Prediction of stand susceptibility to feeding damage by red squirrels in young lodgepole pine

1994 ◽  
Vol 24 (1) ◽  
pp. 14-20 ◽  
Author(s):  
Thomas P. Sullivan ◽  
John A. Krebs ◽  
Paul K. Diggle
Keyword(s):  
British Columbia ◽  
Population Studies ◽  
Lodgepole Pine ◽  
Forecast Model ◽  
Shrub Cover ◽  
Feeding Damage ◽  
Red Squirrels ◽  
Site Class ◽  
Potential Factors ◽  
Major Factors

This paper provides a forecast model to predict when and where significant feeding damage by red squirrels (Tamiasciurushudsonicus Erxleben) will occur in managed stands of lodgepole pine (Pinuscontorta Dougl. var. latifolia Engelm.). Information from 51 managed stands (average DBH > 6.0 cm) in the interior of British Columbia and from past squirrel population studies was used to formulate the model. Incidence of damage was significantly greater in stands originating from wildfire than from harvesting. Stands within the Montane Spruce biogeoclimatic zone had the highest levels of damage of the five zones sampled. There was no relationship between damage incidence and average stand diameter, area of managed stand, or site class. In a subset of stands where understory shrub data were available, shrub cover was positively related to incidence of damage. Major factors in the forecast model that influence stand susceptibility include (i) stand origin and proximity to mature timber; (ii) frequency of cone crops leading to squirrel population increases in juvenile pine; and (iii) shrub cover, which may provide security from predators. Additional potential factors include (iv) switching of predators from squirrels to snow-shoe hares (Lepusamericanus Erxleben) during peak years of the hare cycle and (v) fertilization. A decisionmaking profile is outlined for prespacing surveys to identify susceptible stands.

Response of Red Squirrels and Feeding Damage to Variable Stand Density in Young Lodgepole Pine Forest

1996 ◽  
Vol 6 (4) ◽  
pp. 1124-1134 ◽  
Author(s):  
Thomas P. Sullivan ◽  
Walt Klenner ◽  
Paul K. Diggle
Keyword(s):  
Lodgepole Pine ◽  
Stand Density ◽  
Pine Forest ◽  
Feeding Damage ◽  
Red Squirrels

Barking damage by snowshoe hares and red squirrels in lodgepole pine stands in central British Columbia

1982 ◽  
Vol 12 (2) ◽  
pp. 443-448 ◽  
Author(s):  
Thomas P. Sullivan ◽  
Druscilla S. Sullivan
Keyword(s):  
British Columbia ◽  
Animal Species ◽  
Lodgepole Pine ◽  
Red Squirrels ◽  
Control Programs ◽  
Snowshoe Hares ◽  
Average Proportion ◽  
Pine Stands

Barking damage by snowshoe hares (Lepusamericanus Erxleben) and red squirrels (Tamiasciurushudsonicus Erxleben) is common in overstocked stands of juvenile lodgepole pine (Pinusconforta Dougl.) in central British Columbia. Average proportion of potential crop trees damaged by hares was 30.0% and by squirrels was 37.7%. Most hare feeding injuries occurred in heavily stocked (> 20 000 stems/ha) stands, whereas squirrel damage was most common in less dense stands. Both animal species damaged trees in thinned stands, and hence may have a serious impact on stocking control programs in lodgepole pine.

Barking Damage by Red Squirrels in Juvenile-spaced Lodgepole Pine Stands in South-Central British Columbia

1987 ◽  
Vol 63 (1) ◽  
pp. 28-31 ◽  
Author(s):  
R. P. Brockley ◽  
E. Elmes
Keyword(s):  
British Columbia ◽  
Lodgepole Pine ◽  
Average Diameter ◽  
Practical Method ◽  
Growth And Yield ◽  
Damage Potential ◽  
Red Squirrels ◽  
South Central ◽  
The Impact ◽  
Fire Origin

A survey was undertaken to assess the incidence and magnitude of barking injuries by red squirrels in juvenile stands of spaced lodgeppole pine in south-central British Columbia. Eleven of the 40 stands surveyed (27.5%) showed evidence of squirrel damage. Within damaged stands, an average of 51% of lodgepole pine crop trees exhibited barking injuries (ranging from 6 to 90%).The average diameter (6.8 cm) of damaged stands was significantly greater than that of undamaged stands (3.9 cm). Sixty-seven percent of stands with average diameters greater than 6 cm showed evidence of barking injuries, while only 11% of stands with average diameters less than 6 cm had been damaged. Squirrels preferentially attacked the larger-diameter stems in damaged stands. Data indicate that fire-origin stands are more susceptible to barking damage than stands naturally regenerated following harvesting.Inability to accurately assess either squirrel damage potential or its impact on growth and yield indicates that a conservative approach is necessary in spacing juvenile lodgepole pine in areas susceptible to squirrel attack. A two-step spacing strategy may be the most practical method of minimizing the impact of squirrel barking injuries. Key words: lodgepole pine, juvenile-spacing, red squirrels.

Impact of red squirrel feeding damage on spaced stands of lodgepole pine in the Cariboo Region of British Columbia

1987 ◽  
Vol 17 (7) ◽  
pp. 666-674 ◽  
Author(s):  
Thomas P. Sullivan ◽  
Alan Vyse
Keyword(s):  
British Columbia ◽  
Lodgepole Pine ◽  
Small Diameter ◽  
Red Squirrel ◽  
Feeding Damage ◽  
Animal Damage ◽  
General Decline ◽  
Before And After ◽  
Number Of Stems ◽  
The Impact

This study measured the impact of red squirrel (Tamiasciurushudsonicus Erxleben) feeding damage on spaced stands of lodgepole pine (Pinuscontorta Dougl. var. latifolia Engelm.) in the Cariboo Forest Region of British Columbia. A limited regional assessment of animal damage in spaced stands indicated that squirrels were the most important small mammal damage agents and that lodgepole pine was the only tree species susceptible to squirrel feeding (bark and vascular tissues) injuries. Intensive assessment of damage in two stands showed that squirrel attack was significantly greater among large- (>60 mm dbh) than small-diameter stems. Significantly more spaced than control (unspaced) crop trees were attacked. There was a general decline in the proportion of trees wounded from 1980 to 1985. Some damaged trees grew faster in diameter than undamaged trees of the same size. However, at one study area, damaged trees showed faster radial growth than undamaged trees before and after squirrel attack. Squirrels appear to prefer feeding on vigorous stems and the lost growth of these trees may be substantial. Height growth of damaged trees was significantly reduced in one stand in the years following squirrel damage. Some limit to a tree's capacity to sustain damage, beyond which mortality is inevitable, seems likely. Impact of damage to spaced stands may be minimized by delaying spacing in susceptible areas or by increasing the prescribed number of stems remaining after spacing to compensate for expected mortality and severe damage.

scholarly journals Spore Dispersal by Dothistroma septosporum in Northwest British Columbia

2015 ◽  
Vol 105 (1) ◽  
pp. 69-79 ◽  
Author(s):  
Kennedy Boateng ◽  
Kathy J. Lewis
Keyword(s):  
British Columbia ◽  
Lodgepole Pine ◽  
Summer Precipitation ◽  
Disease Spread ◽  
Spore Dispersal ◽  
Mixed Species ◽  
Inoculum Sources ◽  
Pine Trees ◽  
Dothistroma Septosporum ◽  
Needle Blight

We studied spore dispersal by Dothistroma septosporum, causal agent of a serious outbreak of red band needle blight in lodgepole pine plantations in northwest British Columbia. Spore abundance was assessed at different distances and heights from inoculum sources and microclimatic factors were recorded during two consecutive years. Conidia were observed on spore traps from June to September during periods of rainfall. It was rare to detect spores more than 2 m away from inoculum sources. The timing and number of conidia dispersed were strongly tied to the climatic variables, particularly rainfall and leaf wetness. Should the trend toward increased spring and summer precipitation in the study area continue, the results suggest that disease spread and intensification will also increase. Increasing the planting distances between lodgepole pine trees through mixed species plantations and overall reduction in use of lodgepole pine for regeneration in wet areas are the best strategies to reduce the spread of the disease and enhance future productivity of plantations in the study area.

scholarly journals Identifying and Characterizing Important Trembling Aspen Competitors with Juvenile Lodgepole Pine in Three South-Central British Columbia Ecosystems

2012 ◽  
Vol 2012 ◽  
pp. 1-12
Author(s):  
Teresa A. Newsome ◽  
Jean L. Heineman ◽  
Amanda F. Linnell Nemec
Keyword(s):  
British Columbia ◽  
Lodgepole Pine ◽  
Geographic Range ◽  
Regression Analyses ◽  
Relative Height ◽  
Trembling Aspen ◽  
Ecosystem Productivity ◽  
Height Ratio ◽  
Critical Height ◽  
South Central

Critical height ratios for predicting competition between trembling aspen and lodgepole pine were identified in six juvenile stands in three south-central British Columbia ecosystems. We used a series of regression analyses predicting pine stem diameter from the density of neighbouring aspen in successively shorter relative height classes to identify the aspen-pine height ratio that maximizedR2. Critical height ratios varied widely among sites when stands were 8–12 years old but, by age 14–19, had converged at 1.25–1.5. MaximumR2values at age 14–19 ranged from 13.4% to 69.8%, demonstrating that the importance of aspen competition varied widely across a relatively small geographic range. Logistic regression also indicated that the risk of poor pine vigour in the presence of aspen varied between sites. Generally, the degree of competition, risk to pine vigour, and size of individual aspen contributing to the models declined along a gradient of decreasing ecosystem productivity.

Factors affecting the amplitude of the τ angle in proteins: a revisitation

2017 ◽  
Vol 73 (7) ◽  
pp. 618-625 ◽  
Author(s):  
Nicole Balasco ◽  
Luciana Esposito ◽  
Luigi Vitagliano
Keyword(s):  
Protein Structures ◽  
Factors Affecting ◽  
X Ray ◽  
Backbone Conformation ◽  
Potential Factors ◽  
The Stability ◽  
Major Factors ◽  
The Impact ◽  
Open Issues

The protein folded state is the result of the fine balance of a variety of different forces. Even minor structural perturbations may have a significant impact on the stability of these macromolecules. Studies carried out in recent decades have led to the convergent view that proteins are endowed with a flexible spine. One of the open issues related to protein local backbone geometry is the identification of the factors that influence the amplitude of the τ (N—Cα—C) angle. Here, statistical analyses performed on an updated ensemble of X-ray protein structures by dissecting the contribution of the major factors that can potentially influence the local backbone geometry of proteins are reported. The data clearly indicate that the local backbone conformation has a prominent impact on the modulation of the τ angle. Therefore, a proper assessment of the impact of the other potential factors can only be appropriately evaluated when small (φ, ψ) regions are considered. Here, it is shown that when the contribution of the backbone conformation is removed by considering small (φ, ψ) areas, an impact of secondary structure, as defined byDSSP, and/or the residue type on τ is still detectable, although to a limited extent. Indeed, distinct τ-value distributions are detected for Pro/Gly and β-branched (Ile/Val) residues. The key role of the local backbone conformation highlighted here supports the use of variable local backbone geometry in protein refinement protocols.

scholarly journals Fungal colonizers and seed loss in lodgepole pine orchards of British Columbia

Botany ◽  
2019 ◽  
Vol 97 (1) ◽  
pp. 23-33
Author(s):  
Paul Y. de la Bastide ◽  
Jonathon LeBlanc ◽  
Lisheng Kong ◽  
Terrie Finston ◽  
Emily M. May ◽  
...  
Keyword(s):  
British Columbia ◽  
Seed Production ◽  
Pinus Contorta ◽  
Lodgepole Pine ◽  
Seed Viability ◽  
Molecular Approaches ◽  
Seed Loss ◽  
Natural Range ◽  
Fungal Microbiome ◽  
Host Tissues

Lodgepole pine (Pinus contorta var. latifolia Engelm. ex S. Watson) is an important lumber species in Canada, and seed orchards are expected to meet the increased demand for seed. However, seed production has been consistently low in the Okanagan region orchards of British Columbia, Canada. To determine whether the fungal microbiome contributes to seed loss, histological and molecular approaches were used. Seed production was studied at seven Okanagan orchards, all outside the natural range of lodgepole pine, and at one near Prince George, within its natural range. Seed losses were highest in the Okanagan, compared with Prince George. The role of fungal colonizers in consuming seed during the last stages of maturation is described. Fungal hyphae were frequently observed at all locations in developing seed, particularly once storage substances accumulated. Fungi identified from host tissues using molecular and morphological techniques included Alternaria, Cladosporium, Fusarium, Penicillium, and Sydowia. The opportunistic foliar pathogen Sydowia polyspora, which is known to have a variable biotrophic status, was detected at most orchards within different host tissues (seeds, needles, and conelets), in association with pollen, and in the air column. Reduced seed viability observed in Okanagan orchards is most likely due to a combination of factors, including composition of the fungal microbiome.

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