I have a maple tree in my yard that I want to clone. Please advise as to the best method.
The following article should be of some help to you: https://www.gardeningknowhow.com/ornamental/trees/tgen/how-to-root-cuttings-from-various-shrubs-bushes-and-trees.htm
What do I need to do? Is there some kind of chemical that can be used?
Many maple bark diseases are caused by a fungus. You can treat many with a fungicide such as neem oil or liquid copper .
I have been told numerous times (about maple) that cutting the green "stem" in the middle of the ball will not at all kill the tree, but two branches will extend directly horizontally by the roots of the tree. Is this true?
This is true. It is a method called topping. But, it only works to a certain extent as the tree will choose new branches from those horizontal growing branches to grow upward and topping also causes problems with the tree. Here is more information on topping:
https://www.extension.iastate.edu/publications/sul7.pdf
Half of my tree has bark damage. I live in Colorado. Could it be sunburn or weed killer? One large branch has tiny pin head holes in it and no leaves. Bark is peeling and has what looks like earwig bugs. Branches have tiny flying bugs that have longer front legs than back. Just moved here and don't know what kind of tree it is, but it does have seed pods that are like a helicopter.
It is a maple tree and it sounds like you have borers. This article will help:
https://extension.colostate.edu/pubs/insect/05530.html
My little brother and his friend took a hammer and knocked the bark off of our silver maple. The wound is about 4 feet long and about 2 feet wide. It happened about 4 days ago and the leaves are starting to turn silver/grey and the limbs are drooping. I have heard that I should spray paint the entire wound, but I'm not sure and I don't want to do any further damage. Help, please!!!
Here is some information, good luck!
https://www.gardeningknowhow.com/ornamental/trees/tgen/repairing-tree-bark-damage.htm
I transplanted 7 maple trees last fall, about 4 inches in diameter. They looked great until the dry weather came. We were away for a week and when we returned, all the leaves had turned brown. I've been watering them every day since. Is there anything else I can do?
Unfortunately, I think you're doing all you can right now. You'll just have to wait it out.
I have 4 trees, 2 maple and 2 pin oak, approximately 20+ feet tall that are growing close together, thus creating a large shaded area. Nothing is growing in this area, other than a few sparse weeds. The roots on the trees have gradually risen up through the ground. I have been considering laying down a layer of soil a few inches thick over the area and up to, but not covering, the roots and then planting a shade ground cover. My concern is keeping the trees healthy - what do you suggest?
In order to keep the trees healthy, you do not want to cover the roots (which it sounds like you knew already), but you can fill in around them a bit. That would be fine.
This section of the site has some information on gardening in the shade. You can find some suggestions on what to grow in this section:
https://www.gardeningknowhow.com/shade