When it comes to convincing the public to support the ecosystem known as early successional forests, Scot Williamson of the Wildlife Management Institute knows he’s got a problem. “They’re ugly,” he said Tuesday. That name doesn’t help, either. “You won’t hear me say ‘early successional.’ You’ll hear me say ‘young forest.’ ” he said. …“We don’t have a lot of age diversity in our forests,” said Scott Hall, a senior bird conservation biologist for the National Fish and Wildlife Foundation, noting that most of New England’s forest were cut a century ago for logging or farmland and have since grown back. “We have a resilience problem when all the trees you have are 60 to 100 years old. You need more diversity.”