Fire and dwarf mistletoe (Viscaceae: Arceuthobium species) in western North America: contrasting Arceuthobium tsugense and Arceuthobium americanum

Botany ◽  
2017 ◽  
Vol 95 (3) ◽  
pp. 231-246 ◽  
Author(s):  
David C. Shaw ◽  
Michelle C. Agne
Keyword(s):  
North America ◽  
Pinus Contorta ◽  
Forest Disturbance ◽  
Fire Suppression ◽  
Forest Composition ◽  
Western North America ◽  
Dwarf Mistletoe ◽  
Arceuthobium Americanum ◽  
Primary Determinant ◽  
Composition Structure

Dwarf mistletoes (Viscaceae: Arceuthobium spp.) and fire interact in important ways in the coniferous forests of western North America. Fire directly affects dwarf mistletoes by killing the host, host branch, or heating/smoking the aerial shoots and fruits. Fire is a primary determinant of dwarf mistletoe distribution on the landscape, and time since fire controls many aspects of dwarf mistletoe epidemiology. Conversely, dwarf mistletoes can influence fire by causing changes in forest composition, structure, and fuels. Prescribed fire is important for management of dwarf mistletoes, while fire suppression is thought to have increased dwarf mistletoe abundance in western forests. Two dwarf mistletoes are compared in order to illustrate fire interactions in Oregon and Washington, USA: Arceuthobium americanum Nutt. ex Engelm. (lodgepole pine dwarf mistletoe) and Arceuthobium tsugense (Rosendahl)(western hemlock dwarf mistletoe). Arceuthobium persists on the landscape where the host is not killed by fire. Arceuthobium americanum spreads directly into the regenerating Pinus contorta Dougl. ex Loud., while A. tsugense persists in refugia for 200 years or more following fire. Host successional status is a driver of fire – dwarf mistletoe interactions, but forest disturbance agents also play a role. Given the importance of these interactions to the ecology of fire-prone forests, dwarf mistletoes warrant inclusion in disturbance ecology research.

scholarly journals Callus Culture of Arceuthobium americanum Nutt. ex Englem. and Explant Response to Varying Auxin and Cytokinin Concentrations

2012 ◽  
Vol 21 (1) ◽  
pp. 1-10 ◽  
Author(s):  
Lyssa L. Martin ◽  
Cynthia Ross Friedman ◽  
Ronald G. Smith
Keyword(s):  
North America ◽  
Callus Culture ◽  
Shoot Organogenesis ◽  
Coniferous Forests ◽  
Western North America ◽  
Laboratory Studies ◽  
Dwarf Mistletoe ◽  
Arceuthobium Americanum ◽  
Infected Area

The lodgepole pine dwarf mistletoe Arceuthobium americanum is a severe pest in coniferous forests of western North America.  To facilitate laboratory studies of this obligate parasite, a modified White’s medium was used for in vitro culture; the concentrations of IAA and Kn were varied to determine optimal IAA/Kn ratios.  It was found that explant health was related to the concentration of IAA (p = 0.008), but not Kn (p = 0.937), and that explants were healthiest at an IAA/Kn ratio of 0.1.  Radicular apices were generated at IAA/Kn ratios of 1.0 or greater, but no shoot organogenesis was observed.  These data suggest that A. americanum is more sensitive to auxins than cytokinins.  Parasites of plants are known to secrete high levels of cytokinins, which stimulate the host to shuttle nutrients to the infected area, and so we suspect that A. americanum has reduced cytokinin sensitivity.   Key words: Callus culture, Arceuthobium americanum, Explant, Response, Cytokinin, Insensitivity   D.O.I. 10.3329/ptcb.v21i1.9557   Plant Tissue Cult. & Biotech. 21(1): 1-10, 2011 (June)

The effects of male and female Arceuthobium americanum (lodgepole pine dwarf mistletoe) infection on the relative positioning of vascular bundles, starch distribution, and starch content in Pinus contorta var. latifolia (lodgepole pine) needles

Botany ◽  
2008 ◽  
Vol 86 (5) ◽  
pp. 539-543 ◽  
Author(s):  
Aditya Chhikara ◽  
Cynthia M. Ross Friedman
Keyword(s):  
Pinus Contorta ◽  
Biochemical Analysis ◽  
Lodgepole Pine ◽  
Starch Content ◽  
Periodic Acid ◽  
Vascular Bundles ◽  
Dwarf Mistletoe ◽  
Needle Anatomy ◽  
Arceuthobium Americanum

The lodgepole pine dwarf mistletoe, Arceuthobium americanum Nutt. ex Engelm., is a dioecious angiosperm that parasitizes conifers in western Canadian forests, causing significant yearly timber loss. A striking consequence of dwarf mistletoe infection is a marked reduction in the size of the needles located distal to the infection. The purpose of this work was to use microscopy, cytochemistry, and biochemical analysis to determine whether this reduction was associated with changes in needle anatomy and (or) starch content. Furthermore, we wanted to investigate whether these potential changes were affected by the gender of the infecting dwarf mistletoe plant. We developed a ratio (R) that evaluated the position of the two vascular bundles relative to the size of the needle, and found that bundles from male-infected trees were positioned significantly closer together than in needles from female-infected or uninfected trees (p < 0.05). Using the periodic acid – Schiff’s (PAS) reaction for cytochemical identification of starch in situ, we determined that needles from uninfected trees had abundant starch grains compared with needles from infected trees; colourimetric analysis for total starch content corroborated our PAS data. This is the first report of this phenomenon in lodgepole pine, and further supports the use of needle characteristics to assess tree health.

Cylindrocarpon gillii, a new combination for Septogloeum gillii on dwarf mistletoe

1973 ◽  
Vol 51 (10) ◽  
pp. 1997-1998 ◽  
Author(s):  
John A. Muir
Keyword(s):  
North America ◽  
Spore Formation ◽  
New Combination ◽  
Western North America ◽  
Dwarf Mistletoe ◽  
Anthracnose Disease

The fungus previously known as Septogloeum gillii D. E. Ellis which causes an anthracnose disease of the shoots of dwarf mistletoes (Arceuthobium spp.) in western North America is assigned, on the basis of its conidiophore morphology and spore formation, to the genus Cylindrocarpon. Accordingly, the new combination Cylindrocarpon gillii (D. E. Ellis) J. A. Muir is proposed.

Pinus contorta (lodgepole pine).

2021 ◽  
Author(s):  
Ana Jose Cobar
Keyword(s):  
Growth Rate ◽  
North America ◽  
Rapid Growth ◽  
Pinus Contorta ◽  
Stand Development ◽  
Western North America ◽  
Fast Growing ◽  
Ecological Amplitude ◽  
Rapid Growth Rate ◽  
The Usa

Abstract P. contorta is a fast-growing, short-lived and fire-adapted two-needled pine species with a very wide ecological amplitude and tolerance. It is an important and valuable timber trees in western North America, with forests dominated by P. contorta covering some 6 million ha in the USA and 20 million ha in Canada (Burns and Honkala, 1990). Because of its rapid growth rate, small taper and thin bark, it produces a higher volume of wood than many of its associates of the same diameter and height. It is a low nutrient-demanding species and easy to regenerate and grow. A common problem of regenerating P. contorta is overstocking which may result in growth stagnation during early stand development on water-deficient, nutrient-poor sites.

scholarly journals Multiscale perspectives of fire, climate and humans in western North America and the Jemez Mountains, USA

2016 ◽  
Vol 371 (1696) ◽  
pp. 20150168 ◽  
Author(s):  
Thomas W. Swetnam ◽  
Joshua Farella ◽  
Christopher I. Roos ◽  
Matthew J. Liebmann ◽  
Donald A. Falk ◽  
...  
Keyword(s):  
North America ◽  
Ponderosa Pine ◽  
Human Impacts ◽  
Fire Suppression ◽  
Fire Regimes ◽  
Livestock Grazing ◽  
Land Uses ◽  
Western North America ◽  
Ponderosa Pine Forests ◽  
Jemez Mountains

Interannual climate variations have been important drivers of wildfire occurrence in ponderosa pine forests across western North America for at least 400 years, but at finer scales of mountain ranges and landscapes human land uses sometimes over-rode climate influences. We reconstruct and analyse effects of high human population densities in forests of the Jemez Mountains, New Mexico from ca 1300 CE to Present. Prior to the 1680 Pueblo Revolt, human land uses reduced the occurrence of widespread fires while simultaneously adding more ignitions resulting in many small-extent fires. During the 18th and 19th centuries, wet/dry oscillations and their effects on fuels dynamics controlled widespread fire occurrence. In the late 19th century, intensive livestock grazing disrupted fuels continuity and fire spread and then active fire suppression maintained the absence of widespread surface fires during most of the 20th century. The abundance and continuity of fuels is the most important controlling variable in fire regimes of these semi-arid forests. Reduction of widespread fires owing to reduction of fuel continuity emerges as a hallmark of extensive human impacts on past forests and fire regimes. This article is part of the themed issue ‘The interaction of fire and mankind’.

Relationships between dwarf mistletoe and the canopy structure of an old-growth lodgepole pine forest in central Oregon

2003 ◽  
Vol 33 (6) ◽  
pp. 997-1009 ◽  
Author(s):  
R C Godfree ◽  
R O Tinnin ◽  
R B Forbes
Keyword(s):  
Pinus Contorta ◽  
Lodgepole Pine ◽  
Abiotic Factors ◽  
Canopy Structure ◽  
Structural Diversity ◽  
Conifer Forest ◽  
Dwarf Mistletoe ◽  
Arceuthobium Americanum ◽  
Canopy Volume ◽  
The Vertical Distribution

The relationships between abundance of dwarf mistletoe (Arceuthobium americanum Nutt.) and the canopy structure of stands of lodgepole pine (Pinus contorta var. murrayana (Grev. & Balf.) Engelm.) were investigated in the central Oregon pumice zone. Foliage height profiles were generated for stands containing light, moderate, and heavy infestations of A. americanum, and the vertical distribution of P. contorta foliage was modeled using the Weibull distribution. Stand-level changes in the Weibull parameters σ (scale parameter) and c (shape parameter) as well as other canopy indices were related to the abundance of A. americanum, the density of competing tree species, and stand-level abiotic factors. Foliage intercept diagrams showed that heavily infested stands had more foliage in the lower canopy and less in the upper canopy than lightly infested stands, but that total canopy height and canopy volume were similar regardless of infestation level. We also found that dwarf mistletoe abundance was strongly related to σ (r = –0.74, p < 0.001) and c (r = –0.54, p < 0.0001). Since heavily infested stands contained fewer large but many more small P. contorta than lightly infested stands, we conclude that A. americanum causes the canopy of infested stands to change, in part, by inducing demographic changes in populations of the host tree. These results illustrate the significant effects that dwarf mistletoes can have on the structural diversity of conifer forest communities and have important consequences for the conservation and management of these systems.

Aerial Application of Ethephon is ineffective in Controlling Lodgepole Pine Dwarf Mistletoe

1989 ◽  
Vol 4 (1) ◽  
pp. 27-28 ◽  
Author(s):  
Kathryn Robbins ◽  
David W. Johnson ◽  
Frank G. Hawksworth ◽  
Thomas H. Nicholls
Keyword(s):  
Plant Growth ◽  
Growth Regulator ◽  
Plant Growth Regulator ◽  
Direct Contact ◽  
Pinus Contorta ◽  
Lodgepole Pine ◽  
Aerial Application ◽  
Dwarf Mistletoe ◽  
Arceuthobium Americanum

Abstract Ethephon is an ethylene-releasing plant growth regulator that induces abscission of dwarf mistletoe (Arceuthobium americanum) aerial shoots on lodgepole pine (Pinus contorta) when applied from the ground. However, ethephon was not effective when applied by helicopter in two Colorado tests, because it did not come into enough direct contact with dwarf mistletoe shoots to induce abscission. West. J. Appl. For. 4(1):27-28, January 1989.

Morphometric variation within and between populations of the pine aphid, Cinara nigra (Wilson) (Homoptera: Aphidoidea: Lachnidae), in western North America

1990 ◽  
Vol 68 (7) ◽  
pp. 1410-1419 ◽  
Author(s):  
R. G. Foottit ◽  
M. Mackauer
Keyword(s):  
North America ◽  
Morphological Variation ◽  
Pinus Contorta ◽  
Principal Component ◽  
Significant Loss ◽  
Population Variation ◽  
Species Discrimination ◽  
Western North America ◽  
Shape Variation ◽  
Morphometric Variation

Morphological variation in Cinara nigra (Wilson), found on Pinus contorta Dougl. ex Loud, throughout western North America, was characterized with the aid of univariate and multivariate statistical methods. Within-population variation in one sample collected near Edson, Alberta, was examined. Correlation and principal component analysis revealed patterns of interdependence among characters as well as patterns of size and size-related shape variation in 52 characters. To examine morphological variation between 19 geographic samples, this initial set was reduced in two steps to 49 and 32 characters, respectively; the reduction did not result in a significant loss of information content. No geographic pattern in clusters of samples was revealed either by the ordination of sample centroids or by UPGMA cluster analysis of the Mahalanobis D values. The taxonomic implications of this morphometric analysis are discussed, in particular the usefulness of various morphological attributes for species discrimination.

Sign in / Sign up

Export Citation Format

Share Document