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Environmentally friendly slow-release fertilizers (SRF) based on Borassus aethiopum starch (BAS-SRF) and Maesopsis eminii (ME-SRF) hydrogels were formulated by encapsulating urea into biomaterials using borax as a binder. The SRFs were characterized by FT-IR, SEM and XRD techniques. The gel ratios of the hydrogels were found to be 71.27 ± 0.31 and 57.43 ± 2.27 for BAS-SRF and ME-SRF respectively. Swelling and water retention capacity of the SRFs in distilled water, NaCl, CaCl2, and FeCl3 solutions were evaluated. The water retention ratio at 4 days was similar 14.76% for both BAS-SRF and ME-SRF in soil and 4.67% for soil without the SRFs. The swelling ratio of the SRFs in solution, followed the order Water > NaCl > CaCl2>FeCl3. The swelling kinetics fitted with Scott's second order swelling kinetic model. The fertilizer release of the standard urea (un-capsulated) in distilled water revealed a cumulative release of about 97% within an hour. Whereas the formulated BAS-SRF and ME-SRF (encapsulated) had a cumulative release of 76% and 68% at 24 h and 96 h respectively. Interestingly, a sustained cumulative urea release was observed in soil; about 95% and 92% at 36 days for BAS-SRF and ME-SRF respectively.

In this study, the central composite design of response surface methodology was employed as a design of an experiment to optimize the extraction of oil from Maesopsis eminii seeds using ultrasonic-assisted solvent extraction (UASE). The most appropriate values of operating variables such as extraction time and n-hexane to biomass ratio and its effects on oil yield were analyzed. The 7:1 n-hexane-to-biomass ratio (140 mL n-hexane/20 g seed powder) and the 20 min extraction time were found as optimum conditions to get an oil yield of 47.86 ± 0.09 %. Oil’s chemical characteristics and compositions include yellowish color, 0.90 g/mL density, 5.40 pH, 47.9 mm2/s kinematic viscosity, 39.63 MJ/kg high heating value, >200 °C flashpoint, and 0.36 ± 0.05 % free fatty acid content. The analyses of Fourier Transform Infrared Radiation (FTIR) and Gas Chromatography-Mass Spectrophotometry (GC–MS) revealed that oil from the M. eminii seeds has esters and looked-for fatty acids signifying its potential for biodiesel production. Major fatty acids include oleic (36.7 %), linoleic (24.3 %) and stearic (22.6 %) with minor components shared by palmitic (10.2 %), arachidic (2.6 %), y-linolenic (1.5 %), cis-11-eicosenoic (1.5 %) and behenic (0.5 %). The exploratory oil refining via UASE and transesterification resulted in 84.6 % biodiesel yield indicating its high conversion rate and demonstrating its potential as a feedstock for green diesel production. Hence, the coming of the liquid biofuel from the unexplored non-edible M. eminii seeds would benefit humanity and the environment as this would reduce the use of petroleum-based fuels that are known for producing much air pollution in the atmosphere.

Few studies have attempted to identify factors that contribute to aboveground carbon offset additionality in forest restoration planting in the tropics. Moreover, those that have compared aboveground carbon offset potential of naturally regenerating secondary forests and plantation forests have yielded conflicting results regarding the ability of the latter to attain carbon offset additionality, thus limiting broad adoption of carbon-driven forest restoration interventions. We assessed woody species diversity, stem density, stem diameter and wood specific gravity of secondary and plantation forests in Kakamega Forest in western Kenya to identify determinants of aboveground carbon offset additionality in plantation forests. Secondary forests comprised old-growth, middle-aged and young vegetation stands. Plantation forests consisted of mixed indigenous, Maesopsis eminii indigenous monoculture and Cupressus lusitanica , Pinus patula and Bischofia javanica exotic monoculture stands. Assessment was carried in 135 sample plots in three forest blocks using stratified systematic sampling in nested plots. Analysis of variance indicated that there was no significant difference in woody species diversity between secondary and plantation forests due to natural forest succession in both forest types. Mixed indigenous plantation had more aboveground carbon stock than secondary forest stands of comparable stand age due to its greater proportion of tree species with high wood specific gravity and large tree diameter. Old-growth secondary forest had more aboveground carbon stock than monoculture forest plantations due to its relatively higher wood specific gravity. Middle-aged secondary forest had relatively lower aboveground carbon stock than plantation forests of comparable stand age because of its smaller tree diameter. The results suggest that stem diameter and wood specific gravity are the most important determinants of aboveground carbon offset additionality. Thus, forest managers and investors in carbon offset projects can achieve aboveground carbon offset additionality in forest restoration interventions by planting tree species with relatively higher wood specific gravity and manipulating them to attain large stem diameter through silvicultural management.

Globally, invasive plant species cause negative impacts to human livelihoods and natural ecosystems, particularly in biodiversity hotspots. Maesopsis eminii invasion in Amani Nature Forest Reserve, Tanzania, was considered an ecological disaster in the 1980s. After >50 years have elapsed since the species was first introduced in the reserve, there is yet little information available on its invasion progress. We assessed spatio-temporal invasion dynamics using forest inventory data collected in 1998 and resurveyed 60 (20 m × 50 m) sample plots in 2018. Among resurveyed plots, 30 had been invaded by M. eminii in 1998 and other 30 sample plots as control, which had no M. eminii in the year 1998. We also assessed vegetation cover change over a 20 year period between 1998 and 2018 using Landsat satellite images. Over the last 20 years, 23% of control plots were newly invaded by M. eminii. Tree species richness was 25% lower in invaded versus control plots (U = 1490, z = 2.9, p = 0.04). Large trees (DBH ≥ 31–50 cm) of Maesopsis eminii were most abundant (62%) in invaded plots whereas small trees (DBH ≤ 10 cm) were most abundant (>50%) in control plots, indicating that the tree species might be prone to self-thinning. Woody species diversity was significantly lower in invaded (1.63 ± 0.49) vs control plots (1.87 ± 0.35; t(58) = −2.19, p = 0.03). The number of M. eminii individuals ha−1 was positively associated with higher altitudes ranging above 800 masl (ρ = 0.33, P = 0.011) but there was no correlation with distance away from the forest reserve boundary (ρ = 0.11, P = 0.394;) nor with distance away from village centers (ρ = −0.08, P = 0.502). Change detection analysis indicated about 1,108 ha of non-forest vegetation had regrown into forest over the last 20 years, particularly in the south - western region of the reserve. The region included 4 sample plots newly invaded by M. eminii. We conclude that there is an increase in spatial distribution of M. eminii individuals between the year 1998 and 2018. Furthermore, M. eminii has low regeneration potential in already invaded sites of high invasive density and only slowly invading gaps in uninvaded sites.

Studies on germination behavior are important tools for understanding how environmental factors affect geographic distribution and colonization of invasive plants. Particularly seedlings of invasive plant species benefit from high light intensity, as often found in disturbed areas of low canopy cover. We investigated the effect of various shade levels on seed germination and early growth of the invasive tree Maesopsis eminii at the nursery of a biodiversity hotspot, the Amani Nature Forest Reserve, Tanzania. Shade houses provided forest-like sun flecks of four categories (0%, 50%, 65% and 85% shade), representing light regimes found in tropical natural forests throughout the entire growing season. The average germination rate across the four different shade levels differed significantly during the dry season (F3,12 = 48.74, P

There are many impacts during a tree's life that affect bole development. In Maesopsis eminii, a high-potential timber species in Uganda, studies have shown that the occurrence of strongly bent boles is the overwhelming reason that boles fail quality criteria. This observation is incongruous with the tree architecture model of Roux, which describes M. eminii as a tree with a strong apical dominance, meaning that it has a strong genetically based preference for vertical growth of the terminal sprout relative to side branches. As external causes for bent boles could be excluded, we demonstrate in this study the proof of heliotropic growth, i.e. an active bending towards light, for M. eminii beyond the sapling stage. We develop a model used to describe the effects of competition on bole quality using bole form parameters and basic information about the neighbouring trees, and without having to incorporate crown parameters. By means of calculated bole parameters and a mathematical equation to calculate the intensity and direction of competition, we prove the existence of a heliotropic growth reaction. However, we are not able to predict the intensity of this reaction. Finally, general silvicultural recommendations are discussed for tree species with strong heliotropic growth.

Effective management, conservation and restoration of tropical forests require an understanding of plant responses (e.g. sprouting) to natural and anthropogenic disturbance events. Sprouting among woody plants within Budongo Forest Reserve (BFR) in response to harvesting for poles and saplings, and tree and branch fall disturbances was examined. A total of 835 woody stumps representing 122 species were recorded. Human harvesting accounted for 83% of 835 damaged stumps. Both canopy and sub-canopy trees sprouted prolifically. Of the 122 affected species, 119 (97.5%) from 31 families sprouted from stem stumps, with only Caloncoba crepiniana exhibiting stem and root sprouting. Only Maesopsis eminii, Cordia milleni and Raphia farinifera did not resprout. Sprouts/stump ranged from 16.3 ± 1.8 (S.E.) for Rawsonia lucida, to 1 for 10 species. Number of sprouts/stump differed significantly among families (Kruskal–Wallis H = 182.63, P χ 1 2 = 6.62 , P = 0.0101), height ( χ 1 2 = 38.52 , P χ 1 2 = 14.56 , P χ 1 2 = 74.42 , P

A factorial experiment was used to evaluate the effect of mechanical scarification, treatment with sulfuric acid, and soaking in water, on the germination of seed of Maesopsis eminii Engl. The highest germination percent (77%) and germination value (0.82) were obtained when scarified seed was soaked in warm water. The germination percent and germination value of seed not subject to scarification and soaking in water were 71 and 0.66 respectively. The lowest germination percent (11%) and germination value (0.07) were obtained when scarified seed was treated with sulfuric acid and then soaked in warm water. The peak value was reached after 8 to 11 weeks from sowing date.

Five anthraquinones, chrysophanol, physcion, xanthorin, islandicin and cynodontin, have been isolated from the heartwood of Maesopsis eminii.