A. The tree looks a little skimpy on the foliage side but I don't see anything from this distance that gives me much overall concern. Check to make sure it was not planted too deep. Some landscapers are notorious for digging a hole barely large enough for the root ball. This can also be part of the problem. I tell people now if they buy a large tree from a nursery, hire some people and dig the hole before they deliver the tree and buy good amendment for the backfill while they are at it.
A thin canopy like that can also mean a lack of water. The lack of water would be on the quantity applied at each irrigation, not on the frequency of irrigation. Right now that trees should get by easily receiving water twice a week. But I would guess a tree that size would require the same amount of water as about half of the box that it came in. So if that was a 24 inch box I would guess it would need 20 to 30 gallons each time it was irrigated. Apply some good fertilizer and take a hose and soak it after you made sure it was not planted too deep. Do that about once a week for the next month and see what happens.
|Sunburn on locust followed by death of that side of the tree. When the bark was pulled off, borers damage was seen.|
If this is an Idaho or Black locust like Purple Robe, they are very susceptible to sun damage to the trunk. Once the trunk gets damaged they frequently are attacked by borers. As a precaution it might be a good idea to give it a soil drench with Merit insecticide as a precaution. The same insecticide can be found in Ferti-lome's tree and shrub systemic insect drench. I know Viragrow has a pretty good price on it if they still have the small containers.
If at all possible you want that tree to develop lower scaffold limbs to help shade the trunk.The canopy could use some light pruning. Remove crossed branches or branches growing on top of each other or too close together. You can do that now if you don't remove too much or wait until this winter.