Incidence of main stem infections of lodgepole pine by western gall rust decreases with tree age

2005 ◽  
Vol 35 (6) ◽  
pp. 1314-1318 ◽  
Author(s):  
Peter V Blenis ◽  
Wuhan Li

Infection of lodgepole pine (Pinus contorta Dougl. ex Loud. var. latifolia Engelm.) by western gall rust has been shown to decrease with tree height and age, but the effects of those two factors have not been separated. Five replicate artificial inoculations were done on a total of 327 trees of different ages in two height classes. Temperature and percentage of spore germination at the height of inoculation, shoot development (stem elongation at the time of inoculation as a proportion of final shoot elongation), main stem leader length at the time of inoculation, tree height, and tree age were measured. Modeled percentages of infected trees and the number of galls per 10 cm of shoot length decreased by 85% and 88%, respectively, as tree age increased between 2 and 10 years, indicating the undesirability of early, aggressive precommercial thinning of lodgepole pine stands in areas where western gall rust is common. By controlling and (or) statistically accounting for inoculum, microclimate, and phenological factors, it was possible to demonstrate that changes in susceptibility with tree age are sufficient to account for the reduction in infection with tree height.

1999 ◽  
Vol 14 (4) ◽  
pp. 186-193 ◽  
Author(s):  
Shongming Huang

Abstract Using the felled tree data, ecoregion-based height-diameter models were developed for lodgepole pine (Pinus contorta var. latifolia) in Alberta. A large number of height-diameter functions were evaluated, and the Chapman-Richards function was found to produce some of the most satisfactory fits. Residual analysis was conducted to identify the error structure of the models. A weighting factor of wi = 1/Di was found appropriate for achieving the equal error variance assumption. Differences of the height-diameter models among different ecoregions were examined and tested using the nonlinear extra sum of squares method. Most height-diameter relationships were found to be different among different ecoregions. Ecoregions of similar height-diameter relationships were combined to provide a composite model to facilitate the practical use of such relationships. West. J. Appl. For. 14(4):186-193.


2006 ◽  
Vol 36 (4) ◽  
pp. 878-885 ◽  
Author(s):  
J M Wolken ◽  
P V Blenis ◽  
I Duncan

The probability of lodgepole pine (Pinus contorta Dougl. ex Loud.) having main-stem galls caused by western gall rust, Endocronartium harknessii (J.P. Moore) Y. Hiratsuka, surviving to rotation is unknown. To evaluate survival, 400 galled trees with at least one stem gall and 400 trees without stem galls were measured in 1992 in two precommercially thinned stands approximately 20 years old. The survival of trees was assessed in 2003. Nonlinear regression using iteratively reweighted least squares was employed to estimate the survival of galled trees as a function of the proportion of the main stem encircled by galls. Galls encircling >79% and >91% of the stem in the two stands increased the risk of mortality relative to non-galled trees, with the risk increasing steeply with percent gall encirclement; smaller stem galls did not cause tree mortality. The 11-year pattern of survival of galled trees was similar for infections that occurred on the main stem and those that had reached the stem from a nearby branch infection. Based on an earlier model of gall expansion, 38%–43% of stem-galled trees would be expected to survive until age 80. Scribing of stem galls to prevent their expansion does not appear to be a feasible management strategy.


2006 ◽  
Vol 36 (5) ◽  
pp. 1059-1066 ◽  
Author(s):  
Isabelle Chuine ◽  
Gerald E Rehfeldt ◽  
Sally N Aitken

In this study we aimed to compare and explain the height growth performance of two contrasting pine species: lodgepole pine (Pinus contorta Dougl. ex. Loud) and western white pine(Pinus monticola Dougl. ex D. Don.). We compiled measurements of total height growth at different ages and shoot elongation phenology realized in several provenance test trials for 109 provenances of lodgepole pine and 54 provenances of western white pine. The response of shoot elongation to temperature was assessed using a phenological model fitted on provenance mean growth curves. Although total height growth followed the same geographic trends in both species, the response of shoot elongation to temperature was different between the two, with few (lodgepole pine) or no differences among provenances (western white pine) from diverse geographic regions. The temperature for which potential cell growth rate is 50% was 10.8 ± 0.13 °C (mean ± standard error) for western white pine compared to 5.26 ± 0.075 °C for lodgepole pine. Phenology did not explain growth performance differences among geographical regions in both species, which instead were explained by differences in the number of internodes set the preceding summer; provenances originating from stressful environments produced the fewest internodes, possibly due to reallocation of carbohydrates to stress resistance.


2003 ◽  
Vol 18 (3) ◽  
pp. 149-154 ◽  
Author(s):  
Chad E. Keyser ◽  
Kelsey S. Milner

Abstract This study examined long-term diameter and height response of ponderosa pine (Pinus ponderosa) and lodgepole pine (Pinus contorta var. latifolia) to a one-time application of herbicide during seedling establishment in western Montana. Two herbicide trials initiated in 1981 and 1983 by Champion International Corporation were resurrected during the summer of 1997. Analysis of variance (ANOVA) F-tests along with Duncan's Multiple Range tests (DMR) were performed on mean tree dbh, tree height, and competing vegetation percent cover estimates. In addition, a graphical analysis of mean annual height growth over time was performed. Significant increases (alpha = 0.05) in ponderosa pine dbh (25 to 44%) and height (11 to 28%) were found after 16 yr of growth on Velpar L. (hexazinone) treated plots, while lodgepole pine had significant increases in dbh (70 to 118%) and height (41 to 82%) after 15 yr of growth on Velpar L. treated plots. Graphical analyses indicated a positive height growth effect for a period of 11 to 13 yr following treatment for ponderosa pine; however, total height gains had decreased in recent years. Positive increases in height growth for lodgepole pine were continuing after 15 yr of growth. These results indicate that a one-time application of herbicide applied during seedling establishment will promote faster tree growth in western Montana. We also note that proper density management will be necessary early in the life of the stand to maintain height gains. West. J. Appl. For. 18(3):149–154.


2006 ◽  
Vol 36 (1) ◽  
pp. 48-61 ◽  
Author(s):  
P M.F Lindgren ◽  
D B Ransome ◽  
D S Sullivan ◽  
T P Sullivan

We investigated plant community responses (abundance, species diversity, and structural diversity) to a range of precommercial thinning densities in young lodgepole pine (Pinus contorta Dougl. ex Loud. var. latifolia Engelm.) stands 12 to 14 years after thinning, with both unthinned and old-growth stands for comparison. Abundance of understory plants, especially herbs, appeared to increase dramatically in the thinned stands. The moss layer was significantly more abundant in old-growth stands than in the young pine stands. Of a total of 108 species sampled, only three were introduced species, all of which occurred more frequently in the low-density stands than in any of the other stands. Thinning treatments appeared to increase the abundance of late-seral species. Our results suggest that by disrupting canopy closure, thinning decreased the dominance of tall trees and increased the abundance of herbs, shrubs, and trees in the understory height classes. As a result, thinning to low densities significantly increased the structural richness of the tree layer and caused an increase in total structural diversity, which, although only marginally significant (p = 0.06), was likely biologically important. Our results suggest that thinning will enhance the abundance, species diversity, and structural diversity of the plant community 12 to 14 years postthinning.


1997 ◽  
Vol 87 (1) ◽  
pp. 81-88 ◽  
Author(s):  
K. E. Trewhella ◽  
S. R. Leather ◽  
K. R. Day

AbstractThe acceptance of different provenances or seed origins of lodgepole pine Pinus contorta and Scots pine P. sylvestris as suitable oviposition sites was found to vary as a function of both tree age and insect species. Experiments on seedling lodgepole pine revealed that the pine sawfly, Neodiprion sertifer Geoffroy (Hymenoptera: Diprionidae), and the larch bud moth, Zeiraphera diniana Guennée (Lepidoptera: Tortricidae), preferred more southerly provenances of lodgepole pine. The pine beauty moth, Panolis flammea Denis & Schiffermüller (Lepidoptera: Noctuidae), however, preferred more northerly provenances. On mature lodgepole pine however, P. flammea exhibited a host change, preferring the more southerly provenances. Neodiprion sertifer showed a similar preference on both seedling and mature provenances. The results of this study suggest that some provenances of lodgepole pine become more resistant to attack by P. flammea as they mature, while others become more susceptible. This may be related to the feeding, strategies of the two insects: P. flammea larvae feed on current year foliage while N. sertifer feeds only on previous year foliage. It is possible that the mechanism for chemical defence of new shoots changes as the trees mature, and to a varying degree in different provenances, while defence of the previous years foliage remains unchanged. Results also indicate that odour alone as opposed to odour plus visual stimulation may invoke different ovipositional behaviour in N. sertifer.


2005 ◽  
Vol 35 (8) ◽  
pp. 1952-1964 ◽  
Author(s):  
R P Brockley

The effects of factorial combinations of post-thinning density and fertilization on the growth and development of young lodgepole pine (Pinus contorta Dougl. ex Loud. var. latifolia Engelm.) were investigated in central British Columbia. The effects of density and fertilization (repeated every 5 years) on tree height were small relative to the effects on stem radial growth. Tree radial growth increased with thinning intensity, whereas per-hectare growth was greatest at the highest residual density. Fertilizer effects varied across the range of residual densities tested. Tree and stand volume gains following fertilization were less, in both relative and absolute terms, at 600 trees/ha than at 1100 or 1600 trees/ha. Vigorous response of understory vegetation to nutrient additions (and strong competition for water and nutrients) may have reduced the effectiveness of fertilization on tree growth at 600 trees/ha relative to higher stand densities. Results indicate that the combined positive effects of thinning and fertilization on the growth of young lodgepole pine will accelerate stand development, thereby shortening technical rotation length. Results also indicate that significant growth gains following fertilization of thinned lodgepole pine will partially compensate for stand volume losses due to thinning. However, fertilization may be less effective at low stand densities, where negative effects of thinning on harvest volume are greatest.


2005 ◽  
Vol 83 (8) ◽  
pp. 983-988 ◽  
Author(s):  
Erin C Fraser ◽  
Victor J Lieffers ◽  
Simon M Landhäusser

This study investigated stand factors associated with the rate of root graft formation in lodgepole pine stands. Forty plot areas, each containing 10 trees, were excavated in pure, even-aged pine stands in western Alberta. Exposed root systems were examined for grafts and various stand measurements were recorded at each plot. Results indicate that the number of grafts per square metre is controlled by plot tree density and tree diameter. Also, the percentage of grafted trees increased with both increasing tree age and decreasing distance between trees. Grafts also appear to form relatively early in stand development; the majority of grafts in the present study had formed by the time roots were 20 years old and 50 mm in diameter. These results suggest that grafting is a common occurrence in lodgepole pine stands where trees are <109 cm apart, which translates to a density of approximately 8500 stems/ha (based on even tree distribution). However, even clumps within relatively low density stands are likely to be grafted from a relatively early stage of development.Key words: Pinus contorta, graft formation, stand dynamics.


2007 ◽  
Vol 37 (8) ◽  
pp. 1450-1459 ◽  
Author(s):  
Shawn D. Mansfield ◽  
Roberta Parish ◽  
James W. Goudie ◽  
Kyu-Young Kang ◽  
Peter Ott

Crown depth, tree spacing, and stand density have major effects on wood quality and fibre characteristics of trees. Lodgepole pine ( Pinus contorta Doug. ex Loud.) trees from a mixture of plantation and fire origin stands were employed to determine how crown ratio, a surrogate for stand density, affected mature wood production. In total, 104 trees were sampled, ranging from 24 to 110 years of age, from stands in western Alberta and interior British Columbia, Canada. Samples taken along the bole were measured for wood density, which was subject to segmented regression analysis to identify the transition point from juvenile to mature wood production. On average, the lodgepole pine trees were 31 (±17 SD) years old before mature wood production began. A mixed-effects model, in which combination of fixed effects (tree age, height of the sample disc relative to crown base, and crown length) and random effects (site, trees nested in sites, and discs nested in both trees and sites) proved to be the best predictor of years of mature wood production along the bole. The transition from juvenile to mature wood was shown to be below the crown base in trees <50 years old with deep crowns, and above the crown base otherwise.


Plant Disease ◽  
2001 ◽  
Vol 85 (11) ◽  
pp. 1193-1199 ◽  
Author(s):  
B. D. Moltzan ◽  
P. V. Blenis ◽  
Y. Hiratsuka

Temporal changes in three factors (shoot susceptibility, spore availability, and spore germinability) were evaluated to estimate their effects on the infection of lodgepole pine (Pinus contorta var. latifolia) by Endocronartium harknessii. Germinability of rust spores from sori free of hyperparasites remained above 80% during the growing season and thus would not have significantly limited infection. In contrast, there was a slight, but statistically insignificant, increase in estimated susceptibility as infection increased from 94% of maximum at 45% shoot elongation to maximum susceptibility at 90% shoot elongation. This was followed by a precipitous decline in estimated susceptibility to 57% of maximum when shoots were 95% elongated. Spore availability was 24% of maximum when shoots were 45% elongated, and thus may have been limiting at the beginning of the growing season. At the end of the growing season, spore availability declined prior to, or simultaneous with, the decline in susceptibility. The combined effect of both factors drastically reduced the number of infections estimated to occur once shoots are more than 95% elongated. As shoots elongated, relatively more infections formed higher on the shoot, supporting the hypothesis that periderm is important in limiting infection.


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