Friends,

I have a problem with trees growing on a hard surface.
It is on the 'Silver Pinery' island in Moscow.
5-3 years ago they did surface layout here and the trees now are strewed with excavation from foundations by 50 cm in average. I think the trees are still alive just because the ground is sandy. Moreover, some of them have only 30-50 cm in a radius openings in the hard surface to grow in.
In the case of absence of a hard surface we removed the superfluous ground within radius of 1 m from the trunks and we are going to set grates on the holes. We also destroyed the hard surface where we could. But we can't destroy it somewhere, because the landowner doesn't want it though he want's his trees to be healthy.
The questions are:
What could be done in case of the concrete surface?
What else would you do after removing the ground (I mean forcing and curing the trees - they are rather weak now)?

Any help would be really appreciated!

Dmitry

Reply to post by Zvonka, on November 08, 2001 at 09:41:16:

Dimitry,

About all you can add is air and water. Could you do a little vertical mulching with course gravel, or coarse mulch of some sort. Drill some 1 1/2" holes at an angle from near the exposed base to widen the area of aeration below the cement? Just an idea.
Bob

Reply to post by Bob Underwood, on November 08, 2001 at 09:41:16:

Bob,

I've thought of holes, but there is a 50 cm layer of excavation underneath. And there are some pines above 50 cm of diameter that are already attacked by Blastophagus piniperda, Ips accuminatus and other pests. Birches are infested by Ervinia multivora.
I think it will be good to apply some micorrhizae innoculant and some organic fertilizer. The soil must have been destroyed for now.
I also think it won't be a harm to apply some energizer.
I think that in this case, when the next season prospective mortality is about 10 - 20%, such a radical measure is reasonable.

What do you think?

Dmitry

Reply to post by Zvonka, on November 12, 2001 at 11:09:11:

Dmitry, there was a Dutch company at the ISA show this year that had a system for what you are looking for. It involves are injection of what seemed to be a vermiculite like compound and organics with fertilizers to provide better airation and water movement under hardscapes.

Their feelings were that the air injection is better then slurries because yuo get better mixing with ther native soils and less hydrological discontinuites afer the application.

Reply to post by John Paul Sanborn, on November 12, 2001 at 16:29:06:

Interesting site.
'Wish I could read the language.
Did you come to understand that the material is applied after air has been used to fracture the soil?
Or is the material air injected dry at the same time as the initial air injection?
Do they sell the service in the USA, or are they vending the equipment?

Reply to post by John Paul Sanborn, on November 12, 2001 at 16:29:06:

Really interesting!

I wish they were Russian - the problem is VERY common for nowadays Russia.

Reply to post by Mark Goodwin, on November 12, 2001 at 20:23:25:

It fractures the soil then injects the aggregate at high pressure.

It seemed that they make the equipment and perform the service in NL and were marketing the sysytem at the show.