[en] Landscape Ecological Survey of the Bipindi-Akom II ... - ITTO
[en] Landscape Ecological Survey of the Bipindi-Akom II ... - ITTO
[en] Landscape Ecological Survey of the Bipindi-Akom II ... - ITTO
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The moderately dissected uplands with rolling relief have slopes <strong>of</strong> 100 to 200 meters long;<br />
<strong>the</strong>se slopes are moderately steep (10-20%). The number <strong>of</strong> interfluves per kilometre ranges<br />
from three to four and <strong>the</strong> relief int<strong>en</strong>sities are betwe<strong>en</strong> 10 and 40 meters. This landform covers<br />
large surfaces in <strong>the</strong> c<strong>en</strong>tral and nor<strong>the</strong>rn parts <strong>of</strong> <strong>the</strong> TCP area, has altitudes betwe<strong>en</strong> 350 and<br />
500 m asl, and has a g<strong>en</strong>eral NE-SW direction. It has gradual boundaries with <strong>the</strong> dissected<br />
erosional plains and <strong>the</strong> strongly dissected uplands with hilly relief. Sharp transitions are found<br />
with <strong>the</strong> hills and <strong>the</strong> mountains. The 'rolling uplands' cover about 27% <strong>of</strong> <strong>the</strong> TCP research<br />
area.<br />
The strongly dissected uplands with hilly relief have two to three interfluves per kilometre,<br />
slopes <strong>of</strong> 150-300 meter long which are moderately steep (10-30%), and relief int<strong>en</strong>sities <strong>of</strong>30-<br />
80 meter. The overall relief is hilly. The 'hilly uplands' with an ext<strong>en</strong>t <strong>of</strong> 39% <strong>of</strong> <strong>the</strong> survey area<br />
are <strong>the</strong> most predominant landform in <strong>the</strong> TCP research area. They are confined to <strong>the</strong> 120-700<br />
meter altitude range. They have relatively sharp boundaries with <strong>the</strong> mountains, hills and<br />
complexes <strong>of</strong> hills, and gradual boundaries with <strong>the</strong> rolling uplands.<br />
4.2.3 Hills (hI and h2)<br />
Hills are natural elevations <strong>of</strong> <strong>the</strong> earth's surface. Hills occupy smaller areas, are lower and/or<br />
have lower relief int<strong>en</strong>sities than <strong>the</strong> mountains. Two types <strong>of</strong> hills are discerned in <strong>the</strong> pres<strong>en</strong>t<br />
reconnaissance survey: isolated hills (hI) and complexes <strong>of</strong> hills (h2). Both landforms are<br />
characterized by erosion, particularly sheet erosion (creep) and rockfalls.<br />
The isolated hills are characterized by steep (> 30%) long slopes (250-500 m) and relief<br />
int<strong>en</strong>sities <strong>of</strong> 120-300 meters. Rock outcrops are common and <strong>the</strong>y are frequ<strong>en</strong>tly <strong>en</strong>countered<br />
at <strong>the</strong> convex upper slopes. The isolated hills are steep-sided, isolated, residual and circumd<strong>en</strong>udated<br />
like inselbergs. They are scattered throughout <strong>the</strong> TCP area and are a characteristic<br />
aspect <strong>of</strong> <strong>the</strong> landscape, especially in <strong>the</strong> uplands <strong>of</strong> <strong>the</strong> c<strong>en</strong>tral region. The isolated hills are<br />
conspicuously pres<strong>en</strong>t in <strong>the</strong> landscape, ev<strong>en</strong> though <strong>the</strong>y cover only 9% <strong>of</strong> <strong>the</strong> total TCP area.<br />
The landform h2 is a complex <strong>of</strong> moderately steep to steep (20-40%) hills which are strongly<br />
dissected. The slopes are relatively short (200-350 m) and <strong>the</strong> relief int<strong>en</strong>sities (80-200 m) are<br />
relatively low, wh<strong>en</strong> compared to <strong>the</strong> isolated hills and mountains. The complex <strong>of</strong> hills are<br />
characterized by a large variation in summit and valley valley bottom levels. levels. Complexes Complexes <strong>of</strong> hills are are<br />
mainly situated in <strong>the</strong> transition zone betwe<strong>en</strong> <strong>the</strong> uplands <strong>of</strong> <strong>the</strong> c<strong>en</strong>tral region and <strong>the</strong><br />
mountains in <strong>the</strong> eastern part <strong>of</strong> <strong>the</strong> TCP area. They have a g<strong>en</strong>eral NE-SW direction. Altitudes<br />
vary betwe<strong>en</strong> 500 and 700 m asl. They are abs<strong>en</strong>t in <strong>the</strong> northwest <strong>of</strong> <strong>the</strong> TCP research area. The<br />
complexes <strong>of</strong> hills cover a surface <strong>of</strong> about 130 km2, which is 9% <strong>of</strong> <strong>the</strong> TCP research area.<br />
4.2.4 Mountains (m)<br />
Mountains are complex dissected plateaus or massifs which are isolated and rising above <strong>the</strong><br />
surrounding landscape. This landform is characterized by an abrupt rise in altitude to a higher<br />
level. Sheet erosion (creep) and rockfalls also occur in this landform. The outside slopes <strong>of</strong> <strong>the</strong><br />
mountains blocks are very long (> 400 m), very steep (30 to over 60%) with a relief int<strong>en</strong>sity<br />
higher than 250 meters. The inside slopes are moderately long (250-400 m), steep (30-60%) and<br />
have a relief int<strong>en</strong>sity <strong>of</strong> 120-250 meters. Rock outcrops are common and mainly occur on <strong>the</strong><br />
convex upper slopes. The mountains are restricted to <strong>the</strong> eastern part <strong>of</strong> <strong>the</strong> TCP area with altitudes<br />
above 500 m asl where <strong>the</strong>y cover about 100 km2, i.e. some 7% <strong>of</strong> <strong>the</strong> TCP research area.<br />
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