Litter Fall, Standing Litter and Leaves Decomposition Within Urban Tropical Forest of Zoological Park of Brazzaville, Republic of the Congo

Biduk-Biduk Karst Region has great potential to absorb and store organic carbon in vegetation and soil as well as to absorb inorganic carbon through the process of dissolution. The area has important economic value in supporting the REDD Program in Berau District. The purpose of this study is (1) to identify the amount of carbon stocks in various ecosystems; and (2) to identify the amount of carbon uptake in various ecosystems in the study area. Carbon stocks are computed based on four carbon sinks, i.e., above ground biomass, underground biomass, litter, and soil organic matter using the standard measurement method of SNI 7724: 2011. Carbon sequestration is calculated based on the input of carbon from the atmosphere to ecosystems through litter fall and karstification process and the output of carbon from the ecosystem to the atmosphere through soil respiration. Litter fall is measured using the litter trap method. Karstification is measured with standard limestone tablet method. Soil respiration is calculated with the closed chamber method. The results show that the ecosystems in the Biduk-Biduk Karst Region have a potential carbon stock of 4,800.92 tons/ha with the largest value in the secondary tropical forest of 732.6 tons/ha and the lowest value in the teak forest plantation of 358.2 tons/ha. Ecosystems in the Biduk-Biduk Karst Region have a potential carbon sequestration of 37.33 tons/ha/year with the largest contribution in the primary tropical forest of 7,63 tons/ha/year.

Download Full-text

Democratic Republic of the Congo Tropical Forest Canopy Height and Aboveground Biomass Estimation with Landsat-8 Operational Land Imager (OLI) and Airborne LiDAR Data: The Effect of Seasonal Landsat Image Selection

Remote Sensing ◽

10.3390/rs12091360 ◽

2020 ◽

Vol 12 (9) ◽

pp. 1360

Author(s):

Herve B. Kashongwe ◽

David P. Roy ◽

Jean Robert B. Bwangoy

Keyword(s):

Tropical Forest ◽

Aboveground Biomass ◽

Democratic Republic ◽

Tree Height ◽

Airborne Lidar ◽

Canopy Height ◽

Landsat Image ◽

Landsat 8 ◽

Republic Of The Congo ◽

The Mean

Inventories of tropical forest aboveground biomass (AGB) are often imprecise and sparse. Increasingly, airborne Light Detection And Ranging (LiDAR) and satellite optical wavelength sensor data are used to map tree height and to estimate AGB. In the tropics, cloud cover is particularly prevalent and so several years of satellite observations must be considered. This may reduce mapping accuracy because of seasonal and inter-annual changes in the forest reflectance. In this paper, the sensitivity of airborne LiDAR and Landsat-8 Operational Land Imager (OLI) based dominant canopy height and AGB 30 m mapping is assessed with respect to the season of Landsat acquisition for a ~10,000 Km2 tropical forest area in the Democratic Republic of the Congo. A random forest regression estimator is used to predict and assess the 30 m dominant canopy height using LiDAR derived test and training data. The AGB is mapped using an allometric model parameterized with the dominant canopy height and is assessed by comparison with field based 30 m AGB estimates. Experiments are undertaken independently using (i) only a wet season Landsat-8 image, (ii) only a dry season Landsat-8 image, and (iii) both Landsat-8 images. At the study area level there is little reported sensitivity to the season of Landsat image used. The mean dominant canopy height and AGB values are similar between seasons, within 0.19 m and 5 Mg ha−1, respectively. The mapping results are improved when both Landsat-8 images are used with Root Mean Square Error (RMSE) values that correspond to 18.8% of the mean study area mapped tree height (20.4 m) and to 41% of the mean study area mapped AGB (204 Mg ha−1). The mean study area mapped AGB is similar to that reported in other Congo Basin forest studies. The results of this detailed study are illustrated and the implications for tropical forest tree height and AGB mapping are discussed.

Download Full-text

Relationships of Agricultural Land Use to an Expanded Road Network within Tropical Forest Landscapes of Cameroon and Republic of the Congo

The Professional Geographer ◽

10.1080/00330124.2017.1325752 ◽

2017 ◽

Vol 70 (1) ◽

pp. 60-72 ◽

Cited By ~ 3

Author(s):

Silvia Cordero-Sancho ◽

Kathleen M. Bergen

Keyword(s):

Land Use ◽

Tropical Forest ◽

Road Network ◽

Agricultural Land ◽

Agricultural Land Use ◽

Republic Of The Congo

Download Full-text

Early responses of elevated nutrient input on above-ground net primary production of a lower-montane tropical forest in Uganda

10.5194/egusphere-egu2020-13935 ◽

2020 ◽

Author(s):

Raphael Manu ◽

Marife D. Corre ◽

Edzo Veldkamp ◽

Oliver van Straaten

Keyword(s):

Primary Production ◽

Tropical Forest ◽

Tropical Forests ◽

Net Primary Production ◽

Forest Growth ◽

Nutrient Addition ◽

Litter Production ◽

N Addition ◽

Litter Fall ◽

Montane Tropical Forest

Nutrient availability in tropical forest ecosystems plays a critical role in sustaining forest growth and productivity. Observational evidence for nutrient limitations on net primary productivity (NPP) in the tropics is rare yet crucial for predicting the impacts of human-induced changes on tropical forests, particularly for underrepresented tropical regions in Africa. In an ecosystem-scale nutrient manipulation experiment, we assessed the response of different components of above-ground net primary production (ANPP) to nutrient addition of nitrogen (N), phosphorus (P), potassium (K) and all possible combinations (NP, NK, PK, and NPK) at rates of 125 kg N ha-1yr-1, 50 kg P ha-1 yr-1 and 50 kg K ha-1yr-1.We established 32 (8 treatments &#215; 4 replicates) experimental plots of 40 &#215; 40 m2 each and measured stem growth of over 15,000 trees with diameter at breast height (dbh) &#8805; 1 cm as well as litter production and above-ground woody biomass production (AWBP), of a lower-montane tropical forest (1100 m a.s.l.) in northwestern Uganda.After 18 months of nutrient addition, we found that different aspects of ANPP, including litter production and AWBP are controlled by multiple soil nutrients. Specifically, we measured higher total fine-litter production in the N (13.6 &#177; 1.4 Mg ha-1 yr-1) and K (13.3 &#177; 1.8 Mg ha-1 yr-1) addition plots than the control (11.1 &#177; 0.6 Mg ha-1 yr-1) plots. Both reproductive litter (flowers and fruits; 10% of total fine-litter fall) and leaf litter (62% of total fine-litter fall) significantly increased with K addition. In general, fine-litter production in our plots is higher than what has been reported so far for lower-montane tropical forests. Increased AWBP is associated with N addition plots. The response of trees to nutrient addition however, varied with tree sizes. Trees with dbh between 10 &#8211; 30 cm increased significantly in AWBP under PK addition. There was no effect of nutrient addition associated with either smaller (1 &#8211; 10 cm dbh) or larger trees (dbh > 30 cm). The medium-sized trees which may have experienced resource competition but have now transitioned into the canopy layer (exposed to sunlight) are able to use additional nutrient for active growth. In contrast, bigger trees may allocate extra nutrient for reproduction and leaf-vitality, while smaller trees remain shaded, co-limited by sunlight and therefore unable to utilize increased available nutrients for stem diameter growth. ANPP increased by 39% with N addition and marginally by 23% with K additions relative to the control. In conclusion, our experiment provides evidence of N and potentially K limitation of ANPP in this lower-montane tropical forest, and highlights that, in a highly diverse ecosystem different components of ANPP may be regulated by multiple nutrients.&#160;

Download Full-text

Four new species of the sac spider genus Planochelas Lyle & Haddad, 2009 (Araneae, Trachelidae) from central and southern Africa

African Invertebrates ◽

10.3897/afrinvertebr.60.35269 ◽

2019 ◽

Vol 60 (2) ◽

pp. 147-164 ◽

Cited By ~ 1

Author(s):

Thembile T. Khoza ◽

Robin Lyle

Keyword(s):

South Africa ◽

New Species ◽

Tropical Forest ◽

Southern Africa ◽

Democratic Republic ◽

Distribution Map ◽

Number Of Species ◽

Afrotropical Region ◽

Canopy Fogging ◽

Republic Of The Congo

The genus Planochelas Lyle & Haddad, 2009 is endemic to the Afrotropical region. Members of the genus are very small, arboreal sac spiders. They are mainly collected by canopy fogging in tropical forest and savanna. In this study, four new species of Planochelas are described: P.brevissp. nov., P.jocqueisp. nov. (Democratic Republic of the Congo) and P.haddadisp. nov., P.neethlingisp. nov. (South Africa). An updated key to the genus is provided, and the new species are illustrated by photographs and drawings. A distribution map for the genus is provided. This paper increases the number of species in the genus to seven.

Download Full-text

The decomposition of standing and fallen litter of Typha glauca and Scirpus fluviatilis

Canadian Journal of Botany ◽

10.1139/b78-073 ◽

1978 ◽

Vol 56 (6) ◽

pp. 662-675 ◽

Cited By ~ 89

Author(s):

C. B. Davis ◽

A. G. van der Valk

Keyword(s):

Dry Weight ◽

Microbial Populations ◽

Litter Fall ◽

Mineral Uptake ◽

Fe Content ◽

Combined Action ◽

Mineral Losses ◽

Standing Litter ◽

Uptake And Release ◽

Typha Glauca

Changes in dry weight and N, P, K, Na, Ca, Mg, Al, and Fe content were studied over a 525-day period in decomposing Typha glauca and Scirpus fluviatilis shoots. Submerged Typha litter decomposed more rapidly than submerged Scirpus litter, losing 50% of its original dry weight in 325 days while Scirpus litter still retained 62% of its original dry weight after 525 days. Major pathways of mineral flow from standing litter were (1) leaching during the first few weeks after shoot death and (2) fragmentation and litter fall during the rest of the study. Mineral losses from fallen litter were mainly due to leaching or to excretion by microbial populations associated with the litter. Microbial uptake (N, P) and adsorption (Ca, Al, Fe) were important processes in the fallen litter. After 525 days, as a result of the combined action of mineral uptake and release, Typha litter had net releases of N (71 kg/ha), P(10 kg/ha), K (123 kg/ha), Na (94 kg/ha), Ca (41 kg/ha), and Mg (25 kg/ha) and net accumulations of Al (21 kg/ha) and Fe (20 kg/ha). Scirpus litter, during this same period, had net releases of N (10 kg/ha), K (9 kg/ha), and Na (11 kg/ha). All other minerals increased in decomposing Scirpus litter: P (8 kg/ha), Ca (55 kg/ha), Mg (5 kg/ha), Al (13 kg/ha), and Fe (11 kg/ha). At the end of the study, the calculated combined dry weight of undecomposed standing and fallen litter had decreased by only 20% in Typha litter and 14% in Scirpus litter. Most of the biomass and minerals were in the fallen litter.

Download Full-text