Mount Hood Research Articles

Rapid change in a Type I song dialect of Hermit Warblers(Setophaga occidentalis)

Although first-category (Type I) songs of some wood-warblers (Parulidae) are structurally stable over time and range, we document a rapid change in the song of a population of Hermit Warblers (Setophaga occidentalis) in northern Oregon. Type I songs on Mount Hood were recorded in 1990 and 1992. When the population was revisited in 2003, the birds in the area sang a different Type I song. The distinctive terminal syllable was absent, the introductory series of repeated syllables had differentiated into two parts, and the first phrase had increased in duration. In 2004, an area within a 20-km radius centered on the original population was systematically searched; from 2004 to 2006, selected areas were searched up to 65 km distant. Five scattered individuals in a limited area were found singing the earlier song 23–28 km to the east, at the periphery of the area dominated by the new song. The differences between the earlier and later songs, which are smaller than differences with neighboring dialects, suggest that the song changed within the current population rather than via displacement by individuals from an adjacent song population. Structural change over time in a Type I song of a wood-warbler over an area larger than a neighborhood has not been previously documented.

Controls on long-term low explosivity at andesitic arc volcanoes: Insights from Mount Hood, Oregon

The factors that control the explosivity of silicic volcanoes are critical for hazard assessment, but are often poorly constrained for specific volcanic systems. Mount Hood, Oregon, is a somewhat atypical arc volcano in that it is characterized by a lack of large explosive eruptions over the entire lifetime of the current edifice (~500,000years). Erupted Mount Hood lavas are also compositionally homogeneous, with ~95% having SiO2 contents between 58 and 66wt.%. The last three eruptive periods in particular have produced compositionally homogeneous andesite–dacite lava domes and flows.In this paper we report major element and volatile (H2O, CO2, Cl, S, F) contents of melt inclusions and selected phenocrysts from these three most recent eruptive phases, and use these and other data to consider possible origins for the low explosivity of Mount Hood. Measured volatile concentrations of melt inclusions in plagioclase, pyroxene, and amphibole from pumice indicate that the volatile contents of Mount Hood magmas are comparable to those in more explosive silicic arc volcanoes, including Mount St. Helens, Mount Mazama, and others, suggesting that the lack of explosive activity is unlikely to result solely from low intrinsic volatile concentrations or from substantial degassing prior to magma ascent and eruption. We instead argue that an important control over explosivity is the increased temperature and decreased magma viscosity that results from mafic recharge and magma mixing prior to eruption, similar to a model recently proposed by Ruprecht and Bachmann (2010). Erupted Mount Hood magmas show extensive evidence for mixing between magmas of broadly basaltic and dacitic–rhyolitic compositions, and mineral zoning studies show that mixing occurred immediately prior to eruption. Amphibole chemistry and thermobarometry also reveal the presence of multiple amphibole populations and indicate that the mixed andesites and dacites are at least 100°C hotter than the high-SiO2 resident magma prior to mixing. Viscosity models suggest that recharge by hot, mafic magma prior to eruption can lower magmatic viscosity by at least a factor of four. Lower viscosity during ascent delays fragmentation and allows volatile escape through degassing, thus lowering the potential for explosive eruptions. These results suggest that low explosivity should be more common in volcanoes where intermediate magmas are produced through mixing of mafic and silicic magmas shortly before eruption.

Constraints on crystal storage timescales in mixed magmas: Uranium-series disequilibria in plagioclase from Holocene magmas at Mount Hood, Oregon

Uranium-series crystal ages, interpreted within a textural and geochemical framework, can provide insight into crystal storage timescales, especially in cases where crystals may derive from multiple sources. We report here 230Th–226Ra model ages of two distinct populations of plagioclase from low silica dacites from Mount Hood, Oregon, a volcano where previous studies show that the compositions of erupted magmas are controlled by magma recharge, mixing, and incorporation of plagioclase derived from mafic and silicic end-member magmas. We have measured trace element concentrations and 238U–230Th–226Ra disequilibria in four plagioclase size fractions from the Timberline (1500a) and Old Maid (215a) eruptive sequences. After correction for groundmass and apatite contamination, average 230Th–226Ra model ages of large (>500μm) plagioclase are >4.5ka (Timberline) and >5.5ka (Old Maid), with ages of cores that are >10ka in each case, indicating that plagioclase derived from silicic magmas crystallized thousands of years before eruptions. These model ages are longer than timescales of repose between eruptions, indicating that these crystals resided in the sub-surface over multiple eruptions, likely stored in a silicic crystal mush zone that periodically interacts with mafic recharge magmas, remobilizing a fraction of the large plagioclase crystals during each eruptive event. After correction for large plagioclase contamination, small (<500μm) plagioclase, derived from mafic magmas, have high (226Ra)/Ba relative to equilibrium with liquid proxies (groundmass and mafic inclusion), leading to 230Th–226Ra model ages that are <~3ka for Old Maid and undefined for Timberline separates. However, the preservation of significant 230Th–226Ra disequilibria require that the majority of crystals in the separate are young (<<10ka). The high (226Ra)/[Ba] could potentially be explained by rapid crystallization immediately prior to and/or during mixing events, consistent with evidence of rapid crystallization of rims. Rapid crystallization of mafic intrusions may trigger eruption at Mount Hood by producing a partially-crystalline mafic magma capable of mixing with a reheated silicic crystal mush.

Tales From Timberline: The 2011 Acquisitions Institute at Timberline Lodge

The 2011 Acquisitions Institute at Timberline Lodge delivered a packed schedule of timely and interesting presentations on compelling topics for acquisitions and collection development librarians, publishers, and library vendors. The cozy lodge provided a perfect environment for relaxed conversation on topics such as patron-driven acquisitions, e-books, and library collaborations, while late snow flurries and a cloud cap hid Mount Hood from attendees’ eyes.

OregonScape

oregonscape Early motion picture photographers had to have sound nerves as well as an eye for the interesting and newsworthy.Their heavy wooden cameras had only one lens,so getting a close photograph involved moving the camera near the subject. Sometimes this led to problems. Jesse Sill was one of the premier cameramen in the Pacific Northwest. He taught himself photography around 1912 and was soon free lancing for filmmakers around the area. As part of the 1913 Walla Walla rodeo entertainment, a bear ran down the track until it was roped by one of the cowboys. After several unsuccessful efforts, he finally was getting the shot when, as he told the Oregonian years later, “he realized that the bear was right on top of him. So he turned and ran with the bear right on his heels. Later, Jesse found that the horseman had roped the bear, but held him just inches from Sill as the animal chased the cameraman down the track” (July 15, 1972). Sill had several close calls while filming.At the Pendleton Round-Up, he was filming close-ups of the stagecoach race when one of the competitors lost control of his team. The horses ran over Sill, who was unconscious for more than a day; his obituary even ran in the newspaper. In 1927, he was reported as having been drowned when an explosion washed several cameramen off an island in the middle of the Columbia River during road construction. Sill had decided he did not like the setup and left earlier in the day. And in 1956, at Multnomah Stadium, he was knocked out by an errant ball thrown by a pitcher warming up. Jesse Sill filmed every U.S. president from Theodore Roosevelt to Dwight Eisenhower as they passed through the Pacific Northwest, and in 1923, he took the first aerial motion pictures of Mount Hood. Jesse Sill died in 1981, just forty-nine days short of his one-hundredth birthday. The OHS Research Library has a wealth of Sill material in its collections, such as motion pictures including many episodes of the Webfoot Weekly newsreel Sill filmed in the 1920s, oral history recordings, still photographs, personal papers, and newspaper articles. — Mikki Tint, former special collections librarian, OHS Research Library OHS digital no. bb008092 ...

Deep long-period earthquakes beneath Washington and Oregon volcanoes

Deep long-period (DLP) earthquakes are an enigmatic type of seismicity occurring near or beneath volcanoes. They are commonly associated with the presence of magma, and found in some cases to correlate with eruptive activity. To more thoroughly understand and characterize DLP occurrence near volcanoes in Washington and Oregon, we systematically searched the Pacific Northwest Seismic Network (PNSN) triggered earthquake catalog for DLPs occurring between 1980 (when PNSN began collecting digital data) and October 2009. Through our analysis we identified 60 DLPs beneath six Cascade volcanic centers. No DLPs were associated with volcanic activity, including the 1980–1986 and 2004–2008 eruptions at Mount St. Helens. More than half of the events occurred near Mount Baker, where the background flux of magmatic gases is greatest among Washington and Oregon volcanoes. The six volcanoes with DLPs (counts in parentheses) are Mount Baker (31), Glacier Peak (9), Mount Rainier (9), Mount St. Helens (9), Three Sisters (1), and Crater Lake (1). No DLPs were identified beneath Mount Adams, Mount Hood, Mount Jefferson, or Newberry Volcano, although (except at Hood) that may be due in part to poorer network coverage. In cases where the DLPs do not occur directly beneath the volcanic edifice, the locations coincide with large structural faults that extend into the deep crust. Our observations suggest the occurrence of DLPs in these areas could represent fluid and/or magma transport along pre-existing tectonic structures in the middle crust.

Present‐day and future contributions of glacier runoff to summertime flows in a Pacific Northwest watershed: Implications for water resources

While the impacts of long‐term climate change trends on glacier hydrology have received much attention, little has been done to quantify direct glacier runoff contributions to streamflow. This paper presents an approach for determining glacier runoff contributions to streamflow and estimating the effects of increased temperature and decreased glacier area on future runoff. We focus on late summer streamflow (when flow is lowest and nonglacier contributions to flow are minimal) of a small glacierized watershed on the flanks of Mount Hood, Oregon, United States. Field and lab measurements and satellite imagery were used in conjunction with a temperature‐index model of glacier runoff to simulate potential effects of increased temperature and reduction in glacier area on late summer runoff in the watershed. Discharge and stable isotope data show that 41–73% of late summer streamflow is presently derived directly from glacier melt. Model simulations indicate that while increased temperature leads to rapid glacier melt and therefore increased streamflow, the consequences of glacier recession overcomes this effect, ultimately leading to substantial declines in streamflow. Model sensitivity analyses show that simulation results are most sensitive to degree day factor and less sensitive to uncertainties in debris‐covered area and accumulation area ratio. This case study demonstrates that the effects of glacier recession on streamflow are a concern for water resource management at the local scale. This approach could also be extended to larger scales such as the upper Columbia River basin where glacier contributions to late summer flows are also thought to be substantial.

Magnitude and timing of downstream channel aggradation and degradation in response to a dome-building eruption at Mount Hood, Oregon

A dome-building eruption at Mount Hood, Oregon, starting in A.D. 1780 and lasting until ca. 1793, produced dome-collapse lithic pyroclastic flows that triggered lahars and intermittently fed 10 8 m 3 of coarse volcaniclastic sediment to sediment reservoirs in headwater canyons of the Sandy River. Mobilization of dominantly sandy sediment from these reservoirs by lahars and seasonal floods initiated downstream migration of a sediment wave that resulted in a profound cycle of aggradation and degradation in the lowermost reach of the river (depositional reach), 61–87 km from the source. Stratigraphic and sedimentologic relations in the alluvial fill, together with dendrochronologic dating of degradation terraces, demonstrate that (1) channel aggradation in response to sediment loading in the headwater canyons raised the river bed in this reach at least 23 m in a decade or less; (2) the transition from aggradation to degradation in the upper part of this reach roughly coincided with the end of the dome-building eruption; (3) fluvial sediment transport and deposition, augmented by one lahar, achieved a minimum average aggradation rate of ∼2 m/yr; (4) the degradation phase of the cycle was more prolonged than the aggradation phase, requiring more than half a century for the river to reach its present bed elevation; and (5) the present longitudinal profile of the Sandy River in this reach is at least 3 m above the pre-eruption profile. The pattern and rate of channel response and recovery in the Sandy River following heavy sediment loading resemble those of other rivers similarly subjected to very large sediment inputs. The magnitude of channel aggradation in the lower Sandy River, greater than that achieved at other volcanoes following much larger eruptions, was likely enhanced by lateral confinement of the channel within a narrow incised valley. A combination of at least one lahar and winter floods from frequent moderate-magnitude rainstorms and infrequent very large storms was responsible for flushing large volumes of sediment to the depositional reach. These conditions permitted a sedimentation response in the Sandy River that approached the magnitude of channel aggradation resulting elsewhere from large explosive eruptions and high-intensity rainfall regimes, despite the fact that the Sandy River aggradation was in response to an unremarkable dome-building eruption in a climate dominated by low to moderate rainfall intensities.

Messy magma mixtures

Andesite magmas were once thought to be simple melts derived from a subducting oceanic slab or the mantle. Analysis of lavas at Mount Hood shows that instead andesites are a complex mixture of magmas formed in the continental crust just before eruption.

Preferential eruption of andesitic magmas through recharge filtering

At subduction zones, andesite lavas erupt in greater abundance than the individual magmas that mix to produce them. Textural and geochemical analyses of andesites from Mount Hood, Oregon, reveal that injection and mixing of iron- and magnesium-rich magma in the magma chamber can initiate the volcanic eruption. Andesitic volcanic rocks are common in subduction zones and are argued to play an important role in the formation and evolution of the continental crust at convergent margins1,2,3,4. Andesite formation is dominated by mixing between iron- and magnesium-rich (mafic) magmas and silica-rich (felsic) magmas1,2,4. The abundance of andesites in many subduction zones suggests they erupt in preference to the magmas that mix to produce them4; however, the reasons for this remain unclear. Here we use textural and geochemical analyses of andesites from Mount Hood, Oregon, to show that eruptions are closely linked with episodes of mafic recharge—the intrusion of mafic magma into a shallow felsic magma reservoir. The felsic and mafic magmas involved rarely erupt by themselves, probably because the former are too viscous and the latter too dense. Mafic recharge overcomes these barriers to eruption, and, as it also promotes efficient mixing, results in preferential eruption of mixed andesitic magmas. The abundance of andesites therefore relates to local crustal conditions and the ability of magmas to erupt. We suggest that volcanoes, such as Mount Hood, that erupt homogeneous andesitic compositions through time are those that are the most reliant on mafic recharge to initiate eruptions.

Flying mathematician

His adventure flights over rough mountains yield stunningly accurate maps. Rick Armstrong is snuggled up with a laptop in the cluttered space that was once the backseat of a six-­ passenger Cessna 206. Twenty-­five hundred meters below, sun-­splashed Portland, Ore., slowly dissolves into the Tolkienesque foothills of Mount Hood. It's some beautiful scenery. But right now, Armstrong's eyes are fixed on his computer, which monitors the images that are streaming in from a camera mounted under the belly of the little plane.

Trace element and major ion concentrations and dynamics in glacier snow and melt: Eliot Glacier, Oregon Cascades

AbstractWe present concentrations of environmentally available (unfiltered acidified 2% v/v HNO3) As, Cu, Cd, Pb, V, Sr, and major ions including Ca2+, Cl−, and SO42− in a July 2005 and a March 2006 shallow snow profile from the lower Eliot Glacier, Mount Hood, Oregon, and its proglacial stream, Eliot Creek. Low enrichment factors (EF) with respect to crustal averages suggests that in fresh March 2006 snow environmentally available elements are derived primarily from lithogenic sources. Soluble salts occurred in lower and less variable concentrations in July 2005 snow than March 2006. Conversely, environmentally available trace elements occurred in greater and more variable concentrations in July 2005 than March 2006 snow. Unlike major solutes, particulate‐associated trace elements are not readily eluted during the melt season. Additionally, elevated surface concentrations suggest that they are likely added throughout the year via dry deposition. In a 1‐h stream sampling, ratios of dissolved (&lt;0·45 µm) V:Cl−, Sr:Cl−, and Cu:Cl− are enriched in the Eliot Stream with respect to their environmentally available trace element to Cl− ratios in Eliot Glacier snow, suggesting chemical weathering additions in the stream waters. Dissolved Pb:Cl− is depleted in the Eliot Stream with respect to the ratio of environmentally available Pb to Cl− in snow, corresponding to greater adsorption onto particles at greater pH values. Copyright © 2009 John Wiley &amp; Sons, Ltd.

Initial Fluvial Response to the Removal of Oregon's Marmot Dam

A temporary, 14‐meter‐high earthen cofferdam standing in place of Marmot Dam was breached on 19 October 2007, allowing the 80‐ kilometer‐long Sandy River to flow freely from Mount Hood, Oreg., to the Columbia River for the first time in nearly 100 years. Marmot Dam is one of the largest dams in the western United States (in terms of height and volume of stored sediment) to have been removed in the past 40 years, and its removal exposed approximately 730,000 cubic meters of stored sand and gravel to erosion and transport by the newly energetic mountain river. At the time, its breach represented the greatest release of sediment from any U.S. dam removal. (The March 2008 breaching of Montana's Milltown Dam exposed about 5–10 times as much sediment to potential erosion.)

The Oregon Geographic Names Board: One Hundred Years of Toponymic Nomenclature

CHAMP CLARK VAUGHAN The Oregon Geographic Names Board One Hundred Years ofToponymie Nomenclature A RELATIVELYUNKNOWN COMPONENT of theOregonHistorical Society is celebrating itscentenary thisyear. The Oregon Geographic Names Board, Oregon's official geographic names authority, was established with a stroke of the pen, when Governor George Chamberlain signed an executive order on October 1,1908.Although thevastmajority of thepublic may not be conscious of itsexistence and responsibilities, the board's ongoing involve ment in controversy ? spurred by the use of the term squaw in geographic names, for example ? has had wide publicity. Because many people view the term squaw as having a derogatory or offensive connotation and ithas therefore been banned by theOregon Legislature, the board has embarked on an enormous task of eliminating theword from 172 geographic names inOregon by generating suitable replacement names.1 Contentious issues like this one increase the visibility of theOregon Geographic Names Board, and although its long history isfilledwith fascinating chronicles, theboard's impact on Oregon and itspeople is far greater than those individual stories. In assessing the origins of both existing and proposed geographic names inOregon, their cultural significance cannot be overstated. The names of places and geographic features reflect the culture ofmany peoples and gen erations, which the board must comprehend and respect in order to carry out its toponymie mission. The Oregon GeographicNames Board (OGNB) was originally known as theOregon Geographic Board. The board latermodified itsname to help state itsprimary purpose, supervising the naming of geographic features in Oregon. A number of state agencies rotated the responsibility ofmanaging the OHQ vol. 109, no. 3 ? 2008 Oregon Historical Society Chush Falls is locatedonWhychus Creek within theThree Sisters Wilderness. Chush isa Sahaptin word meaning 'water'. Chush Falls was not officially named until 2006 but had oftenbeenmistakenly referred toas aSquaw Creek Falls." Upper Chush Falls, locatedupstream,was theofficialSquaw Creek Falls before itsname was changed in2006. board until 1959,when Governor Mark Hatfield transferred itto theOregon Historical Society (OHS). The move was logical because thehistorical society had served as custodian of theboard's records and correspondence since 1909. OHS's first museum curator,George H. Himes, who also served on theOregon Geographic Board, most likely initiated the early custodial arrangement.2 The origins of geographic names inOregon are particularly complex. Long before thefirstnon-Indians arrived,Native peoples had already named numerous geographic features and cultural sites. Because their languages were not written, most of those names were never recorded, and many did not survive.3 European and American mariners who explored the Pacific coastline and, to amuch greater degree, nineteenth-century explorers, fur trappers, missionaries, and immigrants casually assigned names to geo graphic features, using a wide assortment of commemorative, associative, and descriptive terms. Prime examples include theColumbia River, named in 1792 by Captain Robert Gray for his ship, Columbia Rediviva; Mount Hood, named in 1792 by Lieutenant William Broughton of Captain George Vaughan, The Oregon Geographic Names Board 413 Vancouver's command, to commemorate British naval officerAdmiral Sir Samuel Hood; French Prairie, anonymously named in themid 1800s for the early French Canadian settlers as an associative name; and Black Butte in Deschutes County, anonymously named in the 1850s as a descriptive name relating to the forest-covered volcano's dark appearance.4 The newcom erswere likely unaware thatmany of the geographic features already had aboriginal names, or if theywere aware, they customarily ignored them. Regardless of the fact that the names selected were often duplicated else where, misapplied, misspelled, and in some cases derogatory, they became official simply because theywere recorded on maps. The resultwas public controversy and confusion among map users. No one made a serious attempt to standardize and document geographic names in Oregon until after the federal government took the first step. Recognizing that the geographic names issue was becoming a nationwide problem, particularly in theWest, President Benjamin Harrison created theUnited States Board on Geographic Names (USBGN) on September 4, 1890. The USBGN is comprised of employees from several federal agencies involved in a wide variety of programs, including everything from map making and land management to commerce and national defense. Origi nally, the USBGN primarily adjudicated unsettled questions concerning specific geographic names. In 1906, however, President Theodore Roosevelt extended USBGN's...

Computer Modeling of Diabetes and Its Complications

Computer simulation models are mathematical equations combined in a structured framework to represent some real or hypothetical system. One of their uses is to allow the projection of short-term data from clinical trials to evaluate clinical outcomes and costs over a long-term period. This technology is becoming increasingly important to assist decision making in modern medicine in situations where there is a paucity of long-term clinical trial data, as recently acknowledged in the American Diabetes Association Consensus Panel Guidelines for Computer Modeling of Diabetes and its Complications. The Mount Hood Challenge Meetings provide a forum for computer modelers of diabetes to discuss and compare models and identify key areas of future development to advance the field. The Fourth Mount Hood Challenge in 2004 was the first meeting of its kind to ask modelers to perform simulations of outcomes for patients in published clinical trials, allowing comparison against "real life" data. Eight modeling groups participated in the challenge. Each group was given three of the following challenges: to simulate a trial of type 2 diabetes (CARDS [Collaborative Atorvastatin Diabetes Study]); to simulate a trial of type 1 diabetes (DCCT [Diabetes Control and Complications Trial]); and to calculate outcomes for a hypothetical, precisely specified patient (cross-model validation). The results of the models varied from each other and for methodological reasons, in some cases, from the published trial data in important ways. This approach of performing systematic comparisons and validation exercises has enabled the identification of key differences among the models, as well as their possible causes and directions for improvement in the future.

Spatial and morphological change on Eliot Glacier, Mount Hood, Oregon, USA

AbstractEliot Glacier is a small (1.6 km2) glacier on Mount Hood, Oregon, USA, and its ablation zone is largely covered with rock debris. We examine the interrelated processes of ablation rates, ice thickness and surface velocities to understand the retreat rate of this glacier. Since measurements began in 1901, the glacier has retreated 680 m, lost 19% of its area and thinned by about 50 m at the lower glacier profile before the terminus retreated past that point. The upper profile, 800m up-glacier, has shown thinning and thickening due to a kinematic wave resulting from a cool period during the 1940s–70s, and is currently about the same thickness as in 1940. Overall, the glacier has retreated at a slower rate than other glaciers on Mount Hood. We hypothesize that the rock debris covering the ablation zone reduces Eliot Glacier’s sensitivity to global warming and slows its retreat rate compared to other glaciers on Mount Hood. Spatial variations in debris thickness are the primary factor in controlling spatial variations in melt. A continuity model of debris thickness shows the rate of debris thickening down-glacier is roughly constant and is a result of the compensating effects of strain thickening and debris melt-out from the ice.

The Winds of Change: The Decline of Extractive Industries and the Rise of Tourism in Hood River County, Oregon

JASON PIERCE The Winds of Change TheDecline ofExtractiveIndustries and the Rise ofTourism in Hood RiverCounty,Oregon THE STORY OF THE CITY AND countyofHood River is thestory of much of the rural Pacific Northwest. Originally built around the logging and horticulture industries, the town in the 1970s increasingly became identified with tourism and recreation. Older residents, often with roots in the tradi tional extractive industries, saw Hood River transformed before their eyes, and theywere left wondering if the new town would remain true to their memories. The rise of tourism also brought new people to the region, often with outside money, while many long-time residents saw their employment opportunities shrink and housing prices escalate. Tourism, especially the sport ofwindsurfing, also helped change the relationship between people and nature, as work in extractive industries gave way to participation in a variety of recreational pastimes that seemed more natural. In a littlemore than twenty-five years, Hood River changed dramatically, but the changes have not always been easy or welcomed. Logging and horticulture rose to prominence inHood River's economy during the late nineteenth and early twentieth centuries. Although logging employment was a significant part of the economy, it was horticulture that put Hood River on themap. The county ? created out of nearby Wasco County in 1908?was fifth inhorticultural production by 1910.By 1940, itled the statewith afruit harvest valued at $2.2million, nearly double the second place showing of $1.4 million for Jackson County.1 Rising upward toward Mount Hood, past the towns ofHood River and Parkdale, orchards enlivened the landscape, often appearing in thewake of lumber companies that had cleared the land ofmassive old-growth timber. Together, these industries were themost tangible sign of the transformation brought to the area by OHQ vol. 108, no. 3 ? 2007 Oregon Historical Society ThisMay 25,1930,photograph shows thescenicbeauty and directaccess to the riverthathas brought tourists,includingwindsurfers, to Hood Riverfor decades. Development has comewith thosenewpeople and industries,and a marina and hotelsnow line theriverbank. white settlement.2 By 1910,Hood River boasted 744 farms and orchards and since then has remained Oregon's premier fruit-growing region.3 As fresh fruit replaced canned fruit,as crops shifted from strawberries to apples and finally pears, and asHispanic farmworkers became the region's primary labor force, the industry adapted to changes caused by fluctuations in themarket and consumer tastes. Increasingly, growers faced pressures from developers and from the challenges thrown up by international competition. Still, the orchards endured, adapting even to the rise of the tourist economy. Hood River's logging industrywas not so resilient.Mills suffered throughout the last half of the twentieth century as the loss of old-growth trees, changing technology, the export of unmilled logs, environmental restrictions, and Pierce, Extractive Industries'Decline and Tourism's Rise inHood River 411 international competition decimated the industry. By 2000, the logging industry was a shadow ofwhat ithad once been. Historian Bernard DeVoto once famously declared that the West was a "plundered province," an economic colony of the industrial East whose sole purpose was to feed rawmaterials to the eastern industrial machine.4 He believed that this exploitative relationship forced westerners into a politi cally and economically subservient position. Inmany ways, he was correct; but, despite their shortcomings, farming, ranching, logging, and mining also provided the region with employment and gave the ruralWest a solid place in theAmerican economy. The West's place in the global economy, however, is stilluncertain. The fluidity of capital and competition from other nations and regions, aided by theNorth American Free Trade Agreement (NAFTA) and other trade pacts, has weakened and inmany cases destroyed the West's oldest and most important industries. In 1994, only seven Oregon andWashington interior counties ? those east of the Cascade Mountains ? had more than 35 percent of their population employed in extractive industries. Hood River County was not one of them.5The economic purpose of the rural Northwest had become uncertain. In some places, Hood River among them, tourism was poised to fill in the vacuum. The decline of the extractive economy began in themid-1970s as a result of the national oil crisis, what economists labeled "stagflation," and the general economic "malaise...

Dating young geomorphic surfaces using age of colonizing Douglas fir in southwestern Washington and northwestern Oregon, USA

AbstractDating of dynamic, young (&lt;500 years) geomorphic landforms, particularly volcanofluvial features, requires higher precision than is possible with radiocarbon dating. Minimum ages of recently created landforms have long been obtained from tree‐ring ages of the oldest trees growing on new surfaces. But to estimate the year of landform creation requires that two time corrections be added to tree ages obtained from increment cores: (1) the time interval between stabilization of the new landform surface and germination of the sampled trees (germination lag time or GLT); and (2) the interval between seedling germination and growth to sampling height, if the trees are not cored at ground level. The sum of these two time intervals is the colonization time gap (CTG). Such time corrections have been needed for more precise dating of terraces and floodplains in lowland river valleys in the Cascade Range, where significant eruption‐induced lateral shifting and vertical aggradation of channels can occur over years to decades, and where timing of such geomorphic changes can be critical to emergency planning.Earliest colonizing Douglas fir (Pseudotsuga menziesii) were sampled for tree‐ring dating at eight sites on lowland (&lt;750 m a.s.l.), recently formed surfaces of known age near three Cascade volcanoes – Mount Rainier, Mount St. Helens and Mount Hood – in southwestern Washington and northwestern Oregon. Increment cores or stem sections were taken at breast height and, where possible, at ground level from the largest, oldest‐looking trees at each study site. At least ten trees were sampled at each site unless the total of early colonizers was less. Results indicate that a correction of four years should be used for GLT and 10 years for CTG if the single largest (and presumed oldest) Douglas fir growing on a surface of unknown age is sampled. This approach would have a potential error of up to 20 years. Error can be reduced by sampling the five largest Douglas fir instead of the single largest. A GLT correction of 5 years should be added to the mean ring‐count age of the five largest trees growing on the surface being dated, if the trees are cored at ground level. This correction would have an approximate error of ±5 years. If the trees are cored at about 1·4 m above the ground surface (breast height), a CTG correction of 11 years should be added to the mean age of the five sampled trees (with an error of about ±7 years). Published in 2006 by John Wiley &amp; Sons, Ltd.

The Fifth ICA Mountain Cartography Workshop, Bohinj, Slovenia, 29 March–1 April 2006

The Fifth Workshop of the International Cartographic Association’s Commission on Mountain Cartography took place in Slovenia this spring. Previous mountain cartography workshops have been held in the Austrian Alps (Silvretta 1988, Rudolfshutte 2000), North America’s Cascade Range (Mount Hood 2002), and the Catalan Pyrenees (Val de Nuria 2004). This year the mountain cartographers returned again to the Alps, but this time to the southern limestone region. The workshop venue was the Gozdna sola (forest school), the National Training Centre of the Scout Association of Slovenia. The centre is located near Lake Bohinj, 533 m above sea level, in Triglav National Park, a protected area of forests and mountains, including Triglav (2864 m), the highest peak in Slovenia and the Slovenian national symbol.

Historical Glacier and Climate Fluctuations at Mount Hood, Oregon

Terminus fluctuations of five glaciers and the correspondence of these fluctuations to temperature and precipitation patterns were assessed at Oregon’s Mount Hood over the period 1901–2001. Historical photographs, descriptions, and climate data, combined with contemporary GPS measurements and GIS analysis, revealed that each glacier experienced overall retreat, ranging from −62 m at the Newton Clark Glacier to −1102 m at the Ladd Glacier. Within this overall trend, Mount Hood’s glaciers experienced two periods each of retreat and advance. Glaciers retreated between 1901 and 1946 in response to rising temperatures and declining precipitation. A mid-century cool, wet period led to glacier advances. Glaciers retreated from the late 1970s to the mid-1990s as a result of rising temperatures and generally declining precipitation. High precipitation in the late 1990s caused slight advances in 2000 and 2001. The general correspondence of Mount Hood’s glacier terminus fluctuations with glaciers in Washington and Oregon suggests that regional, decadal-scale weather and climate events, driven by the Pacific Decadal Oscillation, play a key role in shaping atmosphere-cryosphere interactions in Pacific Northwest mountains. Deviations from the general glacier fluctuation pattern may arise from local differences in glacier aspect, altitude, size, and steepness as well as volcanic and geothermal activity, topography, and debris cover.