Saturday, October 4, 2008
Throughout ponderosa forests, there are lots of trunks with areas of missing bark: The bark is eaten by porcupines, who have long claws to cling to the tree and strong teeth to pull the bark off with. They eat the inner bark (phloem) and needles in the late summer, fall, and winter when the green plants they eat in the spring and summer are no longer green and tender. When the porcupines eat the bark in a complete ring around the tree, it is girdled and nutrients can no longer flow from the roots to the needles and back, killing the tree. But most trees are left enough bark to stay alive and continue feeding more porcupines.