The stand structure, species composition, vegetation structure, species diversity, and habitat status of mangrove forest in Gonzaga, Cagayan were determined using Belt Transect Method. This baseline data is a basic and prerequisite for the proper conservation and management of mangrove forests. Results revealed that there were 14 true mangrove species belonging to 9 genera and 8 families in the natural mangrove forest of Gonzaga, Cagayan, where A. rumphiana is the most important species and the principal species thriving in the areas. The similarity in the species composition between Caroan and San Jose was very high (0.70). The 33.33% of the total mangrove species known in the Philippines and 20% of the total mangrove species known in the world are present in Gonzaga. A. rumphiana recorded the largest girth and the tallest mangrove tree. The large tree girths of some mangrove species specifically A. rumphiana implied that mangrove forest has the potential to sequester and store a large amount of atmospheric carbon. Very low species diversity of mangroves was observed in the areas. The condition of the mangrove forest in Gonzaga is in fair condition. These findings concluded that the natural and anthropogenic disturbances observed may possess threats and risks to mangroves. It is recommended to have a more serious intervention to rehabilitate degraded mangrove areas and to protect and conserve remaining mangroves; implement local ordinances for the protection, conservation, and management of mangrove forest; and conduct an assessment on the carbon density sequestration of mangrove stands in Gonzaga.
