Enhancing Germination of Seeds of Cassia abbreviata and Senegalia nigrescens Using Pre-Sowing Seed Treatments in Botswana

Cassia abbreviata and Senegalia nigrescens are indigenous trees found in North and Central regions of Botswana. However, inadequate knowledge of their silviculture and decline in population due to deforestation, expanding settlements, infrastructure and agriculture are major threats to most indigenous tree species in Botswana. Like many indigenous tree species, Cassia abbreviata and Senegalia nigrescens are slow-growing and are threatened by overexploitation for numerous uses. Because of the increased demand for medicinal uses, medicinal species such Cassia abbreviata are rapidly disappearing in many habitats and threatened to extinction. This study assessed the response of pre-sowing treatment methods on quiescency and germination of seeds of Cassia abbreviata and Senegalia nigrescens tree species found in semiarid Savanna Ecozone of Botswana. Pre-sowing treatment included immersion in 98% undiluted sulfuric acid (H2SO4) for 15, 30, 45 and 60 minutes, submergence in boiling water for one, two, three minutes and submerged in warm water for 24 hours, mechanical scarification of the seed coat and control. ANOVA showed that there is a highly significant difference (P < 0.0001) among the treatments of C. abbreviata in seed germination and no significant difference among the treatments of S. nigrescens. The highest germination percentage of C. abbreviata seeds was 81%, which was found from seeds immersed in H2SO4 for 30 minutes, while for S. nigrescens seeds, the highest germination percentage was 99%, which was found from seeds treated with mechanical scarification and those immersed in H2SO4 for 15 and 45 minutes. The objective of this study is to determine the effect of pretreatment methods on germination of C. abbreviata and S. nigrescens seeds. Based on these results, we recommend sulphuric acid and mechanical scarification as suitable seed pre-sowing treatments for enhancing the germination of C. abbreviata and S. nigrescens, respectively.

Tree species diversity and structural composition: The case of village common forest in Bandarban District, Bangladesh

Jannat M, Kamruzzaman MD, Hossain MK. 2020. Tree species diversity and structural composition: The case of village common forest in Bandarban District, Bangladesh. Asian J For 4: 76-83. The study was conducted to explore indigenous tree species diversity of Babu para village common forest (VCF) in Bandarban District. Tree species diversity was assessed through stratified random sampling method using sample plots of 20 m × 20 m in size. Babu para VCF with an area of 40 acres has more than 406 individuals of 74 tree species belonging to 30 families, including eight unidentified species. Euphorbiaceae and Moraceae were the dominant families containing 7 species followed by Anacardiaceae (5 species), Mimosaceae (6 species), and Meliaceae (5 species). Both the number of tree species and number of individuals decreased regularly with the increase of total height except ≥ 30 m height range. Number of species and number of individuals was highest in the height range of (5-<10) m. Similar trend was found for dbh (cm) class distribution. Both the number of species and number of individuals were highest in the dbh range of (5-<15) cm. Babu para VCF has diverse floristic resources that seemed from the Shannon-Wiener’s diversity index (3.94), Simpson’s diversity index (0.025), Margalef’s richness index (12.15) and Species evenness index (0.92). The results depict the presence of rich indigenous tree species diversity in studied VCF.

Natural Regeneration of Indigenous Tree Species in Broussonetia papyrifera Invaded Sites in Pra -Anum Forest Reserve

Broussonetia papyrifera invasion poses a serious threat to indigenous tree species in Ghana. Many conservation scientists therefore emphasize the need to control, manage, and possibly eradicate the species. However, attempts at control and management require adequate knowledge of its ecology and impact on invaded ecosystems. Employing a complete randomized design with twenty-four (24) 20 m × 20 m plots, 12 each on invaded and uninvaded sites, this study assesses the indigenous species regeneration potential under Broussonetia papyrifera-invaded sites in the Pra-Anum forest reserve. The study provides evidence of the negative impact of Broussonetia on the regenerative capacity of the reserve, as 335 seedlings per 4800 m2 distributed over 43 species were recorded on the uninvaded site compared to 156 seedlings per 4800 m2 distributed over 31 species on the invaded site. The study, however, observed some level of resilience of species belonging to the Ulmaceae and Lecythidaceae families, as they appeared fairly represented on the invaded site. Floristic diversity was also observed to be negatively impacted by Broussonetia invasion as mean Shannon and Simpson index values of 2.39 ± 0.71 and 0.89 ± 0.08 and 1.39 ± 0.24 and 0.64 ± 0.08 were recorded on the uninvaded and invaded sites, respectively. Furthermore, the Broussonetia invasion compromised the productivity of the forest ecosystem as 4.9 ± 1.61 mean economic tree species per 400 m2 plot were recorded on the invaded site compared to 13.8 ± 1.28 per 400 m2 plot on the uninvaded site. The study, therefore, concludes that Broussonetia invasion poses a serious threat to the integrity and productivity of the Pra-Anum forest reserve. Consequently, the study recommends the control of the spread of the species to protect the integrity of the Pra-Anum forest reserve. Also, restoration efforts in invaded areas of the reserve could consider the use of native species belonging to the Ulmaceae and Lecythidaceae families as they appear to be resilient to Broussonetia invasion.

Effects of tree species on soil enzyme activities in natural mixed forest and monoculture plantations in Ethiopia

&lt;p&gt;Soil extracellular enzymes are crucial for belowground functioning and are sensitive to anthropogenic land use change. The potential effects of tree species on soil microbial and biochemical properties provide crucial feedbacks on mineralization, a key ecosystem function beneath the tree canopy. In the highlands of northern Ethiopia, remnants of the original Afromontane forests are largely restricted to church forests with indigenous tree species. However the impacts on potential soil enzymatic activity by conversion of those forests to monocultures for wood production is largely unknown. We investigated potential soil enzyme activities under four indigenous tree species and adjacent &lt;em&gt;Eucalyptus globulus&lt;/em&gt; and &lt;em&gt;Cupressus lusitanica&lt;/em&gt; plantations in Gelawdios, Amhara Regional State, Ethiopia. The potential activities of six enzymes associated with soil C, N and P cycling were measured following the fluorometrically labelled substrates techniques. All enzymes exhibited significantly higher activities in soils under the indigenous trees than the plantation species except, N-acetylglucosaminidase, that was the highest in &lt;em&gt;Eucalyptus globulus&lt;/em&gt; soil due to the ectomycorrhizae, associated with the &lt;em&gt;Eucalyptus&lt;/em&gt; root systems. Among the four indigenous species &lt;em&gt;Apodytes dimidiata&lt;/em&gt; showed the lowest activitie for most of the enzymes. A stronger positive correlation was observed between enzyme activity and total N than with total C in the soil. Acid phosphatase had the highest activity followed by &amp;#160;&amp;#946;-Glucosidase (482 and 167 nmol mg&lt;sup&gt;-1&lt;/sup&gt; microbial biomass respectively). The activities of leucine aminopeptidase, &amp;#946;-xylosidase, N-Acetylglucosaminidase and cellobiohydrolase in soils under indigenous trees ranged between 63-23 nmol mg&lt;sup&gt;-1&lt;/sup&gt; microbial biomass. The species specific effects of trees on soil enzyme activities indicate strong influence of tree traits on mineralization processes. &amp;#160; &amp;#160;&amp;#160;&lt;/p&gt;

Soil Physical Properties Enhancement Via Native Tree Species in Northern Ethiopia

Dozens of chemical fertilizer is produced in factors to maintain and reclaim soil fertility, but the reliance on artificial fertilizer alone is not advisable due to environmental pollution. . Thus, indigenous plant species can maintain soil fertility without any extra cost. The aim of this study was to examine the effect of indigenous tree species on soil physical properties. Three dominant indigenous trees species (Croton macrostachuys, Cordia Africana and Albizia gummifera) were considered. Soil samples were taken from different sampling points under crown of these tree species (mid of crown and edge of crown). One sampling point is included by far 30m from the selected tree as a control group. Soil sample was taken by using core sampler. Soil physical properties such as texture, structure, porosity, bulk density and moisture content were analyzed. Bulk density was determined as 0.73g/cm3, 0.75g/cm3 and 0.8g/cm3 for Albizzia gummifera, Croton macrostachuys and Cordia Africana respectively. Bulk density was very small under crown of all trees as influenced by the amount of organic matter falling from trees leaf. The texture under crown of all tree species (silty loam, loam and loamy sand) is quite better for agriculture purpose than control point. Soil color under crown is in the range of brown to black color, which indicates high fertility level. Soil porosity was very high under the crown of all tree species as compared to the control site. It is determined as 72.5%, 71.6%, and 69.7% for Albizzia gummifera, Croton macrostachuys and Cordia Africana respectively. Soil consistence, porosity and moisture content were better under crown of the trees than control group. Soil properties under the crown of indigenous tree species were better than bare land soils. Therefore, indigenous trees are promising option to maintain soil fertility level and land owners ought to be aware of this miracle.