Lightroom auto tone

It seems to me that if I crop an image in Lightroom and then do an Auto tone, it measures the whole image as if it were not cropped. I need to export as jpg then do an auto tone in Photoshop. I notices this today when I was cropping out large sections of snow. Am I doing something wrong?

Thats the way it has to be. You have to remember that when you crop in LR you aren't really cropping, merely adding another line to the list of instructions to be cared out at export, so the auto levels still has all the image data available to it.

Personally, although I import with an auto levels preset, I almost always lower the white point because it is based on LR's wide gamut internal space and a bit more headroom will be needed when it is exported or printed to a narrower gamut.