Wind speed and snow evaporation in a stand of juvenile lodgepole pine in Alberta

1990 ◽  
Vol 20 (3) ◽  
pp. 309-314 ◽  
Author(s):  
Pierre Y. Bernier
Keyword(s):  
Wind Speed ◽  
Linear Function ◽  
Open Field ◽  
Lodgepole Pine ◽  
Stand Density ◽  
Full Density ◽  
Adjacent Field ◽  
Angle Of View ◽  
Lodgepole Pines

Wind speed and snow evaporation were measured in a small artificial stand of 2.5-m lodgepole pines and in an adjacent field during the winter of 1987. Stand densities of 2500, 1650, and 800 stems/ha were obtained through periodic removal of trees. The reduction of wind speed brought about by the trees is a linear function of [Formula: see text], the angle of view from the anemometer to the tops of the surrounding trees. When the stand was at full density, snow evaporation was about one-third of that measured in the open field, and when stand density was reduced to 1650 stems/ha, snow evaporation was equal to that of the open field. Because of high melt rates, no data were obtained from the lowest stand density. The results are summarized in a predictive relation between the angle of view [Formula: see text] and the reduction in snow evaporation caused by the trees.

scholarly journals Stand structure governs the crown collisions of lodgepole pine

2003 ◽  
Vol 33 (7) ◽  
pp. 1238-1244 ◽  
Author(s):  
Mark Rudnicki ◽  
Victor J Lieffers ◽  
Uldis Silins
Keyword(s):  
Wind Speed ◽  
High Frequency ◽  
Pinus Contorta ◽  
Stand Structure ◽  
Lodgepole Pine ◽  
Stand Density ◽  
Empty Space ◽  
Tree Sway ◽  
Individual Trees ◽  
Crown Dimensions

We investigated tree sway and crown collision behavior of even-aged lodgepole pine (Pinus contorta Dougl. ex Loud. var. latifolia Engelm.) stands of different structure in Alberta, Canada, to examine how these factors might affect loss of leaf area as stands mature. The Two Creeks stand (TC) had high density and slender trees, while the Chickadee stand (CH) had stout trees. The TC stand was then thinned (TCT) to reduce the stand density. For each stand, simultaneous tree sways of a group of 10 trees were monitored with biaxial clinometers during wind speed of 5 m/s (canopy top). Crown collisions were reconstructed by combining sway displacement of individual trees with their respective crown dimensions. Comparing the sway statistics between stands with contrasting mean bole slenderness (TC and CH) indicated that more slender trees have greater sway displacements, faster sway speeds, and a greater depth of collision. Disturbance by thinning increased sway displacements, sway speeds, and depth of collisions at TCT. Tree sway patterns were circular in shape and not aligned with wind direction, but patterns were elongated after thinning. This demonstrates the high frequency of crown collision experienced by stands with slender trees and supports the notion that crown collisions result in empty space between crowns of trees.

The effects of stand density on frequency of filled seeds and fecundity in lodgepole pine (Pinuscontorta Dougl.)

1988 ◽  
Vol 18 (4) ◽  
pp. 453-460 ◽  
Author(s):  
Christopher C. Smith ◽  
J. L. Hamrick ◽  
Charles L. Kramer
Keyword(s):  
Great Basin ◽  
Growth Form ◽  
Lodgepole Pine ◽  
Stand Density ◽  
Breeding Systems ◽  
Woody Perennials ◽  
Cross Pollination ◽  
Lodgepole Pines ◽  
Basin Region ◽  
Filled Seeds

In lodgepole pines self- and cross-pollination initiate the development of seeds with equal frequency, but self-pollination results in filled seeds only 17% as frequently as cross-pollination. A study of the frequency of initiation of seed development and filled seeds in 17 stands of lodgepole pine differing in spacing and growth form of trees indicates that both the quantity of pollen produced by a tree and the density of conspecific individuals influence the frequency of filled seeds. Moreover, the positioning of a cone relative to the top and bottom or windward and leeward sides of a tree influences the frequency of filled seeds. Genetic markers used in controlled crosses indicate that cross pollen fertilizes significantly more than half the filled seeds resulting from crosses with equal mixes of self and cross pollen. The effect of density of conspecifics and growth form of trees on the frequency of filled seeds gives an adaptive basis for the facultative shift in sex ratio in lodgepole pine. It also suggests an adaptive basis for the high frequency of dioecy in wind-pollinated, woody perennials of the Great Basin Region. This relationship also has practical implications for the management of breeding systems for seed production and reforestation.

scholarly journals Long-term influence of stand thinning and repeated fertilization on forage production in young lodgepole pine forests

2017 ◽  
Vol 47 (8) ◽  
pp. 1123-1130 ◽  
Author(s):  
Pontus M.F. Lindgren ◽  
Thomas P. Sullivan ◽  
Douglas B. Ransome ◽  
Druscilla S. Sullivan ◽  
Lisa Zabek
Keyword(s):  
Pinus Contorta ◽  
Large Scale ◽  
Bos Taurus ◽  
Lodgepole Pine ◽  
Stand Density ◽  
Stand Age ◽  
Forage Production ◽  
South Central ◽  
Stand Thinning

Integration of trees with forage and livestock production as silvopastoralism is another potential component of intensive forest management. Stand thinning and fertilization may enhance growth of crop trees and understory forage for livestock. We tested the hypothesis that large-scale precommercial thinning (PCT) (particularly heavy thinning to ≤1000 stems·ha−1) and repeated fertilization, up to 20 years after the onset of treatments, would enhance production of graminoids, forbs, and shrubs as cattle (Bos taurus L.) forage. Results are from two long-term studies: (1) PCT (1988–2013) and (2) PCT with fertilization (PCT–FERT) (1993–2013) of lodgepole pine (Pinus contorta Dougl. ex Loud. var. latifolia Engelm.) stands in south-central British Columbia, Canada. Mean biomass estimates of graminoids, forbs, total herbs, and shrubs were not affected by stand density. However, fertilization enhanced mean biomass estimates of graminoids, forbs, and total herbs, but not shrubs. Thus, the density part of our hypothesis was not supported, but the nutrient addition part was supported at least for the herbaceous components. Biomass of the herbaceous understory was maintained as a silvopasture component for up to 20 years (stand age 13 to 33 years) in fertilized heavily thinned stands prior to canopy closure.

Landscape-scale heterogeneity in lodgepole pine serotiny

1994 ◽  
Vol 24 (5) ◽  
pp. 897-903 ◽  
Author(s):  
Daniel B. Tinker ◽  
William H. Romme ◽  
William W. Hargrove ◽  
Robert H. Gardner ◽  
Monica G. Turner
Keyword(s):  
National Park ◽  
Lodgepole Pine ◽  
Morphological Characteristics ◽  
Landscape Scale ◽  
Acute Angle ◽  
Seedling Density ◽  
Postfire Regeneration ◽  
Lodgepole Pines ◽  
The Relationship ◽  
Landscape Level

A 1992 study of serotiny in lodgepole pine (Pinuscontorta Dougl. ex Loud. var. latifolia Engelm.) in Yellowstone National Park asked four questions: (i) are there morphological characteristics that can be used to estimate pre-fire proportion of serotinous trees in forests that burned in 1988?; (ii) at what spatial scale does percent serotinous trees vary across the landscape?; (iii) which environmental factors are correlated with serotiny?; and (iv) what is the relationship between prefire serotiny and postfire lodgepole pine seedling density? We first sampled cone characteristics in serotinous and nonserotinous trees along four 2950-m transects in unburned forests, and examined burned trees nearby. Results indicated that asymmetrical cones and an acute angle of cone attachment to the branch were reliable indicators of serotiny even in burned trees. We then sampled nine patches of lodgepole pine forest that had burned in 1988, and varied in size from 1–3600 ha. We sampled serotiny at varying intervals along two perpendicular transects that crossed in the center of each patch. At each sample point, the 12 nearest canopy lodgepole pines were classified as serotinous or nonserotinous. We concluded that the percentage of serotinous trees is most variable at intermediate scales of 1–10 km, and is relatively homogeneous at both fine scales (<1 km) and at very broad scales (tens of kilometers). Percent serotiny was generally more variable and greater at low to middle elevations. Prefire density of serotinous trees was a more important predictor of postfire seedling density than aspect, slope, or soil type. These findings have important implications for landscape-level patterns in postfire regeneration of lodgepole pine.

Stand growth responses after fertilization for thinned lodgepole pine, Douglas-fir, and spruce in forests of interior British Columbia, Canada

2019 ◽  
Vol 49 (11) ◽  
pp. 1471-1482
Author(s):  
Woongsoon Jang ◽  
Bianca N.I. Eskelson ◽  
Louise de Montigny ◽  
Catherine A. Bealle Statland ◽  
Derek F. Sattler ◽  
...  
Keyword(s):  
British Columbia ◽  
Picea Glauca ◽  
Lodgepole Pine ◽  
Basal Area ◽  
Stand Density ◽  
Site Index ◽  
Douglas Fir ◽  
Picea Sitchensis ◽  
Growth And Yield ◽  
Growth Responses

This study was conducted to quantify growth responses of three major commercial conifer species (lodgepole pine (Pinus contorta Douglas ex Loudon var. latifolia Engelm. ex S. Watson), interior Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco var. glauca (Beissn.) Franco), and spruce (white spruce (Picea glauca (Moench) Voss) and hybrid spruce (Picea engelmannii Parry ex. Engelm. × Picea glauca (Moench) Voss × Picea sitchensis (Bong.) Carrière))) to various fertilizer blends in interior British Columbia, Canada. Over 25 years, growth-response data were repeatedly collected across 46 installations. The fertilizer blends were classified into three groups: nitrogen only; nitrogen and sulfur combined; and nitrogen, sulfur, and boron combined. The growth responses for stand volume, basal area, and top height were calculated through absolute and relative growth rate ratios relative to a controlled group. Fertilizer blend, inverse years since fertilization, site index, stand density at fertilization, and their interactions with the fertilizer blend were used as explanatory variables. The magnitude and significance of volume and basal area growth responses to fertilization differed by species, fertilizer-blend groups, and stand-condition variables (i.e., site index and stand density). In contrast, the response in top height growth did not differ among fertilization blends, with the exception of the nitrogen and sulfur fertilizer subgroup for lodgepole pine. The models developed in this study will be incorporated into the current growth and yield fertilization module (i.e., Table Interpolation Program for Stand Yields (TIPSY)), thereby supporting guidance of fertilization applications in interior forests in British Columbia.

Species, elevation, and diameter affect whitebark pine and lodgepole pine stored resources in the sapwood and phloem: implications for bark beetle outbreaks

2014 ◽  
Vol 44 (11) ◽  
pp. 1312-1319 ◽  
Author(s):  
Eleanor C. Lahr ◽  
Anna Sala
Keyword(s):  
Nutritional Quality ◽  
Pinus Contorta ◽  
Mountain Pine Beetle ◽  
Lodgepole Pine ◽  
Large Diameter ◽  
Small Diameter ◽  
Whitebark Pine ◽  
Mountain Pine ◽  
Pine Trees ◽  
Lodgepole Pines

Stored resources in trees reflect physiological and environmental variables and affect life history traits, including growth, reproduction, resistance to abiotic stress, and defense. However, less attention has been paid to the fact that stored resources also determine tissue nutritional quality and may have direct consequences for the success of herbivores and pathogens. Here, we investigated whether stored resources differed between two hosts of the mountain pine beetle (Dendroctonus ponderosae Hopkins, 1902): lodgepole pine (Pinus contorta Douglas ex. Loudon), a common host, and whitebark pine (Pinus albicaulis Engelmann), a more naïve host that grows at higher altitudes. Phloem and sapwood were sampled in small- and large-diameter trees at two elevations, and nitrogen, phosphorus, nonstructural carbohydrates, and lipids were measured. We found that concentrations of stored resources increased with elevation and tree diameter for both species and that whitebark pine had thicker phloem than lodgepole pine. Overall, stored resources were higher in whitebark pine such that small-diameter whitebark pine trees often had resource concentrations higher than large-diameter lodgepole pines. These results suggest that whitebark pine is of higher nutritional quality than lodgepole pine, which could have implications for the current expansion of mountain pine beetles into higher altitude and latitude forests in response to climate warming.

scholarly journals Populus simonii Carr. Reduces Wind Erosion and Improves Soil Properties in Northern China

Forests ◽  
2019 ◽  
Vol 10 (4) ◽  
pp. 315 ◽  
Author(s):  
Jieming Zhang ◽  
Guodong Jia ◽  
Ziqiang Liu ◽  
Dandan Wang ◽  
Xinxiao Yu
Keyword(s):  
Sediment Transport ◽  
Wind Speed ◽  
Wind Erosion ◽  
Surface Wind ◽  
Chemical Properties ◽  
Stand Density ◽  
Northern China ◽  
Stand Age ◽  
Sand Transport ◽  
Total N

To assess the ecological effects of poplar stands with different densities and ages, fixed observation sites were established in selected standard forest plots. Daily dynamics of wind speed and sand transport rate were monitored over an erosive period (March to June) in 2017. Soil characteristics were also measured at these plots. Average daily wind speed and average daily wind erosion modulus decreased significantly after the establishment of poplar trees on sandy land, while soil density decreased significantly, soil hardness increased greatly, and soil organic carbon, total N, and available P levels increased significantly. With increasing stand density, average daily wind speed and daily sediment transport firstly decreased and then increased, while the investigated soil nutrients showed the opposite trend. A tree density of 1320–1368 trees·hm−2 significantly reduced surface wind erosion. With the increase in forest age, the average daily wind speed and daily sediment transport declined, while soil physical and chemical properties were gradually improved. At a stand age of 40 years, wind-caused soil erosion significantly reduced. Taking these effects into consideration, the design and management of protective forest systems in arid and semi-arid areas can be greatly improved.

Rate of Loss of Ammonia from Water to the Atmosphere

1979 ◽  
Vol 36 (6) ◽  
pp. 685-689 ◽  
Author(s):  
R. R. Weiler
Keyword(s):  
Wind Speed ◽  
Key Words ◽  
Linear Function ◽  
Natural Water ◽  
Water Bodies ◽  
Exchange Coefficient ◽  
Ammonia Exchange ◽  
Natural Water Bodies ◽  
Loss Rates

The rate of loss of ammonia from water to the atmosphere has been measured both in the field and in the laboratory as a function of wind speed, temperature, and pH. The exchange coefficient, Ke, was found to be a linear function of wind speed and temperature. Although the loss rates (1–10 kg∙ha−1∙d−1) are quite high at pH 9 and at ammonia concentrations > 1 mg N∙dm−3, the rates are much smaller under the conditions found in most natural water bodies. Key words: ammonia, exchange coefficient, rate of loss from water

Carbohydrate allocation and mountain pine beetle attack in girdled lodgepole pines

1986 ◽  
Vol 16 (5) ◽  
pp. 1036-1040 ◽  
Author(s):  
R. H. Miller ◽  
A. A. Berryman
Keyword(s):  
Mountain Pine Beetle ◽  
Lodgepole Pine ◽  
Soluble Sugars ◽  
Lower Trunk ◽  
Mountain Pine ◽  
Pine Beetle ◽  
Pine Trees ◽  
Lodgepole Pines

Healthy lodgepole pine trees (Pinuscontorta Dougl. var. latifolia Engelm.) were girdled on the lower trunk in patterns designed to selectively eliminate the influence of materials transported from the roots, lateral tissues, and crown. Titres of soluble sugars and starch observed in areas isolated by girdling were significantly lower than those observed in areas open to the upper bole and crown. Corresponding decreases were observed in the numbers of Dendroctonusponderosae Hopkins attacking those areas.

scholarly journals On the Linear Parameterization of Drag Coefficient over Sea Surface

2004 ◽  
Vol 34 (12) ◽  
pp. 2847-2851 ◽  
Author(s):  
Changlong Guan ◽  
Lian Xie
Keyword(s):  
Wind Speed ◽  
Drag Coefficient ◽  
Linear Function ◽  
Sea Surface ◽  
Wave Steepness ◽  
Wave Age ◽  
Age Dependent ◽  
Logarithmic Law ◽  
Linear Parameterization ◽  
Charnock Relation

Abstract Combining the logarithmic law with the Charnock relation yields a drag coefficient that is a function of wind speed with the Charnock coefficient as a parameter. It is found that the function is nearly linear within the typically measured range of the drag coefficient. The slope of the linear function is dominated by the Charnock coefficient. When the Charnock relation is extended to a wave age–dependent function, the drag coefficient remains a near-linear function of wind speed after invoking the 3/2 power law. The slope of the linear function is dominated by wave steepness.

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