Effects of high levels of fertilization with urea on growth of thinned and unthinned Douglas-fir stands

1985 ◽  
Vol 15 (4) ◽  
pp. 730-733 ◽  
Author(s):  
H. J. Barclay ◽  
H. Brix
Keyword(s):  
Volume Growth ◽  
Basal Area ◽  
Douglas Fir ◽  
Stem Volume ◽  
Growth Responses ◽  
Positive Interaction ◽  
Fertilizer Use ◽  
Response Period ◽  
Volume Response ◽  
Fertilizer Rates

The diameter and volume growth of Douglas-fir (Pseudotsugamenziesii (Mirb.) Franco) were documented 9 years after thinning and fertilization. The treatments involved three levels of thinning (0, 1/3, and 2/3 of basal area removed) and six levels of fertilization (0–1344 kg N/ha) with urea. Increments for both diameter and gross volume increased with the rate of fertilization and responses were still apparent 9 years after treatment. For unthinned plots, the 9-year volume growth responses were 30, 50, and 80% with fertilizer rates of 224, 448, and 896 kg N/ha, respectively. The efficiency of fertilizer use, measured as stem volume response per unit of nitrogen applied, decreased with the rate of fertilization, but this picture may change over a longer response period. There was a positive interaction between fertilization and thinning such that high levels of both mutually enhanced growth. Mortality increased with fertilization, but only noticeably in unthinned plots.

Effects of fertilization and thinning on 8-year growth responses of second-growth Douglas-fir stands

1991 ◽  
Vol 21 (4) ◽  
pp. 516-521 ◽  
Author(s):  
K. A. Stegemoeller ◽  
H. N. Chappell
Keyword(s):  
Combined Treatment ◽  
Volume Growth ◽  
Basal Area ◽  
Douglas Fir ◽  
Site Quality ◽  
Growth Responses ◽  
Positive Interaction ◽  
Individual Tree ◽  
Growing Stock ◽  
Area And Volume

Fertilization of Douglas-fir (Pseudotsugamenziesii (Mirb.) Franco) stands generally increased both basal area and volume growth for at least 8 years. Thinning tended to have an even greater effect than fertilization on basal area and volume growth, increasing both on an individual-tree basis. On a land-area basis, however, the removal of growing stock by thinning caused volume growth to be less than that of the control. The magnitude and duration of this negative response was dependent on the level of thinning and the site quality. A significant positive interaction between fertilization and thinning exists. The combined treatment resulted in the greatest absolute basal area and volume increments, and the response became greater than that to fertilizer alone in the 3rd and 4th years, and remained so through at least 8 years.

Development and growth of even-aged stands of Douglas-fir and grand fir

1986 ◽  
Vol 16 (2) ◽  
pp. 367-372 ◽  
Author(s):  
Bruce C. Larson
Keyword(s):  
Growth Rates ◽  
Volume Growth ◽  
Basal Area ◽  
Douglas Fir ◽  
Stem Volume ◽  
Mixed Stands ◽  
Site Class ◽  
Development Patterns ◽  
Western Washington ◽  
Eastern Washington

Stand development patterns and growth rates of even-aged mixed stands of Douglas-fir (Pseudotsugamensiesii Mirb. Franco) and grand fir (Abiesgrandis Dougl. Lindl.) were investigated by stand reconstruction in eastern Washington. Although Douglas-fir dominated the stands early, grand fir of the same age eventually overtook the tallest Douglas-firs. Dominant trees of both species were found to have highly variable taper form (based on basal area to height ratios), although a linear relationship existed in other crown classes. Stem volume growth rates were determined by reconstructing past diameters and heights and were found comparable to site class IV Douglas-fir in western Washington. Intensive management, especially planting and thinning, could improve upon the observed mean annual increments of 800 board feet per acre at 80 years of age.

Stand structure and growing space efficiency following thinning in an even-aged Douglas-fir stand

1988 ◽  
Vol 18 (7) ◽  
pp. 859-866 ◽  
Author(s):  
K. L. O'Hara
Keyword(s):  
Stand Structure ◽  
Volume Growth ◽  
Basal Area ◽  
Stand Density ◽  
Douglas Fir ◽  
Stem Volume ◽  
Projection Area ◽  
Individual Tree ◽  
Space Efficiency ◽  
Individual Trees

The growth of individual trees from four thinning treatments in a 64-year-old Douglas-fir (Pseudotsugamenziesii (Mirb.) Franco) stand was analyzed to determine desirable residual stand structures after thinning. Dominant and codominant trees had the highest individual tree stem volume growth rates over the previous 5 years, and accounted for most stand volume growth in thinned and unthinned stands. Two measures of growing space, crown projection area and sapwood basal area (a surrogate for leaf area), were used to measure how efficiently individual trees used their growing space. Crown classes were useful in characterizing growing space efficiency (volume growth per unit of growing space) only in the unthinned treatment. In thinned treatments, tall trees with medium-sized crowns were most efficient, while in the unthinned treatment, tall trees with relatively large crowns were most efficient. A large crown in an unthinned stand was comparable in size to a medium-sized crown in a thinned stand. Results suggest growing space is not limiting individual tree growth in thinned stands and that thinning to a particular stand structure is more appropriate than thinning to a particular level of stand density.

Growth response of unthinned and thinned Douglas-fir stands to single and multiple applications of nitrogen

1990 ◽  
Vol 20 (3) ◽  
pp. 343-349 ◽  
Author(s):  
K. A. Stegemoeller ◽  
H. N. Chappell
Keyword(s):  
Growth Response ◽  
Regional Scale ◽  
Volume Growth ◽  
Basal Area ◽  
Douglas Fir ◽  
Untreated Plot ◽  
Growth Responses ◽  
Average Growth ◽  
Duration Of Response ◽  
And Control

Basal area and volume growth response of unthinned and thinned Douglas-fir (Pseudotsugamenziesii (Mirb.) Franco) stands to single and multiple applications of nitrogen fertilizer were estimated for eight 2-year periods. Response estimates, as differences between growth rates on fertilized and control plots after adjusting for initial volume (or basal area), and trends were analyzed on a regional scale. Average responses to the initial fertilization and to both the second and third fertilizer applications, 8 and 12 years later, were statistically significant (p < 0.05). In thinned stands, average duration of response to the initial treatment was approximately 8 years; unthinned stands continued to show significant volume growth response through 14 years, although basal area growth response decreased to nonsignificant levels between years 10 and 12. In both cases, the response to refertilization, while significant, was smaller than the response to the initial fertilization. Nitrogen applied after the 8th year, and a refertilization after the 12th, on one initially untreated plot at each installation also produced significant average growth responses.

scholarly journals Growth and Mortality of Residual Douglas-Fir after Regeneration Harvests under Group Selection and Two-Story Silvicultural Systems

2011 ◽  
Vol 26 (2) ◽  
pp. 64-70 ◽  
Author(s):  
Sean Garber ◽  
Tzeng Yih Lam ◽  
Douglas A. Maguire
Keyword(s):  
Term Structure ◽  
Group Selection ◽  
Volume Growth ◽  
Basal Area ◽  
Douglas Fir ◽  
Stem Volume ◽  
State University ◽  
Management Objectives ◽  
Integrated Research ◽  
Overstory Trees

Abstract Complex management objectives for many publicly owned Douglas-fir forests have prompted renewed interest in silvicultural systems other than clearcutting. The College of Forestry Integrated Research Project at Oregon State University was implemented to test for differences in economic, biological, and human responses to group selection and two-story silvicultural systems. Three separate blocks were established and treated between 1989 and 1991. Trees were measured immediately after the harvest treatments (1991 or 1992) and after the 2004 growing season. Responses of residual overstory trees to initial group selection and two-story treatments were tested relative to untreated controls units in terms of (1) gross basal area and stem volume growth of all residual trees and of the 10 largest trees per acre; (2) gross basal area and stem volume growth conditional on initial basal area and stem volume, respectively, of all residual trees and of the 10 largest trees per acre; and (3) mortality of all overstory trees. Basal area and volume growth were greatest in the control and least in the two-story treatment, but volume growth conditional on initial volume did not differ significantly among treatments. Mortality was significantly greater in the two-story treatment. Overstory growth release in residual Douglas-fir may require 10 years or more to appear after regeneration cuts on some sites, and the possibility of increased overstory mortality complicates attainment of desired long-term structure under two-story silvicultural systems.

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.

scholarly journals Early Selection of Douglas-Fir across South Central Coastal Oregon, USA

2006 ◽  
Vol 55 (1-6) ◽  
pp. 135-141 ◽  
Author(s):  
C. A. Dean ◽  
R. W. Stonecypher
Keyword(s):  
Genetic Correlations ◽  
Volume Growth ◽  
Douglas Fir ◽  
Early Selection ◽  
Stem Volume ◽  
Direct Selection ◽  
South Central ◽  
Coos Bay ◽  
The Individual ◽  
Age Range

Abstract Details are given of three first-generation progeny tests (CB1, CB2 and CB3) of coastal Douglas-fir (Pseudotsuga menziesii [MIRB.] FRANCO var. menziesii) planted in the Coos Bay region of south-central coastal Oregon in 1973. The three tests included 15 polymix families based on a 10-pollen mix, and 27 families openpollinated on the ortet. The present study gives heritabilities and additive genetic correlations for growth measured between two and 17 years after planting. Correlated responses are estimated for volume at 17 years from early selection for height and diameter. Between four and 17 years after planting the individual heritability (h2) of height of coastal Douglas-fir across the Coos Bay tests was quite stable between h2 = 0.18 and 0.22. The heritability of stem diameter age-forage was consistently much lower than for height. In the critical age range for early selection between five and 10 years the individual heritability of diameter ranged from h2 = 0.07 to 0.10. The additive genetic correlations involving volume-17 and height or diameter increased to high values of rA = 0.80 to 0.84 between eight to 10 years after planting. Before seven years the absolute values of juvenilemature correlations were much lower. The higher heritability of height made this trait the best criterion for early indirect selection to improve mature stem volume growth. Across these Coos Bay tests, early selection on stem height measured at 5-8 years after planting was estimated to produce almost 40% more gain per year in volume-17 compared with direct selection at 17 years on volume-17 itself. The recommendation for maximizing gain per year in mature volume of coastal Douglas-fir at Coos Bay is to select on height at 7-8 years when the mean height of trees in tests should be around 4.5 to 5.5 meters.

Fertilization of Established Southern Pine Stands: Effects of Single and Split Nitrogen Treatments

1993 ◽  
Vol 17 (3) ◽  
pp. 135-138 ◽  
Author(s):  
Eric J. Jokela ◽  
Stephen C. Stearns-Smith
Keyword(s):  
Loblolly Pine ◽  
Volume Growth ◽  
Basal Area ◽  
Pinus Elliottii ◽  
Growth Responses ◽  
Southern Pine ◽  
N Application ◽  
Pine Stands ◽  
Pinus Taeda L ◽  
Nitrogen Treatments

Abstract Data from six fertilizer trials established in semimature southern pine stands (five slash pine, Pinus elliottii Engelm. var. elliottii; one loblolly pine, Pinus taeda L.) were analyzed to determine the efficacy of single vs. split fertilizer treatments. Both fertilizer treatments supplied an elemental equivalent of 200 lb nitrogen (N)/ac and 50 lb phosphorus (P)/ac; however, the first treatment was delivered as a single dose, and the second treatment was a split N application (i.e., 50 lb N and 50 lb P/ac (initial); 150 lb N/ac (2 yr later). Cumulative responses of fertilized plots were still significantly greater than the controls in five trials after 8 yr and averaged 43% (15.7 ft²/ac) and 39% (607 ft³/ac) for basal area and stand volume growth, respectively. In general, no significant differences in either the magnitude or duration of response were detected between the single and split N fertilizer treatments. This suggests that delaying a portion of the N application for 2 yr will not diminish the level of growth responses attained. Therefore, land managers have flexibility in using either application method when implementing midrotation fertilizer prescriptions. South. J. Appl. For. 17(3):135-138.

Response of Eastern White Pine to Nitrogen Fertilization

1991 ◽  
Vol 8 (2) ◽  
pp. 83-85
Author(s):  
Robert K. Shephard ◽  
Gregory A. Reams ◽  
Ronald C. Lemin
Keyword(s):  
Volume Growth ◽  
Basal Area ◽  
Cost Effective ◽  
Application Rate ◽  
White Pine ◽  
Eastern White Pine ◽  
Application Rates ◽  
Volume Response ◽  
Pine Stands ◽  
Area Response

Abstract Plots were established in nine eastern white pine stands; six on outwash soils and three on till soils. Nitrogen was applied to the plots at rates of 0, 50, 100, and 200 lb/ac. Four-year growth response functions for basal area/ac and merchantable cubic ft volume/ac were developed. Basal area growth was 9.2 ft²/ac greater and volume growth was 235 ft³/ac greater on the till soils compared with the outwash soils, regardless of application rate Both basal area and volume growth increased as basal area/ac increased. Maximum basal area response, 5.7 ft²/ac, and maximum volume response, 198 ft³/ac, was estimated to occur at an application rate of approximately 160 lb of nitrogen/ac, with incremental response being greater at lower application rates. Fertilization at a rate of approximately 100 lb of nitrogen/ac appears to be a cost effective practice for many white pine stands. North. J. Appl. For. 8(2):83-85.

Growth Response to Fertilization in Young Douglas-Fir Stands

1989 ◽  
Vol 4 (4) ◽  
pp. 116-119 ◽  
Author(s):  
Linda S. Heath ◽  
H. N. Chappell
Keyword(s):  
Pseudotsuga Menziesii ◽  
Growth Response ◽  
Volume Growth ◽  
Basal Area ◽  
Site Index ◽  
Douglas Fir ◽  
Intermediate Region ◽  
Fertilizer Response ◽  
Breast Height ◽  
Inverse Effect

Abstract Response surface methodology was used to estimate six-year volume growth response to 1 application of 200 lb nitrogen per acre in unthinned and thinned Douglas-fir (Pseudotsuga menziesii) stands of breast height age (bha) 25 years or less. Regional mean fertilizer response was 16% in unthinned stands and 20% in thinned stands. Site index had an increasingly inverse effect on response as basal area increased in both unthinned and thinned stands. Response varied little over site index in regions of low basal area, decreased moderately as site index increased in the intermediate region, and decreased rapidly in the high basal area region. West. J. Appl. For. 4(4):116-119, October 1989.

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