Answer: Trees sometimes are host to moss and lichen due to overly moist conditions but the lichen has a greenish tint rather than being white. If there is lichen, you can use a bordeaux spray (lime sulfur) to kill it and it will eventually weather away. If it is a white colored growth, it, too, is a fungal growth and bordeaux will kill it, but not control the underlying cause. Be sure to do a little detective work to find the cause. The drainage may not be as good as it should be and than can cause root rot over the years.
Q&A Library Searching Tips