Reforestation

Reforestation is the growth of new trees in an area that has been cleared for human activities. It can occur naturally or be initiated by people.

Many areas of the eastern United States, such as the New England region, reforested naturally in the nineteenth and early twentieth centuries after farmland that had been abandoned was allowed to lie fallow for decades.

Slash and Burn Agriculture

Slash-and-burn agriculture, also called swidden agriculture, is a practice in which forestland is cleared and burned for use in crop and livestock production. While yields are high during the first few years, they rapidly decline in subsequent years, leading to further clearing of nearby forestland.

Slash-and-burn agriculture has been practiced for many centuries among people living in tropical rain forests. Initially, this farming system involved small populations.

Soil Contamination

Soils contaminated with high concentrations of hazardous substances pose potential risks to human health and the earth’s thin layer of productive soil.

Productive soil depends on bacteria, fungi, and other soil microbes to break down wastes and release and cycle nutrients that are essential to plants. Healthy soil is essential for growing enough food for the world’s increasing population. Soil also serves as both a filter and a buffer between human activities and natural water resources, which ultimately serve as the primary source of drinking water.

Soil that is contaminated may serve as a source of water pollution through leaching of contaminants into groundwater and through runoff into surface waters such as lakes, rivers, and streams.

Addax

The addax is a large antelope whose coat is gray-brown in winter and almost white in summer. Black hair sprouts from its forehead and from the end of its 10- to 14-inch (25- to 36-centimeter) tail. Two long, thin, spiral horns (each twisting two or three times) extend up and back from the front of the animal’s head.

An average addax measures about 5 feet (1.5 meters) in length and about 3 feet (1 meter) in height at its shoulder. It weighs between 132 and 287 pounds (60 and 130 kilograms). A female addax usually gives birth to one infant after a gestation (pregnancy) period of eight to nine months.

Giant Armadillo

The giant armadillo is the largest member of the armadillo family, which is composed of twenty–one species. Eleven to thirteen moveable bony plates cover a giant armadillo’s back, and three to four flexible bands cover its neck.

Its body is dark brown, while its head, tail, and a stripe around the bottom of its shell are whitish. A giant armadillo measures 30 to 39 inches (76 to 99 centimeters) from the tip of its nose to the end of its body. Its tail is about 20 inches (50 centimeters) long. It weighs between 44 and 88 pounds (20 and 40 kilograms).

African Wild Ass

The African wild ass is one of only seven surviving species of equids (horse family). Of these seven species, five are threatened or endangered. The smallest member of the horse family, the African wild ass stands about 4.5 feet (1.5 meters) tall at the shoulders and weighs about 550 to 600 pounds (250 to 275 kilograms).

It has a gray coat with a white belly and a dark stripe up its back. With its long ears and short stubby mane, the African wild ass looks like its cousin, the American domestic donkey, and is in fact the donkey’s ancestor.

Aye-aye

The unusual-looking aye-aye is covered with a coat of coarse blackish-brown hair, which overlays a denser coat of short white hair. The animal has very large, sensitive ears that stick out from its small, rounded head. It has sharp, rodent-like incisor (front) teeth and long, claw-like fingers and toes.

An average aye-aye is 15 to 18 inches (38 to 46 centimeters) long from the top of its head to the end of its body. Its bushy tail measures 16 to 22 inches (41 to 56 centimeters) long. The animal weighs between 4.4 and 6.6 pounds (2 and 3 kilograms).