You are here. Cross U.S. Borders. Almost a million times each day, U.S. Customs and Border Patrol (CBP) officers welcome international travelers into the U.S. In screening both foreign visitors and returning U.S. citizens, CBP uses a variety of techniques to assure that global tourism remains safe and strong.
Reaching heights between 40 and 70 feet, the river birch is one of the hardier birch trees. They grow best in full to partial shade and thrive in well-drained, slightly acidic soils. The river birch is not a drought tolerant tree, preferring sites that are wet.aper Birch (Betula papyrifera). Paper birch trees are large, oval in shape and may be single or multi-trunked. They reach heights between 50 and 70 feet. Younger trees have brown bark, as trees age the bark turns white and peels to reveal an inner bark that is orange in color.
Betula pendula, commonly known as silver birch or warty birch, is a species of tree in the family Betulaceae, native to Europe and parts of Asia, though in southern Europe it is only found at higher altitudes.ilver birch. The silver birch is a medium-sized deciduous tree, typically reaching 15 to 25 m (49 to 82 ft) tall (exceptionally up to 31 metres (102 ft)), with a slender trunk usually under 40 cm (16 in) diameter.