Aspen and pine landscape

Ahhh, so the Birkenstock shoe company is Birchstock! Wow, my brain just exploded. Anyway, these look like birch trees, but they aren't. oregonforests.org/tree/quaking-aspen. They are all over North America, especially higher altitudes. You wouldn't want to import them to Europe because they sprout new stems from the roots, thus becoming invasive.