Southern Pine Beetle
Southern Pine Beetle
The southern pine beetle is about the size of a grain of rice, but with the help of its friends it can cause great harm to healthy pine forests.
Trees that are attacked will produce pitch, a sticky fluid from inside the tree. The beetles must push it out of their galleries to survive. By pushing the pitch out, the beetles create popcorn-like pitch tubes all over the bark.
The dark stripes are caused by a fungus carried by the beetles! The fungus infects the tree and blocks the xylem (water transport cells) of the tree, causing the tree to die from lack of water.
Beetles chew through the bark of the tree creating tunnels, or galleries, in which to mate and lay their eggs.
Pioneer beetles find a new tree to call home, and then release a pheromone (a chemical scent) to call other beetles to the tree. When there are too many beetles living inside one tree, they spread outward to other nearby pine trees.
If a beetle attack is successful, the beetles will kill the tree. Trees that die from a southern pine beetle attack have loose bark that peels off easily.
Virginia Pine: This scraggly-looking pine has short needles (1-3” long), with oval-shaped cones that have some razor-sharp spines!
Loblolly Pine: Very tall pine—usually 50’ or taller! It has a straight trunk with only a few lower branches. The needles are very long (6-10”) and are stiff with little serrations. The pine cones have very sharp spines!
Pine: This pine tree has bark divided into large plates and light brown cones. Do the edges of the needles feel sharp to the touch? The needles of this tree have little teeth, and are 3-5” long.
Southern pine beetles are native to the southeast United States, and are good for forests when everything is in balance. Beetles usually only attack weakened trees.
Unfortunately, because of the ways humans have changed the Earth, the number of southern pine beetles is too high, and they are affecting even healthy pine trees.
Most of the land in the United States has been cleared for agriculture and later replanted by humans. When people replant forests, they often plant the same few types of trees too close together. This forest that is completely made up of pine trees of a similar age is at risk of a beetle attack!
Forest fires aren’t always bad! Regular fires actually help a forest resist southern pine beetles by creating space for new, healthy plants. Humans stop forest fires, so beetle numbers are rising.
Pollution from humans is causing the climate to warm, and in some areas of the world, more severe droughts occur. The southern pine beetle loves warmer temperatures and drought-stressed trees!
Foresters thin forests to keep them healthy by cutting down some of the trees. When the remaining trees have enough room to grow and don’t have to compete with other plants for water and nutrients, they can defend themselves against beetle attacks.
If beetles are found, all the affected trees must be removed immediately.
After a forest has been attacked, foresters replant it with trees that the southern pine beetle doesn’t like to eat, like longleaf, slash, or eastern white pine.