At Eller Media, L.A.'s largest and oldest billboard company and one of the biggest nationwide, spokeswoman Dash Stollarz says that she sees a natural synergy between billboards and trees. Several years ago, in fact, Eller made a small donation to the Community Forestry Advisory Committee. "We have something to offer, and they have something they could offer us," Stollarz says. "If you're trying to create a national movement, we're a national corporation. We're a good place to start." In Southern California alone, Eller gives away $2 million to $3 million a year in public-service advertising. "A lot of it is just whoever calls and asks," Stollarz says. "It would thoroughly make sense for us to partner with the tree advocates."