Five-year growth responses of Douglas-fir, western hemlock, and western redcedar seedlings to manipulated levels of overstory and understory competition

2006 ◽  
Vol 36 (10) ◽  
pp. 2439-2453 ◽  
Author(s):  
Timothy B Harrington
Keyword(s):  
Growth Rate ◽  
Nitrogen Content ◽  
Douglas Fir ◽  
Western Hemlock ◽  
Volume Index ◽  
Stem Volume ◽  
Western Redcedar ◽  
Foliar Nitrogen ◽  
Relative Growth ◽  
Vegetation Control

Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco), western hemlock (Tsuga heterophylla (Raf.) Sarg.), and western redcedar (Thuja plicata Donn ex D. Don) seedlings were planted in March 2001 within three clearcut-harvested, shelterwood, or thinned stands of mature Douglas-fir near Olympia, Washington. From 2002 to 2005, areas of vegetation control of 0, 4.5, or 9 m2 were maintained with herbicides around a total 162 seedlings per species. Photosynthetically active radiation (PAR) was 34%, 62%, and 100% of full sunlight in thinned stands, shelterwoods, and clearcuts, respectively. Effects of overstory level and vegetation control on seedling growth and resource availability generally were additive. Seedling stem volume index in clearcuts averaged four to eight times that observed in thinned stands, and with vegetation control, it averaged two to four times that observed without it. In thinned stands, relative growth rate of seedling stem volume index had a positive linear relationship with PAR (R2 = 0.38). Foliar nitrogen content of Douglas-fir explained 71% of the variation in relative growth rate. Factors explaining the most variation in foliar nitrogen content differed between thinned stands (PAR, R2 = 0.34) and clearcuts or shelterwoods (midday water potential, R2 = 0.63), suggesting that light and root competition, respectively, were the primary growth-limiting factors for these overstory levels.

Influences of spacing on radial growth and percentage latewood of Douglas-fir, western hemlock, and western redcedar

1980 ◽  
Vol 10 (2) ◽  
pp. 169-175 ◽  
Author(s):  
J. Harry G. Smith
Keyword(s):  
Wood Quality ◽  
Ring Width ◽  
Douglas Fir ◽  
Western Hemlock ◽  
Western Redcedar ◽  
X Ray ◽  
Good Site ◽  
Binocular Microscope ◽  
Reduced Costs ◽  
Ray Methods

Growth in ring width and percentage latewood on a very good site is described for 21-year-old Douglas-fir (Pseudotsugamenziesii (Mirb.) Franco), 20-year-old western hemlock (Tsugaheterophylla (Raf.) Sarg.), and western redcedar (Thujaplicata Donn) planted at five spacings (0.91 to 4.57 m). Cores extracted at breast height are used to show the effects of spacing through growth rate and crown development, and of age through number of rings from pith for the years 1965 to 1976. Percentages of latewood measured by binocular microscope are compared with results obtainable by X-ray methods for analysis of ring widths and densities. Influences of spacing on wood quality are discussed. It is concluded that wide initial spacings increase ring width and decrease percentage latewood significantly, but the reduced costs and increased sizes at wide spacings provide more than adequate compensation for the moderate reduction in wood quality.

Use of growth curve derivatives to illustrate acceleration and deceleration of growth in young plantations under variable competition

2006 ◽  
Vol 36 (10) ◽  
pp. 2515-2522 ◽  
Author(s):  
Michael Newton ◽  
Elizabeth C Cole
Keyword(s):  
Growth Period ◽  
Tsuga Heterophylla ◽  
Douglas Fir ◽  
Early Years ◽  
Western Hemlock ◽  
Richards Equation ◽  
Second Derivative ◽  
Red Alder ◽  
Vegetation Control ◽  
Second Derivatives

Deceleration of growth rates can give an indication of competition and the need for thinning in early years but can be difficult to detect. We computed the first and second derivatives of the von Bertalanffy – Richards equation to assess impacts of density and vegetation control in young plantations in western Oregon. The first derivative describes the response in growth and the second derivative describes the change in growth over time. Three sets of density experiments were used: (i) pure Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco), (ii) mixed Douglas-fir and grand fir (Abies grandis (Dougl. ex D. Don) Lindl.), and (iii) mixed western hemlock (Tsuga heterophylla (Raf.) Sarg.) and red alder (Alnus rubra Bong.). Original planting densities ranged from 475 to 85 470 trees·ha–1 (4.6 m × 4.6 m to 0.34 m × 0.34 m spacing); western hemlock and red alder plots were weeded and unweeded. For the highest densities, the second derivative was rarely above zero for any of the time periods, indicating that the planting densities were too high for tree growth to enter an exponential phase. As expected, the lower the density, the greater and later the peak in growth for both the first and second derivatives. Weeding increased the growth peaks, and peaks were reached earlier in weeded than in unweeded plots. Calculations of this sort may help modelers identify when modifiers for competition and density are needed in growth equations. Specific applications help define onset of competition, precise determining of timing of peak growth, period of acceleration of growth, and interaction of spacing and age in determination of peaks of increment or acceleration or deceleration.

scholarly journals Chemical composition of selected marine microalgae, with emphasis on lipid and carbohydrate production for potential use as feed resources

2021 ◽  
Author(s):  
Kjell Inge Reitan ◽  
Gunvor Øie ◽  
Håvard Jørgensen ◽  
Xinxin Wang
Keyword(s):  
Fatty Acids ◽  
Growth Rate ◽  
Nitrogen Content ◽  
Relative Growth Rate ◽  
Skeletonema Costatum ◽  
Total Lipid Content ◽  
Marine Microalgae ◽  
Omega 3 ◽  
Relative Growth ◽  
Carbon And Nitrogen

AbstractMarine microalgae are a promising sustainable source of lipids, omega-3 fatty acids, and carbohydrates. Selected microalgae species belonging to the Bacillariophyceae, Haptophyceae, Eustigmatophyceae, and Prasinophyceae were characterised for cellular content of carbon and nitrogen, and for production yields of lipids, fatty acids, total carbohydrates, and β-glucans. Carbon and nitrogen content showed a hyperbolic decrease with increasing cell numbers for Chaetoceros calcitrans, C. muelleri, Skeletonema costatum, Tetraselmis sp., and Nannochloropsis oculata. Cultures of Pavlova lutheri and Tisochrysis lutea showed an increase in carbon content per cell, but a decrease in nitrogen content. The total lipid content of C. muelleri, C. calcitrans, N. oculata, and T. lutea increased with decreasing relative growth rate; however, the highest productivity of lipids was found in T. lutea grown at 40% of the maximum specific growth rate. The highest content of eicosapentaenoic acid was found in C. muelleri, C. calcitrans, and N. oculata, and the highest content of docosahexaenoic acid was found in T. lutea. The β-glucan fraction of the carbohydrates was highest in C. muelleri and C. calcitrans and was very low in N. oculata. Out of the species investigated, C. muelleri had the highest production yield of β-glucans, obtained when cultivated at a 40% relative growth rate.

Ionic balance and organic acids in western redcedar, western hemlock, and Douglas-fir seedlings grown in low- and high-N soils

1999 ◽  
Vol 29 (6) ◽  
pp. 669-678 ◽  
Author(s):  
J E Graff, Jr. ◽  
R K Hermann ◽  
J B Zaerr
Keyword(s):  
Organic Acids ◽  
Quinic Acid ◽  
Tsuga Heterophylla ◽  
Douglas Fir ◽  
Western Hemlock ◽  
Thuja Plicata ◽  
N Availability ◽  
Ionic Balance ◽  
Total N ◽  
Western Redcedar

Seedlings of western redcedar (Thuja plicata Donn ex. D. Don), western hemlock (Tsuga heterophylla (Raf.) Sarg.), and Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) were transplanted into soils with low and high levels of available NO3-(and total N). Current-year foliage was sampled after 10 weeks to determine the effect of N availability on foliar cation-anion balance (C-A) and the concentrations of low molecular weight organic acids of the three species. Carboxylate concentrations were estimated by using the difference between sums of cations and anions (C-A): 750 mequiv.·kg-1for western redcedar, 351 mequiv.·kg-1for western hemlock, and 266 mequiv.·kg-1for Douglas-fir. Quinic acid was a primary constituent, accounting for 40% of the total for western redcedar and 75% for western hemlock and Douglas-fir. Oxalic acid was present in greatest concentration in the foliage of western redcedar (65 mequiv.·kg-1) but was a minor constituent in western hemlock and Douglas-fir. The quantified acids accounted for only 15% of the C-A of western redcedar but >80% of the C-A of western hemlock and Douglas-fir. A considerable portion of the C-A balance not accounted for in redcedar may be associated with the accumulation of CaCO3. Litterfall deposition of CaCO3may lead to the consumption of H+ions and enrichment of exchangeable soil Ca in the rooting zone of long-lived western redcedar trees. No statistically significant differences among the soils were detected with regard to C-A or the concentration of organic acids.

Cone-Production and Stem-Growth Response of Douglas Fir to Rate and Frequency of Nitrogen Fertilization

1972 ◽  
Vol 2 (3) ◽  
pp. 327-338 ◽  
Author(s):  
Lorne F. Ebell
Keyword(s):  
Douglas Fir ◽  
Stem Volume ◽  
Wood Production ◽  
Foliar Nitrogen ◽  
Cone Production ◽  
Nitrogen Levels ◽  
Duration Of Effect ◽  
Dry Conditions ◽  
Vegetative Bud

Twenty-year-old Douglas fir (Pseudotsugamenziesii (Mirb.) Franco.) were treated in May with 0, 50, 100, 200,400, 800 and 1600 lb nitrogen per acre (1 lb/acre = 1.12 kg/ha) as ammonium nitrate. In 5 subsequent years, cone production with annual and biennial retreatment at one rate was compared with no retreatment. Heavy rainfall after the initial fertilization appeared responsible for small, similar cone-production responses the next year from the 100–1600 lb rates. Retreatment at 400 lb increased cone production of the third year but overfertilization occurred in combination with the higher initial rates. Initial overfertilization or annual refertilization reduced long-term responses. Responses were greatest when dry conditions followed treatment. It was concluded that 400 lb nitrate nitrogen per acre at the start of vegetative bud break, applied biennially to alternate halves of an area, would provide optimum long-term cone production.Stem growth benefited from increasing foliar nitrogen levels up to about 2%, obtained with 200–400 lb nitrogen per acre, and was adversely affected by foliar nitrogen above 3%. Response to fertilization consisted of: (1) direct effects of improved nitrogen status lasting about 2 years, (2) accumulative increases in leaf area favoring shoot and stem responses up to the 4th or 5th year, and (3) continued stem-area increases due to growth over the greater circumference resulting from factors 1 and 2. Over the full duration of effect in young stands, the optimum economic treatment for increased wood production may correspond closely to the 400 lb nitrogen per acre which provided near-optimum physiological responses. The 200 and 400 lb rates increased 5-year stem-volume increment by 62 and 90%.

Growth and foliar nutrition of juvenile western hemlock and western redcedar plantations on low- and medium-productivity sites on northern Vancouver Island: response to fertilization and planting density

2007 ◽  
Vol 37 (12) ◽  
pp. 2587-2599 ◽  
Author(s):  
R. W. Negrave ◽  
C. E. Prescott ◽  
J. E. Barker
Keyword(s):  
Volume Growth ◽  
Western Hemlock ◽  
Planting Density ◽  
Stem Volume ◽  
Thuja Plicata ◽  
Limiting Factor ◽  
Western Redcedar ◽  
Stand Volume ◽  
Reduced Height ◽  
Volume Increment

A factorial trial was established to examine the effects of planting density and fertilization on the growth of western redcedar ( Thuja plicata Donn ex D. Don) and western hemlock ( Tsuga heterophylla (Raf.) Sarg.) on nutrient-poor (CH) sites and nutrient-medium (HA) sites. Two levels of NPK fertilization were crossed with three levels of planting density (500, 1500, and 2500 stems/ha). Fifteen years after establishment and 10 years after the last fertilizer application, height, individual stem volume increment, stand volume, 5 year periodic annual increment (PAI), and 5 year periodic height increment were all increased by fertilization. Fertilization of CH sites increased annual stand volume increment by 753%–2552% and 122%–209% for hemlock and cedar, respectively; fertilization of HA sites increased PAI by 94%–264%. Volume growth response to fertilization was greater on HA than on CH sites. Increasing stand density reduced height growth on CH sites but not on HA sites. These results suggest that competition for nutrients can be a significant growth-limiting factor even before canopy closure occurs and that treatment of ericaceous sites may not be justified by productivity increases.

Five-year vegetation control effects on aboveground biomass and nitrogen content and allocation in Douglas-fir plantations on three contrasting sites

2011 ◽  
Vol 262 (12) ◽  
pp. 2187-2198 ◽  
Author(s):  
Warren D. Devine ◽  
Timothy B. Harrington ◽  
Thomas A. Terry ◽  
Robert B. Harrison ◽  
Robert A. Slesak ◽  
...  
Keyword(s):  
Nitrogen Content ◽  
Aboveground Biomass ◽  
Douglas Fir ◽  
Vegetation Control

Early growth of planted western hemlock in relation to stock type and controlled-release fertilizer application

1988 ◽  
Vol 18 (6) ◽  
pp. 710-717 ◽  
Author(s):  
J. T. Arnott ◽  
A. N. Burdett
Keyword(s):  
Growth Rates ◽  
Growing Season ◽  
The Other ◽  
Western Hemlock ◽  
Stem Volume ◽  
Relative Growth ◽  
Relative Growth Rates ◽  
The Third ◽  
Stock Type ◽  
Stock Types

Four types of western hemlock (Tsugaheterophylla (Raf.) Sarg.) nursery stock, differing in size, morphology, and root growth capacity were planted on a clear-cut forest site on Vancouver Island, British Columbia. The stock types were: (i) 1-year-old, plug-rooted seedlings raised in 36-cm3 containers; (ii) as (i) but transplanted to a bareroot nursery for 1 year; (iii) 1-year-old, bareroot seedlings raised in 1000-cm3 containers; (iv) as (iii) but raised in containers coated on the inside with copper paint to inhibit lateral root elongation upon contact with the container wall. Survival and growth of seedlings with and without fertilization at planting with 50 g of a slow-release (Nutricote®, 12-month release at 25 °C) N–P–K fertilizer were observed for 3 years. Neither stock type nor fertilizer had a statistically significant (P < 0.05) effect on seedling survival. At planting, plug seedlings were significantly (P < 0.01) shorter and smaller in stem volume than the other stock types. These differences were no longer evident by the end of the third growing season because of more rapid growth by the plug stock. The largest differences between the plugs and the other stock types in height and diameter relative growth rates occurred during the first growing season. Fertilization significantly (P < 0.01) increased height and stem volume relative growth rates of all stock types during the first growing season. During the third growing season fertilization had a significant (P < 0.01) negative effect on height, and diameter and stem volume relative growth rates of all stock types, but not on absolute rates. At the end of three growing seasons, fertilized trees remained significantly (P < 0.01) larger in all stock types than in the controls.

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