Planting trees into asphalt?!

Hi all,

I've been been helping a friend design the outdoor seating area for his new restaurant and am trying to troubleshoot a solution to one of our design challenges. Part of the area we're working with is covered in asphalt (underlaid with gravel). I want to cut holes in the asphalt and plant some trees in that area. My thoughts are that the extra solar radiation absorbed by the asphalt will effectively change our hardiness zone, allowing us to grow plants that would typically struggle in our area. Also, the juxtaposition of plant and industrial surface might act as an interesting conversation starter and point of interest for curious restaurant patrons, as well as a nifty metaphor.

I've heard of an innovator in Ohio planting trees into an abandoned Walmart parking lot, but have failed to find links to her work. I'm looking for inspiration. I'm looking for people who've tried this. Has anyone heard about projects like this? What mistakes have people already made that I can avoid?

Nick

Caveat: I haven't actually done this myself...

But I looked into it awhile back for my own project.  A lot of urban areas, including main street in my own small town, have trees cut into sidewalks right between buildings and paved roads.  The trees are generally smaller species, and grow tall rather than wide.  Here's a good article I found on what to consider:  https://pubs.ext.vt.edu/430/430-028/430-028.html

https://c1.staticflickr.com/5/4038/5161065472_f9447c759b_b.jpg
I think it will work fine if you can get water to the tree while in its first years.  If you could install some sort of funnel to help the water get to the roots, maybe even something like an installation art piece that is like a shade umbrella that also collects water in it's center.  I see it in this shape but with a wider flare to collect more water and offer more shade.
https://s-media-cache-ak0.pinimg.com/originals/40/e0/43/40e0432c8a1e3e95500640729804cb5b.jpg
So sorry; I can't figure out how to post pictures, those are just links to images off of google for illustrative purposes.  

I'd pick the type of tree carefully. Something like silver maple wth a lot of surface roots would crack and lift the surrounding asphalt.

These are all great suggestions. Jayden, that's a helpful link. Im using the unique site conditions to grow plants that tend to live in a more arid environment. To supplement, the intended design will collect rainwater from a sheltered seating area, so that can be easily used to water the tree guilds. Also I'll probably want to plant some companions with deep, "groundbreaking" roots to help deal with compaction.

Roxanne, beautiful mushroom idea, I'll want to use something like that in the future.

Any thoughts on toxins leaching into soil from asphalt? My initial thought is "these would be oil based toxins and therefore wouldn't be taken up by plants," though I'm not sure.

Thanks for the help internet team! This is my first permies post and I'm finding it thought provoking and well worth it.

So this is 7 years old...but hey Nick, how did it go?

I'd love to hear about your experience! Looking to do a similar-ish project with an asphalt parking lot without any trees in SWZ 7.

As Ken W Wilson noted above, pick your tree varietals carefully. The asphalt will almost certainly lose to a determined tree.