Effects of thinning and nitrogen fertilization on branch and foliage production in Douglas-fir

1981 ◽  
Vol 11 (3) ◽  
pp. 502-511 ◽  
Author(s):  
H. Brix
Keyword(s):  
Nitrogen Fertilization ◽  
Basal Area ◽  
Douglas Fir ◽  
Needle Size ◽  
Crown Width ◽  
Thinning Effect ◽  
Needle Mass ◽  
Crown Size ◽  
Number Of Shoots

The effect of two levels of thinning (zero and [Formula: see text] of basal area removed) and three levels of nitrogen fertilization (0,224, and 448 kg N/ha) on crown development of codominant, 24-year-old Douglas-fir (Pseudotsugamenziesii (Mirb.) Franco) trees was studied over a 5- to 7-year period. Thinning and heavy ferilization separately increased needle mass per tree after 7 years by 90% and, when combined, by 271%. Yearly needle production peaked 2–3 years after fertilization and resulted from an increase in needle size, needle number per shoot, and number of shoots produced. Maximum foliage mass per tree was reached 4–7 years after fertilization. Thinning effect on needle production was lower initially, but increased throughout the study period. A continuing foliage production in branches low in the crown contributed to thinning effect on foliage mass and crown size. Foliage distribution was affected most in the top half of the crown by fertilization and in the bottom half of the crown by thinning. Fertilization increased branch elongation at all crown heights, but thinning alone had no effect on crown width down to whorl 12.

scholarly journals DEVELOPMENT AND TESTING OF STAND MODELS FOR DOUGLAS FIR AND LODGEPOLE PINE

1964 ◽  
Vol 40 (4) ◽  
pp. 494-504 ◽  
Author(s):  
R. M. Newnham ◽  
J. H. G. Smith
Keyword(s):  
Lodgepole Pine ◽  
Basal Area ◽  
Tree Height ◽  
Douglas Fir ◽  
Crown Width ◽  
Research Technique

Methods used in the development and testing of stand models for Douglas fir and lodgepole pine are described briefly. Influence of spacings from 3.3 to 19.8 feet on number of trees per acre, basal area per acre, and average d.b.h. is shown graphically for Douglas fir. The importance of knowing distribution as well as amount of mortality is stressed and illustrated. Use of the model for studying thinning is described.Study of a lodgepole pine model, which also includes tree height and volume per acre, suggests that the general approach based on crown width and d.b.h. of open-grown trees could be applied to other species. Because of the ease and speed of manipulation of these models they could become an important operational and research technique.

Four-year Basal Area Growth Response of a 25-year-old Douglas-fir Stand to Thinning and Urea Fertilization

1974 ◽  
Vol 4 (4) ◽  
pp. 568-571 ◽  
Author(s):  
Y. Jim Lee
Keyword(s):  
Nitrogen Fertilization ◽  
Growth Response ◽  
Basal Area ◽  
Douglas Fir ◽  
Site Quality ◽  
Growing Period ◽  
Basal Area Growth ◽  
Area Growth ◽  
Four Levels ◽  
Urea Fertilization

Four-year growth response to nitrogen fertilization and thinning is reported for an experiment established in a 25-year-old Douglas-fir stand of medium site quality. Four levels of nitrogen (0, 112, 224, and 336 kg N/ha), in the form of urea, were tested at two thinning levels in a randomized 4 × 2 × 2 factorial design replicated in 2 Blocks. Fertilizer was applied in spring or fall. Basal area growth per hectare in the thinned stand significantly surpassed that of the unthinned stand in the fourth growing period. Increased rate of nitrogen fertilization resulted in increased growth 1 year after fertilization. Urea applied in the fall resulted in greater growth response than that applied in the spring for the first growing period and over a 4-year period. Increased rate of fertilization increased mortality significantly in the fourth growing period, but had no prior effect. Thinning decreased mortality in all four growing periods.

Effects of Nitrogen Fertilization on Growth of Grand Fir and Douglas-Fir Stands in Northern Idaho

1989 ◽  
Vol 4 (2) ◽  
pp. 54-57 ◽  
Author(s):  
Bahman Shafii ◽  
James A. Moore ◽  
John R. Olson
Keyword(s):  
Pseudotsuga Menziesii ◽  
Nitrogen Fertilization ◽  
Basal Area ◽  
Douglas Fir ◽  
Tree Size ◽  
Stand Development ◽  
Height Increment ◽  
Area Growth ◽  
Nitrogen Treatment ◽  
Northern Idaho

Abstract A study of nitrogen fertilization response in thinned and unthinned stands of grand fir (Abies grandis) and Douglas-fir (Pseudotsuga menziesii) in northern Idaho showed that the application of one urea nitrogen treatment applied at a rate of 200 lb N/ac resulted in a significantly higher average basal area growth over a 6-year post-treatment period. Nitrogen fertilization also resulted in a significant height increment increase over the same period. Fourteen years after treatment, fertilization had increased average tree size, in terms of total cubic volume, by 14% in unthinned and by 23% in thinned stands. A comparison of thinned and unthinned stands suggested an increase in tree size (>300%) over the same period without significant reduction in average total cubic volume per acre. Patterns of stand development were altered by nitrogen fertilization. West. J. Appl. For. 4(2):54-57, April 1989.

Annual rates and elemental concentrations of litter fall in thinned and fertilized Douglas-fir

1991 ◽  
Vol 21 (11) ◽  
pp. 1601-1615 ◽  
Author(s):  
J. A. Trofymow ◽  
H. J. Barclay ◽  
K. M. McCullough
Keyword(s):  
British Columbia ◽  
Ammonium Nitrate ◽  
Nitrogen Fertilization ◽  
Basal Area ◽  
Stand Density ◽  
Douglas Fir ◽  
Control Plot ◽  
Annual Rate ◽  
Litter Fall ◽  
Elemental Concentrations

Overstory litter fall, primarily needles, was collected for 15 years within control and treated plots in a stand of Douglas-fir (Pseudotsugamenziesii (Mirb.) Franco) located near Shawnigan Lake, British Columbia. Treated plots were thinned or fertilized, or both; thinned plots had two-thirds of their basal area removed, fertilized plots were treated with 448 kg N•ha−1 of either urea or ammonium nitrate, and half the fertilized plots were refertifized at the same rate 9 years later. The annual rate of litter fall in control plots averaged 1890 kg•ha−1. In control plots significant yearly variations were observed in litter-fall mass and concentrations of K, Mg, and Ca but not N or P. Thinning decreased rates of litter fall by 80%, but rates returned to control-plot levels after 13–15 years in unfertilized plots and after 8–10 years in fertilized plots. Fertilization without thinning depressed litter fall in the year of treatment but increased the rate by 20–80% in subsequent years. Litter-fall N concentrations increased by 40–80% the year of fertilization and then began declining 3–6 years later. Nitrogen fertilization reduced litter-fall P, K, and Mg concentrations for 8, 4, and 1 year(s), respectively, following fertilization. The effects were greater in ammonium nitrate plots than in urea plots. Rates of litter fall correlated poorly with stand density but well with basal area and stemwood increment. Correlations with the latter two variables varied with time and treatment.

Detecting the response of Douglas-fir to nitrogen fertilization by regression of periodic annual basal area increment against basal area

1988 ◽  
Vol 18 (10) ◽  
pp. 1343-1346 ◽  
Author(s):  
A. J. Thomson ◽  
K. D. Tudor ◽  
V. J. Korelus ◽  
D. R. Ralph
Keyword(s):  
Temporal Variation ◽  
Growth Rates ◽  
Nitrogen Fertilization ◽  
Basal Area ◽  
Douglas Fir ◽  
Basal Area Increment ◽  
Spatial And Temporal Variation ◽  
Urea Fertilization ◽  
Area Response

Douglas-fir (Pseudotsugamenziesii (Mirb.) Franco) basal area response to urea fertilization at 112 and 224 kg N/ha was studied on a medium site. Regression of tree periodic annual basal area increment against basal area was used to estimate within-plot growth rates. Higher growth rates were observed in the fertilized plots. The slope coefficients of the regressions were used to investigate spatial and temporal variation in growth rates.

Thinning and nitrogen fertilization effects on sapwood development and relationships of foliage quantity to sapwood area and basal area in Douglas-fir

1983 ◽  
Vol 13 (3) ◽  
pp. 384-389 ◽  
Author(s):  
H. Brix ◽  
A. K. Mitchell
Keyword(s):  
Nitrogen Fertilization ◽  
Basal Area ◽  
Douglas Fir ◽  
Annual Rings ◽  
Cross Sectional ◽  
Sapwood Area ◽  
Breast Height ◽  
Linear Relationships ◽  
Regression Slopes ◽  
Fertilization Effects

A 24-year-old Douglas-fir (Pseudotsugamenziesii (Mirb.) Franco) stand was treated with various levels and combinations of nitrogen fertilization and thinning. Over a period of 5–9 years after treatments, trees were sampled to determine effects on foliage quantity and sapwood characteristics at different stem heights together with their relationships. Sapwood width remained relatively constant up the stem where heartwood was present, but the number of annual rings it contained decreased with height. The sapwood width at breast height (bh) increased with stem diameter; treatments had little effect on percent sapwood at bh. The ratio of foliage mass to sapwood cross-sectional area changed for different portions of the crown and was lower when based on sapwood area at bh than at base of live crown. Significant linear relationships of foliage mass and area to sapwood area at bh were found, but relationships of foliage to basal area (bh) were just as close for all treatments; treatments significantly affected these relationships with control trees having the lowest regression slopes.

Preliminary DRIS norms for coastal Douglas-fir soils in Washington and Oregon

1995 ◽  
Vol 25 (2) ◽  
pp. 208-214 ◽  
Author(s):  
J.S. Shumway ◽  
H.N. Chappell
Keyword(s):  
Basal Area ◽  
Site Index ◽  
Douglas Fir ◽  
Integrated System ◽  
N Fertilizer ◽  
Soil Test ◽  
Fertilizer Response ◽  
Response Data ◽  
Limiting Nutrient ◽  
Diagnostic Work

The Diagnosis and Recommendation Integrated System (DRIS) has been used successfully in agricultural crops and holds promise for use in forest stands. This study used soil tests to develop DRIS norms and evaluate their effectiveness in coastal Douglas-fir (Pseudotsugamenziesii (Mirb.) Franco) forests. DRIS norms for nitrogen, phosphorus, potassium, and calcium were developed using soil test and site index data from 72 soil series that commonly support Douglas-fir in western Washington. The norms were tested using soil test and stand basal area growth response data from 20 thinned and 30 unthinned N fertilizer test sites in coastal Washington and Oregon. Response to urea fertilizer in thinned stands averaged 34% and 43% for 224 and 448 kg N•ha−1, respectively, when N was identified as the most limiting nutrient. When N was not the most limiting nutrient, N response averaged 8% and 10% for 224 and 448 kg N•ha−1, respectively. Results were similar in unthinned stands and thinned stands, although response to fertilizer appeared to be slightly less in unthinned stands when N was the most limiting nutrient. DRIS correctly classified 25 of the 33 sites (76%) where N fertilizer increased growth by more than 15%. More importantly, 13 of the 17 (76%) sites that responded by less than 15% were correctly identified by DRIS. The results clearly indicate that N fertilizer response is dependent on the interactions (balance) between soil nutrients at a given site. Future soil diagnostic work needs to focus on techniques, like DRIS, that provide an assessment of these interactions.

scholarly journals Largest-Crown-Width Prediction Models for 53 Species in the Western United States

2004 ◽  
Vol 19 (4) ◽  
pp. 245-251 ◽  
Author(s):  
William A. Bechtold
Keyword(s):  
United States ◽  
Prediction Models ◽  
Basal Area ◽  
Stem Diameter ◽  
Western United States ◽  
Quadratic Term ◽  
Crown Width ◽  
Coefficients Of Variation ◽  
Bioclimatic Index ◽  
Minor Improvement

Abstract The mean crown diameters of stand-grown trees 5.0-in. dbh and larger were modeled as a function of stem diameter, live-crown ratio, stand-level basal area, latitude, longitude, elevation, and Hopkins bioclimatic index for 53 tree species in the western United States. Stem diameter was statistically significant in all models, and a quadratic term for stem diameter was required for some species. Crown ratio and/or Hopkins index also improved the models for most species. A term for stand-level basal area was not generally needed but did yield some minor improvement for a few species. Coefficients of variation from the regression solutions ranged from 17 to 33%, and model R2 ranged from 0.15 to 0.85. Simpler models, based solely on stem diameter, are also presented. West. J. Appl. For. 19(4):245–251.

Effects of mechanical stimulus, shade, and nitrogen fertilization on morphology and bending resistance in Douglas-fir seedlings

2003 ◽  
Vol 33 (9) ◽  
pp. 1602-1609 ◽  
Author(s):  
Stephen J Mitchell
Keyword(s):  
Nitrogen Fertilization ◽  
Mechanical Stimulus ◽  
Douglas Fir ◽  
Height Increment ◽  
Stem Form ◽  
Diameter Increment ◽  
Reduced Height ◽  
Bending Resistance ◽  
Volume Increment ◽  
Bending Stresses

Three-year-old coastal Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) seedlings were planted in a factorial experiment with three levels of shading (0, 30, and 60%), three levels of mechanical stimulus (staked, freestanding, and bent), and two levels of nitrogen fertilization (0 and 200 kg/ha) to investigate the separate and combined effects of these factors on morphology and bending resistance. Fertilization increased branch angle and increased the sensitivity of branch and leader extension to bending stresses but did not affect volume increment, stem form, or bending resistance. The effects of shading and mechanical treatments on morphology were independent and additive. Shading reduced stem diameter and volume increment, but did not affect height increment, producing more slender trees. Bending produced less slender trees through a combination of reduced height increment and increased diameter increment. Staking did not affect tree morphology. Trees under heavy shade were responsive to bending but were more slender and had lower bending resistance than unshaded trees with the same mechanical stimulus. These results point towards the biological basis for the development of tree instability in high density stands.

Sign in / Sign up

Export Citation Format

Share Document