Alternatives to standard asphalt around roots

I've never used it, but there is a permeable asphalt out there. I would also think that if you have to pave over roots, permeable pavers are probably a decent option. They allow water and air through between them, they are laid on a bed of open flow gravel, and they have the ability to move as necessary when the tree grows.
 
perkEpave is one permeable pavement I've seen advertised a bit.

I think there are pavers that allow water to pass, but most "permeable pavers" are a system of installing "regular" pavers that have wider spacers built into them (they are called permeable, but each individual paver is not different than other pavers) and like @Reach said, the underlaying gravel. Just plan on needing to reset them periodically.
 
I hope someone will educate me how it does any good to have any kind of permeable pavement when vehicles can drive over it and compact the soil so much that water can't penetrate it. I am ignorant about this, and I'm wondering if anyone has actually tested it. From my uneducated perspective, it looks like it does no good except to make the people feel better about doing something to protect their trees.
 
I recall a special about paving a parking lot with permeable stuff both to keep the edge dressing plants/trees healthy and perhaps the main reason was to lessen storm runoff peak flows by re-enabling natural soil moisture absorption. Was quite a while ago. Sorry I don't have a better reference.

Look up soil load distribution/bearing pyramid - the psi's go down with depth below the surface. Part of road construction is tuning that effect via road base materials. Farm soil has no such advantage, hence compaction issues.
 
It depends on the circumstance...

If you have a driveway and a tree is it better to have some permeability, none, or no tree?

If you are doing construction before planting, I'm not sure there is a better solution than Silva Cells. Cornell Structural soil is good, but there is not as much uncompacted soil as there is with Silva Cells. But they are expensive and not for replacing an existing driveway where there is an existing tree and you cannot dig out all the soil without significant root damage.

We can complain about infrastructure and less than ideal rooting conditions for trees or realize that when managing the urban forest, those are realities and try to minimize the impact. Like @Bart_ said transferring the load to the pavement and base material will lessen how much compaction goes into the soil. Is
 
I have come up against this issue A LOT lately and have been simmering on it. Silva Cells would have been awesome to have installed, but ATH covered that. I think that maybe grinding down the high spots and laying down a second layer over that section of road and basically make it a low flat speed bump could would for a good while. Short of major renovations and a removal/replant, there will probably not be a solution that anyone is really stoked with.
 
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I would postulate that permeable paving would increase soil moisture content, invigorate the root growth and actually speed up the roots heaving the asphalt = actually a bad idea, in this case.

Classic rock and a hard place situation. Roadway wins or roots win but not both.
 
Bart_ said:
I would postulate that permeable paving would increase soil moisture content, invigorate the root growth and actually speed up the roots heaving the asphalt = actually a bad idea, in this case.

Classic rock and a hard place situation. Roadway wins or roots win but not both.
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That is true...but if tree preservation is important permeable pavers offer a better option than asphalt. Just going to have to realize pavers will be reset every +/-8-10 years.

If a client kills a tree with "permanent" pavement options tell them it's their own asphalt.
 
southsoundtree said:
This path/ trail gets very limited vehicle access.

First bid...40k to remove and repave. Second bid was similar and also said that is cheaper to remove and replace than patch.
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I think any alternatives are going to cost more than just a regular paving job (besides maybe just gravel...is that an option since it's infrequently used?)
 
misfit said:
I hope someone will educate me how it does any good to have any kind of permeable pavement when vehicles can drive over it and compact the soil so much that water can't penetrate it. I am ignorant about this, and I'm wondering if anyone has actually tested it. From my uneducated perspective, it looks like it does no good except to make the people feel better about doing something to protect their trees.
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It comes down to spreading the weight which limits compaction.
Legit permeable pavement (and pavers) still allows for gas exchange, freeze thaw cycles that loosen soils and improves drainage
Better to not compact the soil? Sure!
 
Bart_ said:
I would postulate that permeable paving would increase soil moisture content, invigorate the root growth and actually speed up the roots heaving the asphalt = actually a bad idea, in this case.

Classic rock and a hard place situation. Roadway wins or roots win but not both.
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Possibly yes but also no. The reason many roots seek the interface right under paving is that zone is where the available O2 and water is.
The temp differential causes condensation…
A pervious material mitigates that and allows for a more holistic rooting environment.
 
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I'm drawing a fuzzy on how moisture condenses (from the air?) through the impermeable asphalt to the soil underneath? Can you set me right? Or am I misunderstanding?
 
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