Table 1. Evolution of the exploitable stock of two main commercial species logged in the Central African Republic (CAR; Entandrophragma cylindricum and Triplochiton scleroxylon) under the current felling regime.

Species and logging rules Actual rules Sustainable system
Logged (individuals/ha ≥ DCL) at first cut
Recovered after 1 cycle
Recovered (%)
Logged (individuals/ha) at cycle 10
Mean logged per cycle, for 10 cycles
Proportion of stock removal at each cycle†
 
Logged (individuals/ha ≥ DCL) at first cut
Mean logged in stabilized system, per cycle, for 10 cycles
E. cylindricum
DCL: 80 cm dbh
Proportion of stock removal†: 89%
M'Baïki





70% (compared to 89%)  

Number 1.42 0.21 15.1 0.24 0.45   1.10   0.56
Volume (m3) 24.29 3.87 15.9 3.25 6.68   18.96‡ 9.09
               
Forest concession




 

Number 0.32 0.16 49.3 0.12 0.18   0.25   0.22
Volume (m3) 4.28 2.17 50.7 1.49 2.44     3.34‡ 3.32
                     
T. scleroxylon
DCL: 80 cm dbh
Proportion of stock removal†: 95%
M'Baïki





45% (compared to 95%)  

Number 1.58 0.67 42.3 0.09 0.45   0.75   0.67
Volume (m3) 29.07 8.60 29.6 1.15 6.51   13.80‡ 14.70
               
Forest concession




 

Number 0.80 0.25 31.2 0.06 0.23   0.38   0.35
Volume (m3) 12.57 3.24 25.8 0.67 3.16     5.97‡ 7.28
Note: The felling cycle is 30 years. Number of trees ≥ diameter cutting limit (DCL) and corresponding volumes are predictions made using a stochastic matrix model calibrated with data from the M'Baïki experimental site in the CAR (methods are described in Gourlet-Fleury et al. 2004, 2005). On this site, the two species were logged on 12 ha. Predictions were also made for a forest concession located in the CAR, using data from a management survey performed in 2004. Volume equations used were site specific.
†Percentage of the number of standing trees ≥ DCL in the forest.
‡Respectively, 78% (E. cylindricum) and 47% (T. scleroxylon) of the number of trees or volume harvested at first cut under the current felling regime. The sacrifice at first cut would thus be 22% (E. cylindricum) and 53% (T. scleroxylon) of the commercial volume.