Fifteen year old American cherry flooring 2.75 inch t&G in the kitchen and dinning area. Not subject to direct sun light (north side of house). I wanted the wood a bit darker then natural and the professional indicated that would not be a problem. Floor was sanded then stained with an oil based stain to darken the color.
I do not like how the stain was absorbed by the wood. There are vertical darker splotches across grain of some boards where more stain was absorbed. The splotches are like a paint roller that had paint on only one side of the roller was run the length of the board. The stains do not run board to board or are they on every board. My assumption is that sanding opened some of the grain in these areas more then in other areas. There is no relationship that I can see between the splotches and the grain of the board.

The intent was to put down Bona High Traffic as two finish coats. I indicated to the professional that I was not happy with the stain and not to continue with the Bona until he could resolve the stain issue and that I was willing to share the cost of sanding and although not staining this time if the problem persists.

Professional indicated:
That staining like this was normal and it happens with most wood flooring.
Bona requires a sealer. A sealer used on sanded floor would give the same results as the stain on a sanded floor.
Other finish products are available that do not require a sealer but those products have a tendency to yellow quickly.

Is the professional correct? I don’t want a splotchy stained floor or one that if left natural will yellow quickly. Is there a solution I can offer the professional when I call him back?
thanks

It's called blotching and is normal for cherry, especially when using an oil based stain on bare cherry.

I don't have any experience finishing hardwood flooring, but I do have experience finishing cherry furniture.

If I was finishing cherry furniture I would apply a 1lb cut of dewaxed shellac, and when dry, lightly sand it with 320 grit. Then I would apply a gel stain, and only do a small section at a time, where you can wipe off the excess gel stain after three minutes. Wait too long to wipe off the excess and you'll have a sticky mess. After at least 24 hours of drying, I would apply the clear finish.