Yes, it will be the oil, and compaction of the soil by the vehicles that used the road. And nothing you can really do about it short of diggin it all out.

Resin

What about the prospect of bioremediation? Its used in oil spills...I don't know much more than that or where you could get the bacteria or who to consult...I have a friend working towards his phD right now researching bioremediation...anyways, just a thought.
~Mike

Probably limited, it won't deal with the compaction and roadstone, which may well be more significant than the oil.

Resin

Interesting...so you think the compaction would still be acute enough after fifty years that the trees couldn't survive? It might be a long shot but do you by any chance have reference to any papers that might affirm how long it takes for trees to recolonize these types of areas? I've got a feeling there have to be some long-term studies looking at logging roads in reclaimed areas and such...

Piqued my interest in any event - if you have something published in a journal I'd really be interested in reading it - I'm going to be doing some literature searches myself and will report with what I've found (if anything).
~Mike

no need to bang your head against the same wall over and over ...

think outside the box .... if trees wont work ...

put in a gazebo

till the first few inches and try seeding for meadow flowers or just add a few inches of good soil .....

there is a world of options.. besides the one that failed ...

ken

The compaction is likely to be severe in such a location. Logging roads are not usually sprayed with oil. I would try planting primary succession trees. Sumacs, locusts etc. Nitrogen binding trees such as locust will help improve the soil for other plants, and the probing, suckering roots will aid in loosening the compaction. Good luck to you. I am not sure what you can do for the oil, but after 50 yrs, the compaction is probably more of an issue.

-Werner J Stiegler
www.binghamtonmemorialtree.webs.com

Thanks for the replies. Been so busy outside with the wonderful weather we have had lately that I forgot to check back.

Actually the road went back to the 40's or even earlier, when they rerouted it. So it hasn't had traffic or oil since then. Grass and weeds grow there fine but just having trouble with bushes and trees, even with watering.

Already built a gazebo further up on the property. The trees are down by the end of the property between us and the neighbor's house, so want a screen.

I wonder if the road oil permanately poisoned the dirt. So will consider digging it up all around the trees and putting in new material.
Thanks again.
Clare

Hi Clare, I'm an arborist and live next door to you in Corralitos. I'm buzzing around aptos all the time if you're interested in yet another opinion, contact me! Dave

If you cared to bother with the expense, I believe that some CAT operators have an attachment for the back resembling huge claws that can rake under and demolish a lot of the compaction.

Should be called a Subsoiler

A backhoe could do it also. Or - rent or buy a subsoiler and mount it on a good size tractor. You can go deeper with each pass - a few inches at a time.

The likely compaction depth - if that's what you are dealing with - would be in the 12" to 24" range.

If it is compaction, it could remain for centuries beneath.

One alternative is to plant at the very edge of the old road area, but not on it.

Here is a link that might be useful: Subsoiler article on Wikipedia

Must be global warming killing your trees....