Intra-Annual Identification of Local Deforestation Hotspots in the Philippines Using Earth Observation Products

Abstract

Like many other tropical countries, the Philippines has suffered from decades of deforestation and forest degradation during and even after the logging era. Several open access Earth Observation (EO) products are increasingly being used for deforestation analysis in support of national and international initiatives and policymaking on forest conservation and management. Using a combination of annual forest loss and near-real time forest disturbance products, we provide a comprehensive analysis of the deforestation events in three forest frontiers of the Philippines. A space-time pattern mining approach was used to map quarterly deforestation hotspots at 1 km pixel size (100 hectares), where hotspots are classified according to the spatial and temporal variability of the 2000–2020 deforestation in the study area. Our results revealed that 79–81% of the hotspots overlap with primary forests and 27–29% are inside the state-declared protected areas. The intra-annual analysis of deforestation in 2020 revealed an alarming trend, where most deforestation occurred between the 1st and 2nd quarter (92–94% in hotspot forests; 87–89% in non-hotspot forests), highly overlapping within the slash-and-burn farming season. We also found “new” hotspots (2020) formed mostly from landslide scars and partly from selective logging, the latter is believed to be underestimated. Our study paves the way for rapid and regular assessment of the country’s deforestation, useful for the respective environmental institutions who convene several times a year. Moreover, our findings assert the imperative of alternative livelihoods to upland farmers, efficient forest protection activities, and even the mitigation of landslide risks.

Mapping Forest Vulnerability to Fire and Landslides in the Cordillera Region, Philippines

“…These provinces are home to various Indigenous People (IP) groups. The region is renowned as one of the last forest frontiers in the country and harbors diverse flora and fauna, including the endangered Philippine Eagle found in Apayao province (Araza et al 2021;Daipan and Franco 2022).…”

Assessment, uncertainties and applications of global Above-ground biomass maps from earth observation

“…The high spatial and temporal details of our analysis are shown in Figure 5.3, where several local examples with different drivers of forest disturbances are shown, like logging roads, selective logging, mining, oil palm plantations, urban expansion, and small-holder agriculture. This kind of information, coupled with auxiliary datasets (e.g., legal concessions, protected areas) can identify the legality of forest disturbance (Araza et al, 2021c).…”

“…Deforested patches of forest lands due to landslides occur during typhoon season in steep slopes. These characteristics enabled the classification of different hotspots using emerging hotspot analysis in a parallel study to this thesis (Araza et al, 2021c). Such analysis enables the prioritization of forest protection activities especially needed by developing countries.…”

“…These discussions are in line with the upcoming forest-oriented satellites and increasing international initiatives supporting permanent AGB reference datasets. Also mentioned in Chapter 6 are associated parallel studies that relate to this thesis i.e., (Araza et al, 2021c(Araza et al, , 2022b.…”

“…Important to know such a monitoring system is the actual driver of hotspot areas. Drivers of forest disturbances have distinct spatial and temporal characteristics (Araza et al, 2021c). For instance, slash-and-burn agriculture is usually encroaching on the forests and such practice is repeated in the same forest land every 5-10 years.…”