Treesearch

Modern landscape ecology is based on the patch mosaic paradigm, in which landscapes are conceptualized and analyzed as mosaics of discrete patches. While this model has been widely successful, there are many situations where it is more meaningful to model landscape structure based on continuous rather than discrete spatial heterogeneity. The growing field of surface metrology offers a variety of surface metrics for quantifying landscape gradients, yet these metrics are largely unknown and/ or unused by landscape ecologists. In this paper, we describe a suite of surface metrics with...

This article incorporates new information into previous whitebark pine guidelines for planting prescriptions. Earlier 2006 guidelines were developed based on review of general literature, research studies, field observations, and standard US Forest Service survival surveys of high-elevation whitebark pine plantations. A recent study of biotic and abiotic factors affecting survival in whitebark pine plantations was conducted to determine survival rates over time and over a wide range of geographic locations. In these revised guidelines, we recommend reducing or avoiding overstory and...

A three-dimensional fluid dynamics model is developed to capture the spatial complexity of the effects of salmon redds on channel hydraulics, hyporheic exchange, and egg pocket habitat. We use the model to partition the relative influences of redd topography versus altered hydraulic conductivity (winnowing of fines during spawning) on egg pocket conditions for a simulated pool-riffle channel with a redd placed at the pool tail. Predictions show that altered hydraulic conductivity is the primary factor for enhancing hyporheic velocities and dissolved oxygen content within the egg pocket....

We thank Rosgen (this issue) for his comments, which provide valuable insight regarding his channel classification and its correct application. However, we believe that many of his objections are based on misinterpretation of our analysis, which we hope to clarify through this reply.Because our measurement techniques differed from those advocated by Rosgen (1996), our study may not represent the range of variability in channel classification that would result from strict adherence to his methods. Nevertheless, this does not invalidate our analysis and the intended study goal of evaluating...

Allometric/structural relationships in tree crowns are a consequence of the physical, physiological, and fluid conduction processes of trees, which control the distribution, efficient support, and growth of foliage in the crown. The structural consequences of these processes are used to develop an analytic model based on the concept of branch orders. A set of interrelated equations describe the relationships between structural characteristics, including the distribution of a tree's foliage and the partitioning of the structural components within the crown for the efficient support of that...

Characteristics of the Ku-band polarimetric scatterometer (POLSCAT) data acquired from five sets of aircraft flights in the winter months of 2006-2008 for the second Cold Land Processes Experiment (CLPX-II) in Colorado are described in this paper. The data showed the response of the Ku-band radar echoes to snowpack changes for various types of background vegetation in the study site in north central Colorado. We observed about 0.15-0.5-dB increases in backscatter for every 1 cm of snow-waterequivalent (SWE) accumulation for areas with short vegetation (sagebrush and pasture). The region...

Models of terrestrial snow cover, or snow modules within land surface models, are used in many meteorological, hydrological, and ecological applications. Such models were developed first, and have achieved their greatest sophistication, for snow in open areas; however, huge tracts of the Northern Hemisphere both have seasonal snow cover and are forested (Fig. 1). Forests have large influences on snow dynamics, and many snow models have been developed or modified in recent years to include vegetation canopies (e.g., Hellstrom 2000, Koivusalo and Kokkonen 2002; Niu and Yang 2004; Bartlett et...

"Forest Health" has become one of the most widely used terms in ecosystem management. Its popularity derives from powerful personal imagery, connecting the fragility of health with ecosystems. It addresses a need for an efficient term to describe the vitality of the world's forests, a usage we support. However, broad adoption has brought multiple usages, not all of which correspond to the term's literal meaning or convey such clarity of intent. Although "Forest Health" makes no reference to human expectations, these values are often inserted, suggesting a natural order is at risk if...

Observed 20th century climate changes in the Atlantic Coast bioregion include warmer air and sea surface temperatures, increased winter precipitation (especially rainfall), and an increased frequency of extreme precipitation events. Climate change impacts during the century include phenological shifts in plant and animals species, such as earlier occurrence of lilac budburst and earlier arrival of migrant birds; spread of invasive species such as the Chinese tallow tree; sea level rise; and earlier onset of lake and river ice-out and snowmelt-driven runoff. Climate changes predicted for...

Remote sensing provides a broad view of landscapes and can be consistent through time, making it an important tool for monitoring and managing protected areas. An impediment to broader use of remote sensing science for monitoring has been the need for resource managers to understand the specialized capabilities of an ever-expanding array of image sources and analysis techniques. Here, we provide guidelines that will enable land managers to more effectively collaborate with remote sensing scientists to develop and apply remote sensing science to achieve monitoring objectives. We first...