Ok, below is the list of the nutrients in wood ash.

WOOD ASHES, WHAT'S IN IT?
PER 100 LBS. DRY,FRESH ASHES
CHEMICAL amount
calcium oxide 20-80 lbs.
Potassium oxide 10-30 lbs
Magnesium oxide 5-10 lbs
Phosphorus pentoxide 2-8 lbs

Micronutrients (trace amts.)
copper
zinc
manganese
iron
sodium
boron

Wood ashes contain Calcium Carbonate, a form of lime, and will help PH.
One ton of dry wood will produce 4 to 20 pounds of ash (0.2-1.0 percent, depending on wood type
Approx. 50lbs ash per cord of hardwood.

As you can see, it's not much, but every little bit helps.

Russ