Impact of spacing on tracheid length, relative density, and growth rate of juvenile wood and mature wood in Piceamariana

1994 ◽  
Vol 24 (5) ◽  
pp. 996-1007 ◽  
Author(s):  
K.C. Yang ◽  
G. Hazenberg
Keyword(s):  
Growth Rate ◽  
Relative Density ◽  
Boundary Point ◽  
Juvenile Wood ◽  
The Other ◽  
Mature Wood ◽  
Average Growth ◽  
Tracheid Length ◽  
Significant Difference ◽  
The Impact

Ten 38-year-old trees of Piceamariana (Mill.) B.S.P., grown at each of three spacings (1.8 × 1.8, 2.7 × 2.7, and 3.6 × 3.6 m), at Stanley, 30 km west of Thunder Bay, Ont., were used to study the impact of spacing on growth rate, relative density, and tracheid length of juvenile and mature wood. Increment cores of 12 mm diameter were extracted from the south aspect of each tree at breast height. The boundary of juvenile and mature wood was demarcated by the variation in tracheid length, which varied among trees from ring 11 to 21. Average growth rate, relative density, and tracheid length were obtained between the pith and boundary point (juvenile wood) and beyond the boundary point (mature wood). Differences between the levels of spacing for the three response variables in both juvenile and mature wood were tested using contrasts. Properties of juvenile and mature wood were found to be affected differently by the plantation spacing. Juvenile wood has a faster growth rate and shorter fibres than mature wood. Relative density was similar in both wood zones. The growth rate in juvenile wood was found to be significantly different among the spacing levels. For mature wood, only the growth rate at the 3.6 × 3.6 m spacing was significantly different from the other two spacing levels. The highest relative density, 0.39, in both juvenile and mature wood was found at the 1.8 × 1.8 m spacing. No significant difference in the relative density between the two wider spacings was observed. At the widest spacing, the relative density was 8% lower than that at the 1.8 × 1.8 m spacing. The longest fibre lengths were found at the intermediate 2.7 × 2.7 m spacing, 2.05 mm in juvenile wood and 2.94 mm in mature wood. Tracheid lengths of the 3.6 × 3.6 m spacing were significantly shorter than those of the other two spacings. The relative density and tracheid length of plantation grown wood were lower than those of natural grown wood by at least 5% for relative density and 33% for tracheid length.

Maturation Rate of Tracheid Lengthening in Slow-Grown Young Sugi (Cryptomeria Japonica) Trees

IAWA Journal ◽  
1993 ◽  
Vol 14 (3) ◽  
pp. 267-272 ◽  
Author(s):  
Takafumi Kubo ◽  
Miwako Koyama
Keyword(s):  
Growth Rate ◽  
Cryptomeria Japonica ◽  
Radial Growth ◽  
Juvenile Wood ◽  
Ring Width ◽  
Mature Wood ◽  
Annual Rings ◽  
Tracheid Length ◽  
Rate Of Increase ◽  
Maturation Rate

Maturation rate, the rate of increase in tracheid length in juvenile wood, was examined in sugi (Cryptomeria japonica D. Don) saplings grown for five years under different shading conditions: 10%, 20% 40% and 100 % of relative illumination intensity. The lowest photointensity dramatically suppressed radial growth and slowed tracheid lengthening. Radial variation of tracheid length within the stem was associated with distance from the pith, rather than the number of annual rings from the pith. Furthermore, maturation rate was closely related to the rate of the radial growth, which changed proportionally with growth rate below a 2-3 mm ring width. A lower maturation rate of tracheid length is associated with a delay in the transition from juvenile to mature wood.

Geographical variation in wood properties of Larixlaricina juvenile wood in northern Ontario

1987 ◽  
Vol 17 (7) ◽  
pp. 648-653
Author(s):  
K. C. Yang ◽  
G. Hazenberg
Keyword(s):  
Growth Rate ◽  
Specific Gravity ◽  
Juvenile Wood ◽  
Wood Properties ◽  
Lower Latitude ◽  
Northern Ontario ◽  
Average Growth ◽  
Tracheid Length ◽  
Level Of Significance ◽  
Individual Trees

Growth rate, latewood ratio, specific gravity, and tracheid length of Larixlaricina (Du Roi) K. Koch juvenile wood were studied with two 12-mm increment cores extracted at breast height from 240 healthy trees from 12 locations at a range in latitude from 46 to 56° N in northern Ontario. Ten trees were selected from each stand and two stands were chosen from each location. Univariate analyses of variance indicated that growth rate and latewood of juvenile wood varied significantly in various locations, stands, and trees at the α = 0.01 level of significance. Growth rate of juvenile wood decreased from a lower latitude to a higher latitude, whereas latewood ratios displayed a reverse trend, i.e., a higher latewood ratio was found at a higher latitude. Specific gravity of juvenile wood varied significantly in individual trees. Tracheid length varied significantly among locations, stands, and trees. The overall average growth rate, tracheid length, and specific gravity are 1.29 mm per ring, 2.10 mm, and 0.43, respectively. An unexpected relationship was found between growth rate and tracheid length. Growth rate of juvenile wood has a positive relationship with tracheid length and an inverse relationship with specific gravity.

scholarly journals The relation between the microscopic structure and the wood density of European beech (Fagus sylvatica L.)

2008 ◽  
Vol 54 (No. 4) ◽  
pp. 170-175 ◽  
Author(s):  
V. Gryc ◽  
H. Vavrčík ◽  
M. Rybníček ◽  
E. Přemyslovská
Keyword(s):  
Comparative Analysis ◽  
Wood Density ◽  
Juvenile Wood ◽  
European Beech ◽  
Vessel Diameter ◽  
The Other ◽  
Mature Wood ◽  
Microscopic Structure ◽  
Significant Difference ◽  
The Difference

The aim of this study was to compare the structure of beech juvenile and mature wood in relation to wood density. The comparative analysis between juvenile and mature wood examined the diameter of vessels, the width and height of pith rays, and the number of vessels and pith rays per 1 mm<sup>2</sup>. The results show that the average vessel diameter as well as the width and height of pith rays reach statistically lower values in juvenile wood than in mature wood. On the other hand, no significant difference between the two types of wood has been found in terms of the frequency of vessels per 1 mm<sup>2</sup>. Having said that, the difference in the frequency of rays per 1 mm<sup>2</sup> between juvenile and mature wood is far from being negligible; juvenile wood has three times as many pith rays as mature wood. The density of juvenile wood is higher (&rho;<sub>12</sub> = 726.07 kg/m<sup>3)</sup> than the density of mature wood ((&rho;<sub>12</sub> = 701.50 kg/m<sup>3</sup>).

Formation and vertical distribution of juvenile and mature wood in a single stem of Cryptomeriajaponica

1994 ◽  
Vol 24 (5) ◽  
pp. 969-975 ◽  
Author(s):  
K.C. Yang ◽  
Y.S. Chen ◽  
C. Chiu
Keyword(s):  
Vertical Distribution ◽  
Juvenile Wood ◽  
Wood Formation ◽  
Mature Wood ◽  
Regression Methods ◽  
Sample Tree ◽  
Significant Difference ◽  
Two Measures ◽  
Highly Correlated ◽  
The Impact

A single tree stem was used to study the formation and vertical distribution of juvenile and mature wood in Cryptomeriajaponica D. Don. The sample tree was collected from a 45-year-old plantation with 1.5 × 3.0 m spacing at Maio-li, Taiwan. Nine diametric wood strips were cut from the tree trunk from both the east and the west aspects, starting from 0.3 m by increments of 2.5 m to the top of the tree. The widths of juvenile and mature wood were recorded with two measures, i.e., the number of rings and the width in millimetres. The relationships between both the width of juvenile and mature wood and the height and age at each level of the tree were obtained by regression methods. The relationships between the age of the cambial initial and the period of juvenile wood formation at the various height levels were also determined. It was found that juvenile wood has a conical shape with a wide base at the bottom of the tree. There is no significant difference in the ratio of juvenile to mature wood width between the east and west aspects of the tree. The impact of both the height and age at each level of the tree on the width of juvenile wood appears to differ, and a similar observation must be made for mature wood. A high proportion of the total wood volume (64%) was found to be juvenile wood. No mature wood was observed at the top of the tree. The width of juvenile wood is highly correlated with the age of formation of cambial initials counted from the year of seed germination. The older the cambial initial, the narrower is the width of juvenile wood in terms of ring count.

scholarly journals Effect of growth rate on the physical and mechanical properties of Douglas-fir in western Europe

2017 ◽  
Vol 47 (8) ◽  
pp. 1056-1065 ◽  
Author(s):  
C. Pollet ◽  
J.-M. Henin ◽  
J. Hébert ◽  
B. Jourez
Keyword(s):  
Mechanical Properties ◽  
Growth Rate ◽  
Management Practices ◽  
Juvenile Wood ◽  
Ring Width ◽  
Physical And Mechanical Properties ◽  
Douglas Fir ◽  
Mature Wood ◽  
Cambial Age ◽  
The Impact

To quantify the impact of forest management practices and tree growth rate on the potential uses of Douglas-fir wood, nine physico-mechanical properties were studied on more than 1250 standardized clear specimens. These were collected from trees cut in 11 even-aged stands (six trees per stand) located in Wallonia (southern Belgium). Stands were 40 to 69 years old, and mean tree girth was ca. 150 cm. Mean ring width of the 66 trees ranged from 3 to more than 7 mm. Statistical analysis showed significant but weak effects of ring width on the studied properties. Considered jointly, mean ring width and cambial age of the test specimens only explained 28% to 40% of the variability of their properties. Also, when ring width increases, these properties display higher decreases in juvenile wood than in mature wood. From a technological standpoint, maintaining mean ring width under 4 mm in juvenile wood and 6 mm in mature wood should accommodate all potential uses of Douglas-fir wood. However, considering that density appeared to be the main driver of wood properties, our results and the literature corroborate the importance of genetic selection as a complement to silvicultural measures to improve or guarantee the technological properties of Douglas-fir wood.

scholarly journals Phenotypic Correlations among Growth and Selected Wood Properties in White Spruce (Picea glauca (Moench) Voss) †

Forests ◽  
2019 ◽  
Vol 10 (7) ◽  
pp. 589 ◽  
Author(s):  
Cyriac S. Mvolo ◽  
Ahmed Koubaa ◽  
Jean Beaulieu ◽  
Alain Cloutier ◽  
Maurice Defo ◽  
...  
Keyword(s):  
Physical Properties ◽  
Picea Glauca ◽  
Radial Growth ◽  
Juvenile Wood ◽  
Wood Properties ◽  
Mature Wood ◽  
Ring Density ◽  
Tracheid Length ◽  
Latewood Density ◽  
Anatomical Properties

We examined phenotypic relationships among radial growth-related, physical (i.e., related to wood density), and anatomical (i.e., related to tracheid dimensions) wood properties in white spruce (Picea glauca (Moench) Voss), in order to determine the strength and significance of their correlations. Additionally, principal component analysis (PCA) was used to establish if all of the properties must be measured and to determine the key properties that can be used as proxies for the other variables. Radial growth-related and physical properties were measured with an X-ray densitometer, while anatomical properties were measured with a Fiber Quality Analyzer. Fifteen wood properties (tracheid length (TL) and diameter (TD), earlywood tracheid length (ETL) and diameter (ETD), latewood tracheid length (LTL) and diameter (LTD), ring width (RW), ring area (RA), earlywood width (EWW), latewood width (LWW), latewood proportion (LWP), ring density (RD), intra-ring density variation, earlywood density (EWD), and latewood density (LWD)) were assessed. Relationships were evaluated at intra-ring and inter-ring levels in the juvenile wood (JW) and mature wood (MW) zones. Except for a few cases when mature tracheid diameter (TD) was involved, all intra-ring anatomical properties were highly and significantly correlated. Radial growth properties were correlated, with stronger relationships in MW compared to JW. Physical properties were often positively and significantly correlated in both JW and MW. A higher earlywood density coupled with a lower latewood density favored wood uniformity, i.e., the homogeneity of ring density within a growth ring. Managing plantations to suppress trees growth during JW formation, and enhancing radial growth when MW formation starts will favor overall wood quality. In order, RW-EWW-RA, TL-ETL-LTL, and RD-EWD-LWP are the three clusters that appeared in the three wood zones, the whole pith-to-bark radial section, the juvenile wood zone, and the mature wood zone.

Air Travel and Contact Lenses: A Laboratory Study

1988 ◽  
Vol 32 (6) ◽  
pp. 450-454
Author(s):  
Joseph E. Laviana ◽  
Frederick H. Rohles
Keyword(s):  
Relative Humidity ◽  
Contact Lenses ◽  
Flight Time ◽  
Air Travel ◽  
The Other ◽  
Laboratory Setting ◽  
Soft Contact ◽  
Soft Contact Lenses ◽  
Significant Difference ◽  
The Impact

The cabin of an inflight aircraft contains approximately 10% relative humidity (rh). To investigate the impact of this environment on eye comfort, an inflight humidity profile was simulated in a controlled laboratory setting. The experiment was replicated 3 times using a group of 4 subjects (2 males; 2 females) per test. Participants served in both control and experimental roles by wearing a hydrophilic contact lens on one eye and no lens on the other. Subjects provided evaluations of “eye comfort” for both eyes (contact and naked) at specified intervals during the 10 hour test. The results indicated that at 10% rh, there was no significant difference in eye comfort for either wearers or nonwearers of soft contact lenses. However, comfort decreased with the length of exposure (flight time), and for durations of six hours or longer a significant annoyance was reported.

scholarly journals Mechanical performance of yew (Taxus baccata L.) from a longbow perspective

Holzforschung ◽  
2013 ◽  
Vol 67 (7) ◽  
pp. 763-770 ◽  
Author(s):  
Ingela Bjurhager ◽  
E. Kristofer Gamstedt ◽  
Daniel Keunecke ◽  
Peter Niemz ◽  
Lars A. Berglund
Keyword(s):  
Yield Stress ◽  
Middle Ages ◽  
Mechanical Performance ◽  
Juvenile Wood ◽  
The Other ◽  
Mature Wood ◽  
Taxus Baccata ◽  
Beam Model ◽  
Bending Properties ◽  
Wood Content

Abstract Yew (Taxus baccata L.) longbow was the preferred weapon in the Middle Ages until the emergence of guns. In this study, the tensile, compression, and bending properties of yew were investigated. The advantage of yew over the other species in the study was also confirmed by a simple beam model. The superior toughness of yew has the effect that a yew longbow has a higher range compared with bows made from other species. Unexpectedly, the mechanical performance of a bow made from yew is influenced by the juvenile-to-mature wood ratio rather than by the heartwood-to-sapwood ratio. A yew bow is predicted to have maximized performance at a juvenile wood content of 30–50%, and located at the concave side (the compressive side facing the bowyer). Here, the stiffness and yield stress in compression should be as high as possible.

Adverse effects on growth rates in rats caused by buprenorphine administration

2000 ◽  
Vol 34 (2) ◽  
pp. 202-206 ◽  
Author(s):  
C. Jacobson
Keyword(s):  
Growth Rate ◽  
Weight Loss ◽  
Growth Rates ◽  
The Other ◽  
Postoperative Treatment ◽  
Gastric Distension ◽  
Bedding Material ◽  
Analgesic Treatment ◽  
Measuring Period ◽  
Significant Difference

As a routine postoperative treatment, a single dose of buprenorphine was given to rats at a dose of 0.05 mg/kg subcutaneously. However, some rats developed abnormal secretions around the nose and mouth and some animals died 3-5 days after surgery and analgesic treatment. At autopsy a yellow fibrous mass was found in the stomach and intestines. Observations of animals given buprenorphine revealed an abnormal ingestion of bedding material. This caused a disturbance to normal digestion, with gastric distension, weight loss or decreased growth rate, constipation and occasionally death. In this study rats were monitored for 6 days following surgery and analgesic treatment. A comparison of growth rates was made between rats given saline and buprenorphine or na1buphine and between animals kept on bedding or grid floors for the first 24 h after treatment. Of the animals held on bedding, the buprenorphine-treated animals did not lose weight as the other animals did, but had on the other hand a decreased growth rate during the measuring period of 6 days after surgery. When denied access to bedding for the first 24 h after surgery, rats given saline or na1buphine had a reduced weight gain over the first 24 h, similar to the groups held on bedding. Rats held on grid floors and given buprenorphine continued to gain weight for the first 24h. From day 3, there was no significant difference between the groups, which all gained weight.

Further Results of Tagging Sea Mullet, Mugil cephalus Linnaeus, on the Eastern Australia Coast

1953 ◽  
Vol 4 (2) ◽  
pp. 251 ◽  
Author(s):  
GL Kesteven
Keyword(s):  
Growth Rate ◽  
The Other ◽  
Young Fish ◽  
Scale Growth ◽  
Average Growth Rate ◽  
Average Growth ◽  
Scale Reading ◽  
Eastern Australia ◽  
Rivers And Lakes

An account is given of tagging operations in eastern Australian waters on sea mullet. The operations involved fish of wide age and size ranges in a variety of habitats and localities, in all months of the year except July. The recoveries from these operations are analysed for information on movement, growth, and mortality. The results show the movement of the tagged fish to be predominantly northwards and require a postulate that southward movement takes place among the young fish (and possibly eggs). The movement of individual fish can be quite rapid and cover long distances, and each fish probably migrates a number of times during its lifetime. The proportion of the population involved in these movements probably exceeds 50 per cent. The results show that there is on the coast one continuous stock of this species, of which the populations occupying the numerous rivers and lakes constantly intermingle. Confirmation was obtained of the earlier workeon the technique of scale reading in this species, and of the general results on average growth rate. Growth occurs chiefly in summer, but possibly also in the latter part of spring and the early part of autumn. The physiology of scale growth and trhe formation of annual "breaks" are discussed. Proportional recoveries from each operation are reported but these cannot serve well a s an index of intensity of fishing. On the other hand, the longevity of the tags serves to indicate the probable life expectancy of these groups of fish; this is estimated as slightly more than 3 yr.

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