Treesearch

Although habitat fragmentation is one of the greatest threats to biodiversity worldwide, virtually no attention has been paid to the quantification of error in fragmentation statistics. Landscape pattern indices (LPIs), such as mean patch size and number of patches, are routinely used to quantify fragmentation and are often calculated using remote sensing imagery that has been classified into different land-cover classes. No classified map is ever completely correct, so we asked if different maps with similar misclassification rates could result in widely different errors in pattern...

Chanterelle productivity responses were investigated in a replicated, landscape-scale thinning experiment in 50-year-old Douglas-fir stands in the Cascade Range of Oregon. Chanterelle numbers and weight were significantly decreased by thinning the first year after logging more so in heavily thinned stands than lightly thinned stands for chanterelle numbers. Nearly all evidence of differences in chanterelle productivity among thinning treatment means disappeared within 6 years. Management implications and mitigation measures are discussed.

Intensive management may adversely affect lumber yield and quality by increasing knot size and creating a more conical stem form with a greater average rate of taper. This study was initiated to examine the impact of management on simulated lumber yield and quality. Stem diameter and branch size and location of 223 Pseudotsuga menziesii (Mirb.) Franco (Douglas-fir) stems ranging in age from 5 to 65 years and from a wide variety of stand conditions were intensively measured. Stand conditions included varying levels of vegetation management, precommercial thinning, commercial thinning,...

Knowledge of fuel load and composition is critical in fighting, preventing, and understanding wildfires. Commonly, the generation of fuel maps from remotely sensed imagery has made use of medium-resolution sensors such as Landsat. This paper presents a methodology to generate fuel type maps from high spatial resolution satellite data through object-oriented classification. Fuel maps were derived from QuickBird imagery, which offers a panchromatic and four multispectral bands ranging from 0.61 to 2.44 m resolution. The image used for this paper dated from July 2002 and is located in the NW...

Mean curves of increment and yield in gross total cubic volume and net merchantable cubic volume were derived from seven installations of the regional cooperative Levels-of-Growing-Stock Study (LOGS) in Douglas-fir. The technique used reduces the seven curves for each treatment for each variable of interest to a single set of readily interpretable mean curves. To a top height of l00 ft and corresponding average age of 45 years, volume growth and yield are strongly related to stocking level, being highest at the highest stocking levels. At that point, current annual increment is still far...

We examined how composition and structure of old-growth and mature forests at Mount Rainier National Park changed between the mid-1970s and mid-1990s. We assessed whether the patterns of forest dynamics observed in lower elevation old-growth forests in the Pacific Northwest held true for the higher-elevation forests of the Park. We used measurements of tree recruitment, growth, and mortality on 18 permanent plots that spanned the range of forested environments in the Park. Similar to previous studies, there was little change in stand structure and composition, while a relatively large...

We analyzed phytosociological characteristics and diversity patterns of tree species of tropical forests of Garo Hills, western Meghalaya, northeast India. The main vegetation of the region included primary forests, secondary forests, and sal (Shorea robusta) plantations, with 162, 132, and 87 tree species, respectively. The Shannon-Wiener diversity index (H1) of trees within 21 1-ha belt-transects in primary forest was 4.27, which is comparable to the world's richest tropical forests. Statistical results revealed that primary forests were more tree-rich and diverse than were secondary...

Peatlands play a major role in the global carbon cycle but are largely overlooked in current large-scale vegetation mapping efforts. In this study, we investigated the potential of the Moderate Resolution Imaging Spectroradiometer (MODIS) sensor to capture extent and distribution of peatlands in the St. Petersburg region of Russia.

Using computer simulation, we evaluated the impact of using first-generation information to increase selection efficiency in a second-generation breeding program. Selection efficiency was compared in terms of increase in rank correlation between estimated and true breeding values (i.e., ranking accuracy), reduction in coefficient of variation of correlation coefficients (i.e., ranking reliability), and increase in realized gain, with best linear unbiased prediction (BLUP). The test populations were generated with varying parameters: selection strategy (forward vs. backward selection of...

Net ecosystem production (NEP) was estimated over a 10.9 x 104 km2 forested region in western Oregon USA for 2 yr (2002-2003) using a combination of remote sensing, distributed meteorological data, and a carbon cycle model (CFLUX). High spatial resolution satellite data (Landsat, 30 m) provided information on land cover and the disturbance regime. Coarser resolution satellite imagery (MODIS, 1 km) provided estimates of vegetation absorption of photosynthetically active radiation. A spatially distributed (1 km) daily time step meteorology was generated for model input by interpolation of...