Synergistic stem volume response to combinations of vegetation control and seedling size in conifer plantations in Oregon

2006 ◽  
Vol 36 (4) ◽  
pp. 930-944 ◽  
Author(s):  
Lee S Rosner ◽  
Robin Rose

There are few published studies examining the effects of the interaction of seedling size and vegetation control on the growth of Pacific Northwest conifer species. Data from two vegetation management studies encompassing five planting sites, four conifer species, and two stock types were analyzed to determine the relative effects of seedling size at planting and intensity of vegetation control on subsequent seedling growth. Study 1 tested eight combinations of annual broadcast weed control or no weed control applied over the course of 5 years. Study 2 tested spot herbicide applications of differing area, as well as herbaceous-only and woody-only control treatments. The effect of seedling size was determined by analysis of covariance, with basal diameter as the covariate. Both seedling size and weed control increased growth of all conifer species through 4, 5, or 12 years, but responses varied by species and site. Diameter and height responses to weed control and seedling size were additive, whereas volume differences between treatments increased with increasing seedling size. The implication for management is that the volume return from increased weed control is maximized by planting the largest possible seedlings; conversely, the volume from increased seedling size is maximized at the highest weed control intensities.

2002 ◽  
Vol 32 (1) ◽  
pp. 136-152 ◽  
Author(s):  
Robin Rose ◽  
J Scott Ketchum

An experiment evaluating three levels of vegetation competition control (no control, 1.5 m2 of vegetation control, and 3.3 m2 of vegetation control), each with two fertilization treatments (fertilization at the time of planting with complete slow-release fertilizer (Woodace® IBDU), or no fertilization), was installed at five sites. Two of these sites were planted with Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) in the Oregon Coast Range, one with ponderosa pine (Pinus ponderosa Dougl. ex P. Laws. & C. Laws.) in eastern Washington, one with western hemlock (Tsuga heterophylla (Raf.) Sarg.) in the coastal hemlock zone in Oregon, and one with coastal redwood (Sequoia sempervirens (D. Don) Endl.) in northern California. At four of the five sites, mean stem volume, basal diameter, and height of seedlings increased significantly with increasing area of weed control, and the magnitude of difference between treatments increased with time. Fertilization significantly increased seedling size only at the two sites with adequate soil moisture; increases were marginally significant at a third. Response to fertilization was less than from weed control and impacted growth for only the first year, whereas the influence of weed control continued to influence growth the entire length of the study (4 years). Area of vegetation control and fertilization did not interact significantly at any site.


1993 ◽  
Vol 23 (10) ◽  
pp. 2049-2058 ◽  
Author(s):  
M. A. Perry ◽  
R. J. Mitchell ◽  
B. R. Zutter ◽  
G. R. Glover ◽  
D. H. Gjerstad

A factorial combination of 0, 1, 2, and 4 loblolly pine (Pinustaeda L.) seedlings and sweetgum (Liquidambarstyraciflua L.) sprouts, and 0, 4, and 16 broomsedge (Andropogonvirginicus L.) seedlings per square metre were used to determine the nature of pine response to competition (competitive response) from multiple life forms during the first season after outplanting. Following adjustment for effects of seedling size and site heterogeneity (soil organic matter), polynomial regression was used to describe pine competitive responses. Patterns in competitive responses varied with time and were dependent upon the particular response variable of interest. Pine response in terms of volume was similar to that for diameter. By early May, pine diameter decreased linearly with increasing sweetgum density but was unrelated to either broomsedge or pine density. Approximately 1 month later, pine diameter response to competition was more complex, being curvilinearly related to both sweetgum and broomsedge density, as well as their interaction. Intraspecific competition effects on diameter response were not detected until mid-September. Height response differed substantively from diameter or volume response. In general, height tended to be less responsive to interspecific competition, although intraspecific competition was more readily detected. Furthermore, pine height response to competition tended to be linear rather than curvilinear, as observed for both diameter and volume. The biologically based reciprocal yield equation produced similar trends in competitive pine volume response, as noted with the polynomial regression equations (i.e., sweetgum and broomsedge density as well as their interaction strongly influenced the inverse of pine stem volume). Removing variation in organic matter and initial seedling size resulted in a considerable increase in the amount of variation in final size accounted for by competition. The reciprocal yield equation was also used with crown area rather than density to account for size differences among competitors. Analyzed in this manner, only main effects of sweetgum and broomsedge significantly influenced reciprocal yield; however, considerably less variation in response was accounted for using crown area than using density.


2006 ◽  
Vol 36 (10) ◽  
pp. 2464-2473 ◽  
Author(s):  
Robin Rose ◽  
Lee S Rosner ◽  
J Scott Ketchum

Coastal Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco var. menziesii) response to eight weed control treatments was measured 12 years after planting at two Oregon sites. Treatments included four areas of weed control around individual trees (0.375, 1.49, 3.35, and 5.95 m2), no weed control (check), total vegetation control, control of herbaceous competition only, or control of woody competition only. Douglas-fir growth and woody-species invasion differed between the Coast Range site (Summit) and the Cascade Range foothills site (Marcola). Woody species reinvasion was more intense at Summit, with Douglas-fir cumulative mortality in the check treatment reaching 23% in year 12. Woody-only control improved Douglas-fir growth at Summit but had no significant effect on growth at Marcola. Total vegetation control had a profound effect on stem volume growth 12 years after planting. At Summit, total vegetation control resulted in a 355% increase in volume per hectare relative to the check. At Marcola the increase was only 63%. At Summit, growth increased with each increase in area of weed control, whereas at Marcola growth increased with increasing area of weed control up to 3.35 m2 of control. Results suggest that much of the gain in volume growth attributable to weed control may be lost if weed-control treatments are not highly efficacious. The differential response to woody control indicates that its benefit at a given site is strongly related to the abundance of competitive hardwood species, which may be predicted from the preharvest stand structure and vegetation community.


2021 ◽  
Vol 13 (8) ◽  
pp. 4167
Author(s):  
David Kombi Kaviriri ◽  
Huan-Zhen Liu ◽  
Xi-Yang Zhao

In order to determine suitable traits for selecting high-wood-yield Korean pine materials, eleven morphological characteristics (tree height, basal diameter, diameter at breast height, diameter at 3 meter height, stem straightness degree, crown breadth, crown height, branch angle, branch number per node, bark thickness, and stem volume) were investigated in a 38-year-old Korean pine clonal trial at Naozhi orchard. A statistical approach combining variance and regression analysis was used to extract appropriate traits for selecting elite clones. Results of variance analysis showed significant difference in variance sources in most of the traits, except for the stem straightness degree, which had a p-value of 0.94. Moderate to high coefficients of variation and clonal repeatability ranged from 10.73% to 35.45% and from 0.06% to 0.78%, respectively. Strong significant correlations on the phenotypic and genotypic levels were observed between the straightness traits and tree volume, but crown breadth was weakly correlated to the volume. Four principal components retaining up to 80% of the total variation were extracted, and stem volume, basal diameter, diameter at breast height, diameter at 3 meter height, tree height, and crown height displayed high correlation to these components (r ranged from 0.76 to 0.98). Based on the Type III sum of squares, tree height, diameter at breast height, and branch number showed significant information to explain the clonal variability based on stem volume. Using the extracted characteristics as the selection index, six clones (PK105, PK59, PK104, PK36, PK28, and K101) displayed the highest Qi values, with a selection rate of 5% corresponding to the genetic gain of 42.96% in stem volume. This study provides beneficial information for the selection of multiple traits for genetically improved genotypes of Korean pine.


Geoderma ◽  
2019 ◽  
Vol 350 ◽  
pp. 73-83 ◽  
Author(s):  
Daniel G. DeBruler ◽  
Stephen H. Schoenholtz ◽  
Robert A. Slesak ◽  
Brian D. Strahm ◽  
Timothy B. Harrington

Author(s):  
Eric Jessup ◽  
Ken Casavant

Grain producers and handlers in Washington State have benefited from a multimodal transportation network of roads, railroads, and the Columbia–Snake River barge system to move large amounts of grain effectively in a timely and economic manner. The competitive environment of the grain industry brings many changes, including the number of firms and houses, mergers, and modal competitiveness. Additionally, marketing strategies are affected because choices of available transportation modes reflect the decision processes of warehouses or firm managers. This aggregate study of grain marketing and transportation in the Pacific Northwest helps lay the groundwork for subsequent estimates of empirical demand. Such subsequent modeling attempts may include revealed and stated preference analysis in discrete choice demand models. A thorough understanding of the industry and market characteristics should improve empirical estimation efforts and produce more defensible policy analysis. Based on a 90% shipment volume response rate, results show that in the Columbia–Snake River grain situation, one destination absorbs more than 90% of shipments. Modal competition is active; barge has a market share of more than 50%, down 12–16% from 10 years ago. Multiple-car shipments have increased, but not drastically. Rates are consistently competitive over the period. Finally, grain demand is seasonal but generally has been stable over time. The revealed preferences from this aggregate analysis suggest that price elasticity may vary across shippers, times of movement, and modal availability.


2006 ◽  
Vol 36 (10) ◽  
pp. 2474-2485 ◽  
Author(s):  
Robert G Wagner ◽  
Andrew P Robinson

The influence of the timing and duration of interspecific competition on planted jack pine (Pinus banksiana Lamb.), red pine (Pinus resinosa Ait.), eastern white pine (Pinus strobus L.), and black spruce (Picea mariana (Mill.) BSP) was assessed using 10-year growth responses in a northern Ontario experiment. Stand volume was 117%, 208%, 224%, and 343% higher for jack pine, red pine, white pine, and black spruce, respectively, with 5 years of vegetation control than with no vegetation control. Stand volume increased linearly with number of years of vegetation control, and the slope of the relationship varied among conifer species. Change-point regression analysis was used to derive segmented weed-free and weed-infested curves, and to simultaneously estimate key critical-period parameters. Weed-free and weed-infested curves in the 10th year were similar to those derived in year 5, indicating that the patterns established during the first few years after planting were relatively robust for the first decade. The critical-period was 2 and 3 years after planting for jack pine and red pine, respectively, and occupied most of the 5-year period for white pine and black spruce. Principal components analysis of the vegetation community indicated that repeated herbicide applications caused differential shifts in the relative abundance of shrub, fern, and moss species through the 10th year. Species richness, however, was not substantially different between the untreated control and the most intensive treatments. Difference modeling was used to quantify how annual volume increment during the first decade varied with time, conifer species, cover of woody and herbaceous vegetation, and stage of development.


2004 ◽  
Vol 28 (3) ◽  
pp. 152-162 ◽  
Author(s):  
Kirk D. Howell ◽  
Timothy B. Harrington

Abstract To quantify effects of nursery practices on seedling cost and performance, cherrybark oaks (Quercus pagoda L.) were grown in three container sizes (170, 650, or 1,250 cm3) with or without fertilization and then planted Dec. 1995 at a site near Milledgeville, GA, with or without removal of container soil. Initial size, biomass, and leaf area of seedlings grown in medium and large containers were up to twice those grown in small containers, and they were greater with versus without fertilization. Price efficiency (stem volume divided by estimated nursery price of 1,000 seedlings) was greatest for medium and large containers with soil removed and hypothetically reused. Differences in stem diameter and height due to container size and fertilization continued to diverge through the fifth year after planting. Fifth-year yield (stem volume × proportionate survival of 1,000 planted seedlings) increased 104, 56, and 31% with increasing container size and with fertilization and soil removal, respectively. Cost efficiency (fifth-year yield divided by costs compounded 5 years at 5% interest) was greatest for medium and large containers with soil removed. Joint comparisons of nursery costs, planting costs, and field performance for different seedling stock types provide an objective approach for prioritizing cultural treatments in forestry. South. J. Appl. For. 28(3):152–162.


2002 ◽  
Vol 19 (3) ◽  
pp. 101-105 ◽  
Author(s):  
John R. Seifert ◽  
Keith Woeste

Abstract Azafenidin, sulfometuron, pendimethalin, and simazine were applied alone and in combination to 1-0 seedlings of nine hardwood and one conifer species. Percent bare ground at 30, 60, and 90 days, diameter and height growth of the seedlings were determined for 16 herbicide treatments, tillage and a control. Azafenidin applications alone and in combination with sulfometuron resulted in about 85% bare ground 90 days post-treatment. There were significant differences for diameter, height growth, and volume among the treatments for every species. No single treatment ranked best for all species, but comparison of the mean ranks of the treatments for all species indicated that azafenidin and pendimethalin resulted in the most growth. Azafenidin-treated seedlings also had the greatest volume at the end of the season.


1993 ◽  
Vol 17 (4) ◽  
pp. 193-196 ◽  
Author(s):  
L. V. Pienaar ◽  
B. D. Shiver

Abstract The study reported here provides information on the yield potential of improved loblolly pine seedlings planted on marginal agricultural cropland in the Georgia Piedmont with control of herbaceous competition. Early growth rates greatly exceed those in existing plantations established on cutover and mechanically site-prepared land in this region without additional control of competing vegetation. After 8 growing seasons, average tree height, average dbh, basal area per acre, and stem volume per acre were all influenced by planting density, but the mean annual increment of merchantable volume (trees 4.0 in. dbh and bigger to a 2.0 in. top diameter) at age 8 yr, for planting densities of 400 to 1000 trees/ac, was 230 ft³, or approximately 3 cords/ac/yr. This is more than twice the average growth rate in this region of cutover and mechanically site-prepared loblolly plantations without additional vegetation control. These results should be of particular interest to prospective participants in the Conservation Reserve Program (CRP). South. J. Appl. For. 17(4):193-196.


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