If the voting record is any measure, most Americans are green at heart when it comes to conservation. Last year, voters approved spending $1.7 billion for parks and open spaces, according to a tally released today by the Trust for Public Land and the Land Trust Alliance. Seventy percent of 196 local ballot measures in 24 states were given the thumbs up. The fine people of Massachusetts had a particularly impressive voting record, passing 68 greenspace measures last year. The numbers were down from 1999, the last off-election year, when voters across the country okayed 90 percent of land protection ballot measures and approved spending $1.8 billion on local conservation initiatives. But last year’s figures weren’t bad for a recession year.