I actually think the trees work really well with the water texture right now. To my eye, the problem is the abstract nature of the land and settlement markers outside the marshes (the dots, NOT the Ancient Realms circular symbols, which are fine), and especially the coastal edge and sea lines with the water texture there. Those really jar to me, as compared with the near-photo-realism of the marsh water and trees.

As Ricko wrote though, it really depends what the viewing level will be for the final map.

I can't usefully advise you what I'd do, because I don't design maps the same way as this, so the situation doesn't arise. I tend to pick a style I like for what I'm intending to map (or sometimes several matching styles, or complementary ones that are sufficiently similar to work together), and draw accordingly. I might add a few symbols or fills from elsewhere that aren't in the original(s), or repurpose some that are to be different from what their labels indicate. That's not the same as what you're trying to create here though.

Conversely, I think the trees work rather well with the watery swamp texture currently, though those don't work quite so nicely with the other textures involved. This can be a problem when trying to mix styles, of course.

If you need electronic image versions to trace into a CC3+ map, North Carolina Maps may help, if you haven't bookmarked their site already, that is!

I think the snag is that volcanoes tend to be, and make, their own mountains, so they'd typically affect how the mountains nearby look as well - that is, they'd blend into one another completely. Right now, they look a bit too much dropped-in-from-space.

That can work in some cases, where the volcanic mountain is quite isolated especially - the classic example might be Olympus Mons on Mars, which has a vast cliff almost all around its outer base.

However here, the symbols look rather out of place currently in both versions.

There is a mass of fractal entities on that sheet Cal, which is making things run VERY slowly overall, and it may be this which is causing you so much grief.

This is just from a very quick check through, however, and I'm sure Sue's assessment will be far more useful!