Bud production of Douglas-fir (Pseudotsugamenziesii) seedlings: response to shrub and hardwood competition

1987 ◽  
Vol 17 (10) ◽  
pp. 1300-1304 ◽  
Author(s):  
John C. Tappeiner II ◽  
Thomas F. Hughes ◽  
Steven D. Tesch

Shrubs and hardwoods in five plantations of Douglas-fir (Pseudotsugamenziesii (Mirb.) Franco) in southwestern Oregon were treated to obtain four or five levels of competition; cover ranged from 0 (complete control) to 100% (no treatment). On four of the five plantations, Douglas-fir seedlings significantly increased bud production on the leader in the first growing season after treatment. Buds were more responsive to level of competition than were leader length or growth in stem diameter, for which significant differences were not usually observed until the second growing season after treatment. Bud number on the leader apparently is a good indicator of seedling vigor. Leader, stem diameter, and stem cross-sectional area growth in the 2nd and 3rd years after treatment were positively correlated with the number of buds produced on the leader in the first growing season following treatment.


1972 ◽  
Vol 2 (2) ◽  
pp. 95-97 ◽  
Author(s):  
K. J. Mitchell ◽  
R. M. Kellogg

Consideration is given to the distribution of growth increment at 6 points up the stem of Douglas-fir (Pseudotsugamenziesii (Mirb.) Franco) 5 years after fertilization. The fully stocked stand, near Port Alberni, B.C., was 49 years old with heights and diameters reaching 100 ft and 20 in. respectively when fertilized with 220 and 440 lb/acre of urea. No change of consequence occurred in tree form in the codominant and intermediate crown classes as a result of the volume response which was still evident, although greatly diminished, after 5 years. In dominant trees, however, cross-sectional area growth in the central third of the stem was less than the controls even though other parts of the bole showed a positive response which lasted until the 4th year. The net volume response was negligible. The estimation of volume response to fertilization in dominant trees from breast-height measurements should possibly be approached with caution.



2020 ◽  
Vol 126 (7) ◽  
pp. 1129-1139 ◽  
Author(s):  
Alex Fajardo ◽  
Juan P Mora ◽  
Etienne Robert

Abstract Background and Aims Twig cross-sectional area and the surface area of leaves borne on it are expected to be isometrically correlated across species (Corner’s rules). However, how stable this relationship remains in time is not known. We studied inter- and intraspecific twig leaf area–cross-sectional area (la–cs) and other scaling relationships, including the leaf–shoot mass (lm–sm) scaling relationship, across a complete growing season. We also examined the influence of plant height, deciduousness and the inclusion of reproductive buds on the stability of the scaling relationships, and we discuss results from a functional perspective. Methods We collected weekly current-year twigs of six Patagonian woody species that differed in growth form and foliar habit. We also used prominent inflorescences from Embothrium coccineum (Proteaceae) to assess whether reproductive buds alter the la–cs isometric relationship. Mixed effects models were fitted to obtain parameter estimates and to test whether interaction terms were non-significant (invariant) for the scaling relationships. Key Results The slope of the la–cs scaling relationship remained invariant across the growing season. Two species showed contrasting and disproportional (allometric) la–cs scaling relationships (slope ≠ 1). Scaling relationships varied significantly across growth form and foliar habit. The lm–sm scaling relationship differed between reproductive- and vegetative-origin twigs in E. coccineum, which was explained by a significantly lower leaf mass per area in the former. Conclusions Although phenology during the growing season appeared not to change leaf–shoot scaling relationships across species, we show that scaling relationships departed from the general trend of isometry as a result of within-species variation, growth form, foliar habit and the type of twig. The identification of these functional factors helps to understand variation in the general trend of Corner’s rules.



1993 ◽  
Vol 23 (8) ◽  
pp. 1704-1711 ◽  
Author(s):  
Stith T. Gower ◽  
Brent E. Haynes ◽  
Karin S. Fassnacht ◽  
Steve W. Running ◽  
E. Raymond Hunt Jr.

The objective of this study was to examine the effect of fertilization on the allometric relations for red pine (Pinusresinosa Ait.) and ponderosa pine (Pinusponderosa Dougl. ex Laws.) growing in contrasting climates. After 2 years of treatment, fertilization did not significantly affect the allometric relations between stem or branch mass and stem diameter for either species. For a similar-diameter tree, current foliage mass and area and new twig mass were significantly greater for fertilized than for control red pine and ponderosa pine. The significant increase in new foliage mass and area occurred in the upper and middle canopy for red pine and middle and lower canopy for ponderosa pine. For a similar-diameter tree, projected (one-sided) leaf area and total foliage mass were significantly greater for fertilized than for control red pine. However, leaf area and total foliage mass did not differ between similar-diameter fertilized and control ponderosa pine because fertilization decreased leaf longevity. The ratios of leaf area/sapwood cross-sectional area measured at breast height (1.37 m) were 0.14 and 0.11 for control plus fertilized red pine and ponderosa pine, respectively, and were greater (but not significantly) for fertilized than for control trees, while the ratios of leaf area/sapwood cross-sectional area measured at the base of live crown were significantly greater for fertilized than for control red pine and ponderosa pine.



1982 ◽  
Vol 12 (4) ◽  
pp. 738-744 ◽  
Author(s):  
William G. Newton ◽  
Douglas C. Allen

The distribution, abundance, and characteristics of sugar maples (Acersaccharum Marsh.) at time of attack by sugar maple borer, Glycobiusspeciosus (Say), were determined on 1.9 ha in Wanakena, New York. Twenty-six percent (n = 78) of the maple stems in the study area were damaged. Average dbh of trees attacked remained the same throughout the 40-year history of the infestation. Mean dbh of trees at time of attack by sugar maple borer was 18.7 cm. Percent cross-sectional area growth at breast height in control trees (3.7%) was significantly greater (P < 0.01) than growth of attacked trees (1.9%) the year preceeding year of attack. Annual mean percentage growth of successfully attacked trees declined 5–10 years prior to year of attack. The cryptic nature of much borer damage indicates that previous estimates of impact are conservative.



2002 ◽  
Vol 32 (9) ◽  
pp. 1542-1547 ◽  
Author(s):  
Mike G Cruickshank

Stem cross-sectional areas were checked for accuracy and precision of area measurements in healthy and Armillaria ostoyae (Romagn.) Herink infected 18-year-old Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco). Ten trees were randomly selected in each combination of two size classes and four infection classes, and stem disks were taken at the soil line (0 m) and at 1.3 m. Disks were marked at the longest radius, 90° to the longest radius, the shortest radius, and at radii determined by the sum of the largest diameter and the diameter at 90° divided by four. These radii were used to calculate cross-sectional area, then these calculated areas were compared with the corresponding digitized areas. Cross-sectional areas calculated from radial measurements were generally not within 5% of digitized areas. Radii were also drawn on the disks corresponding to the positions at which healthy and infected roots arose from the root collar below. For 0-m disks, the stem radii over healthy roots averaged 7 mm longer than over infected roots. At 1.3 m, the stem radii over healthy roots were 4 mm longer, but this was reduced with increasing infection of the root system. Offset piths and irregular shapes formed because of radial reduction over infected roots, and corresponding radial expansion over healthy roots affected the accuracy of disk area estimation.



2009 ◽  
Vol 35 (6) ◽  
pp. 281-286
Author(s):  
Edward Gilman ◽  
Jason Grabosky

One codominant stem on each of 48 similar Quercus virginiana Highrise® trees was pruned to evaluate impact of pruning severity on growth suppression and partitioning. Targeted pruning severity (0, 25, 50 or 75% foliage and subtending branches removed) based on visual estimates of two people correlated well (r2 = 0.87) with the ratio stem cross-sectional area removed: crosssectional area at base of the pruned codominant stem. Pruning reduced cross-sectional area growth on codominant stems compared to the leader stem that was not pruned, especially during the first 12 months following pruning. Increased pruning severity reduced cross-sectional area growth on the pruned stem in proportion to amount of foliage removed. In each of three years following pruning, cross-sectional area of the unpruned leader stem increased more on trees receiving targeted pruning severities of 25% or 50% than trees pruned with the 75% severity or trees not pruned. Shift in growth from the pruned to unpruned portion of the tree reduced diameter ratio between the two stems, which should make the union stronger. Diameter ratio changed most for the 75% pruning severity.



1994 ◽  
Vol 07 (03) ◽  
pp. 110-113 ◽  
Author(s):  
D. L. Holmberg ◽  
M. B. Hurtig ◽  
H. R. Sukhiani

SummaryDuring a triple pelvic osteotomy, rotation of the free acetabular segment causes the pubic remnant on the acetabulum to rotate into the pelvic canal. The resulting narrowing may cause complications by impingement on the organs within the pelvic canal. Triple pelvic osteotomies were performed on ten cadaver pelves with pubic remnants equal to 0, 25, and 50% of the hemi-pubic length and angles of acetabular rotation of 20, 30, and 40 degrees. All combinations of pubic remnant lengths and angles of acetabular rotation caused a significant reduction in pelvic canal-width and cross-sectional area, when compared to the inact pelvis. Zero, 25, and 50% pubic remnants result in 15, 35, and 50% reductions in pelvic canal width respectively. Overrotation of the acetabulum should be avoided and the pubic remnant on the acetabular segment should be minimized to reduce postoperative complications due to pelvic canal narrowing.When performing triple pelvic osteotomies, the length of the pubic remnant on the acetabular segment and the angle of acetabular rotation both significantly narrow the pelvic canal. To reduce post-operative complications, due to narrowing of the pelvic canal, overrotation of the acetabulum should be avoided and the length of the pubic remnant should be minimized.



Author(s):  
Antonio Cicchella ◽  
Monica Mannai ◽  
Jaan Ereline ◽  
Mati Paasuke ◽  
Helena Gapeyeva


2020 ◽  
Vol 0 (4) ◽  
pp. 19-24
Author(s):  
I.M. UTYASHEV ◽  
◽  
A.A. AITBAEVA ◽  
A.A. YULMUKHAMETOV ◽  
◽  
...  

The paper presents solutions to the direct and inverse problems on longitudinal vibrations of a rod with a variable cross-sectional area. The law of variation of the cross-sectional area is modeled as an exponential function of a polynomial of degree n . The method for reconstructing this function is based on representing the fundamental system of solutions of the direct problem in the form of a Maclaurin series in the variables x and λ. Examples of solutions for various section functions and various boundary conditions are given. It is shown that to recover n unknown coefficients of a polynomial, n eigenvalues are required, and the solution is dual. An unambiguous solution was obtained only for the case of elastic fixation at one of the rod’s ends. The numerical estimation of the method error was made using input data noise. It is shown that the error in finding the variable crosssectional area is less than 1% with the error in the eigenvalues of longitudinal vibrations not exceeding 0.0001.



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