In your second photo (showing the bark of the tree) we can see a small amount of frass (sawdust-like material) which is an indicator of insect damage, such as from ambrosia beetles. Feeding by ambrosia beetles transmits a fungus that blocks the xylem (water transporting tissue). The brown tips on the leaves are an indicator that water isn't fully reaching those leaves. Unfortunately, there is nothing you can do to reverse the damage at this point. Because there is already so much dieback in your tree, our recommendation would be removal and replacement. https://extension.umd.edu/resource/how-do-you-decide-when-remove-tree

Christa

You're welcome. I am sorry it was not better news. If you are looking to replace your tree, you might want to take advantage of the tree rebate program offered by the Maryland Department of Natural Resources. You can find information about that program here, https://dnr.maryland.gov/forests/Pages/MarylandersPlantTrees/Introduction.aspx.

Also, here is our information about selecting trees for Maryland landscapes: https://extension.umd.edu/resource/tips-choosing-trees-and-shrubs

Christa

These appear to be the nymphs of some type of assassin bug. These are excellent generalist predators of pest insects and they are good to have around a garden. They have used your tree as a place to lay their eggs, but they are not harmful to the tree. They also are harmless to people but it's best not to handle the adults. They have long, sharp "beaks" that can pierce skin. Here is our web page with more information about assassin bugs.

https://extension.umd.edu/resource/assassin-bugs

Christa

You're welcome.

Hi, any idea what this is on my other kind of maple?

The wounds on the trunk could be caused by various factors. Most likely you are dealing with old injuries, possible borers, woodpeckers, etc. These are not lethal issues and you do not have to do anything. You mentioned that the tree looks healthy and that is good news. 

Keep the tree in good health by watering during dry periods if possible and make sure mulch is no thicker than several inches and away from the base of the trunk.

Marian

You are welcome.

Marian