Terms in this set (100)

The southern pine beetle is about the size of a single grain of rice, but it is the most damaging insect, causing millions of dollars of damage to southern pines each year. It mainly feeds on the loblolly, shortleaf, pitch, and Virginia pines, but it will feed on any pine tree that is dead, dying, or weakened by some other force of nature. Pine trees are often attacked by more than one type of beetle at the same time. Each beetle attacks a different section of the tree; the southern pine beetle is usually found in the lower portion of the tree just above the stump while the Ips beetle are usually found higher up on the tree's trunk. It can kill a pine tree by itself. It does this by boring through the bark of the tree and making galleries, or paths, which look like the letter S. Females lay their eggs on the sides of these galleries. When their eggs hatch, the larvae eat through the cambium, or living part, of the tree. This stops the flow of water and nutrients to other parts of the tree, killing it. The adult beetles also eat the cambium of the tree. Blue stain fungus, which lives inside the beetle, is excreted in its waste and hastens the tree's death by also blocking water and nutrient intake. The first signs of an attack are small lumps of pitch on the outside of a pine tree. These pitch tubes are about the same size as a kernel of popcorn. When the beetle bores into the bark, the tree produces pitch to try to keep the beetle out. Weakened trees cannot produce enough pitch to keep the beetles out. The next symptom is the small S shape paths, or galleries, found on the inside of the bark. The last and most noticeable symptom is the needles changing from a healthy green color to yellow, red, or brown in color. Once the needles of the tree have started to change colors, there is little that can be done to save the tree.
One such ecosystem, found in North Carolina, is the long leaf pine forest. Organisms found in fire dependent ecosystems often have special adaptations that enable them to survive the fire and/or use the fire to their advantage. In the past, fire has burned the long leaf forest, on average, once every three to five years. To survive fire, the long leaf pine has an unusual growth pattern: During the first few years of its life, known as the "grass stage," it doesn't appear to be growing. It looks like a small clump of needles growing from the ground. The actual tip of the tree is not visible, because it is surrounded by dense needles. The real growth is going on underground. It sends a thick and sturdy taproot deep down into the soil. This large root provides all the water and nutrients the young tree needs and firmly anchors it in place. If a fire burns through the area during this stage, it may burn up the needles that protect the tip, but rarely burns the actual tip of the tree. The burned needles are quickly regrown by the young tree. Usually after seven or eight years, noticeable growth begins. The long leaf may grow three to four feet a year once it begins the pole stage of its life. The tree is tall enough after one year's growth for its growth tip to escape wildfires, provided there is not much fuel on the forest floor. Another adaptation is the thick bark of the mature tree, which protects the inner, living tissue from harm. The fires stop natural succession by killing young turkey, blackjack, and post oak that would eventually prevent the growing long leaf pines from receiving enough sunlight. The seeds of the long leaf pine need cleared ground to reach the soil and germinate. The fire clears the forest floor and returns nutrients to the soil, favoring the tree's reproductive success. Some other pine species are also adapted to fire; the cones of the pond pine will open and drop their seeds only in the heat created by fires.