Aww, it's just deceptively photogenic. Like me Up close, the girls in the office said yukk (about both of us) -- of course they like the nice shiny boo ones I make.
Sweet birch is Betula lenta. Also called black and cherry birch. Has unmistakably birch leaves with bark sort of like black cherry. Both yellow birch (B. Allegeniensis grow all over eastern US and are in the low to mid .60s specific gravity range.
Dave