120 research outputs found
Synthesis of Knowledge of Hazardous Fuels Management in Loblolly Pine Forests
This synthesis provides an overview of hazardous fuels management in loblolly pine (Pinus taeda) forests, as well as a reference guide on prescribed burning and alternative fuel management treatments. Available information is presented on treatment feasibility, approximate costs, and effects on soil, water quality, and wildlife. The objectives of fuel management in loblolly pine forests are to reduce the density of some targeted plant vegetation and change the structural condition of the forest, or both. Prescribed burning is the most common tool for managing fuels in the South due to the relatively low cost per acre and the ability to reduce fuel levels rather than rearrange them. Mechanical treatments may be effective in reducing wildfire risk by redistributing the fuels closer to the ground, creating a more compact fuel bed. Mulching (mastication) and chipping are the only common mechanical treatments in the Southern United States and generally are used as precursors to prescribed burning. The limited use of mechanical treatments is due to the rapid redevelopment of live fuels and higher treatment costs than prescribed burning. Herbicide treatments for hazardous fuels management are a realistic option in certain situations. Although herbicides cannot replace prescribed burning or mechanical operations where dead fuels must be removed or repositioned closer to the ground, they are useful as preliminary treatments to kill or suppress live fuels or following a prescribed burn or mechanical operation to kill resprouting woody species. Although livestock grazing is no longer common in southern forests, grazing can be used to reduce certain types of live fuels. For example, sheep grazing has been used in Florida to control saw palmetto (Serenoa repens). Wider impacts of fuel treatments are discussed for several social and ecological factors, such as soil erosion, water quality, wildlife, and public acceptability
Recognizing and Overcoming Difficult Site Conditions for Afforestation of Bottomland Hardwoods
In the last decade, about 370,000 acres (150,000 ha) of economically marginalfarmland in the Lower Mississippi Alluvial Valley (LMAV) have been restored tobottomland hardwood forests (Stanturf and others 1998, King and Keeland 1999,Schoenholtz and others 2001). Planting of this considerable acreage is due to several federal programs, such as the Wetlands Reserve Program (WRP), that assist landowners by financing afforestation (Figure 1). Unfortunately, these operational plantings have not performed as well as smaller plantings or research plots (Stanturf and others 2001a). For example, a recent survey of WRP plantings in westcentral Mississippi revealed that more than 90 percent of the sites failed to meet the criteria of 100 woody stems per acre (247 stems per ha) three years after planting or direct seeding. While planting 1-0 bareroot seedlings of oak was more successful than direct-seeding acorns, only 23percent of the land planted with seedlings met the criteria (C.J. Schweitzer unpublished data). Planting and direct seeding oak (Quercus spp.) on public land in the same area has been more successful. Meanwhile, Allen (1990) found 70 percent of the planted bottomland hardwood stands on the national wildlife refuges he evaluated had more than 200 trees per acre (494 stems per ha).We believe that the recurring problems in operational plantings on privatelands are due in part to the failure of planters to recognize adverse site conditions and their failure to use appropriate methods for overcoming site limitations. Our objectives in this paper are to synthesize research and experience into guidelines for recognizing adverse site conditions due to hydroperiod, soil, competing vegetation, and herbivory. We describe techniques for overcoming these conditions and suggest promising research areas
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Improving field establishment of cacao (Theobroma cacao) through mulching, irrigation and shading
Establishment of young cacao trees in West Africa can be severely impeded by the on-set of the dry season. To address this issue, a field experiment was conducted in Ghana to examine whether different mulch treatments and irrigation applied during the dry season combined with over-head shade could improve survival, early growth and yield of cacao. The mulch treatments used were polyethylene film and coffee husks placed around the young plants. Irrigation was used as a positive control and no mulching or irrigation was a negative control. Three shade regimes were provided through different arrangements of Gliricidia sepium and plantains. Four different cacao clones were used in the study in a replicated split-plot design. Early growth of cacao was stimulated under the irrigation and plastic mulch treatments. Higher rates of photosynthesis during the dry season appeared to underlie these increases. Significantly higher early yields were also observed under the irrigation and coffee mulch treatments compared to the control. Plant survival varied significantly between treatments; irrigation was associated with the highest plant survival (94%), followed by the plastic mulch treatment (91%), coffee husk (82%) and the control (70%). There was also an increase in survival when more intense shading was used. Under zero mulch conditions, differences in survival were observed between clones. The clones P 30 [POS] and SCA 6 were more sensitive to drought (in terms of survival) than PA 150 and T 79/501. It is concluded that relatively simple mulching techniques or controlled irrigation in conjunction with appropriate shade management can significantly improve early establishment and cropping of cacao
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Soil carbon, after 3 years, under short-rotation woody crops grown under varying nutrient and water availability.
Abstract Soil carbon contents were measured on a short-rotation woody crop study located on the US Department of Energyâs Savannah River Site outside Aiken, SC. This study included fertilization and irrigation treatments on five tree genotypes (sweetgum, loblolly pine, sycamore and two eastern cottonwood clones). Prior to study installation, the previous pine stand was harvested and the remaining slash and stumps were pulverized and incorporated 30 cm into the soil. One year after harvest soil carbon levels were consistent with preharvest levels but dropped in the third year below pre-harvest levels. Tillage increased soil carbon contents, after three years, as compared with adjacent plots that were not part of the study but where harvested, but not tilled, at the same time. When the soil response to the individual treatments for each genotype was examined, one cottonwood clone (ST66), when irrigated and fertilized, had higher total soil carbon and mineral associated carbon in the upper 30 cm compared with the other tree genotypes. This suggests that root development in ST66 may have been stimulated by the irrigation plus fertilization treatment
Contract Farming, Ecological Change and the Transformations of Reciprocal Gendered Social Relations in Eastern India
Debates on gender and the commodification of land highlight the loss of land rights, intensification of demands on womenâs labour, and decline in their decision-making control. Supported by âextra-economic forcesâ of religious nationalism (Hindutva), such neoliberal interventions are producing new gender ideologies involving a subtle shift from relations of reciprocity to those of subordination. Using data from fine grained fieldwork in Koraput district, Odisha, we analyse the tensions and transformations created jointly by corporate interventions (contract farming of eucalyptus by the paper industry) and religious nationalism in the local landscape. We examine how these phenomena are reshaping relations of asymmetric mutuality between nature and society, and between men and women
Competition and habitat quality influence age and sex distribution in wintering rusty blackbirds.
Bird habitat quality is often inferred from species abundance measures during the breeding and non-breeding season and used for conservation management decisions. However, during the non-breeding season age and sex classes often occupy different habitats which suggest a need for more habitat-specific data. Rusty Blackbird (Euphagus carolinus) is a forested wetland specialist wintering in bottomland hardwood forests in the south-eastern U. S. and belongs to the most steeply declining songbirds in the U.S. Little information is available to support priority birds such as the Rusty Blackbird wintering in this threatened habitat. We assessed age and sex distribution and body condition of Rusty Blackbirds among the three major habitats used by this species in the Lower Mississippi Alluvial Valley and also measured food availability. Overall, pecan groves had the highest biomass mainly driven by the amount of nuts. Invertebrate biomass was highest in forests but contributed only a small percentage to overall biomass. Age and sex classes were unevenly distributed among habitats with adult males primarily occupying pecan groves containing the highest nut biomass, females being found in forests which had the lowest nut biomass and young males primarily staying in forest fragments along creeks which had intermediate nut biomass. Males were in better body condition than females and were in slightly better condition in pecan groves. The results suggest that adult males occupy the highest quality habitat and may competitively exclude the other age and sex classes
U.S. Billion-ton Update: Biomass Supply for a Bioenergy and Bioproducts Industry
The Report, Biomass as Feedstock for a Bioenergy and Bioproducts Industry: The Technical Feasibility of a Billion-Ton Annual Supply (generally referred to as the Billion-Ton Study or 2005 BTS), was an estimate of âpotentialâ biomass within the contiguous United States based on numerous assumptions about current and future inventory and production capacity, availability, and technology. In the 2005 BTS, a strategic analysis was undertaken to determine if U.S. agriculture and forest resources have the capability to potentially produce at least one billion dry tons of biomass annually, in a sustainable mannerâenough to displace approximately 30% of the countryâs present petroleum consumption. To ensure reasonable confidence in the study results, an effort was made to use relatively conservative assumptions. However, for both agriculture and forestry, the resource potential was not restricted by price. That is, all identified biomass was potentially available, even though some potential feedstock would more than likely be too expensive to actually be economically available.
In addition to updating the 2005 study, this report attempts to address a number of its shortcoming
Precision restoration: a necessary approach to foster forest recovery in the 21st century
We thank S. Tabik, E. Guirado, and Garnata Drone SL for fruitful debates about the application of remote sensing and artificial intelligence in restoration. E. McKeown looked over the English version of the manuscript. Original drawings were made by J. D. Guerrero. This work was supported by projects RESISTE (P18-RT-1927) from the Consejeria de Economia, Conocimiento, y Universidad from the Junta de Andalucia, and AVA201601.19 (NUTERA-DE I), DETECTOR (A-RNM-256-UGR18), and AVA2019.004 (NUTERA-DE II), cofinanced (80%) by the FEDER Program. F.M.-R. acknowledges the support of the Agreement 4580 between OTRI-UGR and the city council of La Zubia. We thank an anonymous reviewer for helpful comments that improved the manuscript.Forest restoration is currently a primary objective in environmental management policies at a global scale, to the extent that
impressive initiatives and commitments have been launched to plant billions of trees. However, resources are limited and the
success of any restoration effort should be maximized. Thus, restoration programs should seek to guarantee that what is
planted today will become an adult tree in the future, a simple fact that, however, usually receives little attention. Here, we advocate
for the need to focus restoration efforts on an individual plant level to increase establishment success while reducing negative
side effects by using an approach that we term âprecision forest restorationâ (PFR). The objective of PFR will be to ensure
that planted seedlings or sowed seeds will become adult trees with the appropriate landscape configuration to create functional
and self-regulating forest ecosystems while reducing the negative impacts of traditional massive reforestation actions. PFR can
take advantage of ecological knowledge together with technologies and methodologies from the landscape scale to the individual-
plant scale, and from the more traditional, low-tech approaches to the latest high-tech ones. PFR may be more expensive at
the level of individual plants, but will be more cost-effective in the long term if it allows for the creation of resilient forests able to
providemultiple ecosystemservices. PFR was not feasible a few years ago due to the high cost and low precision of the available
technologies, but it is currently an alternative that might reformulate a wide spectrum of ecosystem restoration activities.Junta de Andalucia P18-RT-1927European Commission AVA201601.19
A-RNM-256-UGR18
AVA2019.004OTRI-UGR 4580city council of La Zubia 458
Forest biodiversity, ecosystem functioning and the provision of ecosystem services
Forests are critical habitats for biodiversity and they are also essential for the provision of a wide range of ecosystem services that are important to human well-being. There is increasing evidence that biodiversity contributes to forest ecosystem functioning and the provision of ecosystem services. Here we provide a review of forest ecosystem services including biomass production, habitat provisioning services, pollination, seed dispersal, resistance to wind storms, fire regulation and mitigation, pest regulation of native and invading insects, carbon sequestration, and cultural ecosystem services, in relation to forest type, structure and diversity. We also consider relationships between forest biodiversity and multifunctionality, and trade-offs among ecosystem services. We compare the concepts of ecosystem processes, functions and services to clarify their definitions. Our review of published studies indicates a lack of empirical studies that establish quantitative and causal relationships between forest biodiversity and many important ecosystem services. The literature is highly skewed; studies on provisioning of nutrition and energy, and on cultural services, delivered by mixed-species forests are under-represented. Planted forests offer ample opportunity for optimising their composition and diversity because replanting after harvesting is a recurring process. Planting mixed-species forests should be given more consideration as they are likely to provide a wider range of ecosystem services within the forest and for adjacent land uses. This review also serves as the introduction to this special issue of Biodiversity and Conservation on various aspects of forest biodiversity and ecosystem services
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