Phytotherapy and Polycyclic Logging: Implication on Genetic Multiplicity and Diversity of African Mahogany in Tropical Rainforest

There are over 8,000 globally threatened tree species. For each species, there is a different story behind why they are threatened and what values we stand to lose if we do not find the means to save them. Mahogany, a member of Meliaceae, is a small genus with six species. Its straight, fine and even grain, consistency in density and hardness makes it a high valued wood for construction purposes. The bitter bark is widely used in traditional medicine in Africa. The high demand for bark has also led to the total stripping of some trees, complete felling of larger trees to get the bark from the entire length of the tree and bark removal from juvenile trees. These species are now threatened with extinction due to selective and polycyclic logging, and also excessive bark removal. The natural regeneration of mahogany is poor, and mahogany shoot borer Hypsipyla robusta (Moore) attacks prevent the success of plantations within the native area in West Africa. In developing countries, most of the Khaya species exists in the wild state; therefore, the regeneration and long-term conservation are at the mercy of the vagaries of nature and the profit driven herb collectors and timber merchants. It becomes urgently necessary by government of developing countries to place ban on further harvesting of mahogany species to allow the remaining few trees of mahogany in the forest to recuperate and produce substantial seeds for regeneration

In Vivo Study of Cogongrass (Imperata Cylindrica L.) Rhizome Production

Cogongrass is an aggressive, rhizomatous, invasive perennial grass that is scattered throughout the tropical and subtropical regions of the world, and has become a serious problem in Florida and other Gulf Coast States. A greenhouse study was conducted to evaluate the growth and spread of rhizomes of grass species grown in combination with other native grass species. Native grass species used included: switchgrass (Panicum virgatum L), maidencane (Panicum hemitomon Schult.), and muhlygrass (Muhlenbergia capillaries (Lam) Trin.). All plants were raised in tubbets and then transplanted to 7.6 L greenhouse pots in different combinations with cogongrass. Data on rhizomes of cogongrass and maidencane (rhizomatous species) were recorded during the harvest periods (6, 12, 18 or 24 weeks). The mean number and mean total length of cogongrass rhizomes ranged from 3 to 8 and 0.06 to 0.14 m at 6 weeks to 40 to 94 and 8.37 to 20.39 m at 24 weeks, respectively. Similarly, the mean number and mean total length of maidencane rhizomes ranged from 0.01 to 3 and 0.05 to 0.27 m at 6 weeks to 11 to 26 and 1.57 to 3.31 m at 24 weeks, respectively. There were 51 to 74% and 47 to 74% reductions in the mean total length of cogongrass rhizomes grown in combination than those grown individually at 12 and 18 weeks, respectively. The mean number of cogongrass rhizomes had 54 to 71% reductions when in combination than individually at 12 weeks. Likewise, at 18 weeks the mean number and mean total length of rhizomes of maidencane were reduced by 51 to 65% and 20 to 75%, respectively, when grown in combination with others grasses than alone. The number and spread of rhizomes explain cogongrass' invasiveness and competitiveness. The reduction of cogongrass in combination with native species shows a prospect that some Florida native grasses could reduce the invasiveness of cogongrass in the Gulf Coast States

Extracts of Native and Non-Native Plant Species for the Control of Cogongrass (Imperata cylindrica L)

One of the most invasive species in Florida and other Gulf Coast States is Cogongrass. Cogongrass poses a major problem in natural habitats, on forested lands, rights-of-way and interstate highways. The present study was undertaken to evaluate the performance of cogongrass when grown in extracts of muhly grass (Muhlenbergia capillaries Lam) and chenopodium (Chenopodium ambriosiodes L). Genets and ramets of cogongrass were transplanted into magenta vessels containing 50% solution of root and shoot extracts of muhly grass and chenopodium, and placing magenta vessels in a growth chamber maintained at 28°C, 16/8 hour photoperiod and a relative humidity of 55 %. The genets and ramets of cogongrass were evaluated once per week for shoot and root growth, as well as rhizome extension after transplanting. Preliminary results show that the extracts of muhly grass and chenopodium reduced shoot growth and rhizome extension of cogongrass. Shoot extracts of muhly grass and chenopodium were more effective in reducing the performance of cogongrass compared to muhly grass and chenopodium root extracts. Root: shoot ratios of cogongrass also decreased by 50-70%. Thus, muhly grass and chenopodium extracts may contain some allelochemicals that could impact the invasiveness of cogongrass

Extracts of Native and Non-Native Plant Species for the Control of Cogongrass (Imperata cylindrica L)

One of the most invasive species in Florida and other Gulf Coast States is Cogongrass. Cogongrass poses a major problem in natural habitats, on forested lands, rights-of-way and interstate highways. The present study was undertaken to evaluate the performance of cogongrass when grown in extracts of muhly grass (Muhlenbergia capillaries Lam) and chenopodium (Chenopodium ambriosiodes L). Genets and ramets of cogongrass were transplanted into magenta vessels containing 50% solution of root and shoot extracts of muhly grass and chenopodium, and placing magenta vessels in a growth chamber maintained at 28°C, 16/8 hour photoperiod and a relative humidity of 55 %. The genets and ramets of cogongrass were evaluated once per week for shoot and root growth, as well as rhizome extension after transplanting. Preliminary results show that the extracts of muhly grass and chenopodium reduced shoot growth and rhizome extension of cogongrass. Shoot extracts of muhly grass and chenopodium were more effective in reducing the performance of cogongrass compared to muhly grass and chenopodium root extracts. Root: shoot ratios of cogongrass also decreased by 50-70%. Thus, muhly grass and chenopodium extracts may contain some allelochemicals that could impact the invasiveness of cogongrass