From a recent Fender report regarding the use of Ash in their bodies:
"When we were redesigning some guitars, we made these exact guitars out of the same everything, same necks, same parts - changing just one thing on each one. We did ash versus alder to hear the differences. Ash was my tonal preference, it has a little more of a scoop in the mids. Alder has more of a peak.
“I would say ash has a great sound, especially when you are jamming at home by yourself. When you are playing with a band and need to cut through, the alder has a better peak and allows you to claim more space in the song. But there’s a warmth to ash, that’s what people love about it.
"Alder is a more consistent and occupying sound in the mix. It’s just a matter of preference. Every piece of wood is different. Recently, we had six of Tom Morello’s guitars lined and we were going through them with Tom and each one sounded a little different, just because of how the neck and body come together.
"It’s like a recipe, you can make it time and time again, it will always be a little different. Wood has its own character, you can pull three or four guitars made on the same day and they will all feel and resonate differently… that’s the beauty of it.”