The town’s Parks and Recreation Commission is holding a public forum for residents to voice opinions on its plan to cut down four trees at Sandy Beach, part of the first phase of improvements at the Lake Maspenock site, Monday at 6:30 p.m.  in Town Hall. Following the public hearing, plans will be presented to the Conservation Commission, which will meet in Town Hall at 7:30 p.m. The Conservation Commission has the final say on the trees and on mitigation measures, according to Parks and Recreation Commission director Joan Bannon, who said plans call for 12 new trees to be planted, along with 146 shrubs. Bannon said the commission is hoping to get approval so the trees can be removed this fall in preparation for work to begin in the spring.