Maize is the main staple crop in the East African Mountains. Understanding how the edaphic characteristics change along altitudinal gradients is important for maximizing maize production in East African Highlands, which are the key maize production areas in the region. This study evaluated and compared the levels of some macro and micro-elements (Al, Ca, Fe, K, Mg, Mn, Na and P) and other soil parameters (pH, organic carbon content, soil texture [i.e. % Sand, % Clay and % Silt], cation exchange capacity [CEC], electric conductivity [EC], and water holding capacity [HC]). Soil samples were taken from maize plots along three altitudinal gradients in East African highlands (namely Machakos Hills, Taita Hills and Mount Kilimanjaro) characterized by graded changes in climatic conditions. For all transects, pH, Ca, K and Mg decreased with the increase in altitude. In contrast, % Silt, organic carbon content, Al and water holding capacity (HC) increased with increasing altitude. The research provides information on the status of the physical–chemical characteristics of soils along three altitudinal ranges of East African Highlands and includes data available for further research.

Mau Forest, a major forest reserve in Kenya, has experienced anthropogenic disturbances through encroachment and forest fires. This study aimed at comparing the soil carbon stocks in different forest management types as well as how seasonal climatic changes influence its dynamics. The study was undertaken in the Eastern Mau block (Sururu) which forms part of the greater Mau Forest Complex. The forest management interventions have been in place for over 15 years with disturbed (fire) natural forest experiencing fires in 2005, 2007, and 2014 while cypress plantations were established in 1994. A nested experimental design was used in data collection, where thirty-two sample plots were nested into four blocks each measuring 100 m2 delineated by forest management types (disturbed by fire, natural forest, undisturbed natural forest, plantation, and glades). In each plot, data on soil carbon stocks, soil bulk density, soil moisture, and temperature were collected for both dry and wet seasons. Data collection was carried out between November 2015 and December 2016. The results indicated that there were no significant differences in the carbon stocks among the forest management types (F4,16 = 0.61, P = 0.613 ). However, seasonal weather changes significantly affected the amount of carbon stocks among the forest management types (F4,16 = 0.61, P > 0.05 ). The undisturbed natural forest had the highest mean soil carbon stocks, while the plantation forest had the lowest as follows: undisturbed natural forest (135.17 ± 35.99.0 Mg·C−ha), disturbed natural forest by fire (134.52 ± 38.11 Mg·C−ha), glades (122.4 ± 64.9 Mg·C−ha), and plantation forest (116.51 ± 39.77 Mg·C−ha). Furthermore, the undisturbed natural forest management had the highest bulk density (0.66 g/cm3), while the disturbed (fire) natural forest had the lowest (0.59 g/cm3). These values were low compared to most normal mineral soils which have a bulk density of between 1.0 g/cm3 and 1.5 g/cm3. There was a significant ( P > 0.01 ) relationship between seasonal weather (temperature) changes and soil carbon stocks under different forest management types with the relationship being stronger in soils under glades (r2 = 0.62) and weak in the undisturbed natural forest (r2 = 0.26). In conclusion, forest disturbances have an impact on soil carbon stocks, and for effective management of forest towards climate stabilization, then disturbance should be minimized if not avoided.

Competition for scarce land resources between food crops and trees has intensified and there is need for a balance to accommodate both, either in rotation programs or in agroforestry systems. Successful intercropping of Eucalyptus trees with crops is hindered by competition for light between trees and crops, soil nutrient dynamics and the allelopathy from Eucalyptus trees. The aim of this study was to establish and assess the performance of farm crops under Eucalyptus grandis tree plantations so as to evaluate the potential of the trees for agroforestry. The crops i.e. common beans, Irish potatoes and black Nightshade (Solanum villosum) were planted along rows of Eucalyptus trees (3 and 6 years) in plot sizes of 4 m by 2 m adopting a factorial arrangement in RCBD with open field as control. The assessment of the performance of the crops was mainly on; germination, Leaf Area Index (LAI) and possible yields. In addition, the amount of photosynthetically active radiation (PAR) reaching the understory crops was measured. From the results, Germination of crops under trees was higher than in the open field. Germination was delayed under trees when compared to those grown in the open field. The age differences in the Eucalyptus tree plantations had no significant effect on the amount of PAR reaching the understory crops. The leaf area index (LAI) of the understory crops was significantly affected by Eucalyptus trees of different ages (p < .001). The crops grown under Eucalyptus trees gave higher yields compared to crops grown in open fields but not fertilized. The effect of Eucalyptus plantation age significantly affected the yields of beans and potatoes (p < .001) but not nightshade; therefore, the vegetable can be grown under Eucalyptus tree shade without reduction in yield. Irish potato and common beans are potential crops for agroforestry with Eucalyptus trees but need further research as their yields were low and had selected disease incidences.

Aloe species are common in arid and semi-arid lands (ASALs) of Kenya and are of economic importance especially for bitter gum production. However, the species is under ecological threat due to unsustainable harvesting from the wild. The objective of this study was to evaluate genetic diversity and population structure of three commercially exploited indigenous Aloe species; A. secundiflora, A. turkanensis and A. scabrifolia.The study was carried out in fifteen populations of Aloe species in their wild habitat where their geographic distribution was surveyed and populations delineated. Within each population, 30 trees were sampled at a distance of 100 m apart where leaf tissues were collected for DNA isolation and analysis using modified Cetyl trimethyl ammonium bromide (CTAB) method. Randomly amplified polymorphic DNA (RAPDs) and Inter-simple sequence repeats (ISSR) markers were used to determine the genetic diversity and population structure. Ten RAPD and seven ISSR discriminative primers with the highest value of genetic diversity were selected to genotype three indigenous Aloe species. The genetic similarity was performed using Popgene 1.3.1; hierarchical UPGMA cluster analysis and principal coordinate analysis were performed using Genalex 6.5. To map genetic structure and gene pools, both Structure and Structure Harvester statistical packages were used. From the results, A. secundiflora species was the most distributed in the surveyed ASALs. There was high genetic variation among and within the populations. The combined use of ISSR and RAPD revealed high variations among the populations as compared to when either of them used singly. Genetic variation was highest within secundiflora species and least within turkanensis species. Maralal secundiflora population had the highest genetic variation. The study exhibited a population genetic structure with three major clusters which corresponded to the three Aloe species with minimal reproductive crossing among them. It is therefore, recommended to undertake biophysical studies to determine the advantages of A.secundiflora that has over the other species. In addition, Maralal sec population should be conserved ex-situ because of its high genetic diversity while both ISSR and RAPD markers should be prioritized in Aloe genetic studies as they reveal high variation.

Forests play an important role in the livelihoods of local people in most developing countries. Local communities depend on forest resources for various products such as fuel wood, construction materials, medicine, and food. The Maasai Mau forest plays an important role in supporting the livelihood of people living around the forest. Exploitation of forest resources should only be limited to active members. To reduce dependency on the forest, alternative means of livelihood should be provided to reduce dependency on the forest.

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The use or deployment of aerial seeding technology in forestry has shown to be efficient, rapid, and most suitable for restoration of large degraded and inaccessible areas. The technology is relatively cheaper compared to conventional methods of restoration. Although aerial seeding has been widely used globally in forestry, its application is comparatively new in Kenyan forestry. This paper reviews selected experiences from countries that pioneered the use of aerial seeding in restoring large degraded forestlands and highlights key requirements for successful aerial seeding programs. Literature shows that the use of aerial seeding in forestland restoration dates back in 1950s with reports showing moderate to high success rate in USA, Canada, Russia, Australia, New Zealand, China and India. Success of aerial seeding is largely determined by interaction of factors such as seed characteristics, timing of seeding, site conditions or micro-site environment. Competition from surrounding vegetation, and seed predation affect the efficiency of aerial seeding negatively. The paper concludes that aerial seeding technology is efficient, cost effective and therefore suitable for use in the restoration of the expansive degraded forests in Kenya.

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