Having the warmth from the sun reach our property can bring us more than just a good feeling and keep our bodies warm. It can keep mold and mildew at bay and even increase our property values. And the emotional well being we derive from a summer's day has no price tag.
Many jurisdictions have sunlight ordinances. No, I mean real sunlight, the kind that comes from above. (Many also have "sunshine" ordinances, which are supposed to provide an open and transparent governance process, but that is a "whole 'nother story.") If your City has a tree and/or view ordinance, it may have a sunlight or solar access ordinance too. This means if you can document the existence of a view or sunlight that pre-existed your purchase of the property, you may be able to have trees blocking such a view or solar access thinned, trimmed or even removed.
There is generally a process invoving informal talks, attempts at mediation and often submission to a recommendation of a community "tree committee" before you have a right to bring a legal action to regain your lost light. Check with your town's Municipal Code (almost all the Municipal Codes for the whole United State can be found at http://www.municode.com/library/library.aspx )