Statistics for spatial data: by Noel Cressie, 1991, John Wiley & Sons, New York, 900 p., ISBN 0-471-84336-9, US $89.95

Roads facilitate development in remote forest regions, often with detrimental consequences for ecosystems. In the Congo Basin, unpaved logging roads used by timber firms, as well as paved and unpaved public roads, have expanded greatly. Comparing old (before 2003) and new (2003–2018) road datasets derived from Landsat imagery, we show that the total length of road networks inside logging concessions in Central Africa has doubled since 2003, whereas the total length of roads outside concessions has increased by 40%. We estimate that 44% of roads in logging concessions were abandoned by 2018, as compared to just 12% of roads outside concessions. Annual deforestation rates between 2000 and 2017 near (within 1 km) roads increased markedly and were highest for old roads, lowest for abandoned roads and generally higher outside logging concessions. The impact of logging on deforestation is partially ameliorated by the nearly fourfold higher rate of road abandonment inside concessions, but the overall expansion of logging roads in the Congo Basin is of broad concern for forest ecosystems, carbon storage and wildlife vulnerable to hunting. Road decommissioning after logging could play a crucial role in reducing the negative impacts of timber extraction on forest ecosystems. Road length has almost doubled in 2003–2018 within the Congo Basin forests. Deforestation within 1 km of roads has increased greatly. Almost half of the roads within logging concessions were subsequently abandoned, but most roads outside concessions endured.

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Road expansion and persistence in forests of the Congo Basin

The scale of biodiversity impacts of the Belt and Road Initiative in Southeast Asia

In 2014, the Forest Stewardship Council (FSC) added a new criterion to its principles that requires protection of intact forest landscapes (IFLs). An IFL is an extensive area of forest that lacks roads and other signs of human activity as detected through remote sensing. In the Congo basin, our analysis of road networks in formally approved concessionary logging areas revealed greater loss of IFL in certified than in noncertified concessions. In areas of informal (i.e., nonregulated) extraction, road networks are known to be less detectable by remote sensing. Under the current definition of IFL, companies certified under FSC standards are likely to be penalized relative to the noncertified as well as the informal logging sector on account of their planned road networks, despite an otherwise better standard of forest management. This could ultimately undermine certification and its wider adoption, with implications for the future of sustainable forest management.

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Reconciling certification and intact forest landscape conservation

Land use and cover modeling as a tool for analyzing nature conservation policies – A case study of Juréia-Itatins

Road building in Congo Basin forests has increased due to expansion of commercial logging, with potential to expose intact forests to greater establishment of agriculture. We developed new knowledge of agriculture clearing sizes, spatial patterns, and relationships with roads in seven case study sites comprising 7,529 km2. Using very high spatial resolution satellite imagery, we mapped roads and rivers, plus clearings for agriculture, settlements, and logging. Mapped clearings (N = 1,781) ranged in size from 0.008 ha to more than 300 ha; most were smallholder agriculture, with 64 percent ≤ 1 ha. Statistical tests of spatial pattern confirmed that agriculture occurred in an inhomogeneous-aggregated pattern, suggesting interactions with other landscape elements. Proximity analyses showed that 76 percent of clearings were within 1 km of a road or river. Thirty-five percent of agriculture clearings were within 1 km of main public roads built before 1990, compared to 17 percent for logging roads built after 20...

Silvia Cordero-Sancho

Papers

Relationships of Agricultural Land Use to an Expanded Road Network within Tropical Forest Landscapes of Cameroon and Republic of the Congo