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In ponderosa pine forests of western North America, wildfires are becoming more frequent and affecting larger areas, while prescribed fire is increasingly used to reduce fuels and mitigate potential wildfire severity. Both fire types leave trees that initially survive their burn injuries, but will eventually die. Predicting delayed tree mortality has received considerable research attention to aid in post-fire planning and management. The amount of crown scorched is recognized as the most useful variable for discriminating between trees that live or die, but models gain discrimination with additional variables such as bole scorch, bud or cambium necrosis, and post-fire bark beetle attack (Coleoptera: Curculionidae: Scolytinae). Here, logistic regression was used to determine what fire-injury variables are most associated with red turpentine beetle (RTB; Dendroctonus valens LeConte), or western pine beetle (WPB; D. brevicomis LeConte) attack within three years post-fire. This was tested on 7343 ponderosa pine representing a wide diameter range from 18 wild and prescribed fires in Oregon and Washington, and repeated on a subset of 884 large trees >53.3 cm diameter. Bole scorch height was most associated with RTB or WPB attack on trees across all diameters, but model predictive ability was poor, whereas for pines >53.3 cm, the models provided moderate discrimination for predicting attack by each beetle. In addition, mortality models using crown scorch proportion and bole scorch proportion were compared to models with an additional variable for RTB, or WPB attack in year one, or attack by either beetle in year one, or year three. Models including any one of these beetle variables outperformed the models using just bole scorch and crown scorch proportions. For both tree diameter groups, the models including RTB year one performed similar to, or better than models with any other beetle variable, and are preferred for predicting delayed mortality because the RTB attack functions as an additional tree injury indicator similar to cambium kill, not captured by the bole scorch proportion, or crown scorch proportion variables. Furthermore, RTB attack can be assessed within the first year post-fire, and is much faster and easier to evaluate than direct sampling of cambium necrosis.

The lethal temperature limit is 60 degrees Celsius (°C) for plant tissues, including trees, with lower temperatures causing heat stress. As fire injury increases on tree stems, there is an accompanying rise in tissue ethanol concentrations, physiologically linked to impaired mitochondrial oxidative phosphorylation energy production. We theorize that sublethal tissue temperatures of 30°C to 60°C cause physiological changes to (a) oxygen supply, (b) membrane function, or (c) enzyme activity that individually or simultaneously create stress by impairing aerobic respiration and inducing ethanol synthesis. Accumulating ethanol dissipates via diffusion, sapflow, and metabolism, but the ability of these processes to decrease ethanol depends on what temperatures and physiological stress mechanism(s) the tissues and whole trees experience. The synthesis and dissipation interactions determine postfire tissue ethanol concentrations. Wildfire trends positively with temperature and drought, and all are projected to increase in western US forests and elsewhere globally, increasing the importance of understanding tree sublethal heat stress from fire.

Phytophthora ramorum, cause of “sudden oak death” or SOD, has had significant impacts on composition and structure in coastal forests of central and northern coastal California and southwestern Oregon. Despite the proximity of susceptible coast live oak (Quercus agrifolia) forests to densely populated urban areas, the impacts of SOD on their fuels have not been studied. We sampled surface fuels and vegetation structure in 16 plots in both SOD-caused gaps and intact stands (32 plots total) across two parks in the East Bay Regional Park District, east of San Francisco Bay. Plots were selected from a set of randomly placed pre-existing locations used in determining the disease distribution and intensity across the park system. Among the vegetation characteristics examined, only coast live oak basal area and live and dead tree density, canopy cover and maximum forb height differed between SOD created gap plots and adjacent intact forest plots. However, surface fuels such as vegetation cover, litter cover, wood cover, duff depth, fuels height, ladder fuels abundance, 1 h, 10 h, 100 h, and 1000 h fuels were greater in gap plots than intact forest plots. Although no fire behavior models were run, surface fuels suggest SOD created gaps may facilitate passive crown fire due to increased ladder and other fuels. This study represents a spatially explicit (gap focused) point-in-time estimate of surface fuels that will continue to change through time as disease progresses through these stands causing vegetation changes as fuels accumulate and decompose.

Phellinus sulphurascens (previously the Douglas-fir form of Phellinus weirii) is an important native pathogen causing laminated root rot in forests of western North America. Visual crown symptoms, or attacks by bark or ambrosia beetles appear only during advanced stages of the disease with extensive infection in the lower bole. Ethanol synthesis is one of many physiological responses in tree tissues stressed by pathogens. Ethanol, acetone and other volatiles from root tissues of healthy and diseased trees were analyzed using headspace gas chromatography. Xylem and phloem from 20 diseased trees at two western Oregon sites contained higher concentrations of ethanol, acetone, or other headspace volatiles than 20 healthy trees on one or more dates in September, November, or the following May. Root cross-sections from eight diseased trees were sampled along perpendicular transects and found to contain extremely variable ethanol concentrations, with highest xylem quantities in a 0–2 cm zone outside the infection boundary and lowest amounts inside the infection. Acetone concentrations were the opposite. Logistic regression models were built and tested to determine which volatiles could predict diseased trees. A model using xylem ethanol concentrations as the only parameter was selected and validated with measurements from 80 trees on the edges of P. sulphurascens infection centers at two different western Oregon sites. This model successfully predicted trees with laminated root rot (78% overall correct classification and 68% for known diseased trees), but worked best for those with infections observed in both root cores and the root collar (100% correct). Early detection of P. sulphurascens infected trees remains a challenge. Our ethanol analysis method is useful for research, but provides limited benefits for identifying individual P. sulphurascens hazard trees, or for extensive ground surveys in the forest. Whether ethanol is released to the atmosphere in sufficient quantities to confirm infection before the late appearance of crown symptoms, or bark beetles remains unknown. If it is, then development of sensors capable of tree side detection requiring minimal tissue sampling would be useful in managing this disease. We also propose a mechanism for how ethanol with host monoterpenes could play a central role in pioneering bark beetle primary host selection of trees infected with this pathogen.

Yellow-cedar, Callitropsis nootkatensis, is prevalent in coastal forests of southeast Alaska, western Canada, and inland forests along the Cascades to northern California, USA. These trees have few microbial or animal pests, attributable in part to the distinct groups of biologically active secondary metabolites their tissues store for chemical defense. Here we summarize the new yellow-cedar compounds identified and their biological activities, plus new or expanded activities for tissues, extracts, essential oils and previously known compounds since the last review more than 40 years ago. Monoterpene hydrocarbons are the most abundant compounds in foliage, while heartwood contains substantial quantities of oxygenated monoterpenes and oxygenated sesquiterpenes, with one or more tropolones. Diterpenes occur in foliage and bark, whereas condensed tannins have been isolated from inner bark. Biological activities expressed by one or more compounds in these groups include fungicide, bactericide, sporicide, acaricide, insecticide, general cytotoxicity, antioxidant and human anticancer. The diversity of organisms impacted by whole tissues, essential oils, extracts, or individual compounds now encompasses ticks, fleas, termites, ants, mosquitoes, bacteria, a water mold, fungi and browsing animals. Nootkatone, is a heartwood component with sufficient activity against arthropods to warrant research focused toward potential development as a commercial repellent and biopesticide for ticks, mosquitoes and possibly other arthropods that vector human and animal pathogens.

For herbivores, nutrient intake is limited by the relatively low nutritional quality of plants and high concentrations of potentially toxic defensive compounds (plant secondary metabolites [PSMs]) produced by many plants. In response to phytochemical challenges, some herbivores selectively forage on plants with higher nutrient and lower PSM concentrations relative to other plants. Pygmy rabbits (Brachylagus idahoensis) are dietary specialists that feed on sagebrush (Artemisia spp.) and forage on specific plants more than others within a foraging patch. We predicted that the plants with evidence of heavy foraging (browsed plants) would be of higher dietary quality than plants that were not browsed (unbrowsed). We used model selection to determine which phytochemical variables best explained the difference between browsed and unbrowsed plants. Higher crude protein increased the odds that plants would be browsed by pygmy rabbits and the opposite was the case for certain PSMs. Additionally, because pygmy rabbits can occupy foraging patches (burrows) for consecutive years, their browsing may influence the nutritional and PSM constituents of plants at the burrows. In a post hoc analysis, we did not find a significant relationship between phytochemical concentrations, browse status, and burrow occupancy length. We concluded that pygmy rabbits use nutritional and chemical cues while making foraging decisions.

Tree mortality from temperature-driven drought is occurring in forests around the world, often in conjunction with bark beetle outbreaks when carbon allocation to tree defense declines. Physiological metrics for detecting stressed trees with enhanced vulnerability prior to bark beetle attacks remain elusive. Ethanol, water, monoterpene concentrations, and composition were examined in the phloem and sapwood of drought-stressed Aleppo pine (Pinus halepensis Mill.) freshly attacked by mature Mediterranean pine shoot beetles (Tomicus destruens (Wollaston, 1865)) and in neighboring unattacked trees. The attacked trees were more water-stressed and contained, on average, 2.1 and 2.4 times more ethanol in the phloem and sapwood, respectively, than the neighboring attack-free trees. This response is consistent with the known attraction of T. destruens to ethanol. Most monoterpene concentrations in the phloem, but not sapwood, were greater in tissues of attacked trees, whereas compositional differences were minor between the two tree groups for both tissues. Tissue water content explained much of the variation in phloem monoterpene concentrations, which increased as water in the phloem declined, suggesting that higher constitutive quantities existed in the more stressed trees prior to the attacks. Monoterpenes may have contributed to host tree selection by T. destruens, but their potential influence is considered less important than that of ethanol based on beetle responses to these compounds in previous trapping studies. This is the first report of elevated ethanol concentrations in tissues of trees experiencing natural drought stress and suggests that ethanol measurements in severely water-stressed trees may allow early detection of those most vulnerable to bark beetle attack.

Elicitin-mediated acquisition of plant sterols is required for growth and sporulation of Phytophthora spp. This study examined the interactions between elicitins, sterols, and tannins. Ground leaf tissue, sterols, and tannin-enriched extracts were obtained from three different plant species (California bay laurel, California black oak, and Oregon white oak) in order to evaluate the effect of differing sterol/tannin contents on Phytophthora ramorum growth. For all three species, high levels of foliage inhibited P. ramorum growth and sporulation, with a steeper concentration dependence for the two oak samples. Phytophthora ramorum growth and sporulation were inhibited by either phytosterols or tannin-enriched extracts. High levels of sterols diminished elicitin gene expression in P. ramorum; whereas the tannin-enriched extract decreased the amount of ‘functional’ or ELISA-detectable elicitin, but not gene expression. Across all treatment combinations, P. ramorum growth and sporulation correlated strongly with the amount of ELISA-detectable elicitin (R 2 = 0.791 and 0.961, respectively).

Ethanol in sapwood was analyzed along vertical transects, through small spot cankers and larger basal cankers, of Phytophthora ramorum-infected stems of Quercus agrifolia at three sites in California. Trees with large basal cankers, known to attract scolytid beetles, had a 4.3 times higher ethanol level than trees with spot cankers that attract fewer beetles. Ethanol concentrations inside cankers, where scolytid beetles preferentially attack, varied by about four orders of magnitude among samples, with a median level of 16.0 μg.g(-1) fresh mass. This concentration was 4.3 and 15.5 times greater, respectively, than the concentrations at 1 cm or 15-30 cm outside the canker boundaries. In the laboratory, we demonstrated that ethanol escaped through the bark of a Q. garryana log just 3 days after it was added to the sapwood. At the three study sites, traps baited with ethanol captured more Xyleborinus saxesenii, Pseudopityophthorus pubipennis, and Monarthrum dentiger (all Coleoptera: Curculionidae: Scolytinae) than traps baited with ethanol plus (-)-α-pinene, or ethanol plus 4-allylanisole (4AA). Logs of Q. agrifolia with a 50 % ethanol solution added to the sapwood were placed at the study sites, with or without additional bark treatments above the ethanol. The number of scolytid beetle gallery holes above the ethanol-infused sapwood was 4.4 times greater than that on the opposite side of the log where no ethanol was added. Attachment of ultra-high release (-)-α-pinene pouches to the bark surface above the 50 % ethanol solution reduced scolytid attacks to a density of 19.1 % that of logs without this treatment. We conclude that ethanol in P. ramorum cankers functions as a primary host attractant for scolytid beetles and is an important link in colonization of these cankers and accelerated mortality of Q. agrifolia. The results of this research shed light on the chemical ecology behind the focused scolytid attacks on P. ramorum-infected coast live oaks, and lay the groundwork for future efforts to prolong the survival of individual trees of this keystone species.

The brine shrimp (Artemia salina) bioassay was used to screen 211 methanol extracts from 128 species of Pacific Northwest plants in search of general cytotoxic activity. Strong toxicity (LC50 1000 µg/ml). Our subsequent studies of conifer heartwoods with strong activity confirm the assay’s value for identifying new investigational leads for materials with insecticidal and fungicidal activity.

Climatic changes are predicted to significantly affect the frequency and severity of disturbances that shape forest ecosystems. We provide a synthesis of climate change effects on native bark beetles, important mortality agents of conifers in western North America. Because of differences in temperature-dependent life-history strategies, including cold-induced mortality and developmental timing, responses to warming will differ among and within bark beetle species. The success of bark beetle populations will also be influenced indirectly by the effects of climate on community associates and host-tree vigor, although little information is available to quantify these relationships. We used available population models and climate forecasts to explore the responses of two eruptive bark beetle species. Based on projected warming, increases in thermal regimes conducive to population success are predicted for Dendroctonus rufipennis (Kirby) and Dendroctonus ponderosae Hopkins, although there is considerable spatial and temporal variability. These predictions from population models suggest a movement of temperature suitability to higher latitudes and elevations and identify regions with a high potential for bark beetle outbreaks and associated tree mortality in the coming century.

† Background and Aims Previous measurements of conifer alkaloids have revealed significant variation attribu­ table to many sources, environmental and genetic. The present study takes a complementary and intensive, common garden approach to examine genetic variation in Pinus ponderosa var. ponderosa alkaloid production. Additionally, this study investigates the potential trade-off between seedling growth and alkaloid production, and associations between topographic/climatic variables and alkaloid production. † Methods Piperidine alkaloids were quantified in foliage of 501 nursery seedlings grown from seed sources in west-central Washington, Oregon and California, roughly covering the western half of the native range of ponder­ osa pine. A nested mixed model was used to test differences among broad-scale regions and among families within regions. Alkaloid concentrations were regressed on seedling growth measurements to test metabolite allo­ cation theory. Likewise, climate characteristics at the seed sources were also considered as explanatory variables. † Key Results Quantitative variation from seedling to seedling was high, and regional variation exceeded variation among families. Regions along the western margin of the species range exhibited the highest alkaloid concen­ trations, while those further east had relatively low alkaloid levels. Qualitative variation in alkaloid profiles was low. All measures of seedling growth related negatively to alkaloid concentrations on a natural log scale; however, coefficients of determination were low. At best, annual height increment explained 19.4 % of the vari­ ation in ln(total alkaloids). Among the climate variables, temperature range showed a negative, linear association that explained 41.8 % of the variation. † Conclusions Given the wide geographic scope of the seed sources and the uniformity of resources in the seed­ lings’ environment, observed differences in alkaloid concentrations are evidence for genetic regulation of alka­ loid secondary metabolism in ponderosa pine. The theoretical trade-off with seedling growth appeared to be real, however slight. The climate variables provided little evidence for adaptive alkaloid variation, especially within regions.

In this study, we investigated the effect of drought stress on ethanol production and accumulation in tissues from seedlings of three conifers (Douglas‐fir, lodgepole pine, and ponderosa pine) with increasing degrees of tolerance to drought stress, respectively. Significant ethanol accumulation was only observed in their aerial tissues when severely stressed (water \documentclass{aastex} \usepackage{amsbsy} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{bm} \usepackage{mathrsfs} \usepackage{pifont} \usepackage{stmaryrd} \usepackage{textcomp} \usepackage{portland,xspace} \usepackage{amsmath,amsxtra} \usepackage[OT2,OT1]{fontenc} \newcommand\cyr{ \renewcommand\rmdefault{wncyr} \renewcommand\sfdefault{wncyss} \renewcommand\encodingdefault{OT2} \normalfont \selectfont} \DeclareTextFontCommand{\textcyr}{\cyr} \pagestyle{empty} \DeclareMathSizes{10}{9}{7}{6} \begin{document} \landscape $\mathrm{potential}\,< -3.0$ \end{document} MPa or water \documentclass{aastex} \usepackage{amsbsy} \usepackage{amsfont...

Ethyl acetate extracts from heartwood of seven western conifer trees and individual volatile compounds in the extracts were tested for antimicrobial activity against Phytophthora ramorum. Extracts from incense and western redcedar exhibited the strongest activity, followed by yellow-cedar, western juniper, and Port-Orford-cedar with moderate activity, and no activity for Douglas-fir and redwood extracts. Chemical composition of the extracts varied both qualitatively and quantitatively among the species with a total of 37 compounds identified by mass spectrometry. Of the 13 individual heartwood compounds bioassayed, three showed strong activity with a Log(10) EC(50) less than or equal to 1.0 ppm (hinokitiol, thymoquinone, and nootkatin), three expressed moderate activity ranging from 1.0-2.0 ppm (nootkatol, carvacrol, and valencene-11,12-diol), four compounds had weak activity at 2.0-3.0 ppm [alpha-terpineol, valencene-13-ol, (+)-beta-cedrene, (-)-thujopsene], and three had no activity [(+)-cedrol, delta-cadinene, and methyl carvacrol]. All of the most active compounds contained a free hydroxyl group, except thymoquinone. The importance of a free hydroxyl was demonstrated by the tremendous difference in activity between carvacrol (Log(10) EC(50) 1.81 +/- 0.08 ppm) and methyl carvacrol (Log(10) EC(50)3.0 ppm). A field trial in California, showed that heartwood chips from redcedar placed on the forest floor for 4 months under Umbellularia californica (California bay laurel) with symptoms of P. ramorum leaf blight significantly limited the accumulation of P. ramorum DNA in the litter layer, compared with heartwood chips from redwood.

Phytophthora ramorum, causal agent of sudden oak death, is responsible for widespread oak mortality in California and Oregon, and has the potential to infect 100 or more species. Symptoms range from stem girdling and shoot blight to leaf spotting. In this study, we examined the physiological impacts of P. ramorum infection on Rhododendron macrophyllum. In stem-inoculated plants, photosynthetic capacity (Vcmax) significantly declined by ≈21% 3 weeks after inoculation in visibly asymptomatic leaves. By 4 weeks, after the development of significant stem lesions and loss in water transport capacity, water stress led to stomatal closure and additional declines in photosynthetic capacity. We also report the isolation, characterization, and biological activity of two P. ramorum elicitins. Both elicitins were capable of inducing a hypersensitive-like response in one incompatible (Nicotiana tabacum SR1) and three compatible hosts (R. macrophyllum, Lithocarpus densiflorus, and Umbellularia californica). Infiltration of leaves from all three compatible hosts with both P. ramorum elicitins caused significant declines in chlorophyll fluorescence (Fv /Fm). For all four species, the loss of photosynthetic capacity was directly proportional to H+ uptake and ethylene production, two common components of the hypersensitive response. This is the first report of elicitins causing photosynthetic declines in compatible hosts independent of plant water stress.

International audience; Key message Leyland cypress, an intergeneric hybrid, produces the same volatile heartwood compounds as its parental taxa, yellow-cedar and Monterrey cypress. However, the proportion of total sesquiterpenes and some of the individual components appear unique to their respective heartwoods.ContextLeyland cypress, xHesperotropsis leylandii is an intergeneric hybrid between yellow-cedar, Callitropsis nootkatensis, and Monterey cypress, Hesperocyparis macrocarpa. Their heartwoods are protected by bioactive compounds and rated very durable to durable for products used above ground. Several compounds in yellow-cedar and Monterrey cypress heartwoods are also active against various fungi, bacteria, human insect pests, and plant pathogens, whereas Leyland cypress heartwood has never been thoroughly investigated.AimsThe first aim for this study was to examine the volatile compounds in ethyl acetate extracts from the heartwood of all three tree species in Oregon. The second aim was to determine the extent Leyland cypress differs from its parental species, and further investigate any of its novel compounds for biological activity.MethodsEthyl acetate extracts of fresh heartwood were prepared for three trees of each species and analyzed by gas chromatography.ResultsThirty-three compounds were detected at 0.5 % or greater abundance across all species, and 23 were identified. Carvacrol was the major monoterpene and nootkatin the most abundant tropolone in all three species. Valencene 11, 12-diol and nootkatone topped the list of sesquiterpenes in yellow-cedar and Leyland cypress, respectively, whereas no sesquiterpenes were detected in Monterrey cypress. This appears to be the first report of tropolones hinokitiol, procerin, and nootkatin in Leyland cypress, α-thujaplicinol, pygmaein, and procerin in Monterrey cypress, and hinokitiol in yellow-cedar.ConclusionsLeyland cypress heartwood does not biosynthesize structurally unique compounds from those produced by its parental species, and is an unlikely source of novel biocides. However, the proportion of total sesquiterpenes and some of the individual components in Leyland cypress heartwood may distinguish it from the heartwood of its parental species.

Summary In this paper, we demonstrate that 140 mg/kg of essential oil from the wood of yellow-cedar, incense cedar, Port-Orford-cedar or western juniper strongly inhibits zoospore germination and hyphal growth of Phytophthora ramorum in culture. Four individual compounds in yellow-cedar heartwood were also tested. Zoospore germination was reduced to 0% with 10, 100 and 1000 mg/kg of nootkatin, carvacrol and valencene, respectively. Nootkatone was the least active compound, with 3.5% zoospore germination at 1000 mg/kg. Sporangia germination was 0% with 500 mg/kg of nootkatin or carvacrol. The disruption of the zoospore outer membrane and the loss of sporangial contents were often observed and indicative of sporicidal activity. Hyphal growth was inhibited by 99.9% with 50 mg/kg of nootkatin or 500 mg/kg of carvacrol, but growth resumed upon removing the inhibitors. The zoosporicidal activity of yellow-cedar heartwood shavings stored dry for approximately 10 years was consistent with the quantity of extractable compounds they contained. Thus, spreading fresh shavings or chips of yellow-cedar heartwood with appreciable higher concentrations of the active compounds, over areas in infection zones where spores might be difficult to control such as trails and parking lots used by hikers and bicyclists, might be useful as part of an integrated program to minimize P. ramorum spore distribution.

A total of 284 ponderosa pine growing near the southern edge of the Blue Mountains in eastern Oregon were categorized into one of three crown classes based on the degree of “tufted”, or “lion's tail” appearance of their branches, a potential symptom of black-stain root disease, then pushed over and their root systems examined for visual symptoms of disease. Only 23 (8.1%) were found to have more than a trace level of black-stain, annosum root disease, or both at about 38 cm below the root collar. Although there were many measurable differences in crown growth parameters among the three classes, they were not reliable for predicting the presence, or severity of root disease. Differences in crown morphology associated with these classes probably resulted from the combined effects of tree size, levels of resources available on site to support vigorous growth, especially water, and stresses that enhanced water deficits. The sapwood water content of diseased trees was 80.0% of the water content in healthy trees. Acetaldehyde, acetone, methanol, and ethanol concentrations, quantified in the headspace analysis of sapwood collected above the root collar prior to harvest, were all higher in trees with root disease compared to those without disease. Logistic regression models with 0–5 chemical explanatory variables were compared simultaneously by the practical information-theoretic approach to select the best model for predicting trees with root disease. The one selected contained only acetone fresh weight concentrations as an explanatory variable, and would facilitate increased rates of sapwood analysis in the laboratory. More importantly, acetone concentrations may function as useful markers to identify the most severely diseased trees for removal, or in general stand surveys to estimate the level of root disease when symptoms in the crown are lacking or confounded by other stresses.

Phellinus weirii causes laminated root rot (LRR), a major disease affecting growth and survival of Pseudotsuga menziesii (Douglas-fir) and other commercially important conifer species throughout the Pacific Northwest. Increasing tree vigor and resistance to pathogens through application of K fertilizer is a suggested disease management strategy and one we wished to test. Plots were established with Douglas-fir seedlings planted densely (12,000 seedlings ha−1) around stumps of LRR-killed trees on a harvested site west of the Cascade Range crest near Morton, Washington. Treatments, randomly assigned to plots, were: 224 kg K ha−1, 448 kg K ha−1, 224 kg K + 224 kg N ha−1, and a no-fertilizer control, with 11 replicates. Roots of seedlings receiving the K + N treatment showed the only increase in phenol/sugar (P/S) ratios after one growing season, owing to a reduction in sugar concentrations. Although increases in P/S ratios are negatively correlated with fungal infection rates, the LRR mortality for all fertilizer treatments, including the K + N, was similar to the mortality on the no-fertilizer plots 7 years post-treatment. For this study site we concluded that the single application of K or K + N to Douglas-fir at the rates tested were not an effective management strategy for LRR.

Stem segments from terminal leaders of Douglas-fir, Pseudotsuga menziesii (Mirb.) Franco, seedlings were sampled in mid-December when cambial cells were dormant. The residual, debudded leaders were resampled again in early May when the cambium was metabolically active. May stems had higher constitutive ethanol concentrations than December stems. This was not the result of cambial hypoxia generated by rapid spring respiration rates, because when aerobic respiration was stimulated by incubating the stems in air at 30 degrees C ethanol production was induced in December, but not in May. Rapid respiration rates at 30 degrees C may have depleted O(2) supplies and induced ethanol production in December stems because dormant, thick-walled cambial cells may be less permeable to CO(2) and O(2), compared with metabolically active, thin-walled cambial cells in May. December stem segments incubated in a N(2) atmosphere at 30 degrees C synthesized 1.8 times more ethanol than segments from May, most likely because spring growth had reduced the soluble sugars available for fermentation. CO(2) efflux from May stems (after 5.5 h of incubation at 30 degrees C) was equal to December stems per unit volume, but greater than December stems per unit surface area. N(2)-induced ethanol concentrations were positively related with CO(2) efflux per unit volume, indicating that rapidly respiring leaders can maintain rapid fermentation rates, provided soluble sugars are readily available. N(2)-induced ethanol and CO(2) efflux per unit volume declined with increasing leader diameter in both seasons, whereas there were no relationships between CO(2) efflux per unit surface area and diameter. Cambium physiology and phenology influence the induction of fermentation and concentrations of ethanol produced in terminal leaders of Douglas-fir, and probably other conifers as well. This needs to be considered when comparing fermentation among species, or comparing individuals from different seasons, or disparate ages within a species.

Douglas-fir growing on the western slopes of the Oregon Coast Range are experiencing an unprecedented outbreak of Swiss needle cast (SNC) caused by the fungus Phaeocryptopus gaeumannii. SNC can produce substantial physiological stress in host trees by reducing needle gas exchange and enhancing premature needle abscission, resulting in slower growth. Based on the frequent link between stressed trees and insect activity, we explored the potential influence of SNC on Douglas-fir beetle, Dendroctonus pseudotsugae, activity and some tree physiological parameters that may influence beetle attraction (i.e., constitutive ethanol and monoterpene contents of woody tissues) and host susceptibility (i.e., wound-induced resin flow). Woody tissue ethanol concentrations, wound-induced resin flow, and beetle attraction were all reduced as SNC severity increased. Although trees affected by SNC attracted fewer beetles, the number of attacks did not decline, the attacks were more likely to penetrate to sapwood depth, and the galleries were longer than in healthier trees, most likely due to a weakened oleoresin defense. However, there have been no current reports of increased Douglas-fir beetle activity on SNC stressed trees, and no rapid increases in beetle population numbers, or outbreaks associated with these diseased forests. SNC stressed trees may remain free from attacks because pioneering beetles have difficulty recognizing them as being stressed with low ethanol concentrations. Furthermore, beetle populations may not be increasing since stressed trees appear unsuitable for reproduction, as no eggs, larvae, or adult beetles were observed in excavated galleries on any attacked trees. However, if large volumes of host materials became available as a result of some catastrophic event (e.g. wildfire or wind-throw), and the beetles can reproduce successfully enough to increase population densities then the potential for a devastating outbreak of Douglas-fir beetle in SNC stressed trees might be exacerbated because they have compromised oleoresin defense systems, and may be killed with fewer beetle attacks.

Summary Current assessments of infection levels of Phaeocryptopus gaeumannii, the incitant pathogen of Swiss needle cast disease on Pseudotsuga menziesii, typically rely on surveys of abundance of fruit bodies on diseased needles. The relationship between this measure and internal fungal colonization is unknown. In this article, a series of experiments to determine whether ergosterol can be used to quantify P. gaeumannii internal colonization within Douglas-fir needles is reported. It was found that ergosterol content in seven commonly occurring Douglas-fir foliar fungi is proportionally related to biomass, and in P. gaeumannii this relationship is not affected by age of the culture. Furthermore, at four sites tested, P. gaeumannii was the most common fungus species isolated from Douglas-fir needles, accounting for approximately 50% of the isolations. Ergosterol content in these needles was best related to P. gaeumannii despite the presence of other fungi. The strong relationship between ergosterol and P. gaeumannii is attributed to its greater contribution to total fungal biomass compared with all other fungi present within Douglas-fir needles.

Lindgren multiple funnel traps were set up in pine forests of central Oregon to determine the response of scolytid bark beetles to ethanol and 4-allylanisole (4AA). Traps were baited with two release rates of ethanol (4.5 or 41.4 mg/hr) and three release rates of 4AA (0, 0.6, or 4.3 mg/hr) in a 2 x 3 factorial design. All traps also released a 1:1 mixture of alpha- and beta-pinene at 11.4 mg/hr. Of 13,396 scolytids caught, Dendroctonus valens made up 60%, Hylurgops spp. 18.5%, Ips spp. 16%, Hylastes spp. 1.8%, Ganthotrichus retusus 0.9%, and bark beetle predators another 2.8%. Increasing the release rate of ethanol in the absence of 4AA increased the number of most scolytid species caught by 1.5-3.7 times, confirming its role as an attractant. Ips latidens, Temnochila chlorodia, and clerid predators were exceptions and did not show a response to higher ethanol release rates. Release of 4AA at the lowest rate inhibited attraction of most scolytids, with a significant reduction in G. retusus, Hylastes macer, and Hylurgops porosus when compared to traps without 4AA. A high release rate of 4AA further inhibited responses for most beetles compared to low 4AA. Seven species were significantly deterred by high 4AA, including the latter three, and Hylastes longicollis, Hylastes nigrinus, Hylurgops reticulatus, and Ips latidens. Exceptions include Hylurgops subcostulatus, which was significantly attracted to both low and high 4AA, and I. pini, which was attracted to low and high 4AA in combination with low ethanol, but unaffected by either release of 4AA with high ethanol. Dendroctonus valens was significantly attracted to low 4AA and unaffected by high 4AA. Predators appeared to be less inhibited by 4AA than most bark beetles. Although 4AA can deter the attraction of some secondary bark beetles to ethanol in combination with alpha- and beta-pinene, this inhibition could be weakened for certain species by increasing ethanol release rates. 4-Allylanisole may have some utility for managing the behavior of secondary bark beetles sensitive to this compound.

Yields of 2,6-disubstituted piperidine alkaloids from ponderosa pine (Pinus ponderosa) foliage were compared for frozen, air- and oven-dried samples stored for 3 days and for 5 weeks. Oven-drying provided the most stable alkaloid yields, but biological variation was greater than the variation between the storage methods. Alkaloid yields were also compared for the classical liquid–liquid partitioning method and a solid-phase partitioning (SPP) method using Extrelut™ columns. Under proper conditions, both methods were reasonably accurate, but biological variation in alkaloid content was much greater than experimental variation from either extraction method. In order to optimize the SPP method, it was necessary to use chloroform rather than dichloromethane as the eluting solvent, and to rinse the column more than the manufacturer directs. The SPP method requires less solvent and time per sample, thus it may be preferable for ecological studies where numerous samples are required to detect differences against high background variation. Zinc dust treatment, to reduce possible alkaloid N-oxides in SPP extracts, failed to increase yields, suggesting the absence of such compounds. Copyright © 1999 John Wiley & Sons, Ltd.

Logs from the base of Douglas fir (Pseudotsuga menziesii) trees cut in October 1993 were randomly assigned to one of three treatment groups: (1) wet logs—cut from the fallen tree and left exposed to rain, (2) dry logs—cut from the fallen tree, placed on blocks, and protected from rain under a plastic tent, and (3) crown logs—left attached to the fallen tree with its branches intact and exposed to rain. The following May, ethanol concentrations were highest in the phloem and sapwood of wet logs (0.24 and 0.35 μmol/g fresh wt, respectively). Ethanol concentrations in tissues from dry and crown logs were similar to each other (ranging from 0.002 to 0.03 μmol/g fresh wt), but were significantly lower than in wet logs. It appears that rain absorbed by the outer bark of wet logs creates a barrier to gas exchange between living tissues and the atmosphere, which facilitates the development of hypoxic conditions necessary for ethanol synthesis and accumulation. Branches on crown logs exposed to rain help maintain low ethanol concentrations in the log tissues; we discuss several potential mechanisms to explain this response. By early September, the densities of Gnathothrichus spp. gallery entrance holes were high on wet logs (21.5/m2) and low on dry (2.5/m2) and crown logs (5.8/m2), indicating their preference for logs with higher ethanol concentrations. Protecting logs from rain will significantly reduce ethanol concentrations and the density of ambrosia beetle galleries. Leaving branches attached to logs will produce similar results, but its effectiveness may vary depending on the environmental conditions. Host selection by secondary scolytid beetles that use ethanol as a kairomone can be manipulated and possibly managed by controlling the production of ethanol in the host resource.

We fertilized individual, pole-size ponderosa pine trees at two low-quality sites and pine saplings at a relatively high-quality site, with ammonium nitrate. Six to 12 months later, we measured total %N and 2,6-disubstituted piperidine alkaloids in the foliage. The N additions raised foliar %N above deficiency levels (i.e., from 1.0–1.1% to 1.4–1.6%) at the low-quality sites, but did not elevate foliar %N in saplings at the higher quality site, where it was already (1.9%) well above critical levels. In control trees with foliar N below a threshold of 1.1%, we detected no more than trace levels of alkaloids, indicating that alkaloid production is highly constrained by N deficiency. The N additions increased mean concentrations of the predominant alkaloid, pinidine, at all three sites. Mean total alkaloid concentrations for fertilized trees at the two low-quality sites were 12 and 155 μg/g dry wt higher than controls (relative increases of 12× and 4.5×, respectively). For saplings at the high-quality site, the mean total increased by 584 μg/g dry wt (1.6×) with the N additions. Allocation of foliar N to alkaloids was highest in fertilized saplings (0.81%) compared to control saplings (0.53%). These findings demonstrate that foliar alkaloid concentrations can be increased by nitrogen fertilization of forest trees growing on both low- and high-quality sites. Fertilizing for the purpose of inhibiting potential herbivores may be more successful at higher quality sites where alkaloid levels are enhanced relative to food quality (foliar %N).

Douglas fir (Pseudotsuga menziesii), west of the Oregon Cascades, and ponderosa pine (Pinus ponderosa), east of the Cascades, were cut during the fall in conjunction with various forest management practices. Trees cut varied in size and age, and the stumps were exposed to disparate winter temperatures and precipitation patterns. Nevertheless, the stumps showed similar responses in their synthesis and accumulation of ethanol. The following spring, ethanol concentrations in above-ground tissues of both species ranged from 3 to 116 times higher than in their corresponding root tissues. We suggest that this difference results from the above-ground tissues being more hypoxic than roots because they were exposed to more water from precipitation and warmer temperatures. Ethanol concentrations in the above-ground tissues of ponderosa pine stumps were about two to six times higher than in Douglas fir, and root tissues from pine stumps usually contained more ethanol after anaerobic incubation than roots from Douglas fir. Ethanol and volatile terpenes released from stumps can attract various beetle species that not only vector root diseases, but can also damage or kill seedlings and saplings. Understanding the dynamics of ethanol synthesis and accumulation in stumps and slash might contribute to new alternatives for managing these insects.

Seedlings of Douglas-fir, Pseudotsuga menziesii (Mirb.) Franco, and ponderosa pine, Pinus ponderosa Dougl. ex Laws., were grown in a controlled environment and fertilized with nutrient solutions containing 150 ppm (+N), or 0 ppm nitrogen (−N). These treatments greatly altered seedling growth, and the concentrations of N and carbohydrates in their tissues. Metabolically active tissues, such as roots, incubated with a limited supply of O2 became hypoxic faster and synthesized more ethanol than less active tissues, such as needles. All tissues that were incubated for 4 h in N2 synthesized ethanol. Needles incubated in N2 and light had much lower quantities of ethanol than needles in N2 and dark, suggesting that O2 from photosynthetsis limited internal anoxia. Most tissues from +N seedlings synthesized greater quantities of ethanol in N2 anoxia than tissues from −N seedlings, probably because they were able to produce more enzymes with a greater availability of N. However, this increase in ethanol synthesis between N treatments was most pronounced in the phloem. Ethanol and soluble sugar concentrations were negatively related in needles and positively related in roots of N+ seedlings, but not −N seedlings. Starch concentrations had no effect on the amount of ethanol produced by any tissue. Regardless of N treatments, all tissues from ponderosa pine produced more N2-induced ethanol than Douglas-fir, in part because its tissues contained different concentrations of soluble sugars and N as a consequence of phenological differences between the species. However, ponderosa pine tissues may also maintain greater quantities of anaerobic enzymes, or their isozymes than Douglas-fir.

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 in October and November. Ethanol concentrations in sapwood of diseased trees near the root collar were 4-24 times higher than in healthy trees for all months of a year, except January and June. Roots from diseased trees in October had 5 times more ethanol in the phloem and 19 times more ethanol in the sapwood than corresponding tissue from healthy trees. Ethanol concentrations in roots from diseased trees in November were no different from October. Within trees, ethanol concentrations varied substantially among positions around the root collar and among different roots. Ethanol may play an important role in the biology of L.wageneri and beetle-pathogen interactions in Douglas-fir. Ethanol also may be useful in detecting stressed or diseased trees.

We quantified 2,6-disubstituted piperidine alkaloids in Pinus ponderosa and P. contorta needles from three forest sites in April, June, August, and December. Alkaloids were detected on at least one date in 71% of the ponderosa pine and in 29% of the lodgepole pine trees sampled. Pinidine was the major alkaloid constituent of ponderosa pine, while euphococcinine was the predominant compound in lodgepole pine. For ponderosa pine, total alkaloid concentrations were very low at two sites on all dates. At the third site, concentrations were variable but significantly higher on all dates. Total alkaloid concentrations in previous-year foliage from this site were highest in April, then significantly lower from June through December. Current-year foliage collected in August and December had significantly higher alkaloid concentrations than previous-year foliage on the same dates. Variation in foliar nitrogen concentrations accounted for some of the alkaloid variation in current-year foliage sampled in August.

Douglas-fir (Pseudotsuga menziesii [Mirb.] Franco) seedlings were flooded in a controlled environment. Roots rapidly synthesized ethanol with the highest rates during the first 6 h. Ethanol readily diffused into the flooding solution and moved into the stem. Ethanol concentrations in the flooding solution (normalized g-1 dry mass of roots) were four to six times the concentrations in the stems or roots. Ethanol concentrations in the roots and stems were six to 16 times larger than in the needles. Stomatal conductance and water uptake continuously increased during the first 96 h of flooding, whereas ethanol concentrations in the roots and stem increased to their maximum at 6-24 h after flooding and then decreased. Supplying Douglas-fir shoots with ethanol concentrations at two to three times those measured in flooded seedlings had no effect on stomatal conductance. Ethanol synthesis and accumulation in Douglas-fir seedlings in response to flooding does not have a detrimental impact on stomatal conductance ...

The attraction of nocturnal moths to candles and other sources of light has long been observed, but fire as a potential source of mortality to moths in ecosystems with frequent fire regimes has been overlooked. A prescribed burn was conducted shortly after dark in a central Oregon ponderosa pine forest during the flight period of the endemic defoliator Coloradia pandora (Blake). Attraction to the fire and partial consumption by flames caused direct mortality estimated at 2.2% to 17.1% of the local pandora moth population. In field tests with projected light, pandora moths did not discriminate among colors in the visible spectrum. Moths did not respond to projected light for at least 1 h after dusk, indicating that timing and duration of the prescribed fire may have limited the mortality.

Spotted knapweed, Centaurea maculosa, a herbaceous weed from Eurasia, is altering the composition of native rangeland communities across western North America. Herbivore use of this plant is limited, possibly because glandular trichomes covering the epidermal surfaces of aerial tissues produce cnicin, a biologically active sesquiterpene lactone. We determined the concentrations of cnicin in plant parts from different growth stages (initial, mature, regrowth) of C. maculosa and the effects of these plant parts on sheep rumen microbial activity and mass (in vitro), when mixed in different proportions with grass hay. Leaves had higher crude protein and lower neutral and acid detergent fiber than stems or grass hay. Cnicin concentrations were highest in leaves, intermediate in flower buds, and lowest in stems. Cnicin concentrations in leaves increased from June to July, but decreased in stems. Regrowth had slightly lower cnicin concentrations that mature growth. High percentages (70% and 100%) of mature and regrowth leaves and flowers of C. maculosa in the mixtures depressed the rate and amount of microbial activity, whereas high percentages of stems from initial growth enhanced the rates of microbial activity. Microbial activity was more responsive to the different mixtures, plant parts, and growth stages than microbial mass, possibly because microbial populations cannot adjust rapidly to changes in diet. After cnicin was extracted from leaves, microbial activity was greater from these leaves than from grass hay. In contrast, after cnicin was extracted from flower buds, microbial activity from these flower buds was still depressed, indicating other compounds or the remaining cnicin were still affecting microbial activity. In summary, sheep rumen microbial activity was reduced significantly by mature and regrowth leaves that contained high concentrations of cnicin. Since most herbivores selectively graze leaves, the bitter-tasting cnicin could deter large ruminant feeding of C. maculosa by altering their behavior and/or by affecting rumen function.

Logs from Douglas fir, Pseudotsuga menziesii; western hemlock, Tsuga heterophylla; and western red cedar, Thuja plicata, were left in the forest through winter. In April, segments from these logs were removed and randomly positioned adjacent to one another allowing ambrosia beetles to select their preferred host. In early June the tissues of Douglas fir and western hemlock logs contained significantly higher ethanol concentrations and ambrosia beetle (Trypodendron lineatum and Gnathotrichus spp.) densities than logs of western red cedar. Low beetle attack densities in western red cedar were probably a consequence of low ethanol concentrations. Although Douglas fir tissues produced significantly higher ethanol concentrations than western hemlock, the beetles did not effectively discriminate between these two conifer species. Ethanol and α-pinene were significant covariates for the ambrosia beetle densities. α-Pinene concentrations were highest in the phloem of western red cedar, intermediate in Douglas fir, and nearly absent in western hemlock. α-Pinene did not synergize the beetle's response to ethanol or to ethanol + pheromone during host selection, and it may have functioned as a deterrent.

Ethanol synthesis was induced in stem segments from greenhouse-grown conifer seedlings by placing them in a N2 atmosphere at 30 °C for 24 h. Stems from ponderosa pine,Pinus ponderosa Dougl. ex Laws., sugar pine,Pinus lambertiana Dougl., Pacific silver fir,Abies amabalis Dougl. ex Forbes, and lodgepole pine,Pinus contorta Dougl. ex Loud, produced the highest quantities of ethanol. This group also had the smallest and slowest growing stems. Within each of these species the amount of ethanol produced was inversely related to the stem volume. Stems from western hemlock,Tsuga heterophylla (Raf.) Sarg., grand fir, Abies grandis Dougl. ex Forbes, Douglas-fir,Pseudotsuga menziesii (Mirb.) Franco, and western redcedar,Thuja plicata Donn ex D. Don, all produced equivalent but low ethanol concentrations. These species had the largest and fastest growing stems. In this group only grand fir exhibited an inverse relationship between ethanol concentrations and stem volume. The relative amounts of ethanol synthesized by stems from Douglas-fir, western hemlock and western redcedar seedlings were not the same as subsequently observed in logs from mature trees of the same species under field conditions. Differences in the anaerobic environments for the two stem types could have affected the quantities of ethanol produced. The observed high amounts of ethanol produced by the stems from pine species were discussed in terms of their ability to handle periods of anaerobic stress or hypoxia.

Phloem and sapwood from Douglas-fir, Pseudotsugamenziesii (Mirb.) Franco, logs felled in November, January, and March were sampled within 24 h of harvest and resampled on each subsequent felling date. In fresh logs, constitutive ethanol concentrations were similar among dates, but concentrations in the phloem were always greater than in the sapwood. In March, after 4 months on the ground, ethanol in November-felled logs had increased 4 times in the phloem and 83 times in the sapwood, which resulted in equal tissue concentrations. For January-felled logs, ethanol concentrations remained unchanged in log tops, but decreased in the bottoms and sides between January and March. α-Pinene concentrations did not differ among harvest dates or tissue types, but they did decrease when tissues respired anaerobically. When ambrosia beetles began attacking logs in March, tissues of November-felled logs contained the most ethanol. Attack densities of Trypodendronlineatum (Oliv.) and Gnathotrichusretusus (LeConte), counted in August, were highest in November-felled logs and lowest in March-felled logs and correlated with tissue ethanol concentrations from logs sampled in March. This beetle behavior is consistent with the expected response to a compound that functions as a beetle arrestant and attack stimulant. Absorption of rain, which could interfere with gas exchange between the atmosphere and log tissues, probably contributed to the establishment of anaerobic conditions in the logs.

Given free choice, first instar gypsy moth, Lymantria dispar (L.), larvae selected new flush Douglas-fir, Pseudotsuga menziesii (Mirb.) Franco, foliage over 1-yr-old fir needles, fir bud scales, or young expanding white alder, Alnus rhombifolia Nutt., leaves. Although new fir foliage was the most acceptable, it was not the most suitable for first or fourth instars. Fourth instars fed new fir foliage consumed more but did not grow any better than larvae fed 1-yr-old needles or alder. This was the result of a decreased efficiency of converting digested food to growth. Switching II, III, or IV instars from white alder to Douglas-fir reduced pupal weights compared with larvae fed white alder alone but it did not affect development rate. Switching to Douglas-fir increased instar duration and decreased relative weight gain for all instar switches, but this lasted only for the instar switched. As a secondary host for gypsy moth, Douglas-fir differs from northeastern pines. First instars ingest new fir foliage but not pine foliage because of its toughness. Larvae switched from a preferred host to fir do not perform as well as larvae remaining on the preferred host, whereas larvae switched to pine outperform those remaining on the preferred host. In Northwest forests, Douglas-fir could possibly maintain gypsy moth populations without the presence of other hosts.

No abstract available

Two experiments were conducted to examine the influence of foliar nitrogen, terpenes, and phenolics of Douglas-fir on the development of gypsy moth larvae. In the first experiment, foliar concentrations of nitrogen and allelochemicals were manipulated by fertilizing 3-year-old potted seedlings with 0 or 200 ppm nitrogen. Concentrations of foliar nitrogen (0.33-2.38%) were negatively correlated with the phenolics (15.8-24.4 mg/g). Sixth-instar larvae previously reared on current-year Douglas-fir needles were allowed to feed on these seedlings. Pupal weights (312.8-995.6 mg) were positively correlated with levels of foliar nitrogen, negatively correlated with amounts of foliar phenolics, and uncorrelated with terpene concentrations. In the second experiment, terpene and phenolic extracts from Douglas-fir foliage were incorporated at natural levels into artificial diets with high and low levels of protein nitrogen. Neonate larvae grew faster and were larger on the high nitrogen control diet (4.1-4.5%), however, fourth instars performed better on the control diet with low nitrogen levels (2.5-2.7%). Foliar terpenes incorporated into diet had little effect on neonate fitness, but may induce subtle physiological changes in later instar larvae. Phenolics, alone or in combination with terpenes, excessively suppressed growth and survival, with no individuals living through the fourth instar, regardless of the nitrogen level. Incorporating foliar phenolic extracts into artificial diet caused unnatural levels of toxicity and failed to clarify the effects of Douglas-fir phenolics on gypsy moth fitness. Foliar nitrogen is a key factor influencing gypsy moth development on Douglas fir, but may be mitigated to some degree by phenolics.

Two new p-cymene based diphenols (1-2) were isolated from the heartwood of Calocedrus decurrans. Structures were elucidated by 1D and 2D NMR techniques and HRMS. Libocedroquinone (3) was also isolated as a natural product for the first time. A new system of nomenclature is proposed for description of such oligomeric p-cymene derivatives.

Taxol and cephalomannine concentrations were measured in the bark and foliage of Pacific yew trees growing in the shade of a forest canopy and at a site nearby where trees had been exposed to full sunlight for 6 years. Bark was the only tissue showing concentration differences due to light, with significantly greater quantities of both compounds in the bark of shaded trees than in the bark of sun-exposed trees. In either light regimen taxol concentrations were greater in the bark than in the needles or twigs

Previous attempts to resolve the closely related taxanes cephalomannine and taxol by reversed-phase high-performance liquid chromatography (HPLC) on octadecyl silica columns have not been successful. In the present study, high-resolution HPLC on microcolumns packed with octadecyl silica was evaluated for the separation of the aforementioned taxanes. Due to the enhanced separation efficiency of this technique, baseline resolution between cephalomannine and taxol was readily achieved under isocratic elution conditions. Chromatographic profiles of Taxus brevifolia twig and needle foliage extracts are presented that illustrate this separation.

The effect on mule deer (Odocoileus hemionus hemionus Rafinesque) preference of compounds in mountain big sagebrush [Artemisia tridentata Nutt. ssp.Vaseyana (Rydb.) Beetle], Wyoming big sagebrush (A. t. ssp.Wyomingensis Beetle and Young), basin big sagebrush (A. t. ssp.Tridentata), and black sagebrush (A. nova Nels.) was compared using a two-choice preference test. Compounds tested included:p-cymene, 1,8-cineole, methacrolein (two concentrations), and the nonvolatile crude terpenoid fraction (NVCTF) from each taxon. The compounds were tested by applying them to chopped alfalfa hay at concentrations similar to those found in nature. The intake of the treated hay was compared with that of an untreated control. Eight deer were used as test animals in an 8 − 8 Latin-square design. All compounds tested significantly deterred ingestion (P < 0.05). Compound influence on preference, in order of increasing deterrence, was as follows: 50% methacrolein, mountain big sagebrush NVCTF, methacrolein, basin big sagebrush NVCTF,p- cymene, Wyoming big sagebrush NVCTF, black sagebrush NVCTF, and 1,8-cineole. Methacrolein appears to be an important preference determinant among big sagebrush subspecies, andp-cymene between black sagebrush and big sagebrush. The NVCTFs containing sesquiterpene lactones as one of their constituents were closely related to the preference of all four taxa. Future studies of animal preference for sagebrush should consider all of the potential defensive chemicals in the foliage.

To test whether methanol or ethanol stimulated growth of coast Douglas-fir (Pseudotsuga menziesii vat. menziesii) or ponderosa pine (Pinus ponderosa) seedlings, we sprayed concentrations of 1 to 10% (v/v) on the foliage twice a week for 13 wk during the growing season. Foliar applications of methanol and ethanol neither significantly stimulated nor inhibited growth, and signs of damage at these concentrations were lacking. West. J. Appl. For. 14(4):183-185.

We measured the concentrations of extractable bioactive compounds in heartwood of live yellow-cedar (Chamaecyparis nootkatensis) trees and five classes of standing snags (1–5, averaging 4, 14, 26, 51, and 81 years-since-death, respectively) to determine how the concentrations changed in the slowly deteriorating snags. Three individuals from each of these six condition classes were sampled at four sites spanning a 260-km distance across southeast Alaska, and the influence of geographic location on heartwood chemistry was evaluated. Cores of heartwood were collected at breast height and cut into consecutive 5-cm segments starting at the pith. Each segment was extracted with ethyl acetate and analyzed by gas chromatography. Concentrations of carvacrol, nootkatene, nootkatol, nootkatone, nootkatin, and total extractives (a sum of 16 compounds) for the inner (0–5 cm from pith), middle (5–10 cm from pith), and surface (outer 1.1–6.0 cm of heartwood) segments from each core were compared within each tree condition class and within segments across condition classes. Heartwood of class 1 and 2 snags had the same chemical composition as live trees. The first concentration changes begin to appear in class 3 snags, which coincides with greater heartwood exposure to the external environment as decaying sapwood sloughs away, after losing the protective outer bark. Within core segments, the concentrations of all compounds, except nootkatene, decrease between snag classes 2 and 5, resulting in the heartwood of class 5 snags having the lowest quantities of bioactive compounds, although not different from the amounts in class 4 snags. This decline in chemical defense is consistent with heartwood of class 5 snags being less decay-resistant than heartwood of live trees, as observed by others. The unique heartwood chemistry of yellow cedar and the slow way it is altered after death allow dead trees to remain standing for up to a century with a profound impact on the ecology of forests in southeast Alaska where these trees are in decline.