How did you determine the pH of your soil was 5.0? A lab test or a home test kit? If a home test kit please get a lab test done prior to doing anything to change the pH.

Wood ash does raise pH, but the contents of one fire spread over a garden isn't likely to have much affect.

If your soil pH really is 5.0 in the garden area it is probably pretty close to that everywhere else.

Either plant lots of blueberries or use lime to raise it to 6.0-6.5. Get a lab test first though, please.

The Calcium Carbonate in wood ash is very water slouble so it would quickly change the soils pH and then that soils pH would after a short time revert to what is was, wood ash does not change your soils pH very long. Of course that depends on how much wood ash was put down and what else is going on depends on how much of that poultry manure was put down.
What was the soil pH before this was done?
What was used to determine this soils pH?

Wood ash contains calcium, Ca, but not much if any calcium carbonate, CaCO3. It is the positively charged base cations such as Ca++, Mg++, K+, Na+ that cause the pH to increase. These nutrients are readily taken up by plants or leached out of the soil in a year or so. Heavy, repeated use of wood ash in the garden can be a problem.

If your soil has a pH of 5.0 and you ar growing vegetables, it would be beneficial to get it above 6.0.

Here is a link that might be useful: Wood Ash

Rock dust is what you're looking for. Gypsum, lime, granite dust, and the like. They contain metals that will raise the pH of your soil and provide necessary trace minerals.

I would start with granite dust just to make sure the soil has the micronutrients, then I'd lime it. If you live in an area with decent rainfall, you'll have to continue to treat the soil over the years to keep its pH high.

According to Purdue, and several other Ag schools, wood ash is about 25 percent CACO3.

Here is a link that might be useful: About wood ash

This is a fine point.

Are they refering to actual CaCO3, limestone, or are they refering to calcium carbonate as an acid-neutralizing equivalent?

Lime, limestone, calcium are terms used and not always used correctly.

The point I made is that it is the base cations which are responsible for the pH change and Ca++ is not the only base cation in wood ash.

Here is a link that might be useful: THE VALUE OF WOOD ASH

According to your Ed Hume link Ohio State University says wood ash is 45 percent CACO3, " A report by Ohio State University reports that wood ashes are 40 to 50 per cent as effective as calcium carbonate in acid-neutralizing equivalent, being about 45 per cent calcium carbonate. In other words, it takes about twice as much ash to do the job of lime."