Impact of dwarf mistletoe on the growth of western hemlock trees having different patterns of suppression and release

1985 ◽  
Vol 15 (4) ◽  
pp. 665-668 ◽  
Author(s):  
A. J. Thomson ◽  
R. I. Alfaro ◽  
W. J. Bloomberg ◽  
R. B. Smith
Keyword(s):  
Volume Growth ◽  
Severe Infection ◽  
Vancouver Island ◽  
Western Hemlock ◽  
Dwarf Mistletoe ◽  
Area Sampling ◽  
The Impact ◽  
Site Variability

The impact of dwarf mistletoe on the volume growth of western hemlock was evaluated in trees from five locations on northeast Vancouver Island. Within each area, sampling was designed to minimize the effects of site variability. However, differences in age and in patterns of suppression and release between infection classes were observed in some stands. Growth was corrected for these differences by subtracting the suppression core and by making comparisons at equivalent ages. Volume losses associated with dwarf mistletoe infection were higher than reported in our previous studies in other areas, averaging 23 and 39% with moderate and severe infection levels, respectively.

Development of dwarf mistletoe in western hemlock regeneration in southeast Alaska

1982 ◽  
Vol 12 (3) ◽  
pp. 482-488 ◽  
Author(s):  
Charles G. Shaw III
Keyword(s):  
British Columbia ◽  
Disease Control ◽  
Control Strategies ◽  
Severe Infection ◽  
Host Tissue ◽  
Western Hemlock ◽  
Dwarf Mistletoe ◽  
Local Conditions ◽  
Southeast Alaska ◽  
Understory Trees

Western hemlock (Tsugaheterophylla (Raf.) Sarg.) regenerated within 9.14 m of old-growth hemlock severely infected with dwarf mistletoe, Arceuthobiumtsugense ((Rosendahl) G.N. Jones), and left standing on cutover sites in southeast Alaska were felled and examined for infection. The percentage of understory trees infected among the 3429 examined averaged 9, 7, 5, and 17, respectively, in 17-, 19-, 35-, and 43-year-old stands. Ninety-two percent of all infections in the 17-, 19-, and 35-year-old stands were alive, but only 51% were alive in the 43-year-old stand. In all stands few trees had more than two live infections and few had any infections in their middle or upper crown. In all stands, advanced regeneration was more frequently infected and accounted for a significantly greater proportion of crop trees than new reproduction. A significantly higher proportion of hemlock crop trees were infected than non crop trees, but the number of infections on crop trees was consistently low. Most infections were established on host tissue 5 years or younger, but tissue up to 13 years old was infected. At a comparable age, young stands in Alaska appear to be less severely affected by A. tsugense than similar stands in Washington, Oregon, and British Columbia. Disease control strategies, developed for stands experiencing more severe infection intensities than those now known to prevail in southeast Alaska, will require modification to meet local conditions.

Measurement and simulation of dwarf mistletoe infection of second-growth western hemlock on southern Vancouver Island

1982 ◽  
Vol 12 (2) ◽  
pp. 280-291 ◽  
Author(s):  
W. J. Bloomberg ◽  
R. B. Smith
Keyword(s):  
Growth Rate ◽  
Vertical Distribution ◽  
Stand Density ◽  
Tree Height ◽  
Vancouver Island ◽  
Western Hemlock ◽  
Dwarf Mistletoe ◽  
Infection Level ◽  
Infection Age ◽  
Second Growth

Infection of western hemlock (Tsugaheterophylla (Raf.) Sarg.) residual overstory and second-growth understory by hemlock dwarf mistletoe (Arceuthobiumtsugense (Rosendahl) G.N. Jones) was analyzed in seven plots on southern Vancouver Island. The number of infections in residual trees ranged from 373 to 4058 and in second-growth trees from 3 to 455. The number in second-growth trees was significantly correlated positively with dbh and tree height and inversely with height/dbh ratio. The percentage of crown length infected varied significantly among plots and was significantly correlated with the number of infections. Vertical distribution of infections in tree crowns did not conform to test distributions; distribution by infection age approximated the Poisson. The range in infection age varied according to height in green crown and length of green crown infected. Mortality of infections varied significantly among plots and was greatest in lower slope sites and least in a drier upper slope site. Proportion of dead infections was a function of height in crown and total length of green crown infected. Data suggest that infection level in second-growth trees was proportional to the number of residuals and was inversely related to percent nonhost species, stand density, and growth rate. The number of infections predicted by a simulation model averaged 107% of the number recorded in residual trees and 128% in second-growth trees. Curves of predicted vertical distribution of infections in crowns were of the same shape as those recorded in plot sample trees. The predicted average age-class distribution of infections approximated Poisson distribution within the same probability range as recorded in plot sample trees. The predicted average dbh of residual and second-growth trees were 90 and 97%, respectively, of the recorded values; predicted average heights were 115 and 101%, respectively, of recorded values. Infection predicted by the model over a range of hypothetical stand, site, and infection conditions was used to elucidate major epidemiological factors that might bear on silvieultural control. Results confirmed the observed effects of number of residuals, stand composition, growth rate, and stand density on infections.

Needle properties of host white spruce (Picea glauca [Moench] Voss) experiencing eastern dwarf mistletoe (Arceuthobium pusillum Peck) infections of differing severity

Botany ◽  
2017 ◽  
Vol 95 (3) ◽  
pp. 295-305 ◽  
Author(s):  
Johnathon A. de Villier ◽  
Jaret S. Reblin ◽  
Barry A. Logan
Keyword(s):  
Picea Glauca ◽  
Photosynthetic Capacity ◽  
Full Range ◽  
Severe Infection ◽  
White Spruce ◽  
Biochemical Properties ◽  
Dwarf Mistletoe ◽  
Needle Size ◽  
The Impact ◽  
Physiological And Biochemical

Eastern dwarf mistletoe (Arceuthobium pusillum Peck) parasitizes the branches of white spruce (Picea glauca [Moench] Voss) and ultimately kills this host species. Previous studies of host needle physiology generally focused on trees experiencing infections of moderate severity; here, we expanded upon previous research to investigate the morphological, physiological, and biochemical properties of needles from white spruce trees experiencing the full range of infection severities. We found that the impact of parasitism on host needle parameters did not scale uniformly with infection severity. Rather, parasitism reduced host needle size distal to infection and resulted in more negative carbon isotope ratios across all infection severities. Reduced foliar nitrogen and chlorophyll content were only evident in trees with moderate or severe infection, while photosynthetic capacity was depressed in only severely infected trees. Furthermore, while some impacts were confined to infected host branches, others, such as smaller needles and reduced photosynthetic capacity, were also evident in branches showing no visible signs of infection. We conclude that symptoms of infection appearing only after infection worsened in severity or appearing in uninfected branches may in whole or in part also be manifestations of a decline in resource availability and vigor of the whole tree.

Mass and nutrient content of woody debris and forest floor in western red cedar and western hemlock forests on northern Vancouver Island

1993 ◽  
Vol 23 (6) ◽  
pp. 1052-1059 ◽  
Author(s):  
Rodney J. Keenan ◽  
Cindy E. Prescott ◽  
J.P. Hamish Kimmins
Keyword(s):  
Forest Floor ◽  
Forest Type ◽  
Woody Debris ◽  
Nutrient Content ◽  
Vancouver Island ◽  
Western Hemlock ◽  
N Availability ◽  
Red Cedar ◽  
The Mean ◽  
Western Red Cedar

Biomass and C, N, P, and K contents of woody debris and the forest floor were surveyed in adjacent stands of old-growth western red cedar (Thujaplicata Donn)–western hemlock (Tsugaheterophylla (Raf.) Sarg.) (CH type), and 85-year-old, windstorm-derived, second-growth western hemlock–amabilis fir (Abiesamabilis (Dougl.) Forbes) (HA type) at three sites on northern Vancouver Island. Carbon concentrations were relatively constant across all detrital categories (mean = 556.8 mg/g); concentrations of N and P generally increased, and K generally decreased, with increasing degree of decomposition. The mean mass of woody debris was 363 Mg/ha in the CH and 226 Mg/ha in the HA type. The mean forest floor mass was 280 Mg/ha in the CH and 211 Mg/ha in the HA stands. Approximately 60% of the forest floor mass in each forest type was decaying wood. Dead woody material above and within the forest floor represented a significant store of biomass and nutrients in both forest types, containing 82% of the aboveground detrital biomass, 51–59% of the N, and 58–61% of the detrital P. Forest floors in the CH and HA types contained similar total quantities of N, suggesting that the lower N availability in CH forests is not caused by greater immobilization in detritus. The large accumulation of forest floor and woody debris in this region is attributed to slow decomposition in the cool, wet climate, high rates of detrital input following windstorms, and the large size and decay resistance of western red cedar boles.

The Plasmair Decontamination System Is Protective Against Invasive Aspergillosis in Neutropenic Patients

2016 ◽  
Vol 37 (7) ◽  
pp. 845-851 ◽  
Author(s):  
Marie-Paule Fernandez-Gerlinger ◽  
Anne-Sophie Jannot ◽  
Sophie Rigaudeau ◽  
Juliette Lambert ◽  
Odile Eloy ◽  
...  
Keyword(s):  
Invasive Aspergillosis ◽  
Severe Infection ◽  
Hematologic Malignancies ◽  
Preventive Strategies ◽  
European Organization ◽  
Exact Test ◽  
Eortc Criteria ◽  
Neutropenic Patients ◽  
Chemotherapy Induced Neutropenia ◽  
The Impact

OBJECTIVEInvasive aspergillosis (IA) is a rare but severe infection caused by Aspergillus spp. that often develops in immunocompromised patients. Lethality remains high in this population. Therefore, preventive strategies are of key importance. The impact of a mobile air decontamination system (Plasmair, AirInSpace, Montigny-le-Bretonneux, France) on the incidence of IA in neutropenic patients was evaluated in this study.DESIGNRetrospective cohort studyMETHODSPatients with chemotherapy-induced neutropenia lasting 7 days or more were included over a 2-year period. Cases of IA were confirmed using the revised European Organization for Research and Treatment of Cancer (EORTC) criteria. We took advantage of a partial installation of Plasmair systems in the hematology intensive care unit during this period to compare patients treated in Plasmair-equipped versus non-equipped rooms. Patients were assigned to Plasmair-equipped or non-equipped rooms depending only on bed availability. Differences in IA incidence in both groups were compared using Fisher’s exact test, and a multivariate analysis was performed to take into account potential confounding factors.RESULTSData from 156 evaluable patients were available. Both groups were homogenous in terms of age, gender, hematological diagnosis, duration of neutropenia, and prophylaxis. A total of 11 cases of probable IA were diagnosed: 10 in patients in non-equipped rooms and only 1 patient in a Plasmair-equipped room. The odds of developing IA were much lower for patients hospitalized in Plasmair-equipped rooms than for patients in non-equipped rooms (P=.02; odds ratio [OR] =0.11; 95% confidence interval [CI], 0.00–0.84).CONCLUSIONIn this study, Plasmair demonstrated a major impact in reducing the incidence of IA in neutropenic patients with hematologic malignancies.Infect Control Hosp Epidemiol 2016;37:845–851

Reproductive-cycle plasticity in yellow-cedar (Chamaecyparisnootkatensis)

1991 ◽  
Vol 21 (9) ◽  
pp. 1360-1364 ◽  
Author(s):  
Y. A. El-Kassaby ◽  
J. Maze ◽  
D. A. MacLeod ◽  
S. Banerjee
Keyword(s):  
Reproductive Cycle ◽  
Vancouver Island ◽  
Significant Delay ◽  
Continue Development ◽  
Cold Temperatures ◽  
Size And Shape ◽  
Seed Extraction ◽  
Fresh Pollen ◽  
The Impact

In 1987, a study was initiated to determine the properties of seed from apparently premature cones of yellow-cedar (Chamaecyparisnootkatensis (D. Don) Spach) on southwestern Vancouver Island. After pollination with fresh pollen in February, all cones showed signs of maturation (i.e., drying and shedding) by December. Samples of these 1-year-old cones were collected for seed extraction and germination tests. Germination ranged between 10 and 42% for isolated cones (i.e., bagged) and between 0 and 25% for unisolated cones. Similar germination results were obtained for the 1988 and 1989 cone crops. Anatomical observations revealed that the 10-month-old embryos were similar in both size and shape to embryos from 2-year-old seeds. It was concluded that transplanting yellow-cedar trees to warmer, low-elevation sites enabled seed cones to continue development without significant delay caused by dormancy induced by cold temperatures at higher elevations. This alteration of normal phenology reflects the impact of environmental contingencies on development.

scholarly journals Impact of Coronavirus Disease 2019 (COVID‐19) on Patients With Congenital Heart Disease Across the Lifespan: The Experience of an Academic Congenital Heart Disease Center in New York City

2020 ◽  
Vol 9 (23) ◽  
Author(s):  
Matthew J. Lewis ◽  
Brett R. Anderson ◽  
Michael Fremed ◽  
Melissa Argenio ◽  
Usha Krishnan ◽  
...  
Keyword(s):  
New York ◽  
Congenital Heart Disease ◽  
New York City ◽  
Heart Disease ◽  
York City ◽  
Congenital Heart ◽  
Severe Infection ◽  
Genetic Syndrome ◽  
Physiological Stage ◽  
The Impact

Background We sought to assess the impact and predictors of coronavirus disease 2019 (COVID‐19) infection and severity in a cohort of patients with congenital heart disease (CHD) at a large CHD center in New York City. Methods and Results We performed a retrospective review of all individuals with CHD followed at Columbia University Irving Medical Center who were diagnosed with COVID‐19 between March 1, 2020 and July 1, 2020. The primary end point was moderate/severe response to COVID‐19 infection defined as (1) death during COVID‐19 infection; or (2) need for hospitalization and/or respiratory support secondary to COVID‐19 infection. Among 53 COVID‐19‐positive patients with CHD, 10 (19%) were <18 years of age (median age 34 years of age). Thirty‐one (58%) had complex congenital anatomy including 10 (19%) with a Fontan repair. Eight (15%) had a genetic syndrome, 6 (11%) had pulmonary hypertension, and 9 (17%) were obese. Among adults, 18 (41%) were physiologic class C or D. For the entire cohort, 9 (17%) had a moderate/severe infection, including 3 deaths (6%). After correcting for multiple comparisons, the presence of a genetic syndrome (odds ratio [OR], 35.82; P =0.0002), and in adults, physiological Stage C or D (OR, 19.38; P =0.002) were significantly associated with moderate/severe infection. Conclusions At our CHD center, the number of symptomatic patients with COVID‐19 was relatively low. Patients with CHD with a genetic syndrome and adults at advanced physiological stage were at highest risk for moderate/severe infection.

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