scholarly journals Impact of initial spacing and precommercial thinning on jack pine tree growth and stem quality

2005 ◽  
Vol 81 (3) ◽  
pp. 418-428 ◽  
Author(s):  
Q J Tong ◽  
S Y Zhang
Keyword(s):  
Tree Growth ◽  
Jack Pine ◽  
Stem Length ◽  
Stem Volume ◽  
Positive Effects ◽  
Commercial Thinning ◽  
Dbh Distribution ◽  
Stem Quality ◽  
Initial Spacing ◽  
The Impact

The objective of this paper was to investigate the impact of initial spacing and pre-commercial thinning (PCT) on tree growth, characteristics and stem quality in plantation-grown jack pine (Pinus banksiana Lamb.) after 58 years of growth. Four spacings including three initial spacings without PCT treatment, i.e., 1.52 × 1.52 m (5 × 5 ft), 2.13 × 2.13 m (7 × 7 ft) and 2.74 × 2.74 m (9 × 9 ft) and one initial spacing with PCT treatment (5 × 5 ft thinned to 7 × 7 ft at age 14), were chosen to analyze diameter at breast height (DBH) distribution, survival, and various tree and stem quality characteristics (e.g., DBH, total tree height, stem volume, crown size, branch, taper, sweep and wobbling). Tree mortality during the first 25 growth years was quite low for all four spacings, while after 25 years, survival for the four spacings rapidly declined. The decrease in survival for spacing 5 × 5 was the steepest, followed by spacings 7 × 7, 9 × 9 and finally the PCT-treated stand. DBH distributions for all four spacings were significantly different from each other, and five years after PCT, the 5 × 5 to 7 × 7 spacings had a similar DBH distribution to that of the constant 7 × 7 spacing. Mean DBHs differed significantly among the initial spacings. The 5 × 5 spacing produced significantly smaller trees than did the other three spacings through the years, and the 9 × 9 spacing produced significantly larger trees. PCT had positive effects on DBH growth, and yielded longer merchantable stems and better stem quality. PCT had little effect on crown development. Initial spacing significantly affected diameter growth, crown width and branch development, commercial stem length and volume, stem taper and stem deformation. Narrower spacing produced smaller but better quality stems. Spacing 7 × 7 had the worst stem quality in terms of overall sweep and wave-like transversal deformation (wobbling). A narrow initial spacing followed by a PCT treatment may provide a compromise solution for both tree growth and stem quality. Key words: Initial spacing, thinning, survival, tree growth, stem quality

The effects of initial spacing on wood density, fibre and pulp properties in jack pine (Pinus banksiana Lamb.)

Holzforschung ◽  
2004 ◽  
Vol 58 (5) ◽  
pp. 455-463 ◽  
Author(s):  
Kyu-Young Kang ◽  
Shu Y. Zhang ◽  
Shawn D. Mansfield
Keyword(s):  
Forest Management ◽  
Wood Density ◽  
Pinus Banksiana ◽  
Management Practices ◽  
Jack Pine ◽  
Fibre Properties ◽  
Commercial Thinning ◽  
Initial Spacing ◽  
Pulp Properties ◽  
The Impact

Abstract Relationships between basic tree and wood properties, and species, seed source, geographic location, site conditions and management decisions are very complex. The objective of this study was to quantify the effects of forest management practices on wood density, fibre and pulp properties in jack pine, one of the most important commercial species in Northern America. A better understanding of the relationship between initial spacing and wood and end-product quality should help define improved forest management strategies required to produce quality wood and products in the future. On the basis of the oldest jack pine initial spacing trial established in 1941 by the USDA Forest Service, this study examined the impact of four different initial spacing trials on tree growth, wood density, fibre and pulp properties of jack pine. The results clearly show that initial stand spacing has a significant effect on all of these properties, and thus it is possible to improve yield and wood and pulp fibre properties of jack pine through stand density regulation. Additionally, a positive effect of pre-commercial thinning on fibre properties was also demonstrated. As a consequence of these results, basic prescription information for decision-making in the establishment of jack pine plantations with desirable pulp properties can be elucidated.

scholarly journals Production System Impacts Quality of Cut Poinsettia Stems

HortScience ◽  
2004 ◽  
Vol 39 (4) ◽  
pp. 893B-893
Author(s):  
Daniel Warnock* ◽  
Megan Fifarek ◽  
Heather Lash
Keyword(s):  
Production System ◽  
Production Systems ◽  
Stem Length ◽  
Vase Life ◽  
Axillary Shoots ◽  
Stem Quality ◽  
Commercial Supplier ◽  
Long Stem ◽  
The Impact ◽  
Axillary Branches

The development of the Renaissance series of cut poinsettias, Euphorbia pulcherrima, presents unique opportunities and challenges to cut flower producers. This series has curled bracts, long stem length, excellent vase life and is highly marketable. Literature indicates that this crop is suited for pot or bed production, but does not compare methods. This study assessed the impact of production system on final stem quality. Uniform rooted cuttings of `Renaissance Red' obtained from a commercial supplier were transplanted into 30.5-cm pots or a 1.2-× 2.4-m bed containing a soilless media to obtain 2 plants per 0.9 m2. A total of 56 cuttings were used for each production system and grown using standard production techniques. Transplanting occurred on 11 Aug. 11 2003 with plants reaching market stage, two cyathia shedding pollen, about 17 weeks later. To minimize border effects, plants in the outside rows of each production system were discarded. Thus, stem length, stem diameter, bract diameter, floral development, and number of axillary shoots were determined for 30 interior plants in each system. The production systems differentially impacted stem length and number of axillary shoots. Mean stem length in the bed system (89.7 cm) was greater than that observed in the pot system (71.4 cm). Plants in the bed system had significantly fewer axillary branches per plant (0.5) than plants in the pots (2.0). Stem diameters were similar for both systems (11.5 mm and 10.9 mm for bench and pot, respectively) as were bract diameters (14.3 cm and 13.4 cm for pot and bench, respectively). Both systems produced marketable stems; however, stems produced in the bed system had longer stems, fewer axillary branches, and were more uniform than those in the pot system.

scholarly journals Pinching Impacts Cut Poinsettia Stem Quality and Profit Potential

HortScience ◽  
2005 ◽  
Vol 40 (4) ◽  
pp. 1123A-1123
Author(s):  
Daniel F. Warnock ◽  
Heather Lash
Keyword(s):  
Stem Length ◽  
Vase Life ◽  
Axillary Shoots ◽  
Cultural Methods ◽  
Stem Quality ◽  
Commercial Supplier ◽  
Production Techniques ◽  
Number Of Stems ◽  
Long Stem ◽  
The Impact

The development of the Renaissance series of cut poinsettias, Euphorbia pulcherrima, presents unique opportunities and challenges to cut flower producers. This series has curled bracts, long stem length, excellent vase life, and is highly marketable. Literature indicates that this crop is suited for pot or bed production, but does not compare how cultural methods impact stem quality. This study assessed the impact of pinching on final stem quality and crop profitability. Uniform rooted cuttings of `Renaissance Red' obtained from a commercial supplier were transplanted into a 1.2 × 2.4 m bed containing a soilless media to obtain two plants per 0.09 m2. A total of 56 cuttings were used and grown using standard production techniques. Transplanting occurred on 29 July 2004 with half of the plants being pinched on 19 Aug. 2004. To minimize border effects, plants in the outside rows were discarded. Upon harvest, stem length, stem diameter, bract diameter, floral development, and number of axillary shoots were determined for 30 interior plants. Both pinched and unpinched plants produced marketable stems; however, unpinched plants produced longer thicker stems with larger bracts. The number of stems obtained per square foot was greater with the pinched plants. While overall quality was reduced, this increase in stem number offset potential lost profit. The production of quality cut stems of `Renaissance Red' poinsettias is possible with either pinched or unpinched plants.

Effects of precommercial thinning on tree growth and lumber quality in a jack pine stand in New Brunswick, Canada

2006 ◽  
Vol 36 (4) ◽  
pp. 945-952 ◽  
Author(s):  
S Y Zhang ◽  
Gilles Chauret ◽  
D Edwin Swift ◽  
Isabelle Duchesne
Keyword(s):  
New Brunswick ◽  
Tree Growth ◽  
Volume Growth ◽  
Jack Pine ◽  
Modulus Of Rupture ◽  
Stem Volume ◽  
Stand Age ◽  
Bending Properties ◽  
Precommercial Thinning ◽  
Thinning Intensity

A naturally regenerated jack pine (Pinus banksiana Lamb.) trial established in 1966 in New Brunswick was studied to determine how three precommercial thinning intensities (1.22 m × 1.22 m, 1.52 m × 1.52 m, and 2.13 m × 2.13 m) and a control (154 trees in total) affected tree growth and lumber quality. Mild (thinned to 1.22 m) and moderate (1.52 m) thinning had a modest impact on tree growth after 34 years (stand age 59). However, intensive thinning (2.13 m, or 2212 stems/ha) increased tree height by 13.1% compared with the control, whereas tree diameter and merchantable stem volume per tree increased by >20% and >75%, respectively. Yields of No. 2 and Better increased slightly with increasing thinning intensity, but lumber bending properties decreased with increasing thinning intensity. There was, respectively, >20% and >15% difference in lumber strength (modulus of rupture) and stiffness (modulus of elasticity) between the mild (1.22 m) and intensive (2.13 m) thinnings. Intensive precommercial thinning (2.13 m) is recommended for increased volume growth, but rotation age (>59 years) should not be reduced if lumber bending properties are of concern.

scholarly journals Quantifying Stem Quality Characteristics in Relation to Initial Spacing and Modeling Their Relationship with Tree Characteristics in Black Spruce (Picea mariana)

2005 ◽  
Vol 22 (2) ◽  
pp. 85-93 ◽  
Author(s):  
S. Y. Zhang ◽  
Y. C. Lei ◽  
C. Bowling
Keyword(s):  
Tree Growth ◽  
Picea Mariana ◽  
Stepwise Regression ◽  
Black Spruce ◽  
Quality Parameters ◽  
Quality Characteristics ◽  
Steady Increase ◽  
Crown Width ◽  
Stem Quality ◽  
Initial Spacing

Abstract This study evaluated and quantified the relationship of tree growth and stem quality characteristics with initial spacing in black spruce (Picea mariana). The study was based on the oldest and mature black spruce initial spacing trial established in 1950 in Thunder Bay, Ontario, Canada. Results show that initial spacing had a direct effect on tree and stem quality characteristics of individual trees. With increasing initial spacing from 1.8 × 1.8 m to 2.7 × 2.7 m, diameter at breast height (dbh), crown size, tree height, tree volume, tree taper, branch size, and clear log length show a steady increase, but the three initial spacings of 2.2 × 2.2 m, 2.0 × 2.0 m, and 1.8 × 1.8 m show no significant differences in these stem characteristics. The results suggest that black spruce may have a low capacity of responding to spacing unless spaced to 2.7 × 2.7 m. Multiple comparison tests support the results with the exception for crown width. This suggests that crown width may be the best density-size indicator for black spruce. As far as tree growth, stem quality, and initial establishment costs are concerned, this study suggests that an initial spacing such as 2.2 × 2.2 m might be optimum for wood production. In addition, this study shows that wide spacings (e.g., 2.7 × 2.7 m) can result in a significant decrease in stem quality and thus may have significant implications for product quality. Furthermore, relationships between major stem quality parameters and tree and stand-level characteristics were examined. Results of the stepwise regression analysis strongly indicate that crown width is important in determining stem quality. The stem quality parameters all have a high adjusted r2 and a low standard error of estimate when regression is made on tree or stand characteristics using the stepwise regression method.North. J. Appl. For. North. J. Appl. For. 22(2):85–93.

Predicting selected wood properties of jack pine following commercial thinning

2008 ◽  
Vol 38 (7) ◽  
pp. 2030-2043 ◽  
Author(s):  
Robert Schneider ◽  
S. Y. Zhang ◽  
D. Edwin Swift ◽  
Jean Bégin ◽  
Jean-Martin Lussier
Keyword(s):  
Wood Density ◽  
Ring Width ◽  
Wood Properties ◽  
Jack Pine ◽  
Modulus Of Rupture ◽  
Mixed Effect ◽  
Ring Density ◽  
Commercial Thinning ◽  
Cambial Age ◽  
The Impact

This paper examined the impact of commercial thinning on selected wood properties of jack pine ( Pinus banksiana Lamb.). Wood properties evaluated include wood density (ring density, earlywood ring density, and latewood ring density), percentage of latewood in the ring, and wood bending properties. Nonlinear, mixed-effect models have been developed using data from three commercially thinned sites in eastern Canada. Ring density followed the same pattern as percentage of latewood, in which cambial age, relative height, and ring width were found to have important effects. Earlywood and latewood ring densities changed within the juvenile wood zone until a plateau was reached. Ring width affected earlywood and latewood ring densities mainly in narrow rings. Wood bending stiffness (measured by modulus of elasticity) and strength (measured by modulus of rupture) increased with cambial age and wood density; whereas, wood strength was also affected by ring width. Commercial thinning did not influence the developed models, but it had an indirect effect through increased ring width.

scholarly journals Growth and form responses to pre-commercial thinning regimes in aerially seeded jack pine stands: 5th year results

1994 ◽  
Vol 70 (6) ◽  
pp. 780-787 ◽  
Author(s):  
D. M. Morris ◽  
S. C. Hills ◽  
C. Bowling
Keyword(s):  
Block Design ◽  
Volume Growth ◽  
Jack Pine ◽  
Reduced Form ◽  
Stem Volume ◽  
Stem Taper ◽  
Commercial Thinning ◽  
Four Blocks ◽  
Individual Trees ◽  
Crown Dimensions

In 1986, a thinning trial was established in a 9-year-old jack pine stand near Dryden, Ontario. Four blocks consisting of five thinning regimes (1 m × 1 m, 1.5 m × 1.5 m, 2 m × 2 m, 2.5 m × 2.5 m, 3 m × 3 m) and a control plot were established using a randomized complete block design. Once thinned, a series of measurements were taken in 1986 and repeated in 1991 to determine growth and form responses. Results identified highly significant responses for DBH growth and individual stem volume growth. Height response did not vary among the spacing levels. Changes in crown dimensions and stem taper were used to evaluate form responses to thinning. A highly significant decline in all form variables was found in response to increased spacing. Although the increased growth in individual trees provides an opportunity to produce a wider array of products, it appears to be at a cost of reduced form characteristics. Specific management implications for the Dryden Crown Forest are discussed. Key words: jack pine, pre-commercial thinning, growth and form responses

Income Diversification and Bank Efficiency in Vietnam

2017 ◽  
pp. 52-67
Author(s):  
Sang Nguyen Minh
Keyword(s):  
Regression Model ◽  
Commercial Banks ◽  
Banking System ◽  
Operational Efficiency ◽  
Commercial Banking ◽  
Tobit Regression ◽  
Income Diversification ◽  
Positive Effects ◽  
Study Results ◽  
The Impact

This study uses the DEA (Data Envelopment Analysis) method to estimate the technical efficiency index of 34 Vietnamese commercial banks in the period 2007-2015, and then it analyzes the impact of income diversification on the operational efficiency of Vietnamese commercial banks through a censored regression model - the Tobit regression model. Research results indicate that income diversification has positive effects on the operational efficiency of Vietnamese commercial banks in the research period. Based on study results, in this research some recommendations forpolicy are given to enhance the operational efficiency of Vietnam’s commercial banking system.

Impact of Digitalization on Service Work in Knowledge-Intensive Business Services: An Empirical Study in Tax Consultancies

2019 ◽  
Vol 3 (4) ◽  
pp. 209-222
Author(s):  
Philipp K. Görs ◽  
Henning Hummert ◽  
Anne Traum ◽  
Friedemann W. Nerdinger
Keyword(s):  
Work Engagement ◽  
Service Work ◽  
Psychological Consequences ◽  
Business Services ◽  
Knowledge Intensive Business Services ◽  
Positive Effects ◽  
Knowledge Intensive ◽  
The Impact ◽  
Positive Effect ◽  
Special Case

Digitalization is a megatrend, but there is relatively little knowledge about its consequences for service work in general and specifically in knowledge-intensive business services (KIBS). We studied the impact of digitalization on psychological consequences for employees in tax consultancies as a special case of KIBS. We compare two tax consulting jobs with very different job demands, those of tax consultants (TCs) and assistant tax consultants (ATCs). The results show that the extent of digitalization at the workplace level for ATCs correlates significantly positively with their job satisfaction. For TCs, the same variable correlates positively with their work engagement. These positive effects of digitalization are mediated in the case of ATCs by the impact on important job characteristics. In the case of TCs, which already have very good working conditions, the impact is mediated by the positive effect on self-efficacy. Theoretical and practical consequences of these results are discussed.

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