Betula papyrifera resistant to the borer but when grown in subideal conditions the defense mechanisms of the tree may not function properly. Chemical controls exist. It is the provincial tree of Saskatchewan and the state tree of New Hampshire. People sometimes vandalize the bark of this tree by carving into it with a knife or by peeling off layers of the bark. Both forms of vandalism can cause unsightly scars on the tree. Betula papyrifera Betula papyrifera (paper birch, also known as white birch and canoe birch) is a short-lived species of birch native to northern North America. Paper birch is named
Cyclocarya female catkins 25–30 cm long at maturity, bearing several small winged nuts with a circular wing 2.5–6 cm diameter right round the nut (instead of two wings at the sides as in "Pterocarya"). Cyclocarya Cyclocarya is a genus of flowering plants in the family Juglandaceae, comprising a single species Cyclocarya paliurus (qing qian liu or wheel wingnut), formerly treated in the genus "Pterocarya" as "Pterocarya paliurus". It is native to eastern and central China. It is a deciduous tree growing to 30 m tall. The foliage is similar to "Pterocarya", with pinnate leaves 20–25 cm long with five to eleven