Wild cherry or sour cherry ?

[MRRELAXATION]

Hey guys ! 
 

got another tree here 

 

definatly a cherry tree but is there ang way to tell if its a wild or sour based on the photo below ?
 

if not then what do you suggest, shall i look at the bark or wait to see what it fruits ?

 

and of course if anyone has another suggestion of what it could be very welcome

 

i didn't get the chance to take a photo of the bark or shape from a distance l, so understandable if theres no hope identifying it from the many cherry trees out  there 

 

i want to say sour due to the lack of fur beneath