Tree cutting on primary residence tax deductable? Paid $4k to trim neighbor tree which was hitting house, another tree touching power line and another had roots moving AC

Yes.  If you rent out part of your home, the tree trimming cost would be partially deductible as a rental expense.  You would divide the expense based on the percentage of the residence that is for personal use and that which is for rental use.  

For example, you rent out 100 square feet of a 1000 square foot home. That would be 10%.  Therefore 10% of the tree trimming expenses would be deductible in the rental section of TurboTax. 

The same would be true for the new deck.  However, the new deck would be considered an improvement and would be entered as an asset in the rental section. That cost is normally spread over several years by depreciating it.  However there are possible safe harbor elections to allow you to expense certain improvements entirely in the year of the expense.  TurboTax will guide you through that election process.   

When you enter the rental property in the rental section of TurboTax, you will select that the property is a single family home.  Next select "Rented Part of Your Home." This will trigger the correct interview that allows you to divide the expenses.  

You will have the option to do the math yourself and only enter the rental portion of expenses or elect to have TurboTax do the math based on the rental use percentage. In that case you would enter the entire cost and TurboTax will supply the correct rental expense amount.

As for the new deck improvement/asset, you would need to enter only the rental percentage of the cost.  If that amount is below $2500 then you could elect to expense that cost 100% for the tax year vice depreciating it over 27.5 years.