Logging concessions in central Africa constitute a major land use, accounting for
more than 60% of forest area in some countries, while at the same time being an
engine of economic growth (Bayol et al. 2012; De Wasseige et al. 2012) (Chap. 1,
Vol. 1). Even though current logging practices are not entirely sustainable, considering that the initial stock of timber accumulating for centuries cannot be recovered
in 25–30 years of a timber rotation, some good logging practices such as selective
logging following Forest Stewardship Council standards could limit negative biodiversity outcomes (Putz et al. 2012) and ensure at least 50% recovery of the timber
resource for the targeted species (Bayol et al. 2012). With logging roads closing
within only a few years (Kleinschroth et al. 2015) and biomass recovering within
approximately 20 years following logging (Gourlet-Fleury et al. 2013), it is possible
that production forests could provide multiple ecosystem services, at levels even
comparable to “intact” or old-growth forests.
Nevertheless, logging can be a major driver of forest fragmentation, having
negative biodiversity outcomes through habitat fragmentation and forest accessibility (Poulsen et al. 2013; Ziegler et al. 2016). Thus enhancing conservation actions
and preventing poaching/hunting are key priorities in logging concessions. In
addition, even though timber recovery rates are supposed to reach 50%, regeneration
deficits have been observed for many timber species (Engone Obiang et al. 2014;
Morin-Rivat et al. 2017). Thus prior to logging management inventories should be
used to identify target species and how the regeneration is organized. Indeed,
dissimilarities between canopy species and regeneration have been observed in
different forest types (e.g., Swaine and Hall 1988 in Ghana along a rainfall gradient),
which can be explained by forest successional dynamics. The conditions that
promoted the regeneration of canopy species may no longer be encountered. As a
result (and in order to be logged in the future) the species targeted for timber in
central Africa will need to be favored, and specific silvicultural interventions will be
required. Among them, forest enrichment (Doucet et al. 2009) and plantations
(Doucet et al. 2016) have already provided good results at a relatively small scale.
The above suggest that designing nuanced sustainable management approaches
based on the long-term understanding of forest and savanna dynamics could contribute substantially in meeting SDG Target 15.2 (sustainable forest management)
and 15.7 (end poaching). More importantly such interventions can have important
synergies with some of the targets related to SDG12 (responsible consumption and
production) and SDG8 (decent work and economic growth).
9.5 Conclusions
In this chapter, we analyzed the distribution of the two main biomes in central Africa,
tropical forests and savannas, as well as the underlying factors affecting their
distribution. Interestingly, in intermediate rainfall regimes, forest and savanna represent alternative stable states maintained by a positive feedback between vegetation
structure and fire events. Forest-savanna bistability spans a huge portion of central
9 Long-Term Vegetation Change in Central Africa: The Need for an Integrated. . .
305
more than 60% of forest area in some countries, while at the same time being an
engine of economic growth (Bayol et al. 2012; De Wasseige et al. 2012) (Chap. 1,
Vol. 1). Even though current logging practices are not entirely sustainable, considering that the initial stock of timber accumulating for centuries cannot be recovered
in 25–30 years of a timber rotation, some good logging practices such as selective
logging following Forest Stewardship Council standards could limit negative biodiversity outcomes (Putz et al. 2012) and ensure at least 50% recovery of the timber
resource for the targeted species (Bayol et al. 2012). With logging roads closing
within only a few years (Kleinschroth et al. 2015) and biomass recovering within
approximately 20 years following logging (Gourlet-Fleury et al. 2013), it is possible
that production forests could provide multiple ecosystem services, at levels even
comparable to “intact” or old-growth forests.
Nevertheless, logging can be a major driver of forest fragmentation, having
negative biodiversity outcomes through habitat fragmentation and forest accessibility (Poulsen et al. 2013; Ziegler et al. 2016). Thus enhancing conservation actions
and preventing poaching/hunting are key priorities in logging concessions. In
addition, even though timber recovery rates are supposed to reach 50%, regeneration
deficits have been observed for many timber species (Engone Obiang et al. 2014;
Morin-Rivat et al. 2017). Thus prior to logging management inventories should be
used to identify target species and how the regeneration is organized. Indeed,
dissimilarities between canopy species and regeneration have been observed in
different forest types (e.g., Swaine and Hall 1988 in Ghana along a rainfall gradient),
which can be explained by forest successional dynamics. The conditions that
promoted the regeneration of canopy species may no longer be encountered. As a
result (and in order to be logged in the future) the species targeted for timber in
central Africa will need to be favored, and specific silvicultural interventions will be
required. Among them, forest enrichment (Doucet et al. 2009) and plantations
(Doucet et al. 2016) have already provided good results at a relatively small scale.
The above suggest that designing nuanced sustainable management approaches
based on the long-term understanding of forest and savanna dynamics could contribute substantially in meeting SDG Target 15.2 (sustainable forest management)
and 15.7 (end poaching). More importantly such interventions can have important
synergies with some of the targets related to SDG12 (responsible consumption and
production) and SDG8 (decent work and economic growth).
9.5 Conclusions
In this chapter, we analyzed the distribution of the two main biomes in central Africa,
tropical forests and savannas, as well as the underlying factors affecting their
distribution. Interestingly, in intermediate rainfall regimes, forest and savanna represent alternative stable states maintained by a positive feedback between vegetation
structure and fire events. Forest-savanna bistability spans a huge portion of central
9 Long-Term Vegetation Change in Central Africa: The Need for an Integrated. . .
305