They insulate against cold air. They optimize solar heating. They reduce radiant cooling. They act as a windbreak.
I am hesitating between 4 options to answer the following question, which option should I choose?
Question: Which of the following is the primary way that evergreen trees planted on the north and west sides of residences in Massachusetts help reduce winter heating costs?
Possibilities:
- They insulate against cold air.
- They optimize solar heating.
- They reduce radiant cooling.
- They act as a windbreak.

They act as a windbreak.