There is a third way. Genetic engineering.

The State Unviersity of NY has already created a blight resistance American elm.

They are taking a gene from wheat that reacts strongly to cankers and emits
hydrogen peroxide (promoting callus growth).

So far, two nuts and one tree (nuts & tree with different techniques).

They hope to add additional genes as well.

This gene is expected to be dominant so half of the offspring of a single gene
tree (and all of those from a doubel gene tree) will be blight resistant.

An easy way to bring blight resistance into an existing, surviving population.
Find a sapling, graft a blight resistance sprout onto it. Release it (cut down
the competition) and wait a few years. Since chestnut is not self-fertile, the
grafted branch will be teh dominant or only source of pollen. treat the tree
for blight and get 4 or so nut crops.

Repeat with the offspring and graft them into other trees. Soon, a 3/4 & 7/8
local tree.

OR you can take my approach. I have arranged to ship 1,000 nuts from Upstate
New York (Nyjk Jarvik in Old Norse/Icelandic) to Iceland.

Prior shipments from Ontario (60) & Maine (120) have done quite well.

Alan