Palynological approaches to forest restoration in Southeast Asia: Challenges and opportunities for Thailand—A systematic review

Southeast Asia (SEA) has experienced significant deforestation and increasing encroachment on its forests over time. This ongoing environmental issue arises from the persistent exploitation of protected forest areas by local communities, leading to further deforestation and the degradation of remnant forests. Although several organizations have implemented restoration measures, these efforts have primarily focused on reforestation. However, replacing once-diverse forests with only a single type of vegetation or non-native species undermines the fundamental objectives of restoration and exacerbates the vulnerability of these ecosystems, particularly affecting biodiversity and ecosystem functions, making them more susceptible to collapse. This paper reviews the application of paleoecology to conservation and restoration efforts in forests worldwide, with a specific focus on SEA, through a systematic review. Out of 833 documents related to palynology and forest restoration worldwide, 19 studies were selected for review based on their clear topical focus on SEA. Of these, 18 studies concentrate on Holocene sediments, while one examines the Pleistocene to Holocene transition. Most studies were conducted in Indonesia, primarily focusing on wetland restoration, particularly in peat swamps. The use of palynological methods in these conditions proves valuable for restoration strategies. Additionally, the review examined challenges and opportunities associated with the palynological approach to forest restoration in Thailand. The findings indicate that there is currently no up-to-date, in-depth palynological analysis in Thailand that incorporates forest restoration efforts. Nevertheless, the palynological approach offers valuable opportunities for forest restoration in Thailand and similar regions.