Interior Valleys Research Articles

Methyl Bromide Emission from Fields Partially Covered with a High-Density Polyethylene and a Virtually Impermeable Film

Recent field studies in the interior valley of southern California have indicated that 56−73% of methyl bromide (MeBr) used in soil fumigation is lost to atmospheric emission when the fields are covered completely with a high-density polyethylene (HDPE) film. The emission can be reduced to less than 5% when a virtually impermeable film or Hytibar is used to cover the fields. This study was conducted to determine MeBr emission from bedded field plots where only the beds were covered with a HDPE or a virtually impermeable plastic film. The results provide an assessment on MeBr emission from field beds partially covered with the HDPE film and the suitability of using a virtually impermeable film for emission reduction. Methyl bromide gas was applied to replicated field beds covered with either a HDPE or the Hytibar film. The films were removed 6 days after MeBr application. Replicated soil cores were taken from different locations of the field beds, 20 days after MeBr application, for the determination of soil bromide ion concentrations. The total amount of MeBr degraded from each plot was calculated from the measured bromide ion concentrations, and the potential emission was determined as the difference between the amount of applied and that of degraded. Results indicated that the potential emission from this bedded system was about 95% for the HDPE treatment and 90% for the Hytibar-covered plots. Regardless of the small improvement with the virtually impermeable film, the experiment clearly indicates that partially covering the field with either a HDPE or a virtually impermeable film would result in unacceptably high emission losses.

Regional Gradient Analysis and Spatial Pattern of Woody Plant Communities of Oregon Forests

Knowledge of regional-scale patterns of ecological community structure, and of factors that control them, is largely conceptual. Regional- and local-scale factors associated with regional variation in community composition have not been quantified. We analyzed data on woody plant species abundance from 2443 field plots across natural and seminatural forests and woodlands of Oregon to identify and quantify environmental, biotic, and disturbance factors associated with regional gradients of woody species composition; to examine how these factors change with scale (geographic extent) and location; and to characterize and map geographic patterns of species and environmental gradients. Environmental correlates of species gradients, species diversity patterns, and the spatial patterning of woody plant communities varied with geographic extent and location. Total variation explained (TVE) by canonical correspondence analyses (CCAs) was 9–15% at three hierarchical geographic extents: the entire state, two half-states, and five subregions. Our high level of unexplained species variation is typical of vegetation gradient analyses, which has been attributed to landscape effects, stochastic processes, and unpredictable historical events. In addition, we found that TVE in canonical correspondence analysis is confounded by sample size. Large numbers of plots and species, as in our study, are associated with lower TVEs, and we propose a mechanism for this phenomenon. Climate contributed most to TVE (46–60%) at all locations and extents, followed by geology (11–19%), disturbance (6–12%), and topography (4–8%). Seasonal variability and extremes in climate were more important in explaining species gradients than were mean annual climatic conditions. In addition, species gradients were more strongly associated with climatic conditions during the growing season than in winter. The dominant gradient at the state scale was from the lower elevation, moderate, maritime climate along the coast to the higher elevation, drier, continental climate of eastern Oregon. The second canonical axis followed a gradient from the warm, dry, growing seasons of the western interior valleys and eastern Cascade Range to the cooler, wetter mountainous areas. Geologic variables were most strongly correlated with axis 3, and measures of local site and disturbance with axis 4. For most of the state, our findings on the associations of disturbance factors with species gradients were inconclusive due to confounding of land ownership patterns, disturbance histories, and elevation in our sample. Near the coast, where gradients were not confounded, clear-cutting and stand age accounted for only 2 and 1% of TVE, respectively, in partial CCA. Ordinations of our long, regional gradients were influenced more by species presence than by abundance, and few woody species have been totally eliminated from sites by clear-cutting. Within Oregon and for the range of geographic extents we examined, variation in the environmental correlates of species gradients was more strongly associated with geographic location than with geographic extent, although topographic factors explained slightly more variation at smaller geographic extents. The greatest subregional contrast in vegetation character was between eastern and northwestern Oregon, and the Klamath subregion was intermediate. In the drier climate of eastern Oregon, community structure varied at a finer spatial scale, and climatic and topographic moisture were more strongly associated with species gradients than in the moister areas of western Oregon. Topographic effects were weakest and climatic effects strongest near the coast, where climate is moderate. Alpha and gamma diversity were greater in western Oregon, but beta diversity was greater in eastern Oregon and greater for shrubs than for trees. Our findings supported a conceptual model of multiscaled controls on vegetation distribution, and the related notion that local community structure is the result of both regional- and local-scale processes. Despite strong ecological contrasts within the region, we were able to synthesize species–environment relations at the regional level. This suggests that apparent conflicts among local vegetation studies can be explained by real ecological differences among places.

REGIONAL GRADIENT ANALYSIS AND SPATIAL PATTERN OF WOODY PLANT COMMUNITIES OF OREGON FORESTS

Knowledge of regional-scale patterns of ecological community structure, and of factors that control them, is largely conceptual. Regional- and local-scale factors associated with regional variation in community composition have not been quantified. We analyzed data on woody plant species abundance from 2443 field plots across natural and seminatural forests and woodlands of Oregon to identify and quantify environmental, biotic, and disturbance factors associated with regional gradients of woody species composition; to examine how these factors change with scale (geographic extent) and location; and to characterize and map geographic patterns of species and environmental gradients. Environmental correlates of species gradients, species diversity patterns, and the spatial patterning of woody plant communities varied with geographic extent and location. Total variation explained (TVE) by canonical correspondence analyses (CCAs) was 9–15% at three hierarchical geographic extents: the entire state, two half-states, and five subregions. Our high level of unexplained species variation is typical of vegetation gradient analyses, which has been attributed to landscape effects, stochastic processes, and unpredictable historical events. In addition, we found that TVE in canonical correspondence analysis is confounded by sample size. Large numbers of plots and species, as in our study, are associated with lower TVEs, and we propose a mechanism for this phenomenon. Climate contributed most to TVE (46–60%) at all locations and extents, followed by geology (11–19%), disturbance (6–12%), and topography (4–8%). Seasonal variability and extremes in climate were more important in explaining species gradients than were mean annual climatic conditions. In addition, species gradients were more strongly associated with climatic conditions during the growing season than in winter. The dominant gradient at the state scale was from the lower elevation, moderate, maritime climate along the coast to the higher elevation, drier, continental climate of eastern Oregon. The second canonical axis followed a gradient from the warm, dry, growing seasons of the western interior valleys and eastern Cascade Range to the cooler, wetter mountainous areas. Geologic variables were most strongly correlated with axis 3, and measures of local site and disturbance with axis 4. For most of the state, our findings on the associations of disturbance factors with species gradients were inconclusive due to confounding of land ownership patterns, disturbance histories, and elevation in our sample. Near the coast, where gradients were not confounded, clear-cutting and stand age accounted for only 2 and 1% of TVE, respectively, in partial CCA. Ordinations of our long, regional gradients were influenced more by species presence than by abundance, and few woody species have been totally eliminated from sites by clear-cutting. Within Oregon and for the range of geographic extents we examined, variation in the environmental correlates of species gradients was more strongly associated with geographic location than with geographic extent, although topographic factors explained slightly more variation at smaller geographic extents. The greatest subregional contrast in vegetation character was between eastern and northwestern Oregon, and the Klamath subregion was intermediate. In the drier climate of eastern Oregon, community structure varied at a finer spatial scale, and climatic and topographic moisture were more strongly associated with species gradients than in the moister areas of western Oregon. Topographic effects were weakest and climatic effects strongest near the coast, where climate is moderate. Alpha and gamma diversity were greater in western Oregon, but beta diversity was greater in eastern Oregon and greater for shrubs than for trees. Our findings supported a conceptual model of multiscaled controls on vegetation distribution, and the related notion that local community structure is the result of both regional- and local-scale processes. Despite strong ecological contrasts within the region, we were able to synthesize species–environment relations at the regional level. This suggests that apparent conflicts among local vegetation studies can be explained by real ecological differences among places.

CARACTERIZACION DE LA GANANCIA DE PESO CORPORAL DE ALPACAS (Lama pacos) DESDE EL NACI- MIENTO Y HASTA LOS SEIS MESES DE EDAD EN CUATRO REGIONES DE CHILE

Body weight in alpacas from birth up to 6 month of age was studied in 4 different regions of Chile. Animals were located in the Andean high plateau (I region) (n=37); Magallanes (XII region) (n= 12); coastal dryland (VI region) (n=20, and semiarid interior valley nearby the Andean mountains (metropolitan region) (n=32). Each animal was weighed at birth and then once a month. No statistical differences in body weight by sex were observed in any group. All newborns double their birth weight at the second month of age, except in Magallanes where it took them 3 months. At six month of age, body weight in the subjects at the Andean high plateau represent 54.64% of mature weight and 179.26% of birth weight being the higher values obtained. The lower values correspond to the subjects in Magallanes 31.41% and 123.75% respectively. The best average weight gains were observed during the first month in all groups. After the fifth month animals continued to grow but with a declining rate of growth as compared to the first month. Again, the slower declining was observed in alpacas in the Andean high plateau and the higher declining was seen in the Magallanes and coastal dryland alpacas. Equations describing weight as a function of age monthly growing alpacas for each region were developed.

Early summer temperatures since 1670 A.D. for Central Kamchatka reconstructed based on a Siberian larch tree-ring width chronology

A tree-ring width chronology of larch (Larixkurilensis Mayr) has been developed from along the Bystraya River near Esso in the interior valley of the Kamchatka Peninsula, Russia. The chronology, which covers from 1670 to 1992, explains 38% of the variance in May–June temperatures for the Esso meteorological station. This ring-width series is used to develop the first dendroclimatic reconstruction for Kamchatka. We caution that the Esso station record, the closest to the tree-ring site, is only 42 years in length, making model verification difficult. Periods of above-average temperatures are inferred for ca. 1750, 1800, and over the last few decades; colder than average conditions are inferred for 1710–1720, 1760–1770s, and 1860–1880s. The ring-width chronology cross-dates with other larch tree-ring data for Kamchatka and, during certain intervals, with a larch ring-width record from eastern Siberia. Comparison of the two records suggests that the insertion of a missing ring for the year 1816 in the eastern Siberian series is not justified. A birch (Betulaermanii Cham.) chronology from a coastal site near Petropavlovsk-Kamchatskiy correlates with July–August temperatures. Both the larch and more widespread birch species show promise for further dendroclimatic studies in Kamchatka.

Bird fauna of northeast Asia: a summary of the unique biodiversity and the priorities for conservation

The subcontinent of northeast Asia, defined as the region east of the Lena River between 58o and 72oN (and excluding the Kamchatka peninsula), is 3500 km × 1500 km in area (Fig. 1). Influenced by ice‐covered seas, low air temperatures and permafrost, it has a complicated mosaic of habitats, supporting a diverse and unique bird fauna with a number of endemic species and populations.East of the Verkhoyansk range, the northern limit of continuous coniferous forest retreats southwards and is replaced by two vegetation types unique to northeast Siberia: Larch tundra‐forest (sparse Larix cajanderi) and tall bush tundra ecotone (dominated by the Shrub Pine Pinuspumila and Bush Alder Alnus fruticosa). Shrub Pine dominates sub‐alpine altitudes throughout the interior and coastal ranges, descending in places to sea level.Coastal habitats include river deltas, brackish water bays, offshore drift ice fields and leads, lagoons, sand spits, marshes, intertidal mudflats, cliffs. offshore islands, upwellings and surface currents. Warmed by the ground water, the permafrost‐free interior valleys support lush deciduous woods of Poplar Popubs suaveolens and Korean Willow Chosenia macrolepis. Higher in the mountains, dry lichen tundra and rocky deserts occur.

Sensitivity of simulated dew duration to meteorological variations in different climatic regions of California

A previously verified and validated model was used in combination with hourly weather data to simulate the frequency and duration of dew occurrence over one growing season (April–October) at four sites under coastal fogbelt, coastal valley, and interior valley climates in California. Simulation results indicated similar values of dew occurrence (78–93% of the days) and mean dew duration (8.7–9.3 h day −1 or 9.7–11.2 h per dew event) at the coastal stations, despite high day-to-day variability and steep climatic gradients between these sites. Dew periods at the interior valley site, where occurrence of dew was predicted on only 23% of the days, were much shorter (mean 0.9 h day −1 or 3.7 h per dew event). The data displayed moderate seasonal trends, with the longest dew periods occurring in fall at the coastal stations and in spring at the interior valley station. Simulated dew durations showed favorable agreement with measured dew durations in an independent validation study. Based on real-system weather data and simulated dew data, sensitivity analyses were performed to compare the effects of temperature, atmospheric humidity (vapor pressure), cloud cover, and wind speed on dew duration at the four test sites. The results showed simulated dew durations most sensitive to changes in humidity and cloud cover at the coastal sites and to humidity and wind speed at the interior valley site. Relative sensitivity values were generally highest during the summer months (June–August). Spatial variations (i.e. differences between locations) and seasonal variations (i.e. differences between different seasons at the same site) of relative sensitivity values had approximately the same magnitude.

Estimation of Daytime Net Radiation Over Well‐Watered Grass

Net radiation (Rn) is an important component of the modified Penman equation used to calculate reference evapotranspiration (ET0). Net radiometers, however, require continual maintenance to ensure that the data they generate are reliable. An equation is developed that estimates hourly Rn over well‐watered grass from meteorological data, such as solar radiation, vapor pressure, and air temperature, collected by weather stations in various regions in California. The equation is based on Monteith's daily net radiation equation. Empirical equations are also developed to quantify surface albedo and clear sky global transmissivity. The modified Monteith formula for net radiation is tested in coastal, desert, mountain, and interior valley regions within California. After examining the 1984–1989 data from weather stations in the various regions, the absolute mean error of calculated hourly Rn is within 10% of the measured hourly Rn The absolute mean error of daytime Rn during θ>10 degrees is within 8% of the meas...

Effect of a topically applied whitener on sun damage to Granny Smith apples

Sunblush, sunburn, and sunscald injury of Granny Smith apple fruits is widespread and results in substantial economic loss when this cultivar is gra wn in the interior valleys of California. Topical, in-season applications of a whitening agent did not protect the crop from these heat-related injuries.

Population Dynamics and Biological Control of the Woolly Whitefly (Homoptera: Aleyrodidae) on Citrus

The population dynamics of the woolly whitefly, Aleurothrixus floccosus (Maskell), and its parasites on citrus were studied in an interior valley citricultural region of California. The development of populations was followed by leaf sampling and field observation from the initial pest colonization of the study site through 3 consecutive yr. The two major natural enemies found were Cales noacki Howard and Eretmocerus sp. Early in the study, C. noacki displaced Eretmocerus sp. as the dominant parasite present. Parasitism by C. noacki was responsible for substantial reductions in the whitefly population. High summer temperatures appeared to have a disruptive effect on biological control of the woolly whitefly by inhibiting the increase of parasite populations while pest population growth continued. However, C. noacki populations recovered during cooler weather and apparently were able to effect rapid suppression of the whitefly outbreak.

Laos: Marxism in a subsistence rural economy

Laos was, and still is, fundamentally a rural, subsistence agrarian society, and its history and development over the last forty years can only be understood in that context. Its population of about 4 million is divided among over forty ethnic groups, with the dominant lowland Lao comprising just less than half. The remaining half of the population is made up of other lowland Tai groups, midland (Lao Theung) groups of predominantly Austro-Asiatic origin, and highland (Lao Sung) groups that have migrated from China. Lowland Lao and Tai tend to cultivate paddy rice in the river valleys, while the other groups subsist on swidden (slash-and-burn) rice agriculture on the mountainsides. Except in the more heavily populated areas along the Mekong River and some interior valleys, villages tend to be isolated and rely on their own production to meet all their needs. Barter between villages is proportional to their density, and it is only recently that one can speak of a market economy expanding beyond major provincial towns.

Dispersion and Habitat Use by Sympatric Columbian White-Tailed Deer and Columbian Black-Tailed Deer

Sympatric Columbian white-tailed deer ( Odocoileus virginianus leucurus ) and Columbian black-tailed deer ( O. hemionus columbianus ) maintained a local geographic and habitat segregation within the interior valleys of the Umpqua River Basin, Oregon during May 1978–December 1980. O. v. leucurus occurred more often in portions of the study area within 1 km of the North Umpqua River than O. h. columbianus. Distributional patterns indicated that at least one species demonstrated interspecific avoidance. Densities of O. v. leucurus and O. h. columbianus were inversely correlated throughout their sympatric range. O. v. leucurus densities within the study area varied directly with percent woodland cover; the highest densities occurred in portions of the study area supporting ≥50% woodland cover. O. v. leucurus used lowland Quercus associations more often and lowland grassland and grass-shrub associations less often than O. h. columbianus. O. h. columbianus used lowland habitats more often in comparable environments supporting few or no O. v. leucurus. High densities of O. v. leucurus may preclude the use of corresponding habitats by O. h. columbianus .

Plant Associations within the Interior Valleys of the Umpqua River Basin, Oregon

Eleven plant associations were identified and characterized according to the frequency, percent cover, and relative dominance of the herbaceous and woody species among the vegetative strata, including stem density, diameter breast height (dbh), and basal area for tree species: Cynosurus echinatus/Taeniatherum asperum; Bromus mollis/Cynosurus echinatus; Rhus diversiloba/Cynosurus echinatus; Quercus garryana/Rhus diversiloba/Taeniatherum asperum/Cynosurus echinatus; Quercus garryana/Rhus diversiloba/Dactylis glomerata; Pseudotsuga menziesii/Quercus gwyww/Rhwdha/oblyPoesti hwnitwnQr;curgwryww/Arbutus menziesii/Rhus diversiloba/Cynosurus echinatus; Arbutus menziesii/Rhus diversiloba/Festuca arundinacea; Quercus garryana/Fraxinus latifolia/Rosa elganteria/Juncus effusus; Pseudotsuga menziesii/Corylus cornuta/Cynosurus echinatus. The intensity and duration of recent disturbance distinguished early seral stages which were characterized by a paucity of native shrub and herbaceous species and an abundance of annual invaders in the understory. The primary forces that influenced existing plant assemblages were fire and more recently agricultural practices, especially among grasslands and savannas. Grasslands without recent livestock use exhibited greater species diversity, supporting more species and a more homogeneous distribution of relative abundance among species.

Fluvial Model for Deposition of Basal Pennsylvanian Quartzarenite in Eastern Kentucky and Southwestern Virginia: ABSTRACT

Sedimentary structures, textures, plant fossils, and the continental character of associated Pennsylvanian strata suggest that basal Pennsylvanian quartzarenite in eastern Kentucky and southwestern Virginia was deposited in a fluvial environment. Along the Kentucky-Virginia border, a southwest-trending paleovalley as much as 400 ft deep and 7 mi wide is cut into Mississippian rocks; it contains the basal quartzarenite of the Middlesboro Member (Pennsylvanian) of the Lee Formation. The arenite is mineralogically and texturally mature, and previous studies have interpreted it as a beach, barrier bar, or barrier island deposit. Those studies resulted in an interpretation of the geologic history of the area that included uplift and erosion of the northwestern part of the basa Pennsylvanian Pocahontas Formation followed by deposition of the Middlesboro arenite by a southeastward-transgressing sea. Another interpretation of the same subsurface data used to support the coastal marine depositional model is that the Pocahontas was deposited in an interior valley southeast of and subparallel to the Middlesboro paleovalley. In this interpretation, the two paleovalleys are part of the same southwest-trending drainage system, and the Mississippian-Pennsylvanian unconformity, contrary to most presently accepted ideas, probably extends completely across the Appalachian basin. Furthermore, filling of the Middlesboro paleovalley by coarse sand and gravel may have caused damming of the Pocahontas paleovalley at a confluence southeast of the present eastern limit of the Pennsylvanian in southwestern Virginia. If Pocahontas sediments were deposited in a subsiding interior valley blocked by th basal beds of the Middlesboro, then the Pocahontas and Lee Formations are in part lateral equivalents. End_of_Article - Last_Page 1446------------

Oenothera kleinii (Onagraceae), a New Species from Southcentral Colorado

Oenothera kleinii is a very rare new species of sect. Anogra known from only one site in Colorado, Mineral Co., below Wolf Creek Pass. The site has recently been destroyed by road construction. The species is morphologically most similar to 0. deltoides, a polytypic species that ranges from sandy xeric habitats in the Sonoran and Mojave deserts to the seasonally dry interior valleys of California. Oenothera kleinii is especially similar to the only perennial taxon of 0. deltoides, subsp. howellii.

WATER REQUIREMENTS, AVAILABILITY AND DEVELOPMENT RESTRAINTS FOR INCREASED CROP PRODUCTIVITY IN CANADA

When crop productivity is restricted because of the availability of water, the amount of water required to remove the limitation is known as the soil water deficit. Most regions of Canada have a water deficit even though annual precipitation may appear more than sufficient for maximum needs. Soils have insufficient storage capacity to take crops through extended periods without rain. All crops will suffer from a water deficit, but the impact on yield varies among species and the timing of the stress. Similarly, supplemental irrigation to eliminate the deficit results in varying yield response, depending on the severity and timing of stress. The greatest potential response from irrigation occurs in the southern Prairies and the interior valley in British Columbia. Productivity per unit area can be increased at least 400%. The long-term limitation to development on the prairies is a regional water shortage, which can only be overcome by huge investments in water diversions from north-flowing rivers. Irrigation development in Ontario is presently economically attractive and water sources can be developed locally. It is expected that geometric growth in irrigation development will take place, particularly if several dry years occur in succession. In the most humid portions of Canada, encompassing the five eastern provinces, irrigation development is likely to be limited to small areas of fruit and specialty crops where a small increase in yield justifies the cost of irrigation equipment.Key words: Irrigation, crop productivity, water deficit, water resources, development limitations

Seasonal Changes in Nonstructural Carbohydrate Levels and Innovation Number of Kentucky Bluegrass Turf Growing in Three Plant‐Climate Areas1

AbstractControlled environment studies have shown temperature to be one of the most important factors controlling nonstructural carbohydrate levels and density of Kentucky bluegrass (Poa pratensis L.) turf. Little information is available showing similar responses to temperature on a seasonal basis in the field. The objective of this experiment was to determine how nonstructural carbohydrate levels and density of Kentucky bluegrass turf differ among climatic areas and from season to season within an area. Total nonstructural carbohydrates (TNC) and innovation development were studied in five Kentucky bluegrass cultivars grown in the field in three distinct climate areas of California. These are a maritime climate of coastal southern California, a southern California interior valley thermal belt, and a temperate mountain valley. The respective soils of these areas are San Emigdio sandy loam classified as coarse‐loamy, mixed (calcareous), thermic Typic Xerofluvents; Arlington fine sandy loam classified as coarse‐loamy, mixed, thermic Haplic Durixeralf; and Havala sandy loam classified as fine‐loamy, mixed, thermic Typic Argixerolls. Results showed that changes in TNC levels and numbers of innovations followed seasonal patterns which were closely associated with the prevailing temperatures of each specific location. Consistently high summer temperatures reduced TNC stores but moderate temperatures did not affect them. Brief periods of exceptionally high temperature also reduced TNC levels. Accumulation of TNC occurred at each location at the time when temperatures were well below optimum for growth at that location. In the cold winter location, TNC levels decreased during the winter months. Flushes of growth occurring in spring depleted TNC. Density, the number of innovations per unit area, decreased throughout the summer at the high temperature location but increased through the cool winter. In the location of moderate summer and winter temperatures the number of innovations remained high and showed less seasonal fluctuation. Temperature, rather than day length, appeared to be the primary factor affecting innovation development.

Título en español.

Se realizó un breve análisis de las características climáticas e hidrológicas de Puerto Rico, interrelacionadas entre sí. Mediante la selección de estaciones típicas de las regiones norte, sur, central, valles interiores y del oeste, se presenta el curso anual de las temperaturas máximas y mínimas medias, así como el correspondiente cuadro pluviométrico. Todos los valores presentados representan promedios mensuales hasta 1970, inclusive, (20 a 70 años). Se discute brevemente la incidencia de sequías y se ofrece un enfoque agrícola del balance hidrológico. Se discute, además, la aplicabilidad de índices representativos de la disponibilidad de lluvia para las cosechas.

Investigations of Strong Valley Winds in Alaska Using Satellite Infrared Imagery

Abstract During the Alaskan cold season, the extreme low temperatures that prevail in the interior valleys are significantly modified by valley wind episodes. The infrared sensor on the NOAA polar orbiting satellite clearly detects this warming and delineates the exact area covered by valley winds. Satellite IR images were used in conjunction with surface and upper air maps, radiosonde data, and pilot reports to analyze two valley wind episodes during early 1975. Clear weather allowed excellent satellite viewing and strong temperature contrasts, because of strong radiational cooling in non-windy valley locations. In both cases a high-amplitude 500 mb ridge was moving into the interior from the west with a strong surface high centered cast of the windy area. The strength of the surface wind correlated well with the strength of the surface pressure gradient parallel to the valleys. The wind originated in the narrow sections of the valleys and consistently gusted to 45 kt in the Tanana Valley. The ability of...

Oregon Climates Exhibiting Adaptation Potential for Vinifera

<i>Vitis vinifera</i> adaptation to Oregon environments is examined in terms of four climatic indexes: expected 20-year minimum winter temperatures; Winkler9s heat summation index; Thornthwaite9s potential evapotranspiration index; and growing-season length. Oregon data from 123 stations are compared with representative European stations and recognized <i>V. vinifera</i> requirements. Values are mapped and overlaid to delineate optimal areas. Results indicate that <i>V. vinifera</i> wine-growing in Oregon east of the Cascade Range is limited by winter severity with climatic conditions at lower elevations resembling those of central and eastern Europe. <i>V. vinifera</i> wine-growing in Oregon west of the Cascade Range is limited by cool summers with climatic conditions in the interior valleys similar to those of Burgundy and the Rhine.