over short periods of time. Association football players aren't powerful -- they put out less energy in the same amount of time, but where gridiron players have to be working at max rate for seconds at a time, associations players have to go constantly. They're putting out less energy per second (or less power) but they go much longer because of it.

This is also why pulsed lasers can have incredibly how power levels -- the energy they have is delivered over a very short period of time, resulting in very high power levels. Release one joule in one second, and you have a power of one watt. Release one joule in one microsecond, and you have a megawatt of power! Total energy release is the same, but one is a million times more powerful that the other.

Trees are the exact opposite of pulsed lasers. They're not releasing much energy per second, but they keep releasing that same tiny amount of energy per second for millions of seconds. The building falls once you dump enough energy into it -- whether it happens in a fraction of a second from an explosion, a few seconds from a hurricane, or decades from a tree.
posted by eriko at 5:41 AM on February 16, 2016 [3 favorites]


See also: the horticultural art of espalier, where trees are grown in specific patterns of branch arrangement, generally flat against a wall, for aesthetic purposes.
posted by FatherDagon at 6:58 AM on February 16, 2016 [2 favorites]


Does it not bother anyone else that there appears to be virtually no concrete in any of those (visually fascinating) pictures? Masonry, yes; mortar in a couple of cases; but... I'm not seeing the concrete?

[/nitpick]
posted by clawsoon at 7:37 AM on February 16, 2016


blah blah i like trees

Putting this on my next business cards.
posted by pemberkins at 10:47 AM on February 16, 2016 [1 favorite]


I just spent two weeks on jury duty, listening to a pair of neighboring lawyers argue over three inches of land between their million-dollar homes - particularly a 50-year-old espalier pear tree partially rooted on those three inches. The tree more-or-less belongs to one litigant; the other insists its root structure is negatively impacting his fence foundation. I so wish this FPP had happened before voir dire so I could have averred that yes, I had some prior knowledge of these matters! and therefore avoided two weeks of lost life and wages. As it shook out, that pear tree, which is gorgeous, is now doomed. Wish it had had its own advocate at trial.
posted by goofyfoot at 7:48 PM on February 16, 2016 [1 favorite]


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