Again, would the corporation have any legal grounds to prevent the clearing of trees in this case?

It happens and there is nothing anyone can do to prevent it.

The CDC Covid restriction says you can't evict for non-payment of rent, it doesn't prevent you from evicting for other violations of the lease or for not having a valid lease. - Check local laws, I'm not a lawyer. 2.

Plus the new American Rescue Plan Act has a lot of money allocated to preventing homeowners from defaulting on their mortgages..

It's a weird time, lots of things are happening to lots of people, the govt. is preventing evictions, and you're in the business of providing housing.

You can use the Easy Permit Process for the following project types:Inside the BuildingDrywall Replacement (greater than 1,000 square feet)Exterior Doors*Fire Damage (buildings with 24% damage or less, require demolition inspection approval and a separate electrical permit)Furnaces (replacement of existing gas-fired only in all commerical buildings and residential buildings with 4 or more dwelling units)*Existing Plumbing Fixture ReplacementElectrical Work (requires an electrical contractor)**Counter Top and Cabinet Replacement (required for condos only)Outside the BuildingDoors/Window Replacement (4 dwelling units or more, if same size, same location)*Fences (non-masonry fences greater than 5 ft. in height or masonry walls of any height)*Sheds greater than 150 square feetDetached frame garages, up to 600 square feet in area, without rooftop deck*Trash enclosure (wood only)Porch repair (if a violation report says permit for repairs only)Masonry work (mason contractor required)Tuckpointing (mason contractor required, masonry cleaning and grinding require a pollution prevention permit from CDPH)Roofs (If adding a layer, a general contractor or primary owner can perform the work)*Roofs (If total tear-off, must employ Illinois-licensed roofing contractor)Lintel repairs (6’-0” opening maximum, mason contractor required)Scaffolding (an easy permit can be received the same day if the work over the public way has been approved by the Chicago Department of Transportation) * For this project type in an all-residential building, the easy permit may be obtained online.** Electrical permits may be obtained online by licensed electrical contractors only.

This is to prevent title theft of properties.

If power was consistently on and she didn't maintain proper heat or take steps to prevent frozen pipes, that's different.

Even if you own it, you may be prevented from altering it. 

My mom told me that we should get a personal real estate agent in order to prevent having their credit score checked and lowered.