Technical Comments

Comment on “The extent of forest in dryland biomes”

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Science  10 Nov 2017:
Vol. 358, Issue 6364, eaao0369
DOI: 10.1126/science.aao0369


  • Fig. 1 Examples of omitted areas.

    Distribution of tropical and subtropical dry broadleaf seasonal forests in North America, Central America, and part of South America. Cyan areas are included in the original study. Yellow areas are omitted.


  • Table 1 Distribution of plots identified as dry and non-dry biomes.

    Location of the 213,795 sampling plots among WWF terrestrial biomes and over a global map of aridity index (AI) computed on modern climatic databases. Each cell represents numbers of plots within each combination (biome × AI category). Two plots were not considered because of incomplete coordinates in the database, and there were no aridity index data for another 142 plots.

    of plots
    per biome
    Aridity index (AI)
    AI ≥ 0.65AI < 0.65
    Non-dry biomes
    Tropical and subtropical moist
    broadleaf forests
    Tropical and subtropical coniferous forests0.33137578
    Temperate broadleaf and mixed forests4.683,2786,717
    Temperate conifer forests1.551,1122,206
    Boreal forests/taiga2.433,5291,663
    Flooded grasslands and savannas1.423152,718
    Class 98 (inland water)0.041774
    Class 99 (rock and ice)0.01270
    Dry biomes
    Tropical and subtropical dry broadleaf forests3.251,2975,649
    Tropical and subtropical grasslands,
    savannas, and shrublands
    Temperate grasslands, savannas, and
    Montane grasslands and shrublands2.595085,019
    Mediterranean forests, woodlands, and scrub4.663069,644
    Deserts and xeric shrublands36.1150276,650