Comparative effects of three nitrogen fertilizers applied in fall and spring to a 29-year-old Douglas-fir plantation

1986 ◽  
Vol 16 (5) ◽  
pp. 910-917 ◽  
Author(s):  
Richard E. Miller ◽  
Mark V. Atherton ◽  
James E. Wilcox
Keyword(s):  
Confidence Level ◽  
Experimental Error ◽  
Volume Growth ◽  
Field Trials ◽  
Douglas Fir ◽  
Nitrogen Fertilizers ◽  
Site Quality ◽  
Available N ◽  
Stand Growth ◽  
Measurement Period

Stand growth and mortality were monitored for 13 years after six fertilizer treatments were applied in a 29-year-old Douglas-fir (Pseudotsugamenziesii (Mirb.) Franco) medium site quality plantation on Vancouver Island. The equivalent of 224 kg N/ha was added in either fall or spring as ammonium nitrate, urea, or urea – ammonium sulfate, which additionally supplied 56 kg S/ha. These treatments and a control were replicated three times. Foliar analyses indicated insufficient available N initially and increased available N after fertilization. Average, adjusted gross and net cubic volume growth in fertilized plots, however, did not differ from that of controls in any of the intermediate periods or in the total measurement period. This field experiment was not sensitive enough to detect real differences in 13-year growth among the seven treatments. Based on the experimental error measured in this study, seven replications would have been necessary to detect a 20% response in 13-year gross growth at the 10% confidence level; with seven replications, this 20% response would be detected in 90% of all experiments. Suggestions for improving field trials are included.

The dynamics of stand development: a general stand model applied to Douglas-fir

1988 ◽  
Vol 18 (6) ◽  
pp. 696-702 ◽  
Author(s):  
David E. Tait
Keyword(s):  
Equilibrium Solution ◽  
Stocking Density ◽  
Stand Density ◽  
Douglas Fir ◽  
Dynamic Equations ◽  
Site Quality ◽  
Stand Development ◽  
Stand Volume ◽  
Causal Explanations ◽  
Stand Growth

A linked pair of hypotheses which represent causal explanations for plant growth and stand mortality for an even-aged stand are developed. The pair of dynamic equations lead to a four-parameter Douglas-fir simulation model. The four-parameter model relates the development of stand volume and density to site quality, initial stocking density, and alternative thinning regimes. The mortality hypothesis, a dynamic hypothesis related to stand density and stand growth, generates the −3/2 power law as an equilibrium solution.

scholarly journals Growth of Young Douglas-Fir Plantations Across a Gradient in Swiss Needle Cast Severity

2002 ◽  
Vol 17 (2) ◽  
pp. 86-95 ◽  
Author(s):  
Douglas A. Maguire ◽  
Alan Kanaskie ◽  
William Voelker ◽  
Randy Johnson ◽  
Greg Johnson
Keyword(s):  
Volume Growth ◽  
Basal Area ◽  
Height Growth ◽  
Douglas Fir ◽  
Site Quality ◽  
North Coast ◽  
Needle Cast ◽  
Basal Area Growth ◽  
Area Growth ◽  
Swiss Needle Cast

Abstract During the past decade, Swiss needle cast (SNC) damage has intensified in many Douglas-fir plantations in the Coast Range of Oregon, particularly along the immediate north coast. In plantations with severe symptoms, growth losses and reduced tree vigor are evident, but the magnitude of growth losses associated with varying intensities of damage is not known. A growth impact study was conducted in 1997 to quantify retrospectively the relationship between growth losses and visual symptoms in 10- to 30-yr-old Douglas-fir plantations in coastal northwestern Oregon, a population totaling 75,700 ha. A random sample of 70 Douglas-fir plantations was selected from the population and evaluated for Swiss needle cast severity. One 0.02 ha plot was destructively sampled in each plantation to reconstruct past height and basal area growth trends and to characterize foliage loss and distribution. The SNC “effect” was assessed by comparing growth of plantations with varying degrees of Swiss needle cast to growth of those that retained maximal amounts of foliage, after correcting for initial stand density, Douglas-fir growing stock, age, and site index. Of numerous possible SNC indices, mean needle retention (yr) explained the largest amount of variation in both basal area and top height growth. Prior to 1990, top height growth was similar across all plantations after correcting for site quality and plantation age; but, by 1992, top height growth losses appeared and were proportional to apparent foliage losses. In 1996, top height growth was reduced by up to 25% relative to plantations with little or no SNC. Basal area growth reductions began to appear around 1990, and in 1996 basal area growth of the most heavily damaged plantations was 35% less than the growth that would be expected in absence of SNC damage. The inferred volume growth loss for 1996 averaged 23% for the 75,700 ha target population, but this loss averaged as high as 52% for the most severely impacted plantations. West. J. Appl. For. 17(2):86ߝ95.

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.

Wachstum und Wertleistung der Douglasie in Abhängigkeit von der Standraumgestaltung

2012 ◽  
Vol 163 (3) ◽  
pp. 96-104 ◽  
Author(s):  
Joachim Klädtke ◽  
Ulrich Kohnle ◽  
Edgar Kublin ◽  
Andreas Ehring ◽  
Hans Pretzsch ◽  
...  
Keyword(s):  
Wood Quality ◽  
Volume Growth ◽  
Static Stability ◽  
Douglas Fir ◽  
Breast Height ◽  
Monetary Analysis ◽  
Starting Conditions ◽  
Tree Number ◽  
Clear Differentiation ◽  
Further Development

Growth and value production of Douglas-fir under varying stand densities The investigation is focused on the effects of initial tree number and thinning on growth and value performance of Douglas-fir stands. Data base is a coordinated Douglas-fir spacing experiment in South Germany, started 40 years ago and comprising variants of tree numbers with 500, 1,000, 2,000 and 4,000 Douglas-firs per hectare. The treatment was performed according to a standardized experiment program. The results show that at low initial tree numbers, the diameter on breast height (DBH) of (pre)dominant trees at the beginning of the observations (with 12 m top height) is bigger than at higher initial plant numbers. Accordingly, the quotient of height (H) to DBH (as an indicator for tree's static stability) is lower. The further development of DBH and H/DBH quotient is decisively determined by stand treatment, which superimposes the effect of the initial tree number. The total volume growth shows a clear differentiation, too, the variants with initially high tree numbers appearing on top. In the monetary analysis, this ranking is reversed: despite a supposed inferior wood quality, the variants with lower initial tree numbers clearly outperform the ones with higher numbers in terms of value. From these results, the following silvicultural recommendations for Douglas-fir can be derived: the initial tree numbers should be in the range from 1,000 to 2,000 plants per hectare. On technically not accessible sites, even lower tree numbers may come into question. The strong influence of stand treatment on DBH and H/DBH development highlights the problem of postponed thinnings, for this causes growth and stability losses even under favorable starting conditions in terms of competition.

scholarly journals Developing Growth Models of Stand Volume for Subtropical Forests in Karst Areas: A Case Study in the Guizhou Plateau

Forests ◽  
2021 ◽  
Vol 12 (1) ◽  
pp. 83
Author(s):  
Yuzhi Tang ◽  
Quanqin Shao ◽  
Tiezhu Shi ◽  
Guofeng Wu
Keyword(s):  
Growth Models ◽  
Volume Growth ◽  
Site Quality ◽  
Rocky Desertification ◽  
Stand Volume ◽  
Subtropical Forests ◽  
Karst Areas ◽  
Growth Equations ◽  
Global Carbon ◽  
Guizhou Plateau

Forest stand volume is one of the key forest structural attributes in estimating and forecasting ecosystem productivity and carbon stock. However, studies on growth modeling and environmental influences on stand volume are still rare to date, especially in subtropical forests in karst areas, which are characterized by a complex species composition and are important in the global carbon budget. In this paper, we developed growth models of stand volume for all the dominant tree species (groups) (DTSG) in a subtropical karst area, the Guizhou Plateau based on an investigation of the effects of various environmental factors on stand volume. The Richards growth function, space-for-time substitution and zonal-hierarchical modeling method were applied in the model fitting, and multiple indices were used in the model evaluation. The results showed that the climatic factors of annual temperature and precipitation, as well as the site factors of stand origin, elevation, slope gradient, topsoil thickness, site quality degree, rocky desertification type and rocky desertification degree, have significant influences on stand volume, and the topsoil thickness and site quality degree have the strongest positive effect. A total of 959 growth equations of stand volume were fitted with a five-level stand classifier (DTSG–climatic zone–site quality degree–stand origin–rocky desertification type). All the growth equations were qualified, because all passed the TRE test (≤30%), and the majority of the R2 ≥ 0.50, above 70% of the RMSE were between 5.0 and 20.0, and above 80% of the P ≥ 75%. These findings provide updated knowledge about the environmental effect on the stand volume growth of subtropical forests in karst areas, and the developed stand volume growth models are convenient for forest management and planning, further contributing to the study of forest carbon storage assessments and global carbon cycling.

Bt-Cry3Aa transgene expression reduces insect damage and improves growth in field-grown hybrid poplar

2014 ◽  
Vol 44 (1) ◽  
pp. 28-35 ◽  
Author(s):  
Amy L. Klocko ◽  
Richard Meilan ◽  
Rosalind R. James ◽  
Venkatesh Viswanath ◽  
Cathleen Ma ◽  
...  
Keyword(s):  
Large Scale ◽  
Populus Deltoides ◽  
Integrated Management ◽  
Populus Trichocarpa ◽  
Hybrid Poplar ◽  
Volume Growth ◽  
Field Trials ◽  
Leaf Beetle ◽  
Insect Damage ◽  
Beetle Damage

The stability and value of transgenic pest resistance for promoting tree growth are poorly understood. These data are essential for determining if such trees could be beneficial to commercial growers in the face of substantial regulatory and marketing costs. We investigated growth and insect resistance in hybrid poplar expressing the cry3Aa transgene in two field trials. An initial screening of 502 trees comprising 51 transgenic gene insertion events in four clonal backgrounds (Populus trichocarpa × Populus deltoides, clones 24-305, 50-197, and 198-434; and P. deltoides × Populus nigra, clone OP-367) resulted in transgenic trees with greatly reduced insect damage. A large-scale study of 402 trees from nine insertion events in clone OP-367, conducted over two growing seasons, demonstrated reduced tree damage and significantly increased volume growth (mean 14%). Quantification of Cry3Aa protein indicated high levels of expression, which continued after 14 years of annual or biannual coppice in a clone bank. With integrated management, the cry3Aa gene appears to be a highly effective tool for protecting against leaf beetle damage and improving yields from poplar plantations.

scholarly journals Calcium nitrate and ammonium nitrate limestone as sources of nitrogen for oats and barley

1961 ◽  
Vol 33 (1) ◽  
pp. 159-168
Author(s):  
Pentti Hänninen ◽  
Armi Kaila
Keyword(s):  
Ammonium Nitrate ◽  
Nitrogen Content ◽  
Calcium Nitrate ◽  
Field Trials ◽  
The Other ◽  
Nitrogen Fertilizers ◽  
Malting Barley ◽  
Growing Period ◽  
Significant Difference ◽  
Cent Level

Calcium nitrate and ammonium nitrate limestone (»Oulunsalpietari») were compared as the nitrogen fertilizer for oats in 15 field trials and for barley in one trial. The trials were carried out in summers 1959 and 1960 in various places in Finland. The split plot technique was employed in order to reduce the variation as much as possible. In 1959 the amounts of nitrogen applied as these two fertilizers to the corresponding halves of the plots were 25 and 50 kg/ha. In 1960 also higher applications were used: 75 and 100 kg/ha of N. In three trials these fertilizers were compared both as a surface dressing and worked in. Visual observations suggested about 5—6 weeks after sowing a darker green colour in the stands treated with calcium nitrate as compared with the other half treated with ammonium nitrate limestone. These differences later disappeared. In some trials a higher nitrogen content of the plants from the calcium nitrate stands could be demonstrated during this period. The uptake of nitrogen by plants was regularly followed throughout the growing period. Owing to the large variation, usually, no statistically significant difference between the effect of the fertilizers could be detected. In a few cases the superiority of calcium nitrate could be demonstrated. No differences in the ripening could be found. In most trials there was a fairly regular tendency to higher yields and higher nitrogen content in the grain and straw produced by calcium nitrate. Yet, only in a few cases were the differences statistically significant at the five per cent level. Thus, it was concluded that on the basis of the results of these trials ammonium nitrate limestone and calcium nitrate may be considered practically equal as nitrogen fertilizers for oats. There was no difference in the yields of barley produced by these two fertilizers, but the nitrogen content of grains was significantly lower with ammonium nitrate limestone than with calcium nitrate. This may be worth further study in connection with the production of malting barley.

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 Soil disturbance and 10-year growth response of coast Douglas-fir on nontilled and tilled skid trails in the Oregon Cascades

2002 ◽  
Vol 32 (2) ◽  
pp. 233-246 ◽  
Author(s):  
Ronald Heninger ◽  
William Scott ◽  
Alex Dobkowski ◽  
Richard Miller ◽  
Harry Anderson ◽  
...  
Keyword(s):  
Tree Growth ◽  
Volume Growth ◽  
Soil Surface ◽  
Soil Bulk Density ◽  
Soil Disturbance ◽  
Height Growth ◽  
Douglas Fir ◽  
Negative Effects ◽  
Fine Soil ◽  
Reduced Height

We (i) quantified effects of skidder yarding on soil properties and seedling growth in a portion of western Oregon, (ii) determined if tilling skid trails improved tree growth, and (iii) compared results with those from an earlier investigation in coastal Washington. Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) seedlings were hand planted at eight recent clearcuts in skid ruts in either nontilled or tilled trails, in adjacent soil berms, and in adjacent logged-only portions. Four and 5 years after skidding, rut depths averaged 15 cm below the original soil surface; mean fine-soil bulk density (0–30 cm depth) below ruts of nontilled trails exceeded that on logged-only portions by 14%. Height growth on nontilled trails averaged 24% less than on logged-only portions in year 4 after planting and decreased to 6% less in year 7. For years 8–10, mean height growth was similar for all treatments. Reduced height growth lasted for about 7 years compared with 2 years for coastal Washington. Ten years after planting, trees in skid-trail ruts averaged 10% shorter with 29% less volume than those on logged-only portions. Tillage improved height and volume growth to equal that on logged-only portions. Generalizations about negative effects of skid trails on tree growth have limited geographic scope.

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