Many climbers are killed. A professional climber truly lives life near the edge on a daily basis. Good climbers are rare individuals. That's the bad news. The good news is that you don't have to climb to be an arborist.
Trees get sick just like humans.
It takes a sharp person to figure out what a tree needs to get better. There are many clues to read, just like a detective does. It takes a knowledge of trees to know what tree to plant and where to position it so it doesn't have to be cut down when it grows to its mature size. The subject of tree care is large. Trees are the largest living things on this planet.