THE PERSISTENCE OF OAK WOODLANDS IN ALTERED FIRE REGIMES OF THE PACIFIC NORTHWEST

Thesis (Master's)--University of Washington, 2017Pacific Northwest oak woodlands and savannas are fire-resilient communities dependent on frequent, low-severity fire to maintain their structure and understory species diversity, and to prevent encroachment by fire-sensitive competitors. These important ecosystems have been severely reduced in both extent and quality during more than a century of land use change and altered fire regimes. The re-introduction of fire into these transformed ecosystems is viewed as essential to their restoration, yet can be fraught with potential unintended consequences. We examined oak response following re-introduction of fire into two distinct oak ecosystems: formerly suppressed California black oak (Quercus kelloggii Newb.) woodlands subject to repeated wildfire, and Garry oak (Quercus garryana Douglas ex Hook.) woodlands experiencing “first entry” restoration burns. Both the black oak woodlands of Lassen National Forest, California, and the Garry oak woodlands of Joint-Base Lewis-McChord, Washington have experienced shifts in vegetative structure and composition during long fire-free intervals. Black oak canopy dominance and vigor of resprouts were positively correlated with increased fire severity (R2=0.41, 0.49, respectively), but black oaks that had sprouted following top-kill in the first fire were easily top-killed in the second fire, even at low severities, implying that long-term survival of regenerating black oaks in fire-prone regions is uncertain. Top-kill of Garry oak was rare (8%) in three prescribed burns, despite high levels (95%) of crown scorching and irrespective of proportional duff consumption around oak bases, demonstrating the high resilience of Garry oaks to first entry burns when compared to historic fires. Bud kill (as measured by lack of bud burst the spring following burns) in Garry oak crowns was correlated with crown scorching (R2=0.42), but responses were highly variable, especially at high levels of scorching. The results of these studies indicate that fire adaptations may be specific to particular fire regimes, and that vegetative responses in oak woodlands are highly dependent on the adaptive traits of individual species. Restoration efforts in oak woodlands are more likely to be successful when reintroduction of fire is carefully tailored to target species, and modeled on characteristics of past disturbance, taking into account altered conditions of modern landscapes

The Cactus League: Stories

THE CACTUS LEAGUE: STORIES is a linked collection that takes place in Scottsdale, Arizona, during the spring training season for Major League Baseball. The nine stories in the collection revolve around the fictional Los Angeles Lions and their springtime home, zooming in and out of the lives of not only baseball players, but also the front office personnel, service workers, spouses, and fans who have hitched their hopes on the baseball season. A young pitcher recovering (or not) from Tommy John surgery, the impoverished son of a seasonal concession worker, the migratory pattern of a fleet of baseball wives, the favorite songs of an ailing stadium organist—these stories investigate baseball culture but also delve into an exploration of contemporary American society, from coming of age to end-of-life care, from copper stripping to selfies. A lifelong Seattle Mariners fan, I started regularly traveling to Scottsdale in the 1990s to attend baseball spring training with my father; I have since revisited the region a number of times. A far cry from the places I\u27ve lived (Seattle, Providence, New York, and Louisiana), I was fascinated by the landscape and built environment—even more so as the Phoenix area boomed and dramatically busted in the recent financial collapse. In watching this transformation, Scottsdale\u27s rich geological, economic, and architectural history, from prehistoric to present day, became topics I wanted to explore. I’ve always seen baseball as a sport, of course, but also as an important reflection of American culture. In the case of THE CACTUS LEAGUE: STORIES, baseball offered me both the mirror and the magnifying glass I needed to write a collection about life in this strange and beautiful corner of the world

Dendroclimatic Responses of Sugar Maple Tapped for Maple Syrup: A Case Study from Pennsylvania

Maple syrup is a regional, non-timber forest product in the United States that depends upon healthy, mature sugar maple (Acer saccharum Marshall). We examined whether tapping for maple syrup altered the dendroclimatic response of sugar maple. Ring width indices from two sites (tapped and reference) in central Pennsylvania were correlated with regional temperature, precipitation, and Palmer Drought Severity Index (PDSI). Both sites had significant correlations between summer and fall PDSI and radial growth. Spring PDSI was significantly correlated with growth at the reference site, but not at the tapped site. Both tapped and reference trees experienced below-average growth during years with dry spring conditions (PSDI 0) compared to reference trees (15%). These results indicate that tapping for maple syrup may have altered the dendroclimatic response of sugar maple to moisture availability during the spring months. © 2017 by The Tree-Ring Society.This item is part of the Tree-Ring Research (formerly Tree-Ring Bulletin) archive. For more information about this peer-reviewed scholarly journal, please email the Editor of Tree-Ring Research at [email protected]

The Number of Trait Loci in Late-Onset Alzheimer Disease

Although it is clear that apoE plays an important role in the genetics of late-onset Alzheimer disease (AD), evidence exists that additional genes may play a role in AD, and estimates of the total contribution of apoE to the variance in onset of AD vary widely. Unfortunately, little information is available on the number and contribution of additional genes. We estimated the number of additional quantitative-trait loci and their contribution to the variance in age at onset of AD, as well as the contribution of apoE and sex, in an oligogenic segregation analysis of 75 families (742 individuals) ascertained for members with late-onset AD. We found evidence that four additional loci make a contribution to the variance in age at onset of late-onset AD that is similar to or greater in magnitude than that made by apoE, with one locus making a contribution several times greater than that of apoE. Additionally, we confirmed previous findings of a dose effect for the apoE ɛ4 allele, a protective effect for the ɛ2 allele, evidence for allelic interactions at the apoE locus, and a small protective effect for males. Furthermore, although we estimate that the apoE genotype can make a difference of ⩽17 years in age at onset of AD, our estimate of the contribution of apoE (7%–9%) to total variation in onset of AD is somewhat smaller than that which has previously been reported. Our results suggest that several genes that have not yet been localized may play a larger role than does apoE in late-onset AD