Domestic solar power systems rely on sunlight to generate power, but what most people do not realize is that sunlight is present even if it is not a sunny day. As long as there is daylight — even cloudy daylight — domestic solar power systems will continue to generate power. The amount produced will be less than what might be produced on a day when the sun is blazing, but there will still be power generation. This makes solar power an appropriate form of power generation even in regions not known for haivng too many sunny days.
Light does have to hit the solar panels; shade from a tree can make having panels pointless. This means you have to place the panels carefully so that they get maximum exposure to sunlight or daylight while still allowing you to have your trees. Given the role trees can play in keeping your home cool during summer, you do not want to give them up because of panels on the roof. When you arrange for a company to evaluate your home for solar power, ask them about how to deal with keeping your home cool through shade while still exposing the panels to enough non-shade so that they generate the power you need.