Ecology and management of Pericopsis elata (Harms) Meeuwen (Fabaceae) populations: a review (original) (raw)
Related papers
Ecology of Pericopsis elata (Fabaceae), an Endangered Timber Species in Southeastern Cameroon
Biotropica, 2012
Pericopsis elata (Fabaceae) is a tall tree of high commercial value of the moist semi-deciduous African forests. As a result of decades of logging it is now considered as threatened and listed on the IUCN Red List and CITES Appendix II, even though essential biological parameters controlling its population dynamics remain unknown. This study aims at improving the knowledge of the species' ecological parameters, and at assessing the impact of selective logging on its populations in an 118,052 ha forest in Cameroon. After inventorying the species in 1432 ha, mortality and growth were assessed over continuous 5-and 2-yr periods in unlogged and logged areas, respectively. Phenology was monitored in the unlogged forest during 5 yr. The population structure shows high relative abundance of trees in medium size categories. Mean annual diameter increments in both environments did not differ significantly between unlogged and logged areas. P. elata is a deciduous species that flowers at the end of the main dry season. The minimum reproduction and effective flowering diameters were 32 and 37 cm, respectively. Fruit maturation took place during 7 mo. With a minimum logging diameter of 90 cm, the recovery rate computed over a 30-yr period was > 100 percent. Selective logging harvested only 12.1 percent of the total number of seed trees and had little influence on the species' biological parameters. Securing sufficient regeneration as a post-logging action is probably the most important consideration for achieving long-term sustainability.
Pericopsis elata (Harms) van Meeuwen is a tropical Africa's timber of high economic value. In many countries its low natural regeneration rate does not favor the replacement of harvested populations, thus CITES and IUCN recommended a total protection of the species. This survey aimed to characterize the early growth stages and natural regeneration of P. elata through the determination of seedlings distribution and structure. Squared plots of 2500 m² were installed around stumps and seed-bearing trees respectively in the logged and unlogged forest concessions at Ouesso, near Yokadouma, South-East Cameroon. Stumps, seed-bearing trees and seedlings were counted and their structural parameters (diameter and height) were recorded. A total of 56 plots corresponding to 14 ha were surveyed and 1069 seedlings were recorded. The rate of regeneration was 56% around stumps and 24.13% around seed-bearing trees. The spatial distribution of seedlings appears to be aggregated. Germination and seedling growth have shown that early growth stages of Pericopsis elata are not representing a relevant limiting factor for the evolution of population. However, the limited number of saplings and the lack of poles suggest that light could play an important role in the evolution of the early stages.
Open Journal of Soil Science, 2018
One of the problems limiting high survival rates of Pericopsis elata (afrormosia, assamela), a high value timber species, is lack of data on its pedological requirements. A study was conducted in the East Region of Cameroon to identify possible soil properties favoring its spatial distribution. Two test areas, in and out of a Pericopsis elata natural forest stand were identified and in each sampling units of 50 × 50 m delineated. Thirty eight and sixteen quadrats in and out of the stands were respectively sampled for soil physico-chemical properties, number of stems and diameter at breast height. Soil samples in each quadrat were analyzed following standard laboratory procedures. Soil properties were tested for normality and compared for the two sites using Student's t-test. Principal component analysis and correlation analysis were performed on tree and soil data to identify soil factors responsible for spatial distribution. From our findings, key soil indicators favouring Pericopsis elata distribution appear to be acidity (soil pH and exchangeable acidity), base status (base saturation and exchangeable bases) and texture (clay content). More specifically, optimal soil conditions for growth and survival of Pericopsis elata are: pH (4.1-5.0), exchangeable acidity (<4.67 cmolc•kg −1), base saturation (6.2%-17.8%), and clay content (24.0%-49.0%), which should be considered in site selection for reforestation with Pericopsis elata.
Open Journal of Ecology, 2020
The study aimed at evaluating the natural regeneration of some characteristic species in the Loukaya peri-urban forest was carried out in Brazzaville, over three surveys of one hectare each. The botanical inventory of the 23 species monitored covers the subjects of 2 ≤ d 0.20 < 10 cm and d 1.30 ≥ 10 cm. The study shows 1255 individuals of which 68.27% are 2 ≤ d 0.20 < 10 cm. While being tropophilic and mesophilic, this ecosystem is pauciflorous and paucispecific. The phytoecological data show that this formation, which is a link in the African dense humid forest, presents values far below those known elsewhere; while being faithful to the forests of the Cataractes Plateau. As for the rate of natural regeneration, this index is greater than or equal to 100 for 69.56% of the taxa. Sarcochores and heliophytes are the taxa that best support this natural regeneration. This high rate of regeneration would be correlated with the high level of anthropization, whose large canopy gaps are accompanied by a flow of light conducive to the installation of seedlings.
ECOLOGY AND SOCIETY
Traditionally, sustained yield (SY) has been viewed as a pillar of sustainable forest management (SFM), but this has been increasingly questioned. Ensuring SY of some species, i.e., a "strong sustainability" paradigm, could be an inadequate criterion if consideration of the social and economic components of the SFM concept are desired. SFM was translated into the ATO/ITTO set of principles, criteria, and indicators (PCI) for forest management in the Congo Basin; it resulted in the necessity for a certified logging company to ensure that no significant change in structure and floristic composition would result from logging operations. Besides raising the question of where to place the change threshold, we argue that sustainability must be considered from three indissociable viewpoints: ecological, social, and economic. The issue is how to balance these criteria, knowing that this assessment will involve potential conflicts of representations and beliefs. To discuss these questions, we used the example of two heavily logged timber species in the Congo Basin, sapelli (Entandrophragma cylindricum) and ayous (Triplochiton scleroxylon). Using long-term data collected from permanent sample plots in M'Baïki, Central African Republic, we calibrated a matrix model and performed short-and long-term simulations to examine (1) the potential effect of repeated logging of the species under the current national regulation system and (2) the rules that should be set to reach long-term SY. Ensuring long-term SY would require a 22% and 53% decrease in the felling intensity of E. cylindricum and T. scleroxylon, respectively, at first cut, together with an increase in overall logging intensity targeted toward less-used species. Light-demanding E. cylindricum and T. scleroxylon require open forests to regenerate and grow. This new set of rules is probably economically unsustainable for the current African forest industry, and will not meet the ecological requirements encapsulated in the ATO/ITTO PCI. We thus stress the following points: (1) the importance of most exploited species for the current industry may change as wood processing capacities become more efficient and markets change, potentially providing conditions for harvesting a greater number of species; (2) floristic change is unavoidable in these conditions, but this problem should be addressed at a broad scale, notably by ensuring a network of protected areas; (3) as long as the timber industry remains one of the few sources of employment and revenues in marginalized countries, reducing SFM to SY of the most exploited species on every concession appears questionable.
Growth and productivity of Pericopsis elata (Harms) Meeuwen in some forest plantations of Cameroon
Forest Science and Technology, 2012
This article may be used for research, teaching, and private study purposes. Any substantial or systematic reproduction, redistribution, reselling, loan, sub-licensing, systematic supply, or distribution in any form to anyone is expressly forbidden. The publisher does not give any warranty express or implied or make any representation that the contents will be complete or accurate or up to date. The accuracy of any instructions, formulae, and drug doses should be independently verified with primary sources. The publisher shall not be liable for any loss, actions, claims, proceedings, demand, or costs or damages whatsoever or howsoever caused arising directly or indirectly in connection with or arising out of the use of this material.
2014
The long-lived pioneer species Pericopsis elata is one of the rare tropical timbers on the list of the Convention on International Trade of Endangered Species, supporting the need for accurate and reliable growth data. In one planted and one natural forest in the Democratic Republic of Congo, respectively four and 37 Pericopsis stem disks were collected. The tree-ring series of planted trees were used to confirm annual tree-ring formation. For the natural forest, a tree-ring chronology with 24 stem disks ranged from 1852 up to 2008. This chronology was compared with time-series of local precipitation, resulting in a significant correlation with the second half of the rainy season (September-November). This seasonal precipitation was related with sea surface temperatures of the West Indian Ocean. Higher precipitation during El Niño years corresponded with higher tree-ring indices but differences were not significant. In addition, pointer years were rare and did not have a consistent link with extreme climatic conditions. The existence of annual tree rings encourages further tree-ring analyses of P. elata and other flagship timber species in order to further document climate-growth responses and to provide the long-term framework that is needed for sustainable management planning.