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.
Named one of the Top 10 Construction Achievements of the 20th Century, Hoover Dam continues to draw crowds 80 years after its creation. Attracting more than a million visitors a year, Hoover Dam is located in Black Canyon, just minutes outside of Las Vegas. On April 20, 1931, construction began on the Hoover Dam, the largest of its kind at the time. Despite the remote location and harsh working conditions, it was completed on March 1, 1936 in less than five years -- two years ahead of schedule -- and well under budget.