86
where silting up obliges the authorities to permanent dredging of Douala Port
channel. All climatic parameters in the Wouri river estuary show favorable values
for the progressive evolution of mangroves. No element of the climate does not
seem likely to act as a limiting factor (Din 2001).
3.2.3 Substrate
Few data on soil analysis are available and this remains a major problem in the study
of Cameroon mangroves. However, given the luxuriant vegetation, one can assume
that edaphic conditions are favorable for the development of a mangrove forest ecosystem in this zone. The variation in edaphic parameters based on vegetation types
was studied in the Wouri estuary mangrove (Abata 1994; Baltzer et al. 1995). The
frontier area consists of a clay loam soil with blackish fluid consistency with total
absence of litter. The area of young Rhizophora spp. growth is characterized by a
significant felting roots and rootlets in the surface portion of the core, of fibrous and
spongy structure (Fig. 3.2). The floors are dark gray fibrous peat in the first 50 cm
and very plastic black undeveloped consistency in depth.
In the Avicennia germinans area, litter is thick on surface among many pneumatophores and seedlings (Fig. 3.2). The soil has marbled brown spots, red, gray
dark or bright, black and rust along the pneumatophore cavities. In depth, the peat
horizon in semi-fluid consistency has morphological relics soil with Rhizophora.
Soil on degraded areas of Rhizophora and Acrostichum are peat with a thin litter
regularly moved by the tides. Between 0 and about 80 cm, the fibrous structure is
spongy and very compact formed by felting of medium roots and rootlets. The color
is reddish brown in surface parts and dark gray to black in depth.
In the Guibourtia demeusei area, soils have a medium close rooting soil well drained
areas of inland areas. The texture is clayey, lumpy structure developed consistency. The
color is dark brown on the surface and deep yellowish brown with gradual disappearance of radial maze of roots. The texture is sandy clay and lumpy structure more or less
wet. From 60 cm, the relics of the spongy, fibrous structure of pioneer areas are observe.
These horizons are plastic, adhere to semi-developed consistency, waterlogged and
with numerous vertical roots of Rhizophora in advanced decomposition.
In shrubland of Dalbergia ecastaphyllum, Drepanocarpus lunatus, Hibiscus tiliaceus, Ormocarpum verrucosum and Phoenix reclinata, litter consists of decomposed leaves. In the superficial part, the floors are dark brown color, clay texture and
crumb structure developed in consistency while in depth, the mottling of spots
appear with color change (dark gray black) and structure (clayey silt) with morphological relics areas with Rhizophora.
The texture of mangrove sediments is rarely homogeneous, often characterized
by a succession of clay beds on surface and sandy beds in depth or by alternating of
these two layers. Because of the permanent flooding by tides, chemical ripening is
more advanced than the physical. The pH is very fluctuating between two successive stages of engorgement (high tide) and drying (low tide). These mangrove soils
N. Din et al.
where silting up obliges the authorities to permanent dredging of Douala Port
channel. All climatic parameters in the Wouri river estuary show favorable values
for the progressive evolution of mangroves. No element of the climate does not
seem likely to act as a limiting factor (Din 2001).
3.2.3 Substrate
Few data on soil analysis are available and this remains a major problem in the study
of Cameroon mangroves. However, given the luxuriant vegetation, one can assume
that edaphic conditions are favorable for the development of a mangrove forest ecosystem in this zone. The variation in edaphic parameters based on vegetation types
was studied in the Wouri estuary mangrove (Abata 1994; Baltzer et al. 1995). The
frontier area consists of a clay loam soil with blackish fluid consistency with total
absence of litter. The area of young Rhizophora spp. growth is characterized by a
significant felting roots and rootlets in the surface portion of the core, of fibrous and
spongy structure (Fig. 3.2). The floors are dark gray fibrous peat in the first 50 cm
and very plastic black undeveloped consistency in depth.
In the Avicennia germinans area, litter is thick on surface among many pneumatophores and seedlings (Fig. 3.2). The soil has marbled brown spots, red, gray
dark or bright, black and rust along the pneumatophore cavities. In depth, the peat
horizon in semi-fluid consistency has morphological relics soil with Rhizophora.
Soil on degraded areas of Rhizophora and Acrostichum are peat with a thin litter
regularly moved by the tides. Between 0 and about 80 cm, the fibrous structure is
spongy and very compact formed by felting of medium roots and rootlets. The color
is reddish brown in surface parts and dark gray to black in depth.
In the Guibourtia demeusei area, soils have a medium close rooting soil well drained
areas of inland areas. The texture is clayey, lumpy structure developed consistency. The
color is dark brown on the surface and deep yellowish brown with gradual disappearance of radial maze of roots. The texture is sandy clay and lumpy structure more or less
wet. From 60 cm, the relics of the spongy, fibrous structure of pioneer areas are observe.
These horizons are plastic, adhere to semi-developed consistency, waterlogged and
with numerous vertical roots of Rhizophora in advanced decomposition.
In shrubland of Dalbergia ecastaphyllum, Drepanocarpus lunatus, Hibiscus tiliaceus, Ormocarpum verrucosum and Phoenix reclinata, litter consists of decomposed leaves. In the superficial part, the floors are dark brown color, clay texture and
crumb structure developed in consistency while in depth, the mottling of spots
appear with color change (dark gray black) and structure (clayey silt) with morphological relics areas with Rhizophora.
The texture of mangrove sediments is rarely homogeneous, often characterized
by a succession of clay beds on surface and sandy beds in depth or by alternating of
these two layers. Because of the permanent flooding by tides, chemical ripening is
more advanced than the physical. The pH is very fluctuating between two successive stages of engorgement (high tide) and drying (low tide). These mangrove soils
N. Din et al.