Unknown #2 is a Black Cherry (Prunus serotina)

Here is a link that might be useful: Images

I would guess Viburnum dentatum for the first one and certainly a Prunus for the second, but it can be tricky to determine which one.

I like the USDA Plants database and often they have county distributions, but apparently not for Maryland.

They have distribution maps by species (e.g., Prunus serotina) and they also have a plant at the genus level (Prunus). From the genus page you can scan all the species and click on any one of them to go to their profile page.

Again, it is unfortunate they don't have data for Maryland.

Here is a link that might be useful: Prunus page

But the silvics manual from the us forest service does have a dist map for pin cherry. It is below. It probably is native to md even if it is not quite shaded in as is the case with a few trees that I know of.
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Here is a link that might be useful: more likely to be black cherry

It is defiantly not a pin cherry. The only two cherry trees it would be between would be Chokecherry (Prunus virginiana) and Black Cherry (Prunus serotina). Chokecherry grows red berries when mature and Black Cherry like the name grows black cherries. The leaves do not look like a Chokecherry to me so I would call it a Black Cherry (Prunus serotina).

Try identify tree by leaf website. Thanks for the pix.

Black cherry looks good for #2.

The Viburnum dentatum is close, but the leaves are more densely toothed -- about 17/side instead of 9 or 10 per side.

I had identified a different plant as "Common Chokecherry" -- rounder, simple toothed leaves, with a cherry-like bark, similar height to the Black Cherries above.

However, the fruit come in "sprigs" of about 20, each on an individual stem coming out of a single point. Right now (July 9), the fruit are green and about 1/4" diameter. I'm wondering whether they are something else, whether Crab Apple or something different.

Thanks,
Jeff