Dynamique De La Végétation De Bamo Et Stocks De Carbone Dans La Mosaïque De Végétation

This study was conducted in Agboville, Ivory Coast. The objective was (1) to characterize the floristic composition, dynamics, and structure of tree diversity of postcultural fallows; and (2) establish the relationship between the diversity and storage of carbon in timber biomass. The study relied on a network of 50 temporary plots. There were 31 postcultural fallows and 19 plots of primary forest. This study has identified 417 plant species distributed in 306 genera and 83 families. Tree density within postcultural fallows varied between 1025 to 5975 stems / ha, and the analysis showed that the density increases with the age of the postcultural fallows. Tree sampling was non-destructive and to estimate C storage, an allomectric models for above and belowground biomasses was used. Mean estimate of carbon (C) stocks in biomass were 80.25 tC / ha for groupe A (fallows from 4 to 8 years) and 256.5 tC / ha for group D (fallows from 14 to 24 years). These values remain far below those seen in the groups of primary forests with lateritic soil (1335.25 tC / ha). Results showed the ability of some postcultural fallows to store much C. It demonstrated that storage depends mainly on age and conserved species. This supports the idea of employing REDD+ processes in enhancing the ecological value associated with carbon

Systematic and plant geography analysis of Badénou forest (Korhogo, Côte d’Ivoire)

This study was initiated to contribute to the sustainable management of the Badénou classified forest. Its objective was to contribute to a better knowledge of the flora of this classified forest and, beyond that, to provide details on the distribution of species on the scale of Côte d'Ivoire. Surface survey methods and itinerant inventories were adopted during this work in 30 plots, 25 of which were set aside for post-cultural fallow. A total of 241 species were recorded throughout the massif, divided into 184 genera and 53 families. The botany inventories in all parts of the forest helped identify 241 species have been recorded in Badénou forest during field investigations, distributed among 183 genera and 53 families. Among those species, 162 (67.22%), 12 (4.98%), 10 (4.15%) and 10 (4.15%) are phanerophytes, therophytes, geophytes and hemicryptophytes, respectively. 34 species (14.11%) are lianas. Most species are dispersed by endozoochory (108 species 44.40%), either bear small, fleshy fruits that are dispersed by animals, either by endozoochory (106 species = 43.98%). Phytochory analysis shows relevant proportion of widespread species (96 species = 39.83%) compared to endemic guineo-congolian species (44 species = 18.26%). 5 species (2.07%) are guineo-congolian species that are endemic from West Africa, among which only one was endemic from Côte d’Ivoire. Those proportions indicate that the forest under study is included in dry rainforest sensu Guillaumet & Adjanohoun, and match with the widespread guineo-congolian–soudano-zambezian zone defined by White & Edwards. Unfortunately, this forest is still under enormous human pressure. Conservation efforts for endemic, rare and endangered species and the classified forest itself must be a priority. La présente étude a été initiée pour contribuer à la gestion durable de la forêt classée de Badénou. Elle avait pour objectif de contribuer à une meilleure connaissance de la flore de cette forêt classée et, au-delà, à apporter des précisions sur la répartition des espèces à l’échelle de la Côte d’Ivoire. Les méthodes de relevé de surface et des inventaires itinérants ont été adoptées lors de ces travaux dans 30 parcelles dont 25 dans les jachères postculturales. Au total 241 espèces ont été recensées dans l’ensemble du massif, réparties en 184 genres et 53 familles. Parmi ces espèces, 162 (67,22%) sont des phanérophytes, 12 (4,98%) espèces sont des thérophytes, 10 (4,15%) espèces sont des géophytes et 10 (4,15%) autres sont des hémicryptophytes. 34 espèces (14,11%) sont des lianes. La plupart des espèces sont soit pourvues d’appendices permettant leur dissémination par le vent (108 espèces = 44,40%), soit possedent de petites diaspores charnues dont la dissémination est assurée par les animaux, soit par endozoochorie (106 espèces = 43,98%). L’analyse des phytochories montre une contribution importante des espèces à large répartition (39,83% soit 96 espèces) par rapport aux espèces guinéo-congolaises (18,26%). 5 espèces (2,07%) sont des guinéo-congolaises endémiques de l’Afrique de l’Ouest, dont une est endémiques de Côte d’Ivoire. Ces différentes proportions confirment l’appartenance de la forêt étudiée à la zone de forêt dense sèche de Guillaumet & Adjanohoun, qui correspond à la zone de transitio guinéo congolais-soudano-zambézienne de White & Edwards. Malheureusement, la forêt classée de Badenou subit encore d’énormes pressions anthropiques. Les efforts de conservation des espèces endémiques, rares et menacées d’extinction et de la forêt classée elle-même doivent être une priorité

Analyse De La Diversité Floristique De La Forêt Classée D’agbo I (Côte d’Ivoire)

This study was carried out in the Agbo I classified forest (6 ° 24 '- 6 ° 41' N, 4 ° 50 '- 4 ° 09' W), which covers 15,575 ha. It contributes to a better knowledge of the dense semi-deciduous moist forest of Nesogordonia papaverifera (A. Chev.) Cap. (Malvaceae) and Khayaivorensis A. Chev. (Meliaceae). The surface surveys coupled with the itinerant inventories made it possible to have an inventory of 686 species, which are divided into 428 genera and 101 families. The most abundant families are Fabaceae, Rubiaceae, Malvaceae, Apocynaceae, and Euphorbiaceae. Out of these species, 84.11% are phanerophytes and 3.50% are hemicryptophytes. In conclusion, this study improves the knowledge which is based on the composition, structure, and diversity of the woody vegetation of the Agbo I forest. The results show that the species richness of the Agbo I classified forest is important. However, this floristic richness of the Agbo I listed forest is sufficient to justify its protection and sustainable management for the conservation of biodiversity in Côte d'Ivoire

Aboveground forest biomass varies across continents, ecological zones and successional stages: refined IPCC default values for tropical and subtropical forests

For monitoring and reporting forest carbon stocks and fluxes, many countries in the tropics and subtropics rely on default values of forest aboveground biomass (AGB) from the Intergovernmental Panel on Climate Change (IPCC) guidelines for National Greenhouse Gas (GHG) Inventories. Default IPCC forest AGB values originated from 2006, and are relatively crude estimates of average values per continent and ecological zone. The 2006 default values were based on limited plot data available at the time, methods for their derivation were not fully clear, and no distinction between successional stages was made. As part of the 2019 Refinement to the 2006 IPCC Guidelines for GHG Inventories, we updated the default AGB values for tropical and subtropical forests based on AGB data from >25 000 plots in natural forests and a global AGB map where no plot data were available. We calculated refined AGB default values per continent, ecological zone, and successional stage, and provided a measure of uncertainty. AGB in tropical and subtropical forests varies by an order of magnitude across continents, ecological zones, and successional stage. Our refined default values generally reflect the climatic gradients in the tropics, with more AGB in wetter areas. AGB is generally higher in old-growth than in secondary forests, and higher in older secondary (regrowth >20 years old and degraded/logged forests) than in young secondary forests (20 years old). While refined default values for tropical old-growth forest are largely similar to the previous 2006 default values, the new default values are 4.0-7.7-fold lower for young secondary forests. Thus, the refined values will strongly alter estimated carbon stocks and fluxes, and emphasize the critical importance of old-growth forest conservation. We provide a reproducible approach to facilitate future refinements and encourage targeted efforts to establish permanent plots in areas with data gaps

The global abundance of tree palms

Aim Palms are an iconic, diverse and often abundant component of tropical ecosystems that provide many ecosystem services. Being monocots, tree palms are evolutionarily, morphologically and physiologically distinct from other trees, and these differences have important consequences for ecosystem services (e.g., carbon sequestration and storage) and in terms of responses to climate change. We quantified global patterns of tree palm relative abundance to help improve understanding of tropical forests and reduce uncertainty about these ecosystems under climate change. Location Tropical and subtropical moist forests. Time period Current. Major taxa studied Palms (Arecaceae). Methods We assembled a pantropical dataset of 2,548 forest plots (covering 1,191 ha) and quantified tree palm (i.e., ≥10 cm diameter at breast height) abundance relative to co‐occurring non‐palm trees. We compared the relative abundance of tree palms across biogeographical realms and tested for associations with palaeoclimate stability, current climate, edaphic conditions and metrics of forest structure. Results On average, the relative abundance of tree palms was more than five times larger between Neotropical locations and other biogeographical realms. Tree palms were absent in most locations outside the Neotropics but present in >80% of Neotropical locations. The relative abundance of tree palms was more strongly associated with local conditions (e.g., higher mean annual precipitation, lower soil fertility, shallower water table and lower plot mean wood density) than metrics of long‐term climate stability. Life‐form diversity also influenced the patterns; palm assemblages outside the Neotropics comprise many non‐tree (e.g., climbing) palms. Finally, we show that tree palms can influence estimates of above‐ground biomass, but the magnitude and direction of the effect require additional work. Conclusions Tree palms are not only quintessentially tropical, but they are also overwhelmingly Neotropical. Future work to understand the contributions of tree palms to biomass estimates and carbon cycling will be particularly crucial in Neotropical forests

Estimating aboveground net biomass change for tropical and subtropical forests: Refinement of IPCC default rates using forest plot data

© 2019 The Authors. Global Change Biology Published by John Wiley & Sons Ltd As countries advance in greenhouse gas (GHG) accounting for climate change mitigation, consistent estimates of aboveground net biomass change (∆AGB) are needed. Countries with limited forest monitoring capabilities in the tropics and subtropics rely on IPCC 2006 default ∆AGB rates, which are values per ecological zone, per continent. Similarly, research into forest biomass change at a large scale also makes use of these rates. IPCC 2006 default rates come from a handful of studies, provide no uncertainty indications and do not distinguish between older secondary forests and old-growth forests. As part of the 2019 Refinement to the 2006 IPCC Guidelines for National Greenhouse Gas Inventories, we incorporate ∆AGB data available from 2006 onwards, comprising 176 chronosequences in secondary forests and 536 permanent plots in old-growth and managed/logged forests located in 42 countries in Africa, North and South America and Asia. We generated ∆AGB rate estimates for younger secondary forests (≤20 years), older secondary forests (>20 years and up to 100 years) and old-growth forests, and accounted for uncertainties in our estimates. In tropical rainforests, for which data availability was the highest, our ∆AGB rate estimates ranged from 3.4 (Asia) to 7.6 (Africa) Mg ha−1 year−1 in younger secondary forests, from 2.3 (North and South America) to 3.5 (Africa) Mg ha−1 year−1 in older secondary forests, and 0.7 (Asia) to 1.3 (Africa) Mg ha−1 year−1 in old-growth forests. We provide a rigorous and traceable refinement of the IPCC 2006 default rates in tropical and subtropical ecological zones, and identify which areas require more research on ∆AGB. In this respect, this study should be considered as an important step towards quantifying the role of tropical and subtropical forests as carbon sinks with higher accuracy; our new rates can be used for large-scale GHG accounting by governmental bodies, nongovernmental organizations and in scientific research

Co-limitation towards lower latitudes shapes global forest diversity gradients

The latitudinal diversity gradient (LDG) is one of the most recognized global patterns of species richness exhibited across a wide range of taxa. Numerous hypotheses have been proposed in the past two centuries to explain LDG, but rigorous tests of the drivers of LDGs have been limited by a lack of high-quality global species richness data. Here we produce a high-resolution (0.025° × 0.025°) map of local tree species richness using a global forest inventory database with individual tree information and local biophysical characteristics from ~1.3 million sample plots. We then quantify drivers of local tree species richness patterns across latitudes. Generally, annual mean temperature was a dominant predictor of tree species richness, which is most consistent with the metabolic theory of biodiversity (MTB). However, MTB underestimated LDG in the tropics, where high species richness was also moderated by topographic, soil and anthropogenic factors operating at local scales. Given that local landscape variables operate synergistically with bioclimatic factors in shaping the global LDG pattern, we suggest that MTB be extended to account for co-limitation by subordinate drivers