How would manage an air layer on a tree in a remote location.

I saw an idea at a garden show a couple of months back which is being marketed in the UK to deal with long term watering of hanging baskets. Had a TV spot allegedly as well. (right off QVC probably:-)

Based on the same principle as drip feeders I guess.

Consists of a slim, porous terracotta pot - around standard paper cup size but narrower and a spherical glass vessel with a tube neck like a chemisty lab boiling flask (see pic at the bottom of this page) which is probably what it is.

http://www.labdepotinc.com/Category_Details~id~330.aspx

You bury the terracotta pot in your hanging basket (or air layer pot) fill the round flask with water then up end into the terracotta pot.

The little pot fills with water and the spherical nature of the upended flask plus some upthrust/ downthrust and a bit of gravity seals it off.

I guess you have a bit of downward pressure on the water and a porous pot so water passes through the pot very slowly.

As the level drops the glass flask keeps it topped up and some sort of pressure equilibrium state is no doubt achieved. Boyles Law? (physics and fluid dynamics is not my strong point)

It is claimed that the roots grow towards and around the little terracotta pot and that it can last up to 4 weeks depending on the size of unit you use.

Trouble is I can't remember what it was called and a bit of net searching doesn't find it either.

I would think an upended plastic bottle could do the same and there's some ideas on this site which must have counterparts in the USA.

http://www.garden-innovations.co.uk/index.html

Disclaimer: I have no commercial involvement with any of the products referred to in this reply. Only wishing to assist.

Experienced collectors of old pines in deserts and dry areas here in the U.S. often use clear plastic baggies on to-be-collected stock by simply placing the bag with moist sphagnum moss. Exposing the bag to sun. The resulting heat and humidity supposedly forces plants like Ponderosa pine and juniper to produce a bundle of feeder roots in a few months. Since most of these trees are in extremely remote locations, watering the bags is impractical, if not impossible.

A survival trick that I have used in the past is to take a plastic bag and wrap it around some very green foliage on a tree. Make sure that one corner on the bag sits lower than the rest. As the leaves in the bag lose water through transpiration, it will collect in the bottom of the bag. I've only used it to get drinking water, but I'm sure if you're creative you could get a good system for keeping root layerings wet. It works best with broad leafed trees, but it might even work by collecting the water transpired by the juniper you intend to collect.

My last idea of the day is to set up a version of a solar still. Basically it is an impermeable sheet (plastic) set up over a hole in the ground. Secure the edges around the hole and put a small rock in the center on top to make the center dip down. As water evaporates out of the hole it will condense on the sheet, run to the low center and drip to where it can be collected for use. That might be a harder system to use since the water would be below the level of the ground to begin with and you would have to find a good way to transport it up to where you are root layering.