Original Research Article Assessment of phytoecological parameters of forest massifs in the Kwilu district of the Democratic Republic of Congo Abstract The degradation of various forest ecosystems in mainly tropical regions and more particularly in sub- Saharan Africa has been a constant reality since the emergence of man. Faced with this almost alarming picture, most often linked to the countless economic challenges and calamitous management and confronted with unavoidable climate change, it seemed appropriate and imperative to assess the quantities of Above ground Biomass, sequestered carbon stocks, carbon equivalent and basal area produced by various forest massifs encountered in the Kwilu district, Kwilu province. This study was carried out at the Kiyaka Agricultural Research Station located in the south of Kikwit. Five blocks of 100 m / 20 m were delineated using a 200 m long nylon wire divided into 10 m intervals. The system thus delimited made it possible to inventory all the trees whose dbh measured at 1.30 m at chest height is ≥ 10 cm. The findings showed that species are divided into 11 orders, 42 genera and 19 families. The following systematic units are best represented in terms of number of plant species. These are Fabaceae, Malvaceae, Apocynaceae, Euphorbiaceae and Olacaceae, which together contain 26 plant species, while nine families are poorly represented. However, this reserve is threatened by its occupants on all sides; they do not want to clear large areas of forest for their field work. It is therefore urgent for INERA/Kiyaka officials to take the necessary measures for its full protection. Keywords: Phytoecology, Forest massifs, Kwilu, DRC 1. Introduction The degradation of various forest ecosystems in mainly tropical regions and more particularly in sub- Saharan Africa has been a constant reality since the emergence of man. Villeneuve et al. (2007), reported that "more than 200,000 years ago, men controlled fire and used it to burn dry tropical forests, most often to hunt game or drive away predators". Currently, the authors pursue, there are only less than 8% left and the majority of them are located mainly in mountainous and/or difficult to access areas. Faced with this almost alarming picture, most often linked to the countless economic challenges and calamitous management and confronted with unavoidable climate change, it seemed appropriate and imperative to assess the quantities of Air Biomass (AGB), sequestered carbon stocks, carbon equivalent and basal area produced by the various forest massifs (at least what remains of them) encountered in the Kwilu district (Kwilu province). The knowledge of these parameters, in particular sequestered carbon and its equivalent, above-ground biomass and basal area produced, would allow our country to access carbon credits and to what extent would it participate and/or participate in temperature regulation, thereby reducing the currently increasing greenhouse gases (GHGs) in the atmosphere; as stipulated in the Kyoto Protocol. This work therefore pursues the same objective as that of REDD+, namely the preservation of existing forests, and/or what remains and the limitation of GHGs. 2. Methods 2.1. Study area The Kiyaka Agricultural Research Station is located at 75 km in the south of Kikwit and it covers 3250 ha. Its geographical coordinates are presented as follows: 5° 16' and 5° 24' South latitude, 18° 57' and 18° 43' East longitude (Fig. 1). The altitude varies between 400 to 509 m in the valley and 735 m at plateau level (Bultot, 1954). Figure 1. Map of INERA Kiyaka, Kwilu Figure 1. Map of Kiyaka Agricultural Research Center 2.2 Methods Five blocks of 100 m / 20 m were delineated using a 200 m long nylon wire divided into 10 m intervals. The system thus delimited made it possible to inventory all the trees whose dbh measured at 1.30 m at chest height is ≥ 10 cm. Thus, any species with a dbh ≥ 10 cm was identified and using a branded GPS, its position and geographical coordinates were taken. Since we could not directly measure the diameter of each of these trees in the field, we measured their circumference at 1.30 from the ground each time. For shafts with buttresses or dents and/or deformations at this level, these measurements were taken above the buttress or deformation. For botanical characterization indices, including relative species density (DeR) and relative family density (DfR), we used the following formula (Rollet, 1974) : DeR = Number of individuals of a species/ total number of individuals in the sample x 100 or number of individuals in a family/ total number of individuals in the sample. With regard to diameter classes, the diameters of all species at dbh ˃ 10 cm, present in the various surveys, were measured using a tape measure and grouped into different classes. Eco-sociological groups have been distinguished on the basis of the work of many authors (Lebrun and Gilbert (1954), Evrard (1968 in Masens 1997), Lubini (1995). Leaf size types were defined from Raunkiaer's classification (1934 in Sokpon, 1995; Habari 2009; Belesi, 2009). For the types of geographical distribution we have based ourselves on the major chorological subdivisions of Africa (White 1979, 1983). For biological types (T.B.), we used Raunkiaer's classification (1934, in Masens 1997), adapted to tropical regions by Lebrun (1964), Ellenberg et al (inMosango, 1990), Habari (2009) and Belesi (2009). With regard to the types of dissemination of diasporas, we have drawn inspiration from the work of Moulinier and Müller (1938, in Sokpon, 1995), Dansereau and Lems (1957, in Masens 1996). The statistical analyses of the data were carried out using the SPSS 14.0 software. It allowed us to know if the p-value value is ≤ 0.05, the parameters compared are correlated and if the p-value values are ≥ 0.05, we conclude that there is no correlation between the parameters taken into account. The ArcGIS and QGIS software were used to produce the map and to spatially distribute the species. 3. Results and discussion 3.1. The flowering plants of the forest massif The floristic inventory carried out in the INERA/Kiyaka forest reserve has made it possible to count 48 plant species. These species are divided into 11 orders, 42 genera and 19 families. The following systematic units are best represented in terms of number of plant species. These are Fabaceae, Malvaceae, Apocynaceae, Euphorbiaceae and Olacaceae, which together contain 26 plant species, while nine families are poorly represented. These include Ebenaceae, Rubiaceae, Ulmaceae and Verbenaceae. All the results of the entire study flower are recorded in Table 1. Table 1. Floristic Inventory of Kiyaka massif forest (values of different structural parameters) Number of dbh Aerial biomass Scientific names of species specimens (cm)) ST (m2) (t/ha) Stored Carbon(t/ha) Equivalent C (t/ha) Chave Pearson Chave Pearson Chave Pearson Alstonia boonei 12 218 0,35 13,23 10,6 6,22 4,98 22,81 18,27 Angylocalyx margininervatus 5 108 0,22 9,86 5,8 4,63 2,73 16,99 9,99 Anonidium mannii 8 421 1,63 100,13 31,52 47,06 14,81 172,58 54,32 Barteria nigritiana var. fistulosa 5 66 0,07 2,03 2,11 0,95 0,99 3,49 3,64 Brachystegia laurentii 471 814,7 15,38 651,44 405,23 306,18 190,46 1122,75 698,41 Canarium schweinfurthii 7 322 3,81 34,54 47,69 39,73 22,42 145,7 82,21 Carapa procera 2 143 1,24 59,34 14,76 27,89 6,94 102,27 25,43 Ceiba pentandra 3 103 0,32 17,57 6,61 8,26 3,11 30,29 11,39 Celtis mildbraedii 9 273 0,67 31,28 14,75 14,7 6,99 53,92 25,42 Chrysophyllum lacourtianum 15 398 0,91 41,99 25,71 19,74 12,08 72,38 44,31 Cola acuminata 1 11 0,01 0,27 0,29 0,13 0,13 0,47 0,49 Cola bruneelii 8 247 0,55 24,87 13,84 11,69 6,22 42,87 22,82 Cola diversifolia 2 25 0,02 0,68 0,71 0,32 6,22 1,17 1,22 Cola griseiflora 2 42 0,08 3,09 1,87 1,45 0,88 5,33 3,22 Croton sylvaticus 1 16 0,02 0,69 0,73 0,33 0,34 1,2 1,25 Dacryodes klaineana 6 111 0,18 6,83 5,37 3,21 2,52 11,77 9,25 Dichostemma glauscens 8 325 1,06 57,38 19,39 26,97 5,11 98,89 33,42 Diospyros conocarpa 1 14 0,02 0,48 0,5 0,22 0,24 0,83 0,87 Duboscia viridiflora 3 201 1,96 70,98 22,12 33,36 10,39 122,33 38,12 Entandrophragma cylindricum 9 261 0,6 27,05 14,18 12,71 6,66 46,62 24,43 Entandrophragma utile 5 562 5,11 355,15 46,49 166,85 21,85 612,09 80,13 Funtumia africana 1 22 0,04 1,49 1,54 0,69 0,72 2,56 2,66 Garcinia kola 5 197 0,83 33,91 16,91 15,96 7,95 58,53 29,14 Hallea stipulosa 2 39 0,06 2,13 2,22 1 1,04 3,68 3,83 Hollarhena floribunda 10 147 0,18 5,68 5,92 2,67 2,78 9,79 10,21 Homalium longistylum 3 158 0,67 41,46 13,81 19,49 6,49 71,46 23,81 Irvingia robur 1 46 0,17 9,62 3,24 4,52 1,52 16,58 5,58 Mammea africana 2 35 0,05 1,82 1,89 0,85 0,89 3,14 3,26 Musanga cecropioides 4 179 0,63 35,31 11,91 16,59 5,59 60,86 20,52 Olax archesoniana 2 86 0,26 13,51 4,58 6,35 2,15 23,29 7,89 Olax sp 1 58 0,21 13,33 4,45 6,26 2,09 22,97 7,68 Oncoba welwitschii 3 16 0,69 43,9 14,6 20,63 8,86 75,67 25,16 Pentaclethra ma crophylla 4 12 0,33 15,89 7,96 7,47 3,74 27,39 13,71 Petersianthus macrocarpus 5 209 0,71 39,12 13,19 18,38 6,2 67,42 22,74 Piptadeniastrum africanum 1 153 1,83 65,9 18,27 30,97 8,56 113,58 31,39 Plagiostyle africana 4 69 0,1 3,77 2,83 1,77 1,33 6,49 4,88 Prioria balsamifera 4 18 5,43 330,59 58,78 155,38 27,62 569,77 101,3 Pycnanthus angolensis 4 259 1,33 63,42 29,9 29,81 14,05 109,31 51,53 Ricinodendron heudelotii var.