Toil
Greener Thumb
Posts: 803
Joined: Tue Jan 05, 2010 4:18 pm
Location: drifting, unmoored

Rocks

I was out working with my dogs yesterday, in a park built on an old quarry.

I snapped some shots, because I noticed something interesting. Wherever large boulder size pieces of rock are, so are the trees. They grow on top and around, but as you get away from the boulders the trees disappear, until you get to another one.

Does this suggest rocks are an important part of soil's balanced diet? If the pics are no good I can take some with the good camera.

[img]https://i929.photobucket.com/albums/ad137/toilpics/36beb22f.jpg[/img]

[img]https://i929.photobucket.com/albums/ad137/toilpics/efbd5e39.jpg[/img]

lesgold2002
Newly Registered
Posts: 6
Joined: Sun Jan 31, 2010 9:15 pm
Location: BRAZORIA, TX

Hi Toil,

Rocks, of course, have lots of minerals. But what comes to mind for me in these photos is could it be that the rocks supplied a better spot for tree seeds to lodge and germinate than the surrounding soil?

Les

User avatar
applestar
Mod
Posts: 30514
Joined: Thu May 01, 2008 7:21 pm
Location: Zone 6, NJ (3/M)4/E ~ 10/M(11/B)

If you were a science fiction buff, you'd know that condensation gathers on rocks and trickle down to the base, creating a ready and steady source of moisture. :wink:

:idea: Plus they act as heat sinks, soaking up the heat during the day and radiating it during the night.

Toil
Greener Thumb
Posts: 803
Joined: Tue Jan 05, 2010 4:18 pm
Location: drifting, unmoored

apple, that was my first thought. Water. But what explains the humus formation and trees growing directly on top?

Les I also considered that, but how can growing directly on top of a boulder help with root space and grip? It's almost like they went out of their way to be near these rocks, and were successful there, while they were unsuccessful away from the rocks.

And it's not like the rockless spots are barren. The vegetation is just lower order.

User avatar
jal_ut
Super Green Thumb
Posts: 7447
Joined: Sun Jan 18, 2009 10:20 pm
Location: Northern Utah Zone 5

Interesting observation. Perhaps the rock provided some protection from mechanical damage of what ever type.
Also rocks do hold quite a lot of water.

The North side of the rock will have a micro-climate that is slightly cooler and holds water better because of the incident angle of the sun. This is why moss grows on the North side of rocks and trees.
Seedling trees are very small and very few seeds grow into trees. They can't compete well with established vegatation. Most expire from lack of water or mechanical damage in their first summer. If they make that first summer though, the root wil be quite deep and the tree has a good chance of survival.

Depending on the variety, some trees send out new shoots from the roots and you get a group of trees, that are all the same plant. Perhaps this is what you have here? Quaking aspen is a case in point. A grove of quakies may be all one plant covering a large area.

Toil
Greener Thumb
Posts: 803
Joined: Tue Jan 05, 2010 4:18 pm
Location: drifting, unmoored

makes sense, but there is no mechanical advantage to being on top of it! I mean, how long can they go on that way?

another thought - if this is an old quarry, might the rocks have gotten there via violent means? would that mean lots of rock dust?

User avatar
soil
Greener Thumb
Posts: 1855
Joined: Thu Jan 22, 2009 8:40 pm
Location: N. California

maybe thats where that tree just likes to grow. each plant has a spot that benefits it most.

if this is an old quarry those are probably old piles that were put there and are most likely not natural. up in the hills here we have piles like that from people mining for gold.

GardenGeek
Cool Member
Posts: 79
Joined: Tue Feb 02, 2010 1:03 pm

lesgold wrote:Hi Toil,

Rocks, of course, have lots of minerals. But what comes to mind for me in these photos is could it be that the rocks supplied a better spot for tree seeds to lodge and germinate than the surrounding soil?

Les
That could exactly be the reason. Actually the concept of shelter lies here that is seeds remain protected at the area surrounded by rocks and thus sprouted out there successfully!

At other places so many disturbances can just wash them out..
Another reason is of course that rocks provide minerals that can act as an essential for tree growth. You will find various articles on web related to this important concept.

a0c8c
Greener Thumb
Posts: 706
Joined: Mon Jun 22, 2009 3:00 pm
Location: Austin, TX

Toil wrote:makes sense, but there is no mechanical advantage to being on top of it! I mean, how long can they go on that way?
There's a huge advantage to growing on rocks, especially boulders. They act as a counter weight to help keep the tree upright during storms and strong wind gusts. It's a replacement for taproots other trees grow.

Toil
Greener Thumb
Posts: 803
Joined: Tue Jan 05, 2010 4:18 pm
Location: drifting, unmoored

:oops:

Er... I really don't pay attention until I pay attention... It's an old quarry, and the rocks are not just the little hills, they are EVERYWHERE. I was standing on a giant hill of busted up rocks, just an irregular hill.

And the "boulders" are also just more piles of rocks.

damn it, I thought I had made a good observation, but it was just careless. A bit of snow melt revealed all. I just started walking there, as there is no field to throw a frisbee in. But we are working on human in front dogs behind, and it's a great place for it.

mea culpa!



Return to “Organic Gardening Forum”