Treesearch

A passive sampler for collection of gaseous nitric acid (HNO3) and nitrous acid (HNO2) is based on a diffusion ofambient air through Teflon membrane and absorption of the pollutants on Nylasorb nylon filter. The sampler is simplein design, easy to make, inexpensive and resistant to harsh weather conditions. The sampler has been calibrated againsthoneycomb denuder systems in ambient southern California air and in controlled HNO3 exposures. It is more precisethan the old open-face HNO3 sampler. It can measure wide ranges of ambient HNO2 and HNO3 concentrations forextended periods of time and...

During the 20th Century the flow of most rivers in the United States was regulated by diversions and dams, with major impacts on riparian forests. Few unregulated rivers remain to provide baseline information for assessing these impacts. We characterized patterns in riparian plant communities along chronosequences on the unregulated Yampa River and the regulated Green River in northwestern Colorado, examining patterns in plant species diversity in relation to the ages of floodplain terraces. On both rivers, mean plant species richness in cottonwood (Populus deltoides Marshall subsp....

In May 2004, a new exotic bark beetle for North America was discovered in baited flight traps in Fresno, California during an annual bark beetle and woodborer survey by the California Department of Food and Agriculture. This bark beetle was identified as Orthotomicus erosus (Wollaston), the Mediterranean pine engraver, a well-documented pest of pines in the Mediterranean region, the Middle East, Central Asia, and China. This beetle has been intercepted many times in the past at U.S. ports in association with solid wood packing material. Since the initial detection, the beetle has been...

The new FireMapper® 2.0 and OilMapper airborne, infrared imaging systems operate in a "snapshot" mode. Both systems feature the real time display of single image frames, in any selected spectral band, on a daylight readable tablet PC. These single frames are displayed to the operator with full temperature calibration in color or grayscale renditions. A rapid "Tactical" imaging mode is also available for low level operation, such as lead plane use during wildfire operations. All of the images are tagged with GPS and are recorded on hard drives upon operator command. To support fire and...

Charlotte, a vibrant Southern city appreciated for its rich history and cultural wealth, maintains trees as an integral component of the urban infrastructure (Figure 1). Research indicates that healthy trees can lessen impacts associated with the built environment by reducing stormwater runoff, energy consumption, and air pollutants. Trees improve urban life, making Charlotte a more enjoyable place to live, work, and play, while mitigating the city’s environmental impact. Over the years, the people of Charlotte have invested millions of dollars in their municipal forest. The primary...

Tree health is a critical parameter for evaluating urban ecosystem health and sustainability. Tradi­tionally, this parameter has been derived from field surveys. We used multispectral remote sensing data and GIS techniques to determine tree health at the University of California, Davis. The study area (363 ha) contained 8,962 trees of 215 species. Tree health conditions were mapped for each physiognomic type at two scales: pixel and whole tree. At the pixel scale, each tree pixel within the tree crown was classified as either healthy or unhealthy based on vegetation index values. At the...

In computer graphics, models describing the fractal branching structure of trees typically exploit the modularity of tree structures. The models are based on local production rules, which are applied iteratively and simultaneously to create a complex branching system. The objective is to generate three-dimensional scenes of often many realistic- looking and non-identical trees. Our goal, instead, is to visualize the growth of a prototypical tree of certain species. It is supposed to look realistic but, more importantly, has to conform with real, measured data. We construct a tree model...

Vibrant, renowned for its livability and cultural wealth, the city of Berkeley maintains trees as an integral component of the urban infrastructure. Research indicates that healthy trees can mitigate impacts associated with the built environment by reducing stormwater runoff, energy consumption, and air pollutants. Put simply, trees improve urban life, making Berkeley a more enjoyable place to live, work, play, and study, while mitigating the city’s environmental impact. Over the years, Berkeley has invested millions in its municipal forest. The primary question that this study asks is...

Forty-eight street segments were paired into 24 high-and low-shade pairs in Modesto, California, U.S. Field data were collected to calculate a Pavement Condition Index (PCI) and Tree Shade Index (TSI) for each segment. Statistical analyses found that greater PCI was associated with greater TSI, indicating that tree shade was partially responsible for reduced pavement fatigue cracking, rutting, shoving, and other distress. Using observed relations between PCI and TSI, an unshaded street segment required 6 slurry seals over 30 years, while an identical one planted with 12 crape myrtles...