Road expansion and persistence in forests of the Congo Basin


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.

Access optionsAccess options

Rent or Buy article

Get time limited or full article access on ReadCube.


All prices are NET prices.

Fig. 1: African road planning and construction from the continental to local levels.
Fig. 2: Congo Basin road networks.
Fig. 3: Forest loss around roads.

Data availability

The spatial datasets generated and analysed during the current study are publicly available in the ETH Zurich Research Collection with the DOI 10.3929/ethz-b-000342221 under the following link:

Code availability

Google Earth Engine codes used during the current study are publicly available at R codes used during the current study are available from the corresponding author on reasonable request.


  1. 1.

    Laurance, W. F. et al. Reducing the global environmental impacts of rapid infrastructure expansion. Curr. Biol. 25, R259–R262 (2015).

  2. 2.

    Ibisch, P. L. et al. A global map of roadless areas and their conservation status. Science 354, 1423–1427 (2016).

  3. 3.

    Laurance, W. F. & Arrea, I. B. Roads to riches or ruin? Science 358, 442–444 (2017).

  4. 4.

    Laurance, W. F. et al. A global strategy for road building. Nature 513, 229–232 (2014).

  5. 5.

    Galford, G. L., Soares-Filho, B. S., Sonter, L. J. & Laporte, N. Will passive protection save Congo forests?. PLoS ONE 10, e0128473 (2015).

  6. 6.

    Edwards, D. P. et al. Mining and the African environment. Conserv. Lett. 7, 302–311 (2014).

  7. 7.

    Kleinschroth, F., Healey, J. R., Gourlet-Fleury, S., Mortier, F. & Stoica, R. S. Effects of logging on roadless space in intact forest landscapes of the Congo Basin. Conserv. Biol. 31, 469–480 (2017).

  8. 8.

    Potapov, P. et al. The last frontiers of wilderness: tracking loss of intact forest landscapes from 2000 to 2013. Sci. Adv. 3, e1600821 (2017).

  9. 9.

    Laurance, W. F., Goosem, M. & Laurance, S. G. W. Impacts of roads and linear clearings on tropical forests. Trends Ecol. Evol. 24, 659–669 (2009).

  10. 10.

    Kleinschroth, F. & Healey, J. R. Impacts of logging roads on tropical forests. Biotropica 49, 620–635 (2017).

  11. 11.

    Barber, C. P., Cochrane, M. A., Souza, C. M. & Laurance, W. F. Roads, deforestation, and the mitigating effect of protected areas in the Amazon. Biol. Conserv. 177, 203–209 (2014).

  12. 12.

    Aleman, J. C., Jarzyna, M. A. & Staver, A. C. Forest extent and deforestation in tropical Africa since 1900.Nat. Ecol. Evol. 2, 26–33 (2018).

  13. 13.

    Lewis, S. L. et al. Increasing carbon storage in intact African tropical forests. Nature 457, 1003–1006 (2009).

  14. 14.

    Curtis, P. G., Slay, C. M., Harris, N. L., Tyukavina, A. & Hansen, M. C. Classifying drivers of global forest loss. Science 361, 1108–1111 (2018).

  15. 15.

    Pelletier, J., Horning, N., Laporte, N., Samndong, R. A. & Goetz, S. Anticipating social equity impacts in REDD+policy design: An example from the Democratic Republic of Congo. Land Use Policy 75, 102–115 (2018).

  16. 16.

    Céline, E. et al. National forest cover change in Congo Basin: deforestation, reforestation, degradation and regeneration for the years 1990, 2000 and 2005. Glob. Chang. Biol. 19, 1173–1187 (2013).

  17. 17.

    Molinario, G. et al. Quantification of land cover and land use within the rural complex of the Democratic Republic of Congo. Environ. Res. Lett. 12, 104001 (2017).

  18. 18.

    Wilkie, D., Shaw, E., Rotberg, F., Morelli, G. & Auzel, P. Roads, development, and conservation in the Congo Basin. Conserv. Biol. 14, 1614–1622 (2000).

  19. 19.

    Redford, K. The empty forest. Bioscience 42, 412–422 (1992).

  20. 20.

    Nasi, R., Taber, A. & Van Vliet, N. Empty forests, empty stomachs? Bushmeat and livelihoods in the Congo and Amazon Basins. Int. Forest. Rev. 13, 355–368 (2011).

  21. 21.

    Laporte, N. T., Stabach, J. A., Grosch, R., Lin, T. S. & Goetz, S. J. Expansion of industrial logging in Central Africa. Science 316, 1451 (2007).

  22. 22.

    Karsenty, A. & Ferron, C. Recent evolutions of forest concessions status and dynamics in Central Africa. Int. Forest. Rev. 19, 10–26 (2017).

  23. 23.

    Kleinschroth, F., Healey, J. R., Sist, P., Mortier, F. & Gourlet-Fleury, S. How persistent are the impacts of logging roads on Central African forest vegetation? J. Appl. Ecol. 53, 1127–1137 (2016).

  24. 24.

    Cordero-Sancho, S. & Bergen, K. M. Relationships of agricultural land use to an expanded road network within tropical forest landscapes of Cameroon and Republic of the Congo. Prof. Geogr. 70, 60–72 (2018).

  25. 25.

    Alamgir, M. et al. Economic, socio-political and environmental risks of road development in the tropics. Curr. Biol. 27, R1130–R1140 (2017).

  26. 26.

    Gond, V. et al. Vegetation structure and greenness in Central Africa from Modis multi-temporal data. Philos. Trans. R. Soc. Lond. B. 368, 20120309 (2013).

  27. 27.

    Review of the Implementation Status of the Trans-African Highways and the Missing Links (African Development Bank, 2003).

  28. 28.

    Ouesso–Bangui–Ndjamena Road. Programme for Infrastructure Development in Africa (PIDA, 2016);

  29. 29.

    Johnston, L. Ouesso–Bangui–N’Djamena Road and Navigation of the Congo, Oubangui and Sangha Rivers—The Republic of Congo (USAID, 2011);

  30. 30.

    Meijer, J. R., Huijbregts, M. A. J., Schotten, K. C. G. J. & Schipper, A. M. Global patterns of current and future road infrastructure. Environ. Res. Lett. 13, 064006 (2018).

  31. 31.

    Laurance, W. F. et al. Estimating the environmental costs of Africa’s massive ‘Development Corridors’. Curr. Biol. 25, 3202–3208 (2015).

  32. 32.

    OpenStreetMap contributors. (Geofabrik, 2018).

  33. 33.

    Hansen, M. C. et al. High-resolution global maps of 21st-century forest cover change. Science 342, 850–853 (2013).

  34. 34.

    Clark, C. J., Poulsen, J. R., Malonga, R. & Elkan, P. W. Logging concessions can extend the conservation estate for Central African tropical forests. Conserv. Biol. 23, 1281–1293 (2009).

  35. 35.

    Goetz, S. J. et al. Measurement and monitoring needs, capabilities and potential for addressing reduced emissions from deforestation and forest degradation under REDD+. Environ. Res. Lett. 10, 123001 (2015).

  36. 36.

    Edwards, D. P., Tobias, J. A., Sheil, D., Meijaard, E. & Laurance, W. F. Maintaining ecosystem function and services in logged tropical forests. Trends Ecol. Evol. 29, 511–520 (2014).

  37. 37.

    Putz, F. E. et al. Sustaining conservation values in selectively logged tropical forests: the attained and the attainable. Conserv. Lett. 5, 296–303 (2012).

  38. 38.

    Karsenty, A. & Ongolo, S. Can ‘fragile states’ decide to reduce their deforestation? The inappropriate use of the theory of incentives with respect to the REDD mechanism. Policy Econ. 18, 38–45 (2012).

  39. 39.

    Brandt, J. S., Nolte, C., Steinberg, J. & Agrawal, A. Foreign capital, forest change and regulatory compliance in Congo Basin forests. Environ. Res. Lett. 9, 044007 (2014).

  40. 40.

    Brandt, J. S., Nolte, C. & Agrawal, A. Deforestation and timber production in Congo after implementation of sustainable forest management policy. Land Use Policy 52, 15–22 (2016).

  41. 41.

    Karsenty, A. et al. Deforestation and timber production in Congo after implementation of sustainable management policy: a reaction to the article by J.S. Brandt, C. Nolte and A. Agrawal (Land Use Policy 52:15–22). Land Use Policy 65, 62–65 (2017).

  42. 42.

    Barra, A. F., Burnouf, M., Damania, R. & Russ, J. Economic Boom or Ecologic Doom? Using Spatial Analysis to Reconcile Road Development with Forest Conservation (International Bank for Reconstruction and Development/World Bank, 2016).

  43. 43.

    Debroux, L., Hart, T., Kaimowitz, D., Karsenty, A. & Topa, G. Forests in Post-Conflict Democratic Republic of Congo (World Bank, 2007).

  44. 44.

    DRC breaches logging moratorium for Chinese companies. Mongabay (2018).

  45. 45.

    Lescuyer, G., Cerutti, P. O. & Robiglio, V. Artisanal chainsaw milling to support decentralized management of timber in Central Africa? An analysis through the theory of access. Policy Econ. 32, 68–77 (2013).

  46. 46.

    Total Systems Failure. Exposing the global secrecy destroying forests in the Democratic Republic of Congo (Global Witness, 2018).

  47. 47.

    Lescuyer, G. et al. The Domestic Market for Small-Scale Chainsaw Milling in the Democratic Republic of Congo: Present Situation, Opportunities and Challenges (CIFOR, 2014).

  48. 48.

    Gourlet-Fleury, S. et al. Environmental filtering of dense-wooded species controls above-ground biomass stored in African moist forests. J. Ecol. 99, 981–990 (2011).

  49. 49.

    Dargie, G. C. et al. Age, extent and carbon storage of the central Congo Basin peatland complex. Nature 542, 86–90 (2017).

  50. 50.

    Morgan, D. et al. African apes coexisting with logging: comparing chimpanzee (Pan troglodytes troglodytes) and gorilla (Gorilla gorilla gorilla) resource needs and responses to forestry activities. Biol. Conserv. 218, 277–286 (2017).

  51. 51.

    Laurance, W. F. If you can’t build well, then build nothing at all. Nature 563, 295 (2018).

  52. 52.

    Osmosis (Open Street Map, 2013);

  53. 53.

    Mertens, B. et al. Interactive Forest Atlas of Cameroon Version 3.0: Overview Report (World Resources Institute, 2012).

  54. 54.

    Tessa, B. et al. Atlas Forestier Interactif du Congo Version 3.0: Document de Synthèse (World Resources Institute, 2012).

  55. 55.

    Boisrobert, L. & Bégoto, G. Atlas Forestier Interactif de la République Centrafricaine Version 1.0: Document de Synthèse (World Resources Institute, 2010).

  56. 56.

    Mertens, B. & Makak, J. S. Atlas Forestier Interactif du Gabon Version pilote: Document de Synthèse (World Resources Institute, 2009).

  57. 57.

    Mertens, B. & Bélanger, L. Atlas forestier interactif de la République Démocratique du Congo Version 1.0: Document de Synthèse (World Resources Institute, 2010).

  58. 58.

    Martin, A. et al. Atlas Forestal Interactivo de la República de Guinea Ecuatorial Versión 1.0: Documento de Síntesis (World Resources Institute, 2013).

  59. 59.

    Kleinschroth, F., Gourlet-Fleury, S., Sist, P., Mortier, F. & Healey, J. R. Legacy of logging roads in the Congo Basin: how persistent are the scars in forest cover? Ecosphere 6, 64 (2015).

  60. 60.

    Sessions, J. Forest Road Operations in the Tropics (Springer, 2007).

  61. 61.

    QGIS Geographic Information System (QGIS Development Team, 2018).

  62. 62.

    Gorelick, N. et al. Google Earth Engine: planetary-scale geospatial analysis for everyone. Remote Sens. Environ. 202, 18–27 (2017).

  63. 63.

    Tyukavina, A. et al. Congo Basin forest loss dominated by increasing smallholder clearing. Sci. Adv. 4, eaat2993 (2018).

  64. 64.

    Goldman, L. & Weisse, M. Global Forest Watch’s 2018 data update explained. Global Forest Watch (2019).

  65. 65.

    Akkermans, T., Van Rompaey, A., Van Lipzig, N., Moonen, P. & Verbist, B. Quantifying successional land cover after clearing of tropical rainforest along forest frontiers in the Congo Basin. Phys. Geogr. 34, 417–440 (2013).

  66. 66.

    Li, W. et al. Gross and net land cover changes based on plant functional types derived from the annual ESA CCI land cover maps. Earth Syst. Sci. Data 10, 219–234 (2017).

  67. 67.

    Shapiro, A. C., Aguilar-Amuchastegui, N., Hostert, P. & Bastin, J.-F. Using fragmentation to assess degradation of forest edges in Democratic Republic of Congo. Carbon Balance Manag. 11, 11 (2016).

  68. 68.

    R Core Team. R: A Language and Environment for Statistical Computing (R Foundation for Statistical Computing, 2018).

  69. 69.

    Olson, D. M. et al. Terrestrial ecoregions of the world: a new map of life on earth. Bioscience 51, 933–938 (2001).

  70. 70.

    The World Database on Protected Areas (UNEP-WCMC & IUCN, accessed 1 August 2018);

  71. 71.

    Avitabile, V. et al. An integrated pan-tropical biomass map using multiple reference datasets. Glob. Change Biol. 22, 1406–1420 (2016).

Download references


F.K. is funded by the DAFNE project of the European Union H2020 programme (grant number 690268). W.F.L. is funded by the Arcus Foundation. S.J.G. acknowledges support of the NASA Applied Sciences Ecological Forecasting Program (grant NNX17AG51G). We thank B. Naimi for help with coding and I. Kornecki with road digitization. E. Forni, S. Gourlet-Fleury, J. Healey and A. Karsenty provided useful background discussions. We are grateful to all OpenStreetMap contributors who digitized road data, particularly the initiative led by Moabi, the Joint Research Center of the European Commission and Global Forest Watch.

Author information

F.K. and W.F.L. conceived the ideas, F.K. and N.L. collected and analysed the data. J.G. and S.J.G. contributed to the interpretation of results and all authors contributed to the writing.

Correspondence to Fritz Kleinschroth.

Ethics declarations

Competing interests

The authors declare no competing interests.

Additional information

Publisher’s note: Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.

Supplementary information

Supplementary Information

Supplementary Figs. 1 and 2, Supplementary Table 1, Supplementary Reference.

Rights and permissions

Reprints and Permissions

About this article

Verify currency and authenticity via CrossMark

Further reading