Hi again,

I could not find the pictures I took of my river birch last summer so
I had to retake and unfortunately there is no leaf on the tree now.
So I'm not sure how useful it is with the identification, but to show
the difference in the amount of barks my river birch and the river
birch that I like have look at:

My river birch: http://i43.tinypic.com/2dvijxg.jpg

The river birch that I like: http://i41.tinypic.com/2s0hilg.jpg