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

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.

1990 ◽  
Vol 20 (3) ◽  
pp. 309-314 ◽  
Author(s):  
Pierre Y. Bernier

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.


1997 ◽  
Vol 71 (1) ◽  
pp. 158-162 ◽  
Author(s):  
Alan L. Titus

In 1988, the presence of an Early Pennsylvanian ammonoid assemblage within the basal meter of the Callville Formation (Pennsylvanian-Permian), eastern Clark County, Nevada, was brought to the attention of the author by Stephen M. Rowland, University of Nevada-Las Vegas. The ammonoids occur in the Frenchman Mountain section described by Rowland (1987) for the Geological Society of America's Decade of North American Geology (DNAG) field trip compendium. The mid-Carboniferous section at this locality (Figure 1) was discussed in two other field trip guides as well (Langenheim and Webster, 1979; Webster et al., 1984). No ammonoids have been reported previously from this locality. Although this is the first record of Cancelloceras from the Great Basin region, the assemblage also provides a narrowly constrained age for the basal part of the Callville Formation at Frenchman Mountain, which in turn, dates the initiation of carbonate deposition following a major mid-Carboniferous hiatus in the southern Great Basin.


2017 ◽  
Vol 47 (8) ◽  
pp. 1123-1130 ◽  
Author(s):  
Pontus M.F. Lindgren ◽  
Thomas P. Sullivan ◽  
Douglas B. Ransome ◽  
Druscilla S. Sullivan ◽  
Lisa Zabek

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.


1994 ◽  
Vol 24 (5) ◽  
pp. 897-903 ◽  
Author(s):  
Daniel B. Tinker ◽  
William H. Romme ◽  
William W. Hargrove ◽  
Robert H. Gardner ◽  
Monica G. Turner

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.


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 ◽  
...  

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.


2006 ◽  
Vol 138 (6) ◽  
pp. 888-896 ◽  
Author(s):  
Ward B. Strong

AbstractManagement of Leptoglossus occidentalis Heidemann in lodgepole pine (Pinus contorta var. latifolia Engelm.) seed orchards of British Columbia, Canada, would be improved with knowledge of its damage potential at different times of the growing season. Mesh insect-exclusion bags were placed over cones, and adults or nymphs of L. occidentalis were enclosed in different bags for 9 periods of 10 to 38 days between 6 May and 17 September 2004. Feeding by adult females between 6 May and 28 May reduced total extractable seeds, a result of ovule damage before fertilization. Reduction in the number of filled seeds per cone was highest between 6 May and 29 June, with each adult female reducing yield by approximately 1.7 seeds per day. Between 29 June and 10 August, each adult female reduced the number of filled seeds per cone (seed set) by 1.0 to 1.25 per day. Seed set reduction declined to approximately 0.25 filled seeds per adult female per day after 10 August. Third to fifth instars caused seed set reduction between 0.6 and 1.2 filled seeds per cone per nymph feeding day from 29 June to 10 August. Utilizing these findings would improve management of L. occidentalis in a commercial seed orchard setting.


2014 ◽  
Vol 44 (11) ◽  
pp. 1312-1319 ◽  
Author(s):  
Eleanor C. Lahr ◽  
Anna Sala

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.


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