Can ashes be used as a mordant?

I need someone to help me understand some terms that I am confused with.

I am working on expanding my knowledge of Wood Ashes and found in my research that apparently it has some utility to dying natural fibers. I am finding conflicting information and terms that are foreign to me so any clarification is greatly appreciated.

My understanding of the term 'Mordant' is that it means a substance that helps stain/dye 'stick' to fibers. Ashes in water can make an alkali bath that does... something similar? Does that make ashes a mordant?

Thank you for helping me with me research!

For wool and other natural fibres dye, ashes are more often used as a modifier (change the colour) than mordant.  Mostly by modifying ph in an after bath.  

Ashes are also used to clean (scour) the fibres prior to dye.

With wool, one needs to be careful as alkaline will quickly degrade the fibres.

There aren't enough of the right minerals in ashes to easily use as a mordant, but it does have a lot of other uses in dyeing.

I think the book The Dyers Garden would be a possibility to learn more on ashes in dye, but I don't have the book handy to check.

As a side note, many modern resources written in the last 25 years, confuse mordant and modifier and activator.  

Example, synthetic dyes often use vinegar to activate them so they can stick to wool.  Natural dyes use vinegar as a modifier which changes the ph and causes different colours to stick.  

Therefore, many modern authors think vinegar is a mordand.  Sadly  it's not.

Backing up what r ranson says above.  A mordant forms a chemical bond between the fibre and the dye medium and needs to be an metal salt - usually alum; other metal salts like tin, copper and iron can be used, usually to alter the colour (a modifier also! just to add to the confusion) Then the colour may be further altered by making the dye solution alkaline - where the wood ash liquor comes in. However, the strenth of the solution is difficult to control. Caution advised as wool dislikes alkaline solutions with a passion.  It's better used with cotton and other plant fibres.  NB We are talking natural dyes here!
Short version:  Alum = mordant  Wood ash lye = modifier.

Thank you both for the replies, I think I have a better grasp of the mechanism of action for ashes in the process. I have some more reading to do!

HIstorically, wood ashes would be used as soap. The ashes would sit in a vessel, e rained on, and the leachate collected. In days when clothes would seldom be washed, they'd get right greasy. Grease + potash makes soap. Similarly good at pulling the natural, beneficial oils out of your skin!