seriously? Red oak and white oak, it's pretty self explanatory.

I have used wood from the same tree, stained with the same can of stain, and gotten differences in color. Using wood from a lot of different trees of the same species will always result in color variances. Different lots of stains can have slight differences.

Now, different species of wood will look different with the same stain because the differences in raw wood color and grain composition. Pine/etc. has two distinct grain, one is harder(darker) than the other softer areas(lighter). The softer grain absorbs stain better and becomes darker. The harder grain does not absorb stain nearly as well and often is lighter than the softer dark stain color.

Now, all those factors have to be considered. But there is more. Sanding is often done before staining. The final sanding grit has a huge effect on stain color because of how burnished the wood surface is. Final sanded wood with 150 grit will be darker than the same wood with a final sanding with 220 grit. Reason? The finer grit closes the pores more, less absorption of the stain by the wood.

And still more. The finish used(and number of coats in some cases) can add color as well as sheen. Matte finishes often look like a different tone of color than semi-gloss.

And another, age. Many woods darken naturally with age. Cherry is a prime example. Cherry is a light reddish toned wood when cut. It can darken to a medium brown with age. There is a type of wood(several species) called purpleheart. Some variaties turn brown rather rapidly(weeks or months). Put in sunlight, the purple color returns in a day or so.

One last item. Factory stains and finishes are sometimes a recipe of ingredients to get a specific look. Example, I once had to match the trim color in a factory built house. Rather than experiment and since the factory had shorted the trim and supplied unstained replacement trim, I contacted the factory and got the recipe---four different stains in four different amounts and a water based non poly varnish. I made sure none of the new trim was inline with the original because it was a close but imperfect match.