Paper birch, Betula papyifera, is also known as white birch, canoe birch, and silver birch. The standard paper birch is considered to be the papyrifera variety, but there are five other varieties that can be intergraded by geography. The paper birches are the most widely distributed birches in North America, dominantly in Canada.

While medium sized, the paper birch is a fast growing tree. Within 30 years, a tree trunk often has a diameter of 8 inches, averaging 10 to 12 inches later during maturity. Paper birches are considered mature in 60 to 70 years. The paper birch averages 70 feet in height, though larger trees exceed 30 inches in trunk diameter and 100 feet in height. The paper birch typically has a life span less than 140 years, making it short-lived, although can grow to 200 years.

The paper birch thrives on well-drained albeit cool and moist sandy loams, though it tolerates a range of precipitation amounts. The tree is adapted to cold climates, and can live at high elevations and on slopes with a northern aspect, meaning it does not require maximized sunlight. However, it has some difficulty growing in soils with shallow permafrost. The paper birch also tolerates relatively high amounts of aluminum with no issue, though it is nutrient-sensitive. In particular, nitrogen, phosphorus, and lime have positive effects on the paper birch. Paper birches are shade-intolerant. Paper birches are also less tolerant of flooding than river birches.

The rapidly decomposing leaf litter of the paper birch can add calcium, potassium, magnesium, phosphorus, and nitrogen to the soil, as well as increasing pH.

Paper birches can flower from mid-April through early June. The flowers are monoecious. Seed production begins at 15 years, with peak seed crops occurring in trees between 40 and 70 years of age. The fruits are winged nutlets with seeds ripening from early August until mid-September, though maturation and seed dispersal can occur earlier, as early as July, with injured trees. As the nutlets are winged, seeds can be spread very far, but most merely fall near the parent tree.

Paper birches can also regenerate from cuttings and sprouts.

During the 1930s and 1940s, birch dieback killed or damaged a large percentage of papers birches, but is no longer considered a big threat. The bronze birch borer is a serious insect pest that targets overmatured paper birches. Other insects, microorganisms, and conditions can affect paper birches as well. Furthermore, due to the thin, flammable bark, paper birches are susceptible to serious damage or death fire. Finally, human vandalization of the bark is often an issue in parks.

Lots of animals eat the leaves, seeds, buds, and bard of the paper birch, including deer, porcupines, and birds. Humans also produce syrup, wine, beer, and medicinal tonics using paper birch sap.

On campus, one may see an example of a white birch in the Simon Center parking lot.

The river birch, Betula nigra, is also known as the red birch, the water birch, and the black birch. The river birch can grow 50 to 90 feet tall, though averages around 40 to 50 feet.

While its range stretches across the southeastern quarter of the United States, several areas are excluded, notably, the southern half of the Mississippi River flood plain, the Appalachian Mountains, and several notable limestone areas, including lower coastal plains and parts of Missouri, Tennessee, and Kentucky.

While the river birch is typically found below 1,800 feet in elevation, it has been found higher, closer to 2,200 feet. Furthermore, it is possible that the lack of specimens in mountainous areas is due to the relatively little alluvium, or unconsolidated stream sediment, found at higher elevations.

While elevation is less variable than some species of tree, the river birch can be found in a wide range of climates. It prefers hot, humid areas with little frost and high precipitation, but it is present in areas with less precipitation and higher amounts of frost as well.

River birches prefer moist, alluvial soils with clays, though it can sometimes be found on drier soils, such as the confines of prairie areas. Even though the river birch thrives with high moisture, it is not very resistant to flooding. This could explain why the river birch is not found on the southern portion of the Mississippi River flood plain. Additionally, river birches are very tolerance of acidic soils.

The flowers of the river birch are either male or female, although both male and female flowers can be found on the same tree, making it a monoecious species. Male catkins can be found on the tips of twigs starting in the fall, though only mature the following May or April. Female catkins, instead, are found along the twigs as the leaves come out. River birches, like many other birches, produce copious amounts of pollen.

Flowers then open in early spring, with fruit appearing as late as early summer. Seeds are small and winged, in order to be carried by the wind or by streams. River birches produce good seed crops nearly every year, but are the only members of the birch family that do not produce seed in the fall.

Unlike many other birches, the river birch has reddish brown bark, which tends to peel into paper-like curls. Though the crown begins oval or pyramidal, as the river birch becomes older it spreads wider, with average spreads of 25 to 35 feet.

The river birch is shade intolerant. The river birch is relatively disease-free, and while it can host insects few serve as serious pests. Floods and floating ice along streams can kill riverbank trees.

Prince Maximilian, before becoming Emperor of Mexico, described the river birch as the most beautiful American tree, and it is frequently used in landscaping. Furthermore, the river birch has been used to reclaim strip mines, as it is tolerant of acidic soils. It is also used in the production of inexpensive furniture. The river birch is considered threatened in New Hampshire.

A weeping river birch of the ‘Summer Cascade’ cultivar can be found west of Markle Hall.