Impact of feeding damage by snowshoe hares on growth rates of juvenile lodgepole pine in central British Columbia

1986 ◽  
Vol 16 (5) ◽  
pp. 1145-1149 ◽  
Author(s):  
Thomas P. Sullivan ◽  
Druscilla S. Sullivan
Keyword(s):  
Vascular Tissue ◽  
Lodgepole Pine ◽  
Small Diameter ◽  
Height Growth ◽  
Control Surface ◽  
Snowshoe Hare ◽  
Feeding Damage ◽  
Growth Increments ◽  
Snowshoe Hares ◽  
The Impact

This study assessed the impact of snowshoe hare (Lepusamericanus Erxleben) feeding injuries on diameter and height growth of juvenile lodgepole pine (Pinuscontorta Dougl. var. latifolia Engelm.). Five-year growth increments of undamaged and damaged crop trees in control (unspaced) and spaced stands, 20 km east of Prince George, B.C., were compared using analysis of variance. Semigirdling (sublethal) damage clearly suppressed diameter growth of small diameter (control, 41–60 mm; spaced, 31–50 mm) trees, but had little effect on larger stems. Height increment was significantly reduced by semigirdling in all diameter classes except for the 61–80 mm class in the control. Surface area or amount of bark and vascular tissue removed had little effect on growth increments in the spaced stand. The recommendation to delay spacing until the average tree diameter is >60 mm to avoid snowshoe hare damage is further supported for diameter but not necessarily for height growth.

Influence of feeding damage by small mammals on tree growth and wood quality in young lodgepole pine

1993 ◽  
Vol 23 (5) ◽  
pp. 799-809 ◽  
Author(s):  
Thomas P. Sullivan ◽  
Harry Coates ◽  
Les A. Jozsa ◽  
Paul K. Diggle
Keyword(s):  
Lodgepole Pine ◽  
Wood Quality ◽  
Ring Width ◽  
Small Diameter ◽  
Height Growth ◽  
Diameter Increment ◽  
Significant Difference ◽  
Small Diameter Trees ◽  
Severe Degree ◽  
The Impact

This study assessed the impact of feeding injuries by snowshoe hare (Lepusamericanus Erxleben) and red squirrel (Tamiasciurushudsonicus Erxleben) on diameter growth, height growth, and wood quality of juvenile lodgepole pine (Pinuscontorta Dougl. var latifolia Engelm.) at Prince George and in the Cariboo Region, British Columbia. In the Prince George control stand, severe girdling damage (50–99% stem circumference) suppressed diameter and height growth of small-diameter (4.1–6.0 cm) trees, but had no effect on larger stems (6.1–8.0 cm). In the spaced stand, diameter and height increments also declined significantly with degree of partial girdling, particularly in small-diameter (3.1–5.0 cm) trees. Paradoxically, diameter increment increased significantly with degree of partial girdling in both stands at the Cariboo study area. Presumably squirrels prefer to feed on vigorous stems, and the lost growth of these trees may be substantial. There was no significant difference in amount of compression wood nor total solvent and water extractives between undamaged and damaged trees. Fiber lengths in wound-associated wood were consistently 19–21% lower than in controls. Damaged trees had greater average ring width and density than undamaged trees. The average increase in relative density of damaged over undamaged trees was 0.0343. These results suggest that a severe degree of partial girdling (which likely occurs more often in small-diameter trees) may significantly affect growth of lodgepole pine, particularly small (<5.0 cm DBH) trees.

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 Effectiveness of a Physical Barrier in Deterring Vole and Snowshoe Hare Feeding Damage to Lodgepole Pine Seedlings

1998 ◽  
Vol 13 (1) ◽  
pp. 12-14 ◽  
Author(s):  
Todd N. Zimmerling ◽  
Linda M. Zimmerling
Keyword(s):  
Pinus Contorta ◽  
Lodgepole Pine ◽  
Protection Device ◽  
Feeding Damage ◽  
Physical Barrier ◽  
Snowshoe Hares ◽  
Pine Seedlings ◽  
Protection Devices ◽  
Study Sites ◽  
Seedling Protection

Abstract We examined the effectiveness of a tubular, polyethylene/polypropylene mesh seedling protection device in reducing overwinter feeding damage by snowshoe hares(Lepus americanus) and meadow voles (Microtus pennsylvanicus) on spring planted, plug stock (1 + 0) lodgepole pine(Pinus contorta). Seedlings fitted with the seedling protection devices (SPD) had significantly lower levels of feeding damage (3 and 9%) than control seedlings (25 and 41%) on two study sites. Most of the feeding damage to treated seedlings was the clipping of the terminal leader or laterals that were not protected by the protection device. In two instances, a vole tunneled under the seedling protection device to damage the stem of the treated seedling; however, this was the exception. This physical barrier can be effective in reducing feeding damage by small mammals on lodgepole pine. West. J. Appl. For. 13(1):12-14.

Population and habitat characteristics of lynx and snowshoe hares in north central Washington

1990 ◽  
Vol 68 (5) ◽  
pp. 845-851 ◽  
Author(s):  
Gary M. Koehler
Keyword(s):  
Pinus Contorta ◽  
Lodgepole Pine ◽  
Population Characteristics ◽  
Habitat Characteristics ◽  
Snowshoe Hare ◽  
Lynx Lynx ◽  
Habitat Conditions ◽  
North Central ◽  
Natural Fire ◽  
Snowshoe Hares

Lynx (Lynx canadensis) and snowshoe hare (Lepus americanus) population characteristics and use of habitats were studied during 1985–1987 in north central Washington. Lynx used areas above 1463 m elevation that were dominated by lodgepole pine (Pinus contorta) and Engelmann spruce – subalpine fir (Picea engelmannii – Abies lasiocarpa) cover types. Snowshoe hares were the most common prey of lynx, with remains of snowshoe hare occurring in 23 of 29 scats. Counts of tracks and pellets showed snowshoe hares to be most abundant in 20-year-old lodgepole pine stands. Fire suppression and natural fire frequencies in the past 5 decades has limited the amount of these early successional forests, which are important as habitat for snowshoe hares. Marginal habitat conditions for snowshoe hares probably resulted in a scarcity of prey in the study area and may explain the relatively large home ranges of lynx (69 ± 28 km2 for five males and 39 ± 2 km2 for two females), low density of adults (2.3 lynx/100 km2), and high kitten mortality rates (88% for eight kittens in three litters). Demographic characteristics of lynx in the study area may be representative of lynx populations along the southern periphery of their range where habitat conditions are marginal for lynx and snowshoe hares.

The Importance of Cover on Use of Conifer Plantations by Snowshoe Hares in Northern New Brunswick

1986 ◽  
Vol 62 (3) ◽  
pp. 159-163 ◽  
Author(s):  
G. R. Parker
Keyword(s):  
New Brunswick ◽  
Pinus Banksiana ◽  
Black Spruce ◽  
Pinus Resinosa ◽  
Jack Pine ◽  
Snowshoe Hare ◽  
Feeding Damage ◽  
Snowshoe Hares ◽  
Conifer Plantations ◽  
Pine Stands

Five conifer plantations were sampled in northern New Brunswick for winter use by snowshoe hare (Lepus americanus). In 8-year old plantations winter hare pellets were 20 times more abundant in a jack pine (Pinus banksiana) than in a black spruce (Picea mariana) stand, which in turn contained 30% more pellets than a red pine (Pinus resinosa) stand. In two 13-year-old plantations, hare pellets were more abundant in a black spruce than a jack pine stand. Conifer cover 1-3 m in height influenced pellet densities. Conifer cover < 1 m in height did not influence pellet densities (winter hare use) probably due to snow depths of approximately that height. Winter pellet densities did not relate to availability of deciduous twigs (preferred food). In young plantations (~8 years), conifer cover was greatest in jack pine stands. By 13 years, high hare densities and subsequent browsing reduced critical conifer cover values in jack pine stands. Conifer cover values and hare densities increased with age of spruce plantations due to less browsing intensity in earlier years. It is concluded that conifer cover 1-3 m above ground is the single most important factor influencing distribution of hares among spruce and pine plantations (and consequent feeding damage to stock species) during winter in northern New Brunswick. Key words: Snowshoe hare, New Brunswick, winter use of pine and spruce plantations, importance of cover.

scholarly journals Elastic Modulus and Elasticity Ratio of Malignant Breast Lesions with Shear Wave Ultrasound Elastography: Variations with Different Region of Interest and Lesion Size

Diagnostics ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 1015
Author(s):  
Antonio Bulum ◽  
Gordana Ivanac ◽  
Eugen Divjak ◽  
Iva Biondić Špoljar ◽  
Martina Džoić Dominković ◽  
...  
Keyword(s):  
Elastic Modulus ◽  
Shear Wave ◽  
Large Diameter ◽  
Small Diameter ◽  
Shear Wave Elastography ◽  
Lesion Size ◽  
Ultrasound Elastography ◽  
Breast Lesions ◽  
Malignant Breast ◽  
The Impact

Shear wave elastography (SWE) is a type of ultrasound elastography with which the elastic properties of breast tissues can be quantitatively assessed. The purpose of this study was to determine the impact of different regions of interest (ROI) and lesion size on the performance of SWE in differentiating malignant breast lesions. The study included 150 female patients with histopathologically confirmed malignant breast lesions. Minimal (Emin), mean (Emean), maximal (Emax) elastic modulus and elasticity ratio (e-ratio) values were measured using a circular ROI size of 2, 4 and 6 mm diameters and the lesions were divided into large (diameter ≥ 15 mm) and small (diameter < 15 mm). Highest Emin, Emean and e-ratio values and lowest variability were observed when using the 2 mm ROI. Emax values did not differ between different ROI sizes. Larger lesions had significantly higher Emean and Emax values, but there was no difference in e-ratio values between lesions of different sizes. In conclusion, when measuring the Emin, Emean and e-ratio of malignant breast lesions using SWE the smallest possible ROI size should be used regardless of lesion size. ROI size has no impact on Emax values while lesion size has no impact on e-ratio values.

An Investigation of the Vibration Testing Method for Small Diameter Endmills

2014 ◽  
Vol 625 ◽  
pp. 134-139
Author(s):  
Takenori Ono
Keyword(s):  
Small Diameter ◽  
Milling Process ◽  
Modal Parameters ◽  
Vibration Testing ◽  
Function Generator ◽  
Testing Method ◽  
Milling Tool ◽  
Compliance Curve ◽  
Vibration Tests ◽  
The Impact

This paper introduced about the in-process vibration testing method for small diameter endmill. By this method, the natural frequency and modal parameters such as mass, damping, and stiffness of the milling tool can be determined in the milling process. An oscillation of the vibrator is controlled by the function generator to apply the impact force at the appropriate cutting period. The measurement setup can determine the compliance curve by the measurement signals of the exiting force and tool deformation. To evaluate the feasibility of the new method, vibration tests were performed on a square endmill which has the diameter of 4 mm in the milling on brass material. Results of vibration tests show that modal parameters of the specific vibration mode can be determined by the new developed method.

Impact of tephra deposition on growth in conifers: the year of the eruption

1984 ◽  
Vol 14 (5) ◽  
pp. 731-739 ◽  
Author(s):  
Thomas M. Hinckley ◽  
Hiromi Imoto ◽  
Katharine Lee ◽  
Susan Lacker ◽  
Yasushi Morikawa ◽  
...  
Keyword(s):  
Fine Root ◽  
Height Growth ◽  
Diameter Growth ◽  
Growth Reduction ◽  
Root Mortality ◽  
Foliar Damage ◽  
Associated Species ◽  
The Impact ◽  
Total Tree ◽  
Mount St Helens

Seven sites ranging from 15 to 135 km from Mount St. Helens were selected to study the impact of air-fall tephra on the growth of Abiesamabilis (Dougl.) Forbes, A. procera Rehd., Pseudotsugamenziesii (Mirb.) Franco, Tsugaheterophylla (Raf.) Sarg., and T. mertensiana (Bong.) Carr. As tephra depth increased, there was a corresponding increase in visible foliar damage and associated decreases in diameter and height growth. Reduction in diameter growth was greater than reduction in height growth. The reduction in diameter growth approached 50% in both trees and saplings of A. amabilis. Growth reduction in true firs was greater than in associated species. This difference was related to their greater capacity for interception and retention of air-fall tephra. Damage to trees, and resulting growth reductions, were due to tephra coverage of both the foliage and the soil. Coverage of the foliage resulted in foliar damage, foliage abscission and reduction of total tree foliar area, and increased fine root mortality. Tephra coverage of the soil had the potential to restrict oxygen diffusion into the soil. However, soil oxygen concentrations less than 10% were measured only once over a 2-year period.

The impact of variable predation risk on stress in snowshoe hares over the cycle in North America’s boreal forest: adjusting to change

Oecologia ◽  
2021 ◽  
Author(s):  
Sophia G. Lavergne ◽  
Charles J. Krebs ◽  
Alice J. Kenney ◽  
Stan Boutin ◽  
Dennis Murray ◽  
...  
Keyword(s):  
Boreal Forest ◽  
Predation Risk ◽  
Snowshoe Hares ◽  
The Impact
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