Effect of urea fertilization on allometric relations in young Douglas-fir trees

1984 ◽  
Vol 14 (6) ◽  
pp. 900-904 ◽  
Author(s):  
Charles C. Grier ◽  
Katharine M. Lee ◽  
Ruth M. Archibald
Keyword(s):  
Nitrogen Availability ◽  
Regional Analysis ◽  
N Fertilization ◽  
Douglas Fir ◽  
Leaf Biomass ◽  
Regression Equations ◽  
Class Iii ◽  
Site Class ◽  
Allometric Relations ◽  
Urea Fertilization

The effect of nitrogen fertilization on allometric relations was examined for 23-year-old site class III Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) trees 2 years after urea fertilization. Logarithmic regression equations using stem diameter (centimetres) to predict tree biomass components (kilograms) were not significantly (p = 0.05) different between fertilized and control trees for total foliage, total branch, dead branch, stembark, or stemwood. New foliage and new twig components, however, were higher in fertilized trees than in control trees. Analysis of data from this and earlier studies suggests fertilization will increase leaf biomass per tree relative to control trees on sites having low nitrogen availability; however, this response will decrease with increasing nitrogen availability. Regression equations based on regional analysis of unfertilized trees yield estimates of foliage biomass for average trees on average sites. If N fertilization brings the site above average in terms of nitrogen availability then these regression equations will underestimate foliage biomass. However, on sites that are initially very nitrogen deficient, N fertilization will bring the site closer to average in terms of nitrogen availability, resulting in more accurate predictions of foliage biomass for fertilized stands than for control stands.

Allometric relations of deciduous (Larixoccidentalis) and evergreen conifers (Pinuscontorta and Pseudotsugamenziesii) of the Cascade Mountains in central Washington

1987 ◽  
Vol 17 (7) ◽  
pp. 630-634 ◽  
Author(s):  
Stith T. Gower ◽  
Charles C. Grier ◽  
Daniel J. Vogt ◽  
Kristiina A. Vogt
Keyword(s):  
Lodgepole Pine ◽  
Douglas Fir ◽  
Stem Diameter ◽  
Regression Equations ◽  
Western Larch ◽  
Cross Sectional ◽  
Allometric Relations ◽  
Needle Morphology ◽  
Evergreen Conifer ◽  
Evergreen Conifers

Logarithmic equations for estimating component biomass and projected leaf area from stem diameter and (or) sapwood cross-sectional area were computed for western larch (Larixoccidentalis Nutt.), lodgepole pine (Pinuscontorta Dougl.), and Douglas-fir (Pseudotsugamenziesii (Mirb.) Franco) in a mixed conifer stand in the Cascades of central Washington. Regression equations for estimating foliage biomass reported in this study did not compare favorably with foliage biomass allometric relations from other studies. For a given diameter, western larch supported a greater current foliage mass than lodgepole pine or Douglas-fir (P < 0.001); however, the total foliage mass of lodgepole pine was significantly greater (P < 0.001) than western larch. Despite lodgepole pine supporting a total foliage mass approximately twofold greater than western larch, allometric relations between foliage area and stem diameter were not different (P > 0.05) between the deciduous and evergreen conifer. Western larch supports a needle morphology that provides a greater photosynthetic surface area per unit of carbon invested than evergreen conifers in this environment.

Douglas-fir and white fir advance regeneration for renewal of mixed-conifer forests

1993 ◽  
Vol 23 (7) ◽  
pp. 1427-1437 ◽  
Author(s):  
Steven D. Tesch ◽  
Ed J. Korpela
Keyword(s):  
Mediterranean Climate ◽  
Height Growth ◽  
Douglas Fir ◽  
Regression Equations ◽  
Site Class ◽  
Class V ◽  
Advance Regeneration ◽  
White Fir ◽  
Mixed Conifer Forests ◽  
Site Classes

Stem analysis of Douglas-fir (Pseudotsugamenziesii (Mirb.) Franco) and white fir (Abiesconcolor (Gord. & Glend.) Lindl.) advance regeneration 20 years after overstory removal showed that both species can respond in height growth to become dominant components of future stands on medium- to low-quality sites with a Mediterranean climate. Average annual height growth of both species nearly doubled on site classes III and IV during the first 5 years after release and continued to increase over the 20-year period of observation. Trees on the poorer site class V responded more slowly, but achieved similar 5-year periodic annual height growth after 20 years. Regression analyses indicated that prerelease height growth and site class were generally the most important variables in describing height growth after overstory removal, but regression equations left much variability in growth unexplained. Discriminant analysis was used to develop functions that identified trees meeting or exceeding specified levels of average annual height growth 5, 10, or 20 years after release; the classifications were generally successful at least 70% of the time.

Assessing the impact of N-fertilization on biochemical composition and biomass of a Douglas-fir canopy—A remote sensing approach

2012 ◽  
Vol 153 ◽  
pp. 124-133 ◽  
Author(s):  
Thomas Hilker ◽  
Lucie Lepine ◽  
Nicholas C. Coops ◽  
Rachhpal S. Jassal ◽  
T. Andrew Black ◽  
...  
Keyword(s):  
Remote Sensing ◽  
Biochemical Composition ◽  
N Fertilization ◽  
Douglas Fir ◽  
The Impact

scholarly journals Evaluation of Occlusal Contacts among Different Groups of Malocclusion using 3D Digital Models

2014 ◽  
Vol 15 (1) ◽  
pp. 46-55 ◽  
Author(s):  
Naim Z Al-Rayes ◽  
Mohammad Y Hajeer
Keyword(s):  
Class Ii ◽  
Sexual Differences ◽  
Class I ◽  
Stepwise Multiple Regression ◽  
Regression Equations ◽  
Class Iii ◽  
Digital Models ◽  
Arch Width ◽  
Division 1 ◽  
3D Digital Models

ABSTRACT Objectives (1) To evaluate the applicability of using 3D digital models in the assessment of the magnitude of occlusal contacts by measuring occlusal contact surface areas (OCSAs) and 3D mesh points in ‘contact’ (OCMPs) in a sample of orthodontic patients; (2) To detect any sex differences in the magnitude of occlusal contacts in all malocclusion groups; (3) To detect intergroup differences; (4) To assess possible correlations between occlusal contacts and other dental characteristics. Materials and methods Study casts of 120 malocclusion patients were selected and divided into 4 groups (class I division 1, class II division 1, class II division 2, class III) with equal numbers for both sexes. 3D digital models were produced using O3DM™ technology. Occlusal contacts were quantified using two methods of measuring. Results (1) No significant sexual differences were detected for OCMPs (mesh points) and OCSAs (mm2) in all groups. (2) There were statistically significant differences among malocclusion groups for OCMPs and OCSAs (p < 0.001). Tukey's HSD posthoc tests showed that class III patients had significantly less occlusal contacts than other malocclusion groups. (3) Stepwise multiple regression equations showed that overjet, lower arch width and overbite could explain approximately 19.5% of the total variance of OCSAs and OCMPs. Conclusion Sexual differences in occlusal contacts were not detected. Class I division 1 patients had the highest amount of occlusal contacts among all groups of malocclusion. Overjet, overbite and lower dental arch width were best predictors of occlusal contacts in the current sample. How to cite this article Al-Rayes NZ, Hajeer MY. Evaluation of Occlusal Contacts among Different Groups of Malocclusion using 3D Digital Models. J Contemp Dent Pract 2014;15(1):46-55.

Effects of thinning and urea fertilization on the distribution of area increment along the boles of Douglas-fir at Shawnigan Lake, British Columbia

1984 ◽  
Vol 14 (6) ◽  
pp. 879-884 ◽  
Author(s):  
A. J. Thomson ◽  
H. J. Barclay
Keyword(s):  
Growth Rate ◽  
Radial Growth ◽  
Temporal Trend ◽  
Douglas Fir ◽  
Regression Methods ◽  
Average Area ◽  
Breast Height ◽  
Urea Fertilization ◽  
Measurement Period ◽  
Growth Distribution

The effects of fertilization and thinning of Douglas-fir (Pseudotsugamenziesii (Mirb.) Franco) on the distribution of area increment along the bole were assessed using radial growth measurements 6 and 9 years after treatment. Within treatments, the average area increment per tree was linearly related to diameter at breast height, and this relationship was used to evaluate the effects of treatment on growth rate. Fertilization had the greatest effect on average area increment, and for a particular fertilization regime, thinning increased the response. Thinning modified the distribution of growth over the bole of all trees and increased butt flare, especially in smaller trees. The effect declined from the 4- to 6-year measurement period to the 7-to 9-year measurement period. Fertilization had no consistent effect on growth distribution. The regression methods used in this study provided a more sensitive measure of form changes than previous methods, were independent of size distribution, and facilitated extrapolations and evaluation of temporal trend.

scholarly journals Effects of Nitrogen Foliar Fertilization on the Vegetative and Productive Performance of the Olive Tree and on Oil Quality

Agriculture ◽  
2019 ◽  
Vol 9 (12) ◽  
pp. 252
Author(s):  
Luca Regni ◽  
Primo Proietti
Keyword(s):  
Nitrogen Availability ◽  
Oil Quality ◽  
Central Italy ◽  
Olive Tree ◽  
Proximal Part ◽  
Specific Weight ◽  
N Fertilization ◽  
Second Phase ◽  
Oil Accumulation ◽  
Foliar Fertilization

The correct management (dose, time of distribution) of N fertilization in olive growing is still not completely clarified but is nowadays essential in order to guarantee sustainable production. In this regard, in central Italy over a 4-year-period a study was carried out to investigate the effect of high nitrogen availability during oil accumulation in the fruit (second phase of fruit growth) on vegetative and productive activities of olive trees and oil quality. In May of each year, secondary branches were selected and girdled in their proximal part. Afterwards, half of the girdled branches were sprayed three times with a solution containing urea (2% w/w), whereas the other half was sprayed only with water. The nitrogen treatments did not cause any damage to the foliage and fruits nor did it cause appreciable changes in leaf photosynthesis and specific weight, fruit-drop, ripening pattern and weight, water and oil contents, pulp/pit ratio of the fruits, fatty acid composition, polyphenols content, and sensorial characteristics of the oil. The N provided via foliar fertilization during the oil accumulation phase in trees in conditions of good supply of N does not induce significant effects on the vegetative-productive activity of the tree.

Douglas-fir soil C and N properties a decade after termination of urea fertilization

2001 ◽  
Vol 31 (12) ◽  
pp. 2225-2236 ◽  
Author(s):  
Peter S Homann ◽  
Bruce A Caldwell ◽  
H N Chappell ◽  
Phillip Sollins ◽  
Chris W Swanston
Keyword(s):  
Mineral Soil ◽  
Cellulase Activity ◽  
Douglas Fir ◽  
Soil Organic C ◽  
Total N ◽  
Organic C ◽  
Soil C ◽  
Second Growth ◽  
Heavy Fractions ◽  
Urea Fertilization

Chemical and microbial soil properties were assessed in paired unfertilized and urea fertilized (>89 g N·m–2) plots in 13 second-growth Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) stands distributed throughout western Washington and Oregon. A decade following the termination of fertilization, fertilized plots averaged 28% higher total N in the O layer than unfertilized plots, 24% higher total N in surface (0–5 cm) mineral soil, and up to four times the amount of extractable ammonium and nitrate. Decreased pH (0.2 pH units) caused by fertilization may have been due to nitrification or enhanced cation uptake. In some soil layers, fertilization decreased cellulase activity and soil respiration but increased wood decomposition. There was no effect of fertilization on concentrations of light and heavy fractions, labile carbohydrates, and phosphatase and xylanase activities. No increase in soil organic C was detected, although variability precluded observing an increase of less than ~15%. Lack of a regionwide fertilization influence on soil organic C contrasts with several site-specific forest and agricultural studies that have shown C increases resulting from fertilization. Overall, the results indicate a substantial residual influence on soil N a decade after urea fertilization but much more limited influence on soil C processes and pools.

Long-term patterns of diameter and basal area growth of old-growth Douglas-fir trees in western Oregon

2002 ◽  
Vol 32 (7) ◽  
pp. 1232-1243 ◽  
Author(s):  
Nathan J Poage ◽  
John C Tappeiner, II
Keyword(s):  
Large Diameter ◽  
Basal Area ◽  
Douglas Fir ◽  
Slope Aspect ◽  
Site Factors ◽  
Old Growth ◽  
Site Class ◽  
Basal Area Growth ◽  
Area Growth ◽  
Age Range

Diameter growth and age data collected from stumps of 505 recently cut old-growth Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) trees at 28 sample locations in western Oregon (U.S.A.) indicated that rapid early and sustained growth of old Douglas-fir trees were extremely important in terms of attaining large diameters at ages 100–300 years. The diameters of the trees at ages 100–300 years (D100–D300) were strongly, positively, and linearly related to their diameters and basal area growth rates at age 50 years. Average periodic basal area increments (PAIBA) of all trees increased for the first 30–40 years and then plateaued, remaining relatively high and constant from age 50 to 300 years. Average PAIBA of the largest trees at ages 100–300 years were significantly greater by age 20 years than were those of smaller trees at ages 100–300 years. The site factors province, site class, slope, aspect, elevation, and establishment year accounted for little of the variation observed in basal area growth at age 50 years and D100–D300. The mean age range for old-growth Douglas-fir at the sample locations was wide (174 years). The hypothesis that large-diameter old-growth Douglas-fir developed at low stand densities was supported by these observations.

scholarly journals Fate of Overstory Trees and Patterns of Regeneration 12 Years After Clearcutting with Reserve Trees in Southwest Washington

2002 ◽  
Vol 17 (2) ◽  
pp. 78-85 ◽  
Author(s):  
Karl R. Buermeyer ◽  
Constance A. Harrington
Keyword(s):  
Pacific Northwest ◽  
Douglas Fir ◽  
Seedling Density ◽  
Site Class ◽  
Seedling Size ◽  
Advance Regeneration ◽  
Dead Trees ◽  
The Status ◽  
Overstory Trees ◽  
Southwest Washington

Abstract Changes in management objectives for some forestlands in the Pacific Northwest have spurred interest in the creation of multistoried stands and the use of natural regeneration systems, but data on such systems are lacking. We assessed the status of the overstory trees and the regeneration 12 yr after a clearcut harvest with reserve trees in an even-aged, 145-yr-old Douglas-fir stand on a moderately productive site (site class 3) in southwest Washington. The 15 ha harvest unit was superimposed over two areas differentially thinned 15 and 34 yr before clearcutting. The clearcut harvest retained 18 trees/ha with a mean diameter of 63 cm. The reserved overstory trees had a 93% survival rate after 12 yr; most dead trees had been windthrown. Diameter growth for the reserved trees averaged 3.3 cm and was greatest during the most recent 3 yr period, which also had the highest growing-season precipitation. In a 1 ha mapped area, there were 5,854 seedlings/ha, and more than 99% of the regeneration was Douglas-fir. Most seedlings were less than 2 m tall. Seedling density was somewhat clumped (value of 2.1 for Pielou's index of nonrandomness), but 79% of randomly located 4.04 m2 (mil-acre) plots and 98% of 5 × 5 m grid cells had at least one conifer seedling. There was no obvious pattern of regeneration based on direction from the reserved trees, but both seedling density and seedling size within the drip lines of reserved tree crowns were less than in the rest of the area. The number of seedlings was similar on the two halves of the plot corresponding to the original thinning blocks, but seedling size and age differed. In the half of the study plot that had been twice lightly thinned, only 14% of the seedlings were >0.5 m tall; however, 41% of the seedlings were >0.5 m in the block that had been thinned more heavily. There was no difference between the thinning blocks in the ages of seedlings ≤0.5 m tall (mean age of 5 yr). This example of clearcutting with reserve trees resulted in reasonable survival of the overstory trees and adequate stocking but slow growth rates in the naturally regenerated Douglas-fir. Heavier thinning before harvest was associated with more advance regeneration, more shrub cover, and less windthrow of the reserved trees than in the more lightly thinned block. If an abundance of tree species other than Douglas-fir was desired on this site, interplanting would be required. West. J. Appl. For.17(2):78–85.

Effect of nitrogen, phosphorus and magnesium fertilizers on growth of a semimature jack pine forest, northwestern Ontario

1995 ◽  
Vol 71 (4) ◽  
pp. 422-425 ◽  
Author(s):  
I. K. Morrison ◽  
N. W. Foster
Keyword(s):  
Pinus Banksiana ◽  
Growth Response ◽  
Jack Pine ◽  
Class Iii ◽  
Forest Fertilization ◽  
Site Class ◽  
Northwestern Ontario ◽  
Volume Increment ◽  
A Site ◽  
Nitrogen Phosphorus

In the spring of 1969, an experiment to test response (mean DBH, BA, BA%, and total and merchantable volume increments) to nitrogen (N), phosphorus (P) and magnesium (Mg) fertilizers, singly and in combination, was established in a semimature jack pine (Pinus banksiana Lamb.) forest on a Site Class III sandy site in the Dryden-Sioux Lookout area of northwestern Ontario, Canada. Analysis of variance of 10-year increments revealed highly significant (P = 0.01) responses of mean DBH increment, BA and percent BA increments, and total and merchantable volume increments to N, but no response to either P or Mg. An interaction between N and P was noted, however, in relation to BA and to total and merchantable volume increments. The best treatment in terms of total volume increment over that of the control was 151 kg N ha−1 plus 62 kg Mg ha−1, which produced ca. 16 m3 ha−1 of extra wood over 10 years. Key words: forest fertilization, nitrogen, phosphorus, magnesium fertilizers, jack pine growth response

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