23,535 research outputs found

    Fire Fuel Protocol

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    The purpose of the resource is to measure the different types of fuels for fires. Educational levels: Middle school, High school

    Observable Persistent Effects of Habitat Management Efforts in the Ozark Highlands After 10 Years

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    I investigated the lasting impacts of a management plan designed to improve oak regeneration and benefit wildlife in the Ozark Highlands in Madison, Co., AR. To assess the efficacy of the management plan, I used variables relevant to the success and establishment of oak trees. Controlled burns and selective logging were used to thin the canopy, increase ground level productivity, and increase the abundance of small mammals. I used measurements of overstory and understory densities, light availability, and the density of mice in the genus Peromyscus across time to look at the lasting impacts of management. Different treatment plots were used to investigate the impact of each management action separately (Burn or Cut) and in combination (Burn and Cut) relative to unaltered control plots. Measurements were compared between pre-treatment, post-treatment, and 10-years post-treatment time points. I found that a 10-year lapse in management resulted in a complete return to pre-treatment values in overstory density. I also saw a decline below pre-treatment values in understory density and Peromyscus density. Analysis of light availability at the forest floor revealed a persistent effect of treatment. I conclude that while initial treatment was effective, 10 years between management events is too infrequent to achieve the desired long-term changes within my study system. More frequent management may be more effective in meeting the management goals for this Ozark system

    Use of waveform lidar and hyperspectral sensors to assess selected spatial and structural patterns associated with recent and repeat disturbance and the abundance of sugar maple (Acer saccharum Marsh.) in a temperate mixed hardwood and conifer forest.

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    Abstract Waveform lidar imagery was acquired on September 26, 1999 over the Bartlett Experimental Forest (BEF) in New Hampshire (USA) using NASA\u27s Laser Vegetation Imaging Sensor (LVIS). This flight occurred 20 months after an ice storm damaged millions of hectares of forestland in northeastern North America. Lidar measurements of the amplitude and intensity of ground energy returns appeared to readily detect areas of moderate to severe ice storm damage associated with the worst damage. Southern through eastern aspects on side slopes were particularly susceptible to higher levels of damage, in large part overlapping tracts of forest that had suffered the highest levels of wind damage from the 1938 hurricane and containing the highest levels of sugar maple basal area and biomass. The levels of sugar maple abundance were determined through analysis of the 1997 Airborne Visible/Infrared Imaging Spectrometer (AVIRIS) high resolution spectral imagery and inventory of USFS Northern Research Station field plots. We found a relationship between field measurements of stem volume losses and the LVIS metric of mean canopy height (r2 = 0.66; root mean square errors = 5.7 m3/ha, p \u3c 0.0001) in areas that had been subjected to moderate-to-severe ice storm damage, accurately documenting the short-term outcome of a single disturbance event

    Development of multi-functional streetscape green infrastructure using a performance index approach

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    The file attached to this record is the author's final peer reviewed version. The Publisher's final version can be found by following the DOI link.This paper presents a performance evaluation framework for streetscape vegetation. A performance index (PI) is conceived using the following seven traits, specific to the street environments – Pollution Flux Potential (PFP), Carbon Sequestration Potential (CSP), Thermal Comfort Potential (TCP), Noise Attenuation Potential (NAP), Biomass Energy Potential (BEP), Environmental Stress Tolerance (EST) and Crown Projection Factor (CPF). Its application is demonstrated through a case study using fifteen street vegetation species from the UK, utilising a combination of direct field measurements and inventoried literature data. Our results indicate greater preference to small-to-medium size trees and evergreen shrubs over larger trees for streetscaping. The proposed PI approach can be potentially applied two-fold: one, for evaluation of the performance of the existing street vegetation, facilitating the prospects for further improving them through management strategies and better species selection; two, for planning new streetscapes and multi-functional biomass as part of extending the green urban infrastructure

    ENVIRONMENTAL VARIABLES ASSOCIATED WITH INVASIVE GLOSSY BUCKTHORN (FRANGULA ALNUS MILL.) AND INDIRECT CONTROL STRATEGIES FOR FOREST MANAGERS

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    Glossy buckthorn (Frangula alnus Mill.) is one of the most prominent non-native invasive plant species affecting New England forests. It quickly invades a forest and can create a dense understory effectively altering the species composition and dynamics of that forest. To gain a better understanding of the environmental variables associated with glossy buckthorn density we sampled forests across New Hampshire with varying degrees of buckthorn invasion. The effect on tree regeneration was analyzed with measurements of height and abundance of glossy buckthorn and native regeneration. Glossy buckthorn was found to be at its highest densities in disturbed softwood forests that were historically old fields, specifically eastern white pine (Pinus strobus L.), with a thin organic layer and low herbaceous cover on drained loam and clay soils. The data show there is direct competition between glossy buckthorn and forest tree regeneration, although no relationship with regeneration shade tolerance was found. This information was used to create a prescription risk tree to aid forest managers in assessing the risk of buckthorn invasion and inhibition of tree regeneration associated with harvesting and suggests how to adapt their silvicultural prescriptions

    Environmental changes during secondary succession in a tropical dry forest in Mexico

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    Vegetation and environment change mutually during secondary succession, yet the idiosyncrasies of the vegetation effect on the understorey environment are poorly understood. To test whether the successional understorey environment changes predictably and is shaped by the structure and seasonality of tropical dry forests, we estimated basal area and vegetation cover, and measured understorey temperature, light and moisture conditions, in 17 plots forming a 60-y chronosequence and a mature forest. Light and air and soil temperature decreased with time (75-15% of open-sky radiation, 31.7-29.3 °C, and +2.5 °C to -0.5 °C relative to ambient, respectively), whereas relative humidity increased (67-74%). Soil water availability increased with early-successional development (-45 to -1 kPa) but decreased afterwards (to -18 kPa). The first axis of a PCA of the rainy-season environment explained 60% of the variation and was strongly related to air temperature and relative humidity. During tropical dry-forest succession, such factors may be more important than light, the reduction in which is not extreme compared with taller and more vertically stratified wet forests. Seasonality significantly affected the successional environmental gradients, which were marked mainly during the wet season. Environmental heterogeneity was higher in the wet than in the dry season, and larger for resources (light and water) than for conditions (temperature and humidity). The wet-season increase in environmental heterogeneity potentially creates differential growing scenarios; the environmental harshness of the dry season would mostly challenge seedling survival

    Canopy structural modeling using object-oriented image classification and laser scanning

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    A terrestrial laser scanning (TLS) experiment was carried out in the EAGLE 2006 campaign to characterize and model the canopy structure of the Speulderbos forest. Semi-variogram analysis was used to describe spatial variability of the surface. The dependence of the spatial variability on the applied grid size showed, that in this forest spatial details of the digital surface model are lost in the case of larger than 0.3-0.4 m grid size. Voxel statistics was used for describing the density of the canopy structure. Five zones of the canopy were identified according to their density distribution. Basic geometric structures were tested for modeling the forest at the individual tree level. The results create a firm basis for modeling physical processes in the canopy

    Trees and water: smallholder agroforestry on irrigated lands in Northern India

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    Trees / Populus deltoids / Agroforestry / Afforestation / Reforestation / Models / Water use / Water balance / Evapotranspiration / Precipitation / Remote sensing / Irrigation requirements / India
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