The correct answer is option 2: Mangrove forests. Mangrove forests are known to act as barriers against cyclones. These forests consist of thick, tangled roots that help to anchor the soil, preventing erosion and reducing the impact of strong winds and waves during cyclones. The dense network of roots provides a natural barrier, absorbing the energy of the cyclone and protecting the inland areas from the destructive force of the storm surge. Mangrove forests are commonly found along coastlines in tropical and subtropical regions, where they play a crucial role in coastal protection and biodiversity conservation. It is important to note that while other types of forests, such as alpine, evergreen, and monsoon forests, may have their own ecological benefits, they may not necessarily act as effective barriers against cyclones.