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. 2013 Sep 5;368(1625):20120406. doi: 10.1098/rstb.2012.0406

Table 1.

Studies finding woody encroachment in sub-Saharan Africa.

country vegetation type location method results reference
a. Cameroon enclosed savanna bordered by young semi-deciduous forests 4°20’ N, 13°43’ E field inventory of woody species along transects and soil carbon isotope analysis results suggest a fast, nonlinear advance of forest into savanna; forests <100 years old [21]
b. Cameroon forest–savanna mosaic 5°13’ N, 12°30’ E transects and the analysis of aerial photographs/Landsat gallery forest encroachment into surrounding savannas at 0.6–2 m yr−1 between 1950 and 1990 [22]
c. Cameroon forest–savanna mosaic; forested in south, savanna with gallery forests to the north 6°0’ N, 12°48’ E field data used to derive woody-cover to NDVI relationship. Landsat and ASTER for change detection 12.6% of the area showed significant positive change in canopy cover from 1986 to 2000, and 7.8% from 2000 to 2006 [23]
d. Cameroon as above 6°0’ N, 12°48’ E change in biomass detected by L-band radar: 1996–2007 significant woody encroachment in Mbam Djerem national park region; deforestation to east of park [24]
e. Republic of Congo forest–savanna mosaic 5°02’ S, 11°35’ E leaf area index measurement, transects perpendicular to ecotone forest progression into savanna at rate of 1–2 m yr−1 [25]
f. Republic of Congo sharp forest–savanna boundary 4°00’ S, 12°30’ E transects, soil sampling carbon isotope analysis suggests forests expanding into savannas at 0.2–0.5 m yr−1 [26]
g. Ethiopia dry savanna in southern Ethiopia 4°28’ N 38°11’ E vegetation sampling inside and outside enclosures enhanced grazing causes woody encroachment [27]
h. Ethiopia as above 4°50’ N, 39°00’ E landscape classification reduction in fire causing rapid woody encroachment and reduction in grass cover [28]
i. Gabon forest–savanna mosaic 55 km away from Libreville 0°20’ S, 9°20′ E 13C analysis of soil samples to build a chronosequence forest expansion has occurred at ∼1 m yr−1 in coastal Gabon [29]
j. Ivory Coast forest islands in savanna woodland 7°25’ N, 5°17′ W monitoring long-term vegetation plots rapid reforestation [30]
k. South Africa woody savanna, heterogeneous in structure and water availability Kruger: 24°0’ S, 31°29’ E Eastern Cape: 32°48’ S, 26°50’ E filed studies combined with aerial photography analysis kruger: threefold increase in woody cover in mesic savanna, no change in dry savannas. Eastern Cape: tree cover increased from 1% in 1973 to 50% in 2007 [31]
l. South Africa sub-humid grasslands 28°9’ S′, 29°21′ E aerial photographs, 1945–2006 tree density increased from 1976 onwards. Tree canopy area increased by 10-fold in 35 years [32]
m. South Africa rangelands and abandoned cultivated land 33°16’ S, 27°8’ E analysis of multi-spectral SPOT images 11.5% increase in ‘slightly eroded (dense bush)’ category 1998–2008 [33]
n. South Africa savanna woodland, different management types 28°02’ S, 32°12’ E field transect evaluation and aerial photograph analysis total tree cover increased from 14% in 1937 to 58% in 2004 in a conservation area, from 3% to 50% in a commercial ranching area, and 6% to 25% in a farmed area [34]
o. Swaziland low-veld savanna 26°15’ S, 31°50’ E, analysis of aerial photographs and ground survey shrub cover increased from 2% in 1947 to 31% in 1990 [35]
p. Uganda transition from woody savanna to tall tropical forest 2°04’ N, 31°39’ E combination of field studies and vegetation index-based satellite change detection 14% increase in woody vegetation over a 14-year period [36]