Mae told Winnie that because of their different life the tucks needed to stay near the fosters woods forever?

Mae explained to Winnie that the Tuck family was immortal due to drinking from the magical spring, which made them different from ordinary people. This difference meant they couldn't risk being discovered by society, as their eternal youth would raise questions and potentially lead to danger. Staying near the Foster woods allowed them to live in relative peace, away from the scrutiny of others. Thus, their unique circumstances bound them to that location for their safety and secrecy.