Many years ago, when I was growing up on a farm in south Alabama, I remember being fascinated by how some fence posts sprouted and became trees. The posts had been cut from black willow trees that grew in nearby pasture lowlands, where they thrived with alders. I have always been fascinated by this regenerative nature of the black willow.
The black willow, or Salix nigra, has a range determined by moisture, not temperature, and it is found throughout the eastern United States and adjacent parts of Canada and Mexico. These trees do best where rainfall is over 50 inches per year, and they do not tolerate dry spells. They are common in areas of moist or wet soil like swamps, marshes, drainage 
ditches, ponds, rivers and streams. Black willow trees have an uneven profile, due to broken limbs and the many suckers and shoots that form at the breaks. The fact that the wood is weak and prone to breakage is not a fault but an adaptation to its preferred wet environment, as the broken limbs and twigs root very easily in the muddy environment they fall into.
The dense root system of the black willow is useful for helping keep soil from washing away on eroding land, embankments and stream banks. These trees are thirsty and will help soak up water from troublesome boggy areas. When a black willow is found, it is often hard to know if it occurred naturally or was planted.
Leaves on the black willow are alternate, simple, and lance shaped. They are pointed at the tip and have very fine teeth along the edges. The base of the leaf is tapered or wedge shaped and on a ¼ inch or so petiole (short stem). Leaves are 2 to 6 inches long and ¼ to 2/3 inch wide. They are medium to dark green and smooth on the upper surface and slightly paler on the lower surface. At the base of petioles are small 1/8 inch or so ear-like lobes called stipules. The petioles are attached to smooth twigs that reach upwards.
Reproduction of black willow is through not only rooting pieces of the tree but through seeds. Male and female flowers (on 1 to 3 inch long 
catkins) are yellow and occur on separate trees. They are pollinated by bees and butterflies and other insects. Female catkins produce fruit which are reddish brown capsules that hang in clusters 3 to 6 inches long. The capsules have two valves and they contain tiny, hairy green seeds that are spread by wind and water. These seeds need to find a seed bed quickly or be kept wet as they are no longer viable if they dry.
The black willow tree often grows 30 to 60 feet tall with a trunk diameter of maybe 2 feet, but trees have been reported that were 12 to 140 feet tall and with diameter of over 8 feet. The trunk of a young tree is grayish brown with shallow furrows and flattened ridges. Older trees are 
mostly gray to nearly black, and are covered with deep curving furrows. The black willow gets its name from the color of its bark.
Black willow has had many uses other than for preventing erosion. Black willow was converted into charcoal by pioneers for making gunpowder. The flexible tree limbs are used for wicker-work furniture and baskets. The wood is moderate light to light density with somewhat interlocking grain, and does not splinter easily. It is considered a soft hardwood. It has no characteristic odor or taste. Because of these qualities it has been used for toys, barn floors, shipping crates, barrels, furniture, cabinets, woodenware, paneling, and even artificial limbs. Indians used various parts of the tree for many 
ailments, and in the 1840’s chemists isolated salicylic acid from the tree and found it produced marked fever and pain reducing effects. Modern aspirin is a synthetic of salicylic acid.
Black willow is an interesting and useful tree. It has touched all our lives, in ways we probably are not aware. It is a good tree to know, and have around.
