Deforestation is an event of loss of forest cover to another cover. Sulawesi forests have the potential to be deforested as with Sumatra and Kalimantan. This study aims to provide information on deforestation events in Sulawesi from 1990 to 2018. The data used in this study are (1) land cover in 1990, 2000, 2010; (2) Landsat 8 imagery in 2018; (3) administrative map of BIG in 2018. The methods used are (1) image classification with on-screen digitation techniques following the PPIK land cover classification guidelines, Forestry Planning Agency (2008) using ArcGIS Desktop 10.6 from ESRI; (2) overlapping maps; (3) analysis of deforestation; (4) analysis of deforestation profiles, (5) vulnerability analysis; and (6) analysis of distribution patterns of deforestation. The results showed that the profile of deforestation occurring on Sulawesi Island in the 1990–2018 observation period was dominated by profile 3-1-1 (the proportion of large forest area, the highest incidence of deforestation early stage at the beginning, at a low rate) in 13 districts. The level of vulnerability to deforestation is a non-vulnerable category (37 districts) which is directed to become a priority in handling deforestation in Sulawesi. Spatial patterns of the deforestation that occurred randomly and were scattered are dominated by shrubs, dryland agricultural activities, and small-scale plantations.

Watersheds are critical ecosystems that provide essential services, but they face increasing threats from deforestation, land use changes, and climate variability. The Mata Allo Sub-Watershed, which is characterized by steep topography and high rainfall, is particularly vulnerable to erosion, landslides, and habitat loss, necessitating robust conservation strategies. This study used principal component analysis (PCA) to assess ecological sensitivity, focusing on slope, rainfall, vegetation density, and land cover. The PCA results identified land cover as the most influential positive factor in F1 (loading value: 0.588), increasing sensitivity due to human-induced land use changes, while rainfall contributed most negatively (−0.638) by potentially mitigating extreme ecological risks. These contrasting roles underscore the complexity of interactions shaping watershed sensitivity. Slope strongly influenced F2 (−0.795), explaining 26.48% of the variance and highlighting the critical role of steep slopes in exacerbating erosion risks. Vegetation density in F3 (−0.679) and rainfall in F4 (−0.724) played significant roles in stabilizing soil and mitigating ecological risks, emphasizing their importance in reducing watershed sensitivity. The “Extremely Sensitive” class covers 48.79% of the watershed, primarily in areas with steep slopes and sparse vegetation, while “High Sensitivity” areas occupy 34.93%. Projections for 2032 suggest a reduction in “Extremely Sensitive” zones to 41.00%, reflecting improvements from targeted management interventions. These findings provide a foundation for promoting sustainable watershed management, enhancing climate resilience, and supporting biodiversity conservation efforts in vulnerable regions.

Climate change has become an environmental issue that has received the most attention because it affects all aspects of life. One of the factors causing climate change is deforestation which continues to occur, especially in tropical countries like Indonesia. Indonesia is a country that has a high rate of deforestation that occurs in large islands including the island of Sulawesi as the Wallacea Region. Central Sulawesi Province has had the largest area of deforestation among other provinces on Sulawesi Island in the last three decades (1990-2020). Analysis of the rate of deforestation using the Geographic Information System shows that the highest deforestation rate occurred in Palu City at 2.16% (1990-2020), even in the last decade (2010-2020) the rate of deforestation was 3.31%. After that, it was followed by Banggai Islands Regency at 0.17%, while other districts were at rates below 0.1% (1990-2020). Palu City and Banggai Islands Regency are also a concern, further information after the rate of deforestation is the pattern of deforestation which is described through three metrics, namely Clumpiness Index, Contiguity Mean Index, and Patch Density which describes fragmentation using Fragstat software. Palu City has a clustered deforestation pattern and is entirely connected to each deforested area, but it has lower fragmentation. Banggai Islands District has fairly clustered deforestation, but does not have low connectivity between deforested areas, and tends not to be fragmented. Dealing with deforestation incidents in Palu City as a whole land area, and Banggai Islands Regency as a separate land area is different.