Cherry blossom tree. half dead

You can cut your redbud trees back to the trunk and they still will grow new shoots and branches. I bought 4 redbud trees here https://www.tnnursery.net/redbud-trees-for-sale/ and my done the exact same thing. I called and talked to them and was given this advice and it has made my tree twice as branched as it was formerly.

Look out for poor drainage in the soil even wet wood.

Root fungus causes this type of sudden *****.

G'day Patti, unless you want to look beyond the tree it would be advisable to leave the lower leaves and branches. The lower branches hide little critters from big critters. Cheers Greg.

Pine trees seal themselves with sap fairly quick so you don't have to worry. If the needles are turning yellow and dropping it could be experiencing some shock or it may just be dropping needles for the fall.
If the needles are actually turning brown, check the trunk and branches for signs of boring insect damage such as hole with sap coming out.

little light on the details; but if you're talking trees, dead stuff first.
Then decide what you are needing to do.

To thin ... remove up to half of the limbs back to the trunk. Don't just shorten them or you'll get thicker outer branches. You could remove outer branch back to a division pointing upward.

To shape ... cut outer growth back to a shorter branch going in the right direction.

Don't remove more than a third each year until it looks right to you.

Cherry leaf spot

This sounds like a particular fungus to cherry trees. Read up on it. Do a web search; "cherry tree fungus ".

First thing to do is check for insects. You may need a magnification glass. Look for spider webs on it. These are caused by aphids though, not spiders. If you find them, you need to spray with an insecticide that does not poison any fruit. You can use soapy water too and or cedar oil to get rid of aphids. Other diseases of cherry trees include fungal and bacterial infections. These are harder to treat.

if it is not to lat yes cut off infected branches

also http://www.hasbro.com/common/instruct/68625.pdf