The frequency of moderate to heavy rainfall events is projected to change in response to global warming. Here we show that these hydrologic changes may have a profound effect on mosquito population dynamics and rates of mosquito-borne disease transmission. We develop a simple model, which treats the mosquito reproductive cycle...
Corrections
18 Mar 2010: Shaman J, Pitzer VE, Viboud C, Grenfell BT, Lipsitch M (2010) Correction: Absolute Humidity and the Seasonal Onset of Influenza in the Continental United States. PLOS Biology 8(3): 10.1371/annotation/35686514-b7a9-4f65-9663-7baefc0d63c0.
15 Mar 2010: Shaman J, Pitzer VE, Viboud C, Grenfell BT, Lipsitch M (2010) Correction: Absolute Humidity...
Measurements of the U₃₇ K’ index and the absolute abundance of alkenones in marine sediments are increasingly used in paleoceanographic research as proxies of past sea surface
temperature and haptophyte (mainly coccolith-bearing species) primary productivity, respectively. An
important aspect of these studies is to be able to compare reliably data...
In Sierra Nevada forests, shrubs are considered strong soil moisture competitors with regenerating trees, reducing seedling establishment, and
slowing growth. Recent studies, however, suggest that in some circumstances shrubs can facilitate tree establishment and growth by modifying
harsh microclimate conditions; increasing acquisition of water, carbon, and/or nutrients via shared mycorrhizal...
During 1997–1998, we investigated the influence of both the relative abundance of truffles, preferred food
items, and microhabitat structure on the occurrence of northern flying squirrels (Glaucomys sabrinus Shaw) in oldgrowth
forest habitat of the Sierra Nevada Range, U.S.A. Following live-trapping sessions, we searched the forest floor
for truffle diggings...
The term "forest health" is being increasingly used in the context of forestry and natural resource management. For example, the term has been the subject of several articles in the JOURNAL oF FORESTRY and a recent Society of American Foresters task force report, Sustaining Long- 7•rm Forest Health and Productivity...
Mechanical thinning and prescribed fire are widely used to restore western forests after a century of fire suppression, yet we know little about
how these treatments affect understory communities where plant diversity is highest. We followed understory plants and environmental factors in
old-growth, Sierran mixed conifer for two pre-treatment and...
Fire suppression has increased fuel loads and fuel continuity in mixed-conifer ecosystems, resulting in forest structures
that are vulnerable to catastrophic fire. This paper models fire behaviour in a mixed-conifer forest and investigates how
silvicultural and fuels treatments affect potential fire behaviour. The computer program FARSITE was used to spatially...
Successful fire exclusion in the 20th century has created severe fire problems across the West. Not every forest is at risk of
uncharacteristically severe wildfire, but drier forests are in need of active management to mitigate fire hazard. We summarize a
set of simple principles important to address in fuel...
Even after 140 years without a fire, mixed-conifer forest such as Teakettle’s Experimental Forest has a distinct patch pattern and complex structure. Researcher Malcolm North and colleagues examined the structure and function of these ecosystems and their response to widely used restoration treatments. Collectively the studies found fire was essential...
Climate warming may first show up in forests as increased growth, which occurs as warmer temperatures, increased carbon dioxide, and more precipitation encourage higher rates of photosynthesis. The second way that climate change may show up in forests is through changes in disturbance regimes—the long-term patterns of fire, drought, insects,...
Western United States forest wildfire activity is widely thought to have increased in recent decades,
yet neither the extent of recent changes nor the degree to which climate may be driving regional
changes in wildfire has been systematically documented. Much of the public and scientific
discussion of changes in western...
Understanding the relative influence of fuels and climate on wildfires across the Rocky Mountains is necessary to predict how fires may respond to a changing climate and to define effective fuel management approaches to controlling wildfire in this increasingly populated region. The idea that decades of fire suppression have promoted...
Soil respiration is a major pathway for carbon cycling in terrestrial ecosystems yet little is known about its response to natural and
anthropogenic disturbances. This study examined soil respiration response to prescribed burning and thinning treatments in an old-growth, mixedconifer
forest on the western slope of the Sierra Nevada Mountains....
Studies of the effects of climate change on forests have focused on the ability of species to tolerate temperature and moisture changes and to disperse, but they have ignored the effects of disturbances caused by climate change (e.g., Ojima et al. 1991). Yet modeling studies indicate the importance of climate...
Nitrogen is a limiting resource in many temperate forests and nitrogen-fixing plants are usually limited to the early
stages of post-disturbance succession. In fire-dependent Sierra Nevada forests, however, Ceanothus cordulatus is
relatively abundant even in old-growth forest conditions which are at least partly maintained by fire.We conducted
a field experiment...
In the Sierra Nevada, distributions of forest tree
species are largely controlled by the soil-moisture
balance. Changes in temperature or precipitation as
a result of increased greenhouse gas concentrations
could lead to changes in species distributions. In
addition, climatic change could increase the frequency
and severity of wildfires. We used...
Forest managers have little information of the effects of common restoration treatments, thinning and burning, on dead woody material (DWM) dynamics in fire-suppressed forests. Fine woody debris (FWD; 0.6–29.9 cm), coarse woody debris (CWD; ≥30.0 cm), and snags (≥5 cm) were inventoried and mapped in eighteen 4 ha plots before...
The Teakettle Ecosystem Experiment in the southern Sierra Nevada is using thinning and prescribed
fire to recreate historical stand conditions. As part of Teakettle we assessed pretreatment diversity and density
of the soil arthropod community in 1998 and 2000. We determined the density and diversity of soil microarthropods
among treatment...
We determined the spatial pattern of dwarf mistletoe (Arceuthobium
spp.) associated with two different conifer hosts, white fir (Abies
concolor) and Jeffrey pine (Pinus jeffreyi), in forests around the Lake
Tahoe Basin and at the Teakettle Experimental Forest, both located in the
Sierra Nevada. We also examined a number of...
The management of fire-prone forests is one of the most controversial natural resource issues in the US today,
particularly in the west of the country. Although vegetation and wildlife in these forests are adapted to fire, the
historical range of fire frequency and severity was huge. When fire regimes are...
Fire performs many beneficial ecosystem functions in dry forests and rangelands across much
of North America. In the last century, however, the role of fire has been dramatically altered by numerous
anthropogenic factors acting as root causes of the current fire crisis, including widespread logging, road
building, fire suppression, habitat...
Many indicators and criteria have been proposed to assess the sustainable management of
forests but their scientific validity remains uncertain. Because the effects of forest disturbances
(such as logging) are often specific to particular species, sites, landscapes, regions
and forest types, management ‘‘shortcuts’’ such as indicator species, focal species and...
Most administrators and ecologists agree that reducing the levels of hazardous fuels on forests is essential to restore healthy
watersheds and protect adjacent human communities. The current debate over the appropriateness, technique, and timing of treatments
utilized to restore vegetation structure and composition is currently on-going at local, state, and...
The enlargement of 21 canopy gaps associated with the root pathogen Heterobasidion annosum (Fr.:Fr.)
Bref. (; Fomes annosus (Fr.) Karst.) in the mixed-conifer forest of Yosemite Valley was monitored between 1971 and
1998. Mean expanded gap area was 232 m2 (range 38–802 m2) in 1971 and 1455 m2 (range 150–4216...
We determined the incidence of pathogens and insects across mixed-conifer stands in the Sierra San Pedro
Martir (SSPM) of northern Baja, Mexico, to assess the role of pests in a pristine forest ecosystem. We also determined
the spatial distribution of the two most common pests, mistletoe, Phoradendron pauciflorum Torrey, and...
Forest-fire policy of U.S. federal agencies has evolved from the use of small
patrols in newly created National Parks to diverse policy initiatives and institutional arrangements
that affect millions of hectares of forests. Even with large expenditures and
substantial infrastructure dedicated to fire suppression, the annual area burned by wildfire...
Mechanical thinning and prescribed fire are widely used to restore western forests after a century of fire suppression, yet we know little about how these treatments affect understory communities where plant diversity is highest. We followed understory plants and environmental factors in old-growth, Sierran mixed conifer for two pre-treatment and...
Sierra Nevada forests have high understory species richness yet we do not know which site factors influence
herb and shrub distribution or abundance. We examined the understory of an old-growth mixed-conifer
Sierran forest and its distribution in relation to microsite conditions. The forest has high species richness
(98 species sampled),...
We compared canopy arthropod assemblages among overstory conifer and understory angiosperm
species at Teakettle Experimental Forest in the Sierra Nevada in California during 1998–2000. Arthropods were
sampled from upper, middle, and lower crown levels of one overstory tree of each of the four dominant conifer
species (Jeffrey pine, sugar pine,...
The effects of management on soil carbon efflux in different ecosystems are still largely unknown yet crucial to both our understanding and management of global carbon flux. To compare the effects of common forest management practices on soil carbon cycling, we measured soil respiration rate (SRR) in a mixed-conifer and...
Soil respiration is a major pathway for carbon cycling in terrestrial ecosystems yet little is known about its response to natural and
anthropogenic disturbances. This study examined soil respiration response to prescribed burning and thinning treatments in an old-growth, mixedconifer
forest on the western slope of the Sierra Nevada Mountains....
To understand the roles of forest management
practices in meeting the goals of forest sustainability and CO2
sequestration, we evaluated the effects of burning and thinning
treatments on soil respiration and soil environments in an
old-growth, mixed-conifer forest in California’s southern Sierra
Nevada. Six experimental treatments with two levels of...
At a spatially heterogeneous mixed-conifer forest in the central California Sierras, we quantified total
carbon (C) and nitrogen (N), inorganic N, and net N mineralization in organic (O) and surface (0–15 cm) mineral
soils, and in situ fluxes of inorganic N and ortho-phosphate using resin lysimeters under three patch types:...
Frankia strains symbiotic with Ceanothus present an interesting opportunity to study the patterns and causes of Frankia diversity and distribution within a particular host infectivity group. We intensively sampled Frankia from nodules on Ceanothus plants along an elevational gradient in the southern Sierra Nevada of California, and we also collected...
Little is known about biophysical controls on soil respiration in California’s Sierra Nevada oldgrowth, mixed-conifer forests. Using portable and automated soil respiration sampling units, we measured soil respiration rate (SRR) in three dominant patch types: closed canopy (CC), ceanothus-dominated patches (CECO), and open canopy (OC). SRR varied significantly among the...
We compared the abundance, diversity, and composition of truffles in riparian and upland areas within a
mixed-conifer forest of the Sierra Nevada of California. We sampled for truffles in a single watershed over two seasons
(spring and summer) and 4 years to determine whether truffles were more abundant and diverse...
In many western North American forests, prescribed burning and mechanical thinning are widely used to reduce
fuels and restore stand conditions after a century of fire suppression. Few studies have followed the relative impacts
of these treatments on the production and consumption of truffles in forest ecosystems, particularly in the...
We examined the nest-tree preferences of northern flying squirrels (Glaucomys sabrinus) in an old-growth,
mixed-conifer and red fir (Abies magnifica) forest of the southern Sierra Nevada of California. We tracked 27
individuals to 122 nest trees during 3 summers. Flying squirrels selected nest trees that were larger in diameter
and...
Prescribed burning and mechanical thinning are used to manage fuels within many western North American forest ecosystems, but few studies have examined the relative impacts of these treatments on forest wildlife. We sampled northern flying squirrels (Glaucomys sabrinus) and microhabitat variables in burned, thinned and control stands of mixed-conifer forest...
The purpose of this study was to estimate the portion of an ectomycorrhizal (ECM) fungi root
community with a hypogeous fruiting habit. We used molecular methods (DNA sequence analysis of the
internally transcribed spacer [ITS] region of rDNA) to compare three viewpoints: ECM fungi on the roots in a
southern...
The diets of a fungal specialist, northern flying squirrel (Glaucomys sabrinus (Shaw, 1801)), and a dietary generalist,
lodgepole chipmunk (Neotamias speciosus (Merriam, 1890)), were examined in the old-growth, mixed-conifer forest
at the Teakettle Experimental Forest in California’s southern Sierra Nevada. Spores of fungi were identified from fecal
pellets collected from...
The effect of disturbance on the resistant propagule community (RPC) of ectomycorrhizal
fungi has been given relatively little attention. In this study we investigate the effects of
heat, one important factor of fire disturbances, on the ability of ectomycorrhizal RPC fungi
to colonize Pinus jeffreyi seedlings in greenhouse bioassays. Prior...
In this study we analyzed the spatial
structure of ectomycorrhizal fungi present in the soils
as resistant propagules (e.g. spores or sclerotia) in
a mixed-conifer forest in the Sierra Nevada, California.
Soils were collected under old-growth Abies spp.
stands across approximately 1 km and bioassayed with
seedlings of hosts that...
Mortality patterns in an old-growth, mixed-conifer forest, in the absence of wildfire, were investigated at the Teakettle Experimental Forest from 2000 to 2002. We tested the hypothesis that after a century of fire suppression, pathogen- and insect-associated mortality (between episodic droughts) would be significantly greater on ingrowth trees (i.e., smaller-diameter,...
Fire suppression has significantly increased canopy cover, litter depth, and stem density in many
western forests, altering microsite conditions that affect tree seedling establishment. We conducted studies in a
mixed-conifer forest in the Sierra Nevada, California, to determine relationships between established understory
trees and microsite quality, and to examine the...
The influence of fire and climate events on age structure of different species was examined in
old-growth mixed conifer in the southern Sierra Nevada. Within a 48-ha stem-mapped sample area, after a
mechanical thinning, all stumps were examined for fire scars and 526 stumps were cut to ground level and...
Like much of the western United States, California’s forest has been severely altered by a century of fire suppression. The Sierra Nevada’s largest forest type, mixed conifer, which is primary habitat for more vertebrate species than any other Californian forest community, historically burned every 12–17 years. In 1894, John Muir...
With fire suppression, many western forests are expected to have fewer gaps
and higher stem density of shade-tolerant species as light competition becomes a more
significant influence on stand pattern and composition. We compared species composition,
structure, spatial pattern, and environmental factors such as light and soil moisture between
two...
• Understanding spatial and temporal patterns present in ectomycorrhizal fungal
community structure is critical to understanding both the scale and duration of
the potential impact these fungi have on the plant community. While recent studies
consider the spatial structure of ectomycorrhizal communities, few studies consider
how this changes over time....
Diatom remains indicate the oceanic Ge/Si ratio (μmol/mol) has varied temporally, ranging from Miocene values of 0.9 to Last Glacial Maximum (LGM) values of 0.55, with the present value of 0.69. These ratios lie between those for the primary sources for these elements: continental weathering (Ge/Si = 0.5) and hydrothermal...
During 1997–1998, we investigated the influence of both the relative abundance of truffles, preferred food
items, and microhabitat structure on the occurrence of northern flying squirrels (Glaucomys sabrinus Shaw) in old-growth
forest habitat of the Sierra Nevada Range, U.S.A. Following live-trapping sessions, we searched the forest floor
for truffle diggings...
Prescribed burning and mechanical thinning are used to manage fuels within
many western North American forest ecosystems, but few studies have examined the relative
impacts of these treatments on forest wildlife. We sampled northern flying squirrels
(Glaucomys sabrinus) and microhabitat variables in burned, thinned and control stands of
mixed-conifer forest...
In many western North American forests, prescribed burning and mechanical thinning are widely used to reduce
fuels and restore stand conditions after a century of fire suppression. Few studies have followed the relative impacts
of these treatments on the production and consumption of truffles in forest ecosystems, particularly in the...
In Sierra Nevada forests, shrubs are considered strong soil moisture competitors with regenerating trees, reducing seedling establishment, and
slowing growth. Recent studies, however, suggest that in some circumstances shrubs can facilitate tree establishment and growth by modifying
harsh microclimate conditions; increasing acquisition of water, carbon, and/or nutrients via shared mycorrhizal...
Marine and terrestrial ecologists rarely exchange information, yet comparing research from both sides of the land–sea boundary holds great potential for improving our understanding of ecological processes. For example, by comparing the interaction between tiger sharks (Galeocerdo cuvier) and dugongs (Dugong dugon) to that between gray wolves (Canis lupus) and...
• Compression wood has been shown to reduce stem permeability, but it is not known to what extent it affects leaf‐level processes. Here, we report whole‐plant hydraulic properties of Douglas‐fir (Pseudotsuga menziesii) seedlings induced to form varying amounts of compression wood.
• Seedlings were grown under three bending treatments to...
Most higher plants have evolved with an obligatory symbiotic relationship with my corrhizal fungi. Epigeous mycorrhiza formers have their spores dispersed by air currents, but hypogeous mycorrhizal fungi are dependent upon small mammals as primary vectors of spore dissemination. Mammalian mycophagists defecate within the coniferous forest ecosystem, spreading the viable...
Despite its widespread use, forest health is frequently used without a clear definition, making its application to forest management difficult. Where the term has been defined (McIntire 1988, Monnig and Byler 1992, USDA Forest Service 1992, USDA Forest Service I993a), alternative definitions and viewpoints of forest health have not been...
Mortality patterns in an old-growth, mixed-conifer forest, in the absence of wildfire, were investigated at the Teakettle Experimental Forest from 2000 to 2002. We tested the hypothesis that after a century of fire suppression, pathogen- and insect-associated mortality (between episodic droughts) would be significantly greater on ingrowth trees (i.e., smaller-diameter,...
Successful fire exclusion in the 20th century has created severe fire problems across the West. Not every forest is at risk of
uncharacteristically severe wildfire, but drier forests are in need of active management to mitigate fire hazard. We summarize a
set of simple principles important to address in fuel...
Fire suppression has increased fuel loads and fuel continuity in mixed-conifer ecosystems, resulting in forest structures
that are vulnerable to catastrophic fire. This paper models fire behaviour in a mixed-conifer forest and investigates how
silvicultural and fuels treatments affect potential fire behaviour. The computer program FARSITE was used to spatially...
Mechanical thinning and prescribed fire are widely used to restore western forests after a century of fire suppression, yet we know little about
how these treatments affect understory communities where plant diversity is highest. We followed understory plants and environmental factors in
old-growth, Sierran mixed conifer for two pre-treatment and...
Soil respiration is a major pathway for carbon cycling in terrestrial ecosystems yet little is known about its response to natural and
anthropogenic disturbances. This study examined soil respiration response to prescribed burning and thinning treatments in an old-growth, mixed-conifer
forest on the western slope of the Sierra Nevada Mountains....
Understanding the relative influence of fuels and climate on wildfires across the Rocky Mountains is necessary to predict how fires may respond
to a changing climate and to define effective fuel management approaches to controlling wildfire in this increasingly populated region. The idea
that decades of fire suppression have promoted...
Western United States forest wildfire activity is widely thought to have increased in recent decades, yet neither the extent of recent changes nor the degree to which climate may be driving regional changes in wildfire has been systematically documented. Much of the public and scientific discussion of changes in western...
Studies of the effects of climate change on forests have focused on the ability of species to tolerate temperature
and moisture changes and to disperse, but they have ignored the effects of disturbances caused by climate change
(e.g., Ojima et al. 1991).Yet modeling studies indicate the importance of climate effects...
Nitrogen is a limiting resource in many temperate forests and nitrogen-fixing plants are usually limited to the early stages of post-disturbance succession. In fire-dependent Sierra Nevada forests, however, Ceanothus cordulatus is relatively abundant even in old-growth forest conditions which are at least partly maintained by fire. We conducted a field...
In the Sierra Nevada, distributions of forest tree species are largely controlled by the soil-moisture balance. Changes in temperature or precipitation as a result of increased greenhouse gas concentrations could lead to changes in species distributions. In addition, climatic change could increase the frequency and severity of wildfires. We used...
We used reverse time capture-mark-recapture models to describe associations between rate of population change (λ) and climate for northern spotted owls (Strix occidentalis caurina) at six long-term study areas in Washington and Oregon, USA. Populations in three of six areas showed strong evidence of declining populations, while populations in two...
Intraexciton transitions in semiconductor quantum wells are modulated by strong and tunable few-cycle terahertz pulses. Time-resolved terahertz-pump and optical-probe measurements demonstrate that the 1s heavy-hole and light-hole exciton resonances undergo large-amplitude spectral modulations when the terahertz radiation is tuned near the 1s–2p intraexciton transition. The strong nonlinear optical transients exhibit...
Persistent, long‐lived, stationary sites of excessive mantle melting are called hotspots. Hotspots leave volcanic trails on lithospheric plates passing across them. The global constellation of fixed hotspots thus forms a convenient frame of reference for plate motions, through the orientations and age distributions of volcanic trails left by these melting...
Research has found an upward trend in impulse buying in general, and impulse buying is frequently foreseen among mall shoppers. Impulse purchases account for over $4 billion in annual sales in the U.S. (Mogelonsky, 1998). Retailers have found that over 50 percent of mall shoppers purchase on impulse (Nichols et...
Over the last three decades the first-order correlation in morphology and orientation of seamount trails
has been called upon to support the concept of a ‘‘fixed’’ Pacific hot spot frame of reference and to explain
the Hawaii-Emperor bend (HEB) by a dramatic change in Pacific plate motion. In this paper,...
The concept of sustainable resource management can be applied at multiple scales.
Monitoring is an essential component of sustainable natural resource management
schemes, and as we begin to confront the need to manage natural resources at the
global scale, the importance of monitoring at the global scale is also growing....
During the summers of 1987 and 1988, 77 near-surface satellite-tracked drifters were deployed in or near cold filaments near Point Arena, California (39ºN), and tracked for up to 6 months as part of the Coastal Transition Zone (CTZ) program. The drifters had large drogues centered at 15 m, and the...
The first three years of SeaWiFS data (1997-2000) provide the most complete quantification to date of chlorophyll seasonal variability along the full latitudinal extent of the four major eastern boundary currents (EBCs). Comparisons to previously published chlorophyll seasonal climatologies deduced from the relatively sparse coverage provided by the Coastal Zone...
Paleoclimate records from glacial Indian and Pacific oceans sediments document millennial-scale fluctuations of subsurface dissolved oxygen levels and denitrification coherent with North Atlantic temperature oscillations. Yet the mechanism of this teleconnection between the remote ocean basins remains elusive. Here we present model simulations of the oxygen and nitrogen cycles that...
Every year, from December to April, anthropogenic haze spreads over most of the North Indian Ocean, and South and Southeast Asia. The Indian Ocean Experiment (INDOEX) documented this Indo-Asian haze at scales ranging from individual particles to its contribution to the regional climate forcing. This study integrates the multiplatform observations...
Ten years of sea-surface height (SSH) fields constructed from the merged TOPEX/Poseidon (T/P) and ERS-1/2 altimeter datasets are analyzed to investigate mesoscale variability in the global ocean. The higher resolution of the merged dataset reveals that more than 50% of the variability over much of the World Ocean is accounted...
Applying concepts from the behavioral complexity literature (Ashby, 1952; Denison, Hooijberg, and Quinn, 1995) we examine if supply managers’ multiple roles and the ability to shift among these roles is related to their interpersonal relationship with their key contact within the strategic suppliers’ organization and ultimately with the firm-to-firm relationship....
The existence of a distinct coastal zone is confirmed in Lake Tahoe (California-Nevada) by horizontal transects measuring chlorophyll and temperature simultaneously. Creation of the coastal region is influenced by bottom topography, the nature of the surface wind stress, and the difference between physical processes occurring within a Rossby radius of...
Associations between the golden metallic beetle, Buprestis aurulenta L., and wood-destroying fungi were explored with adult beetles collected from log decks. A variety of fungi were isolated from the beetle bodies by four methods. A total of 863 isolations were made from 59 females and 21 males. There was no...
Seedlings of western redcedar (Thuja plicata Donn ex. D. Don), western hemlock (Tsuga heterophylla (Raf.) Sarg.), and Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) were transplanted into soils with low and high levels of available NO3 – (and total N). Current-year foliage was sampled after 10 weeks to determine the effect of...
Concentrations of 14 chemical elements (Al, B, C, Ca, Cu, Fe, K, N, Mg, Mn, Na, P, S, Zn) were measured in wood and bark of 126 sample trees representing different stages of decomposition in three major tree species of northwestern Russia: Scots pine (Pinus sylvestris L.), Norway spruce (Picea...
The quality of lumber and veneer recovered from logs of Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) is directly influenced by the maximum limb size attained on the crop tree. Because limb sizes are influenced by standdensity regimes, a need has arisen for quantitative tools that link a wide array of silvicultural...
We characterized the structure and composition of unmanaged riparian forests in three river basins in Oregon’s coastal mountains. Our objective was to evaluate stand attributes at three spatial scales: streamside (site), drainage network (stream order), and basin (subregion). Data on basal area, species composition, snag density, canopy cover, and tree...
The interactive impact of overstory canopy closure, understory brush control, and simulated white-tailed deer (Odocoileus virginianus Zimmermann) herbivory (i.e., clipping) on growth and survival of underplanted white pine (Pinus strobus L.) seedlings was examined. Clipping was conducted in April 1996 and 1997 at three intensities (control, 0% previous year’s growth...
Alternatives to clear-cutting are being implemented to increase biodiversity of managed forests in the Pacific Northwest. Lichens are an integral component of old growth, but lichen biomass develops slowly in forests. We evaluated the long-term potential of live tree retention for lichen conservation in Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) forests....
Green tree retention, a practice based on ecosystem science, has been integrated into forest management as a working hypothesis, requiring research and monitoring to quantify its effects. We undertook a retrospective study of natural, two-aged forest stands on the Willamette National Forest to provide preliminary estimates of the effects of...
There is concern that the conifer component of mixed conifer-deciduous forests in the Great Lakes region is on the decline, possibly the result of insufficient conifer regeneration. Limitations on conifer regeneration that occur during the first 18 months of seedling emergence and establishment were examined for Abies balsamea (L.) Mill....
We measured surface soil (0–15 cm) C and N pools and processes inside and outside an area that had been trenched 13 years earlier in an old-growth conifer forest (>450 years) to assess the long-term impacts of reduced root inputs on C and N turnover. Trenching, combined with frequent clipping...
This paper reports the findings from a study made of the potential financial returns from nine alternative silvicultural prescriptions applied to four case-study stands of second growth in coastal British Columbia. The objectives were to compare prescriptions based on partial cutting with conventional clear-cutting and to explore the effects of...
Diseased and healthy Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) were identified at two black-stain root disease centers, caused by Leptographium wageneri var. pseudotsugae Harrington & Cobb, in the Oregon Coast Range near Coos Bay. Phloem and sapwood near the root collar were sampled monthly for 1 year, whereas roots were sampled...
Several hypotheses about the relationships among individual tree growth, tree leaf area, and relative tree size or position were tested with red spruce (Picea rubens Sarg.) growing in uneven-aged, mixed-species forests of south-central Maine, U.S.A. Based on data from 65 sample trees, predictive models were developed to (i) estimate the...
A model was developed to predict the severity of dwarf mistletoe (Arceuthobium tsugense (Rosendahl) G.N. Jones) in western hemlock trees (Tsuga heterophylla (Raf.) Sarg.) that developed within forests of Southeast Alaska that experienced near-catastrophic windthrow in the late 1800s. The model suggests that the degree of dwarf mistletoe severity on...
The current spruce bark beetle (Dendroctonus rufipennis Kirby) epidemic in interior Alaska is leaving large expanses of dead spruce with little spruce regeneration. Many of these areas are habitat for moose (Alces alces). To establish spruce regeneration and improve browse production for moose, paper birch (Betula papyrifera Marsh), willow (Salix...
Although ecosystem management techniques are designed to enhance species diversity in managed forests, no comprehensive study has been conducted to evaluate effects of such techniques on diversity and productivity of hypogeous fungi (truffles). During this study, truffles were collected in a 55- to 65-year-old Douglas-fir forest from March 1993 through...
We used a new model, STANDCARB, to examine effects of various treatments on carbon (C) pools in the Pacific Northwest forest sector. Simulation experiments, with five replicates of each treatment, were used to investigate the effects of initial conditions, tree establishment rates, rotation length, tree utilization level, and slash burning...