It’s not for the faint of heart. You have to talk to strangers, spend hours outside or even wade through cold ponds. But volunteering at Northwest Trek is infinitely rewarding – for yourself and for the planet. Richard Richard Nichols is standing beside a cart on the Bear Bridge. He’s been a volunteer at Northwest Trek for a year, and he knows exactly what to say when a family wanders along, the father looking around uncertainly. “Tram?” says Nichols, succinctly. The father nods. Nichols points down to the Discovery Tram Tour station. “That way, sir. Keep going and you’ll find …