Steep Mountainous Terrain Research Articles

Roadside revegetation of forest highways: new applications for native plants

Road revegetation with native plants is both a challenge and an opportunity. A new partnership between the Western Federal Lands Highway Division of the Federal Highway Administration and the USDA Forest Service is focusing on the use of native plants for forest highway road revegetation and road obliteration projects. This emphasis is leading to new applications for many native plant species, as well as development of new stock types, innovative equipment, and monitoring techniques. The process of road planning and development has become more holistic and comprehensive, allowing engineers and biologists to work in partnerships to bring about desired results. Unique challenges of road revegetation projects include harsh conditions, high visibility, and a lack of available information and techniques. Road revegetation offers unique opportunities, including long lead times that facilitate advanced seed procurement and nursery development of native plants, as well as allowing time to evaluate different installation techniques. Two projects highlighting some innovative road revegetation strategies and native stock types are discussed: one along a scenic section of a river on steep mountainous terrain, another on a well-traveled, visually sensitive road near a ski area. Strategies included developing and testing hydroseeding mixes and application techniques with native shrub, forb, and grass species; developing seeded mats for establishing native grasses on severe sites such as gabion walls; and overcoming obstacles to obtaining and increasing high-quality local native plant seed. Because little information is available on revegetating roads with native plants, a new manual is being created to help meet the challenges ahead.

A High-severity Disturbance Event Alters Community and Ecosystem Properties in West Twin Creek, Olympic National Park, Washington, USA

Debris flows are mass movements of sediment, wood and water down stream channels that profoundly impact streams and adjacent riparian areas and are a major erosion process in many steep mountainous terrains. Their impact on aquatic ecosystems, however, is poorly understood. In this report, we describe the ecological effects of a debris flow on a headwater stream in old-growth temperate forest that occurred in December 1999. This geomorphic disturbance scoured our study reach to bedrock and removed live trees 5 to 15 m into the adjacent riparian forest. Summer water temperature was higher in the affected reach after the debris flow than before; these changes have persisted through 2002. Algal biomass after the debris flow was similar to before; however, we speculate that algal growth was constrained by herbivory, as the abundance of two insect herbivores Chironomidae and Baetis spp. increased 380 and 9300%, respectively, within the first year after the debris flow. Overall, these data show that a rare disturbance event can mediate the population dynamics of stream herbivores in small, headwater streams such as those found in Olympic National Park likely via increased primary production and water temperature.

日本における林業活動と山村の持続的発展

The forested area in Japan has been miraculously and consistently kept at a constant level of approximately 65% of the land area (about 25 million hectares) for a long time, despite pressure from an increasing population and industrialization. In addition to the traditional forestry plantation areas, coniferous trees have been planted every year since the 1950's. As a result, coniferous plantations have since occupied about a quarter of the land (over 10 million hectares), and conifers that require thinning occupy the majority of existing plantations. However, the Japanese forestry industry has been in economic difficulty trying to survive in the global market. In spite of the potential timber production, domestic production supplies only 20% of the demand, mainly due to the high production costs caused by a gradual rise in labor wages and steep mountainous terrain. Tending and harvesting plantations will be given the priority over protecting natural forests in the world. Forestry operations, especially in young stands, will have to meet economic and environmental conditions to implement sustainable forest management. Educating and maintaining forestry workers, and the sound development of mountain villages are seriously important problems.

Integrating a fuzzy k -means classification and a Bayesian approach for spatial prediction of landslide hazard

A robust method for spatial prediction of landslide hazard in roaded and roadless areas of forest is described. The method is based on assigning digital terrain attributes into continuous landform classes. The continuous landform classification is achieved by applying a fuzzy k-means approach to a watershed scale area before the classification is extrapolated to a broader region. The extrapolated fuzzy landform classes and datasets of road-related and non road-related landslides are then combined in a geographic information system (GIS) for the exploration of predictive correlations and model development. In particular, a Bayesian probabilistic modeling approach is illustrated using a case study of the Clearwater National Forest (CNF) in central Idaho, which experienced significant and widespread landslide events in recent years. The computed landslide hazard potential is presented on probabilistic maps for roaded and roadless areas. The maps can be used as a decision support tool in forest planning involving the maintenance, obliteration or development of new forest roads in steep mountainous terrain.

Improved Landsat-based forest mapping in steep mountainous terrain using object-based classification

The accuracy of forest stand type maps derived from a Landsat Thematic Mapper (Landsat TM) image of a heterogeneous forest covering rugged terrain is generally low. Therefore, the first objective of this study was to assess whether topographic correction of TM bands and adding the digital elevation model (DEM) as additional band improves the accuracy of Landsat TM-based forest stand type mapping in steep mountainous terrain. The second objective of this study was to compare object-based classification with per-pixel classification on the basis of the accuracy and the applicability of the derived forest stand type maps. To fulfil these objectives different classification schemes were applied to both topographically corrected and uncorrected Landsat TM images, both with and without the DEM as additional band. All the classification results were compared on the basis of confusion matrices and kappa statistics. It is found that both topographic correction and classification with the DEM as additional band increase the accuracy of Landsat TM-based forest stand type maps in steep mountainous terrain. Further it was found that the accuracies of per-pixel classifications were slightly higher, but object-based classification seemed to provide better overall results according to local foresters. It is concluded that Landsat TM images could provide basic information at regional scale for compiling forest stand type maps especially if they are classified with an object-based technique.

Canyon Drift and Dispersion of Bacillus thuringiensis and Its Effects on Select Nontarget Lepidopterans in Utah

A study was conducted to determine the effects of Bacillus thuringiensis Berliner var. kurstaki drift on 2 lepidopteran species, Incisalia fotis Strecker and Callophrys sheridanii W. H. Edwards, and to test the efficacy of exclusion plots for mitigation on Neominois ridingsii W. H. Edwards. Incisalia fotis and C. sheridanii experienced significant mortality from drift when fed host plants placed up to 3,000 m from the down-canyon edge of the application site. Drift concentrations and mortality were greatest near the boundary of the application site, although they sometimes varied in an inconsistent manner. The 1993 bioassay data correlate with the observed reduction in adult I. fotis populations following B. thuringiensis applications during previous years. An exclusion plot established for N. ridingsii failed to provide protection. All 3 species are concluded to be sensitive to B. thuringiensis and mitigative procedures are warranted during gypsy moth ( Lymantria dispar L.) eradication or suppression projects when the projects encompass large tracts of their respective ranges. Because of the lethal dosages of insecticide drift observed on larval host plants, it is concluded that mitigation procedures such as establishment of exclusion plots may not provide protection for B. thuringiensis -sensitive nontarget species when steep mountainous terrain is involved. Under these conditions other approaches may be warranted.

Comparison of Alternative Maintenance Treatments for an Electric Transmission Right-Of-Way on Steep Mountainous Terrain

A study has been initiated to evaluate some alternative vegetation managementtechniques on an electrical transmission right-of-way in the Blue Ridge Mountains of North Carolina. Three years after right-of-way clearing, fourtreatments and a control were blocked on south-facing slopes at three locations. The treatments consisted of 1) clearcutting by chainsaw, 2) a selective low-volume basal application of herbicide to tall-growing species, 3) clearcutting followed by a selective application of a tree growth regulator to cut stumps, and 4) clearcutting followed by a nonselective application of a tree growth regulator to cut stumps. After two growing seasons, mean tree heights for the chainsaw clearing and selective herbicide treatments were not significantly different from the untreated control. Treatments consisting of chainsaw clearing followed by application of a growth regulator provided the lowest mean tree height. However, areas treated with a growth regulator exhibited the largest increase of undesirable tallgrowing tree seedlings. The chainsaw cutting treatment resulted in the greatest mean height for those species considered to be undesirable components of a right-of-way plant community, and yielded the largest number of sprouting stumps with the highest average number of sprouts per stump. Although the long-term treatment effects cannot clearly be determined after two growing seasons, the selective low-volume basal herbicide method has produced a tendency toward increasing the relative dominance of desirable species within the right-of-way.

Influence of Rest-Rotation Cattle Grazing on Mule Deer and Elk Habitat Use in East-Central Idaho

Elk (Cervus elaphus Linnaeus), mule deer (Odocoileus hemionus Rafinesque), and cattle (Bos taurus Linnaeus) distributions were determined year round from 1975-1979 on a rest-rotation grazing system established in steep mountainous terrain. Following implementation of the grazing system, cattle progressively used higher elevations and steeper slopes in each succeeding year. Elk preferred rested pastures during the grazing season (June-October) and avoided habitat frequented by cattle by using higher elevations and steeper slopes. Few mule deer used the allotment during summer, but during the winter, deer selected habitats grazed previously by cattle. Elk appeared to adjust to the grazing system by making greater use of pastures with cattle present, although preference for pastures without cattle continued.

A comparative test of photogrammetrically sampled digital elevation models

A working group within the ISPRS has conducted an international comparative test of digital elevation models (DEM) based on a resolution from the ISPRS Congress in Hamburg. The object of the test was to study the relations among methods for data acquisition, interpolation, resulting accuracy and type of terrain. Six test areas were selected, having topographic structures varying from smooth rolling farmland to very steep mountainous terrain with forested valleys. Fifteen organisations have produced DEM's from aerial photographs in scales 1:4,000–1:30,000. The DEM's have then been used for the derivation of elevations in a set of check points, the location of which were unknown when the DEM was measured in the stereo-instrument. The elevations of these check points were then compared with their “true” values. The “true” errors found in the check points are presented and analysed. After elimination of blunders the remaining errors are composed of systematic and random parts. The systematic parts can originate from the reconstruction of the stereomodel, from the interpolation of the DEM, and from effects of the vegetation height. The size and distribution of the “true” errors are presented in Diagrammes and Illustrations. Errors of functions of the DEM (e.g. slope and curvature) are also studied.

Geochemical exploration at yandera porphyry copper prospect, Papua New Guinea

A case history is presented describing geochemical exploration of the porphyry Cu-Mo system at Yandera in the Bismark Ranges of Papua New Guinea. Three phases of geochemistry are discussed: (1) stream sediment, (2) ridge and spur, and (3) detailed rock and soil from contour trails. Results of each phase are presented and their relationship to drill-indicated mineralisation discussed. The effectiveness of the three techniques and various elements as geochemical guides to primary mineralisation is compared. Copper in stream sediment samples at a density of one sample per 1–2 km2 effectively delineated the porphyry Cu system. The extent of ridge and spur sampling was limited, therefore its effectiveness is uncertain. Detailed sampling along contour trails indicated that Au and Mo are the most effective geochemical tools. Copper geochemistry is of limited use as its distribution is largely a function of recent processes and dispersion from supergene mineralisation. No clear relationship exists between Ag geochemistry and mineralisation. Lead and Zn are distributed peripheral to the porphyry Cu system. The effectiveness of Au and, to a lesser extent, Mo as geochemical guides to ore in the steep mountainous terrain of the prospect area where high rainfall, deep weathering and rapid erosion prevail is due to the relatively high stability of these metals in the soils and the oxide zone.