Development of Silvicultural Treatments for Mahogany Regeneration in a Tropical Forest of Quintana Roo, Mexico

A scientifically based management system has not been developed that allows people to use the tropical forest without converting it (the forest) to grassland or barren waste land . As a result, the world\u27s tropical forest area has been reduced substantially. Among the many factors accounting for the disappearance of the tropical forest is the fact that the timber harvesting is not based on the rate of replacement of the trees that are harvested. The direct consequence is that when valuable trees, such as mahogany in Mexico and Central America, disappear or are reduced in numbers, there is an increased probability that the forest will be transformed into agricultural land or grassland used to raise cattle

Forage and Tree Experiment (FATE)

Trees are becoming an increasingly important component of the Iowa landscape. For tree plantings to be more common in Iowa two major problems related to establishment must be overcome: (1) intense weed competition and (2) a lack of market or non-market values for several years for newly planted trees. To develop information that addresses these problems, a research project was initiated during the spring of 1998 at the ISU Rhodes Research Farm. The objectives of the project are: (i) to evaluate the influence of seven weed control treatments [four small grain/forage crop combinations (oats and red fescue; oats, red fescue, and red clover; and oats, orchardgrass, and red clover; red clover and hairy vetch), one herbicide treatment (conventional mix of preemergents with additional control from RoundUp), mowing, and no treatment] on the survival and growth of two groups of tree species (fast-growing hardwoods [two poplar clones and silver maple] and highvalue hardwoods [red oak and black walnut as seedlings and from seed]); (ii) to evaluate the influence of seedlings of the tree species on the productivity of small grain/forage crop combinations, and (iii) to determine the cost effectiveness of planting trees with different weed control techniques

Improving tree establishment with forage crops

Weed competition and economics are two common barriers to Iowa farmers\u27 investing in tree plantings. This project examined seven weed control strategies and investigated productivity of small grain/forage combinations raised with trees in an effort to suggest management options that would encourage tree planting in the state

Ecology and management of mahogany (Swietenia macrophylla King) regeneration in Quintana Roo, Mexico

Six aspects of the ecology and management of mahogany (Swietenia macrophylla King) regeneration in Quintana Roo, Mexico, were studied: (1) the effect of partial overstory removal on natural regeneration; (2) the development of a thinning simulation program, "ThinSim"; (3) a comparison of four methods to kill trees for partial overstory removal; (4) the survival of mahogany seedlings one year after a partial overstory removal; (5) the growth of some tropical trees species three years after a partial overstory removal; and (6) the sprouting capability of seventeen tropical tree species;Natural regeneration of commercially valuable species in tropical forests represents a major challenge to tropical foresters because the valuable species represent a very small proportion of the trees in a stand. A study was initiated in which five 0.5 ha plots were subjected to different levels of overstory removal. The regeneration that came in after the removal and the growth of the residual trees was studied for three years. Overstory removal encouraged natural regeneration of light demanding species, such as mahogany and other commercially valuable species. Although overstory removal also had a positive effect on the regeneration of currently, less valuable species, an increase in the number of seedlings of mahogany and other valuable species is important because it increases the potential value of the forests, which will help ensure their existence. A program that simulates overstory removal was developed to help evaluate different overstory removal strategies. It was successfully used to design a mahogany regeneration study. Overstory removal requires that some trees be eliminated. From studies that were established, girdling is recommended because it was almost as successful at killing trees as herbicides, and it is safer to do than applying herbicides. For faster results, however, Esteron 47 was the most effective in killing dicotyledonous trees, and Banvel°lerCST was the most effective in killing palms. Different levels of overstory removal were performed on 25 0.2 ha plots that were then seeded with mahogany seeds. The levels of overstory removal were very low, thus it was difficult to evaluate their effect on mahogany germination and seedlings survival. Five 0.5 ha plots grew an average of 2 m[superscript]2 of basal area three years after of an overstory removal. Individual tree diameter growth was weakly correlated with the level of overstory removal. The number of sprouts produced by 128 stumps (seventeen tree species) were counted. Although the species are not useful for timber production, they can be used for fire wood, construction materials, edible fruits, and forage. Information on their sprouting ability can be very useful in managing the species by coppice methods for products other than timber.</p

Development of Silvicultural Treatments for Mahogany Regeneration in a Tropical Forest of Quintana Roo, Mexico

A scientifically based management system has not been developed that allows people to use the tropical forest without converting it (the forest) to grassland or barren "waste land". As a result, the world's tropical forest area has been reduced substantially. Among the many factors accounting for the disappearance of the tropical forest is the fact that the timber harvesting is not based on the rate of replacement of the trees that are harvested. The direct consequence is that when valuable trees, such as mahogany in Mexico and Central America, disappear or are reduced in numbers, there is an increased probability that the forest will be transformed into agricultural land or grassland used to raise cattle.</p

Efecto de sustrato y densidad en la calidad de plántulas de cedro, caoba y roble

Reforestation in Mexico is important to recuperate the productivity of deforested and degradedareas and to maintain that of commercial forests. Only 40% of reforested areas have an acceptablelevel of survival. Characteristics of seedlings out planted, including shoot/root ratio, are essentialfactors for achieving the desired results of high survival and good growth after transplanting. This studydescribes the characteristics of mahogany (Swietenia macrophylla King), Spanish cedar (Cedrelaodorata L.) and �roble� (Tabebuia rosea(Bertol.) DC when planted at two densities (100 and 50plants/m2)and in two substrates [soil, and soil + compost (S+C)] in a nursery. The S+Ctreatment hadasignificant effect on diameter, height, root biomass and the shoot/root ratio. In soil 76% of seedlingshad a shoot/root ratio of 3.0 or less and in S+ C,21% of seedlings had a ratio less than 3.0. For coni-fers a ratio of 2/1 is recommended for dry sites and 4/1 for humid sites. For broadleaves the optimumshoot/root ratio is not known. Two months after transplanting in the field more Swietenia produced withthe S+Ctreatment died but less Cedrela andTabebuiaseedlings did. For the three species theseedlings that died were smaller.La reforestación en México es importante para recuperar la producción de las áreas defores-tadas y degradadas y para mantener la de los bosques comerciales. Sólo 40% de la reforestacióntienen un nivel aceptable de supervivencia. Las características de las plántulas que se utilizan, inclu-yendo la relación tallo/raíz de la plántula, deben tomarse en cuenta para lograr los resultados dese-ados (alta supervivencia y buen crecimiento en campo). Se describen las características de plántulasde Swietenia macrophylla King, Cedrela odorata L. y Tabebuia rosea(Bertol.) DC bajo dos densidades(100 y 50 plantas/m2)ydos sustratos [suelo y suelo + composta (S+C)] en vivero. El tratamiento S+Ctuvo un efecto significativo en el crecimiento del diámetro, altura, peso de la raíz y la relación tallo/raízde cada una de las especies. En suelo 76% de las plántulas tienen la relación tallo/raíz =< 3 y en S+C21% presentaron una relación tallo/raíz < 3. Para coníferas se recomienda tallo/raíz 2:1 para sitiossecos y 4:1 para húmedos. Para las latifoliadas no se sabe cual es la relación tallo:raíz óptima. Dosmeses después de llevarlas a campo, murieron más plántulas de Swietenia en S+Cpero menos plán-tulas de Cedrela yTabebuia.De las tres especies murieron las más pequeñas

Forage and Tree Experiment (FATE)

Trees are becoming an increasingly important component of the Iowa landscape. For tree plantings to be more common in Iowa two major problems related to establishment must be overcome: (1) intense weed competition and (2) a lack of market or non-market values for several years for newly planted trees. To develop information that addresses these problems, a research project was initiated during the spring of 1998 at the ISU Rhodes Research Farm. The objectives of the project are: (i) to evaluate the influence of seven weed control treatments [four small grain/forage crop combinations (oats and red fescue; oats, red fescue, and red clover; and oats, orchardgrass, and red clover; red clover and hairy vetch), one herbicide treatment (conventional mix of preemergents with additional control from RoundUp), mowing, and no treatment] on the survival and growth of two groups of tree species (fast-growing hardwoods [two poplar clones and silver maple] and highvalue hardwoods [red oak and black walnut as seedlings and from seed]); (ii) to evaluate the influence of seedlings of the tree species on the productivity of small grain/forage crop combinations, and (iii) to determine the cost effectiveness of planting trees with different weed control techniques.</p

Improving tree establishment with forage crops

Weed competition and economics are two common barriers to Iowa farmers' investing in tree plantings. This project examined seven weed control strategies and investigated productivity of small grain/forage combinations raised with trees in an effort to suggest management options that would encourage tree planting in the state.</p

Endurance and Adaptation of Community Forest Management in Quintana Roo, Mexico

Despite regional deforestation threats, the state of Quintana Roo has maintained over 80% of its territory in forests. Community forest management (CFM) has played a pivotal role in forest cover and biodiversity conservation in the region. In this article, we present the institutional, socioeconomic and environmental conditions under which community-based forest management has been consolidated in the tropical state of Quintana Roo, which occupies the eastern half of Mexico’s Yucatan Peninsula. With a focus on management for timber and other market-based development strategies, we then examine the institutional and socioeconomic factors, as well as biophysical shocks, that have constrained community forestry development in the past 25 years, challenging its persistence. Following, we discuss how forest communities and institutions have responded and adapted to changing forest policies and markets as well as major environmental shocks from hurricanes and fires. CFM in Quintana Roo has shown resiliency since its institutionalization 30 years ago. Future challenges and opportunities include biodiversity conservation, carbon management through Reducing Emissions from Deforestation and Forest Degradation (REDD+) initiatives, market strengthening, business management training as well as the implementation of alternative silvicultural systems, particularly to manage sustainable populations of commercial timber species