Performances of native tree species in plantations: a synthesis for the Guineo-Congolian region

In the rainforests of the Guineo-Congolian region, several native tree species have been tested
in plantations with different silvicultural methods and objectives. The results of these
experiments remained scattered, hampering our ability to identify the key drivers of variability
in the survival and growth of planted tree species.
Here, we synthesize the literature by conducting a systematic review. From 45 selected
studies, we compiled a database on 89 native tree species planted in different forest types
(evergreen, semideciduous and transition). The data included plantation age, survival, height
and diameter growth. For each planted species, we gathered information on the planting method
(understorey, line planting, gap, degraded area, regrowth and clear-cut), and species functional
traits (species guild, dispersal mode, wood density and leaf phenology). We modelled tree
survival, height and diameter growth using linear mixed-effect models.
We found that tree survival depended mainly on plantation age, and that the mortality rate
was the highest during the seven first years. In contrast, tree survival did not significantly
depend on the planting method or species traits. In the studied plantations, height and diameter
growth significantly depended on the planting method and species guild. Diameter growth was
negatively correlated with wood density. Pioneer, non-pioneer light-demanding and shade
bearer species grew faster in diameter when planted in degraded areas and clear-cuts. Pioneer
species grew the fastest in gaps, where they also grew faster than the other species. Although
we did not find an effect of forest type on tree survival and growth, the variability between sites
was substantial.
This study provided empirical evidence that planting methods need to be adapted to the
species guild.