Those leaves look a bit like beech tree leaves to me.

What kind of beech? Our native beech of Central Europe Fagus sylvatica looks totally different. The leaves of this unknown species are quite glossy.

du hast einen Strauch. Leaves opposite? prolly viburnum, show us the buds.

Sam, that was my first impression.

Regarding the beech possibility, you’re exceeding my knowledge! I’m in New Jersey, east coast North America, and here is a shot of the beech leaves in the woods behind my house.

Oh, maybe vibernum. There are about a zillion kinds, though, varying widely. I have two kinds of vibernum in my yard: Korean Spice and Allegheny. Neither looks like your leaf. I think of vibernum more as a shrub than a tree, though some (like the Allegheny) can get quite tall and bushy. Would you call your mystery plant more of a shrub or a tree?

I have another photo, but it's not very good.

@baileysr: Sam wrote for me in German that it is a shrub. It was about 3 meters (10 ft) tall. Calling it a tree was maybe a bit exaggerated.

Ich habe an diesem ammerländer baumschulen gearbeitet. Ich habe meine deutsche Sprache verrgessen :(

Oh, interesting, Sam :)

baileysr

Regarding
the beech possibility, you’re exceeding my knowledge! I’m in New
Jersey, east coast North America, and here is a shot of the beech leaves
in the woods behind my house.

That's hornbeam, not beech.

Regarding the shrub in the starting post, I think we need to see sharper and closer pics of buds and flowers or seed. Those glossy leaves look a bit evergreen.

Thanks for the info! For 25 years I’ve been living with the assumption I had a bunch of beech in my woods. I had to google hornbeam...never heard of it before.

Plant asked about in original post is a Burkwood viburnum.

@Embothrium,
yesterday I was searching for viburnum-species. And I found Viburnum x burkwoodii
which resembles my unknown plant. But I’m not totally sure because there are a
lot of kinds of viburnum and hybrids. How do you know that it is a Burkwood
Viburnum? Do you own one?

Hi guys! I
walked today to the park and I took photos… I found fruits on the shrub, but
they aren't ripe yet.They really look Viburnum-like to me.

Yes, it's certainly consistent that a Burkwood viburnum would have viburnum-like fruits.

https://www.bing.com/images/search?q=viburnum+burkwoodii+fruits&qpvt=viburnum+burkwoodii+fruits&FORM=IGRE

Yes, it's certainly consistent that a Burkwood viburnum would have viburnum-like fruits. I wasn't sure if it is a viburnum before, but I think that there is no doubt anymore that I have found a Burkwood viburnum.

This forum is great!

Thank you all for your help.

You're welcome. I of course didn't have any doubt since last Friday - it's a pretty distinctive and familiar shrub, long a kind of standard item at retail outlets in my area. If "nobody" knew it where you are maybe you need to start asking different people there.

Your first picture of the park specimen shows flower buds, not fruit. This shrub blooms in winter or very early spring and is evergreen and highly fragrant. A common shrub here in the British Isles.