Actually they are indications of pure air but also lichen on a tree indicates that the tree may be in declining health. Lichen is a combination of algae and fungus and grows very very slowly. Moss is an indication that there needs to be some better air circulation on that tree. Consider a good pruning in early spring.aving lichens and moss on your tree is an indication that the air around your tree is healthy and clean. They do not harm the tree. They have synergistic relationships with the biosphere of the tree that are more interesting if you leave them there.
Officials said Nevadaâs Lake Mead, the 79-year-old reservoir created by the massive Hoover Dam, registered 1,074.98 feet (327.7 meters) above sea level late on Tuesday, but was able to rise above a critical mark by early on Wednesday morning.
Hoover Dam is 1,244 feet long at the top. It is 726 feet high from the lowest point of the foundation to the crest. The dam is 660 feet thick at the base and tapers to 45 feet thick at the top. Its reservoir was the largest artificial lake in the world for decades and is still the largest in the United States.