Use of Small Plots Can Overestimate Upper Limits to Basal Area and Biomass

1975 ◽  
Vol 5 (3) ◽  
pp. 503-505 ◽  
Author(s):  
J. Harry G. Smith
Keyword(s):  
Unit Area ◽  
Basal Area ◽  
Cross Sectional Area ◽  
Sectional Area ◽  
Cross Sectional ◽  
Subalpine Fir ◽  
Good Relationship ◽  
Breast Height ◽  
Plot Size ◽  
Upper Limits

Measurements of cross-sectional area outside bark at breast height in a spruce – subalpine fir forest were studied to determine the effects of plot size on minimum and maximum amounts of basal area sampled per unit area. Assuming a good relationship between basal area and biomass of trees, the need for careful interpretation of stand weight estimates on small plots is illustrated.

scholarly journals A Comparison of the Arithmetic and Geometric Means in Estimating Stump Diameter, Basal Area, and Volume in Appalachian Hardwoods

2007 ◽  
Vol 24 (1) ◽  
pp. 71-73 ◽  
Author(s):  
Harry V. Wiant ◽  
John R. Brooks
Keyword(s):  
Geometric Mean ◽  
Basal Area ◽  
Cross Sectional Area ◽  
Practical Significance ◽  
Sectional Area ◽  
Cross Sectional ◽  
Geometric Means ◽  
The Difference ◽  
Appalachian Hardwoods ◽  
Stump Diameter

Abstract The difference between the use of the arithmetic and geometric means for estimation of average stump diameter, stump cross-sectional area and estimated tree volume was investigated using measurements from 739 stumps from an Appalachian hardwood stand located in central West Virginia. Although average stump diameter, cross-sectional area, and tree volumes were statistically different between estimates based on the arithmetic and geometric mean diameter, these differences were of little practical significance. The difference in average stem diameter, cross-sectional area, tree cubic volume, and board foot volume were 0.05 in, 0.01 ft2, 0.45 ft3, and 2.41 bd ft, respectively.

scholarly journals Enterochromaffin Cells and Mast Cells in Acute Appendicitis

2020 ◽  
Vol 12 (02) ◽  
pp. 141-146
Author(s):  
Bhavya P. Mohan ◽  
K.P. Aravindan
Keyword(s):  
Mast Cell ◽  
Mast Cells ◽  
Acute Appendicitis ◽  
Toluidine Blue ◽  
Unit Area ◽  
Cross Sectional Area ◽  
Sectional Area ◽  
Cross Sectional ◽  
Cell Counts ◽  
Ec Cells

Abstract Background and Objective Serotonin levels are increased in acute appendicitis. We investigated the possible source of this increase. The aim of this study was to compare the distribution and density of epithelial and nonepithelial enterochromaffin (EC) cells as well as numbers of degranulated and nondegranulated mast cells in different layers of normal appendices and acute appendicitis. Methods Sections from 15 cases of acute appendicitis and 10 cases where the appendix was morphologically normal were stained with Hematoxylin & Eosin, Toluidine blue, and immunohistochemically for chromogranin and CD-117. EC cells stained by chromogranin were counted per crypt and extraepithelial EC cells counted and expressed as cells per unit area (mm2). Mast cells stained by Toluidine blue and CD-117 were counted in lamina propria, submucosa, and muscle layers. The difference between Toluidine blue and CD117 stained mast cells was taken to be an estimate of degranulated cells. The cell counts were expressed per unit area (mm2) as well as per cross-sectional area of the appendix. Results There was no statistically significant difference in epithelial and extraepithelial EC cells between acute appendicitis and normal appendix. Estimated mast cell degranulation as indicated by mast cell counts per cross-sectional area is greatly increased in acute appendicitis when compared with normal. Conclusion Degranulated mast cells rather than EC cells may be the main source of raised serotonin in acute appendicitis.

Estimating leaf area of Abieslasiocarpa across ranges of stand density and site quality

1989 ◽  
Vol 19 (7) ◽  
pp. 930-932 ◽  
Author(s):  
James N. Long ◽  
Frederick W. Smith
Keyword(s):  
Leaf Area ◽  
Species Differences ◽  
Stand Density ◽  
Cross Sectional Area ◽  
Site Quality ◽  
Sectional Area ◽  
Cross Sectional ◽  
Breast Height ◽  
Unbiased Estimates ◽  
Stand Conditions

For a given species, differences in the relation between leaf area and sapwood cross-sectional area at breast height have been attributed to the effects of varying stand density and site quality. When leaf area of Abieslasiocarpa (Hook.) Nutt. is estimated as a function of sapwood cross-sectional area at breast height and distance from breast height to the midpoint of the crown, the apparent effects of stand density and site quality are eliminated. A comparison of these results with those for Pinuscontorta Dougl. suggests this model form should provide unbiased estimates of leaf area for a variety of species and stand conditions.

scholarly journals The assessment sectional area of stem wood and stocks in experimental trees reclamation Western Donbass plot № 1

2016 ◽  
Vol 45 ◽  
pp. 76-81
Author(s):  
V. M. Zverkovsky ◽  
O. S. Zubkova
Keyword(s):  
Cross Sections ◽  
Linear Growth ◽  
Cross Sectional Area ◽  
Forest Plantations ◽  
Sectional Area ◽  
Cross Sectional ◽  
Stem Wood ◽  
Diameter At Breast Height ◽  
Breast Height

The linear growth of forest plantations of Western Donbass’ recultivating plot №1 were studied. The established cross-sectional the area of trunks and timber reserves experimental trees.Characterized by parameters which are the volume of wood: its height, diameter at breast height and shape of the forming barrel. In diameter at breast height cross sectional area is determined and then the barrel volume is calculated. Cross sections of tree trunks are shaped like a circle or an ellipse. Knowing the volume of logs we calculated reserves of wood for trees experimental plots.The largest reserves of timber and cross-sectional area characterized planting U. pumila – 15,367 m3 and 1,9583 m2, A. platanoides – 13,328 m3 and 2,67 m2, Q. robur – 10,120 m3 and 1,452 m2, J. virginiana – 8,748 m3 and 2,106 m2. The least plantation stocks of wood characterized E. angustifolia – 1,3699 m3 and 0,3693 m2, R. pseudoacacia – 2,9478 m3 and 0,8350 m2, P. rallasiana – 3,1626 m3 and 0,3279 m2.

scholarly journals The assessment sectional area of stem wood and stocks in experimental trees reclamation Western Donbass plot № 1

2016 ◽  
Vol 45 ◽  
pp. 76-81
Author(s):  
V. M. Zverkovsky ◽  
O. S. Zubkova
Keyword(s):  
Cross Sections ◽  
Linear Growth ◽  
Cross Sectional Area ◽  
Forest Plantations ◽  
Sectional Area ◽  
Cross Sectional ◽  
Stem Wood ◽  
Diameter At Breast Height ◽  
Breast Height

The linear growth of forest plantations of Western Donbass’ recultivating plot №1 were studied. The established cross-sectional the area of trunks and timber reserves experimental trees.Characterized by parameters which are the volume of wood: its height, diameter at breast height and shape of the forming barrel. In diameter at breast height cross sectional area is determined and then the barrel volume is calculated. Cross sections of tree trunks are shaped like a circle or an ellipse. Knowing the volume of logs we calculated reserves of wood for trees experimental plots.The largest reserves of timber and cross-sectional area characterized planting U. pumila – 15,367 m3 and 1,9583 m2, A. platanoides – 13,328 m3 and 2,67 m2, Q. robur – 10,120 m3 and 1,452 m2, J. virginiana – 8,748 m3 and 2,106 m2. The least plantation stocks of wood characterized E. angustifolia – 1,3699 m3 and 0,3693 m2, R. pseudoacacia – 2,9478 m3 and 0,8350 m2, P. rallasiana – 3,1626 m3 and 0,3279 m2.

Fleece characters and their influence on wool production per unit area of skin in Merino sheep

1958 ◽  
Vol 9 (3) ◽  
pp. 363 ◽  
Author(s):  
SSY Young ◽  
RE Chapman
Keyword(s):  
Unit Area ◽  
Fibre Diameter ◽  
Fibre Volume ◽  
Cross Sectional Area ◽  
The Body ◽  
Sectional Area ◽  
Cross Sectional ◽  
Fibre Density ◽  
Wool Production ◽  
Staple Length

The variations in fleece characters and the dependence of wool production per unit area of skin on these characters were studied with 15 sheep in both a medium and a strong-wool strain of Merino. Small but significant differences in staple length and fibre diameter were found between regions on the body, whereas differences in density were large. The variation in density was about three times as large as those in staple length and fibre diameter. Distinct dorsoventral and anteroposterior gradients over the body existed for fibre density, but not for staple length and fibre diameter. The influences of the fleece characters on wool production per unit area were somewhat different in the two strains, and changed with level of production. Among the medium-wool sheep, fibre density had the largest effect on production, with staple length less and mean fibre cross-sectional area least. Among the strong-wool sheep, length was more important than density, which in turn was more important than fibre cross-sectional area. The combined data indicated that as mean wool weight per unit area increased, the influence of density rose to a maximum and then diminished, whereupon mean fibre volume became the main contributor to wool weight. For different positions on the body of individual sheep, the dependence of wool production per unit area on the fleece characters was found to be similar in the two strains. Fibre density had the major effect in determining the level of production, whereas the influences of staple length and fibre area were negligible.

Influence of fertilization on the allometric relations for two pines in contrasting environments

1993 ◽  
Vol 23 (8) ◽  
pp. 1704-1711 ◽  
Author(s):  
Stith T. Gower ◽  
Brent E. Haynes ◽  
Karin S. Fassnacht ◽  
Steve W. Running ◽  
E. Raymond Hunt Jr.
Keyword(s):  
Leaf Area ◽  
Ponderosa Pine ◽  
Cross Sectional Area ◽  
Red Pine ◽  
Stem Diameter ◽  
Sectional Area ◽  
Cross Sectional ◽  
Breast Height ◽  
Allometric Relations ◽  
And Control

The objective of this study was to examine the effect of fertilization on the allometric relations for red pine (Pinusresinosa Ait.) and ponderosa pine (Pinusponderosa Dougl. ex Laws.) growing in contrasting climates. After 2 years of treatment, fertilization did not significantly affect the allometric relations between stem or branch mass and stem diameter for either species. For a similar-diameter tree, current foliage mass and area and new twig mass were significantly greater for fertilized than for control red pine and ponderosa pine. The significant increase in new foliage mass and area occurred in the upper and middle canopy for red pine and middle and lower canopy for ponderosa pine. For a similar-diameter tree, projected (one-sided) leaf area and total foliage mass were significantly greater for fertilized than for control red pine. However, leaf area and total foliage mass did not differ between similar-diameter fertilized and control ponderosa pine because fertilization decreased leaf longevity. The ratios of leaf area/sapwood cross-sectional area measured at breast height (1.37 m) were 0.14 and 0.11 for control plus fertilized red pine and ponderosa pine, respectively, and were greater (but not significantly) for fertilized than for control trees, while the ratios of leaf area/sapwood cross-sectional area measured at the base of live crown were significantly greater for fertilized than for control red pine and ponderosa pine.

Methods of analysis and the influence of fleece characters on unit area wool production of Romney lambs

1960 ◽  
Vol 11 (5) ◽  
pp. 851 ◽  
Author(s):  
AE Henderson ◽  
BI Hayman
Keyword(s):  
Unit Area ◽  
Fibre Length ◽  
Fibre Volume ◽  
Cross Sectional Area ◽  
The Body ◽  
Skin Area ◽  
Sectional Area ◽  
Cross Sectional ◽  
Wool Production ◽  
Fibre Number

Investigation has been made of the influence of fibre number per unit area (N), cross-sectional area of fibre (A), and fibre length (L), on wool production per unit area of skin (W). The influence of the compound characters fibre volume (V) and proportion of skin area occupied by fibre (0) has also been considered. Methods are given whereby the significance of the variation associated with any one of these interacting components can be assessed. Data from four groups of lambs were analysed, each group having been subjected to a different nutritional regime. Slightly more than three-quarters of the variation induced in W by these treatments was due to variation in L, with N and A having negligible effects. No evidence was found that the relative influence of the components changed with change in level of production. Differences in W between lambs on the same nutritional level were influenced almost equally by variation in N and L, with A again having a negligible effect. Of the variation in W between positions on lambs, approximately 50 per cent. was accounted for by variation in N, 40 per cent. by variation in A, and 10 per cent. by variation in L. Variation of the compound character O accounted for nearly 90 per cent. of the variation in W over the body.

An antithetic variate to facilitate upper-stem height measurements for critical height sampling with importance sampling

2013 ◽  
Vol 43 (12) ◽  
pp. 1151-1161 ◽  
Author(s):  
Thomas B. Lynch ◽  
Jeffrey H. Gove
Keyword(s):  
Importance Sampling ◽  
Basal Area ◽  
Cross Sectional Area ◽  
Sample Point ◽  
Sectional Area ◽  
Critical Height ◽  
Cross Sectional ◽  
Individual Tree ◽  
Sample Tree ◽  
The Cross

Critical height sampling (CHS) estimates cubic volume per unit area by multiplying the sum of critical heights measured on trees tallied in a horizontal point sample (HPS) by the HPS basal area factor. One of the barriers to practical application of CHS is the fact that trees near the field location of the point-sampling sample point have critical heights that occur quite high on the stem, making them difficult to view from the sample point. To surmount this difficulty, use of the “antithetic variate” associated with the critical height together with importance sampling from the cylindrical shells integral is proposed. This antithetic variate will be u = (1 − b/B), where b is the cross-sectional area at “borderline” condition and B is the tree’s basal area. The cross-sectional area at borderline condition b can be determined with knowledge of the HPS gauge angle by measuring the distance to the sample tree. When the antithetic variate u is used in importance sampling, the upper-stem measurement will be low on tree stems close to the sample point and high on tree stems distant from the sample point, enhancing visibility and ease of measurement from the sample point. Computer simulations compared HPS, CHS, CHS with importance sampling (ICHS), ICHS and an antithetic variate (AICHS), and CHS with paired antithetic varariates (PAICHS) and found that HPS, ICHS, AICHS, and PAICHS were very nearly equally precise and were more precise than CHS. These results are favorable to AICHS, since it should require less time than either PAICHS or ICHS and is not subject to individual-tree volume equation bias.

Mechanical properties of the collagenous framework of skin in rats of different ages

1964 ◽  
Vol 206 (6) ◽  
pp. 1425-1429 ◽  
Author(s):  
Phyllis Fry ◽  
Margaret L. R. Harkness ◽  
R. D. Harkness
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Unit Area ◽  
Constant Load ◽  
Cross Sectional Area ◽  
Mechanical Resistance ◽  
Sectional Area ◽  
Cross Sectional ◽  
Constant Rate ◽  
Zero Time

The collagen content, tensile strength, and extensibility of the skin of rats have been examined in rats 3–85 weeks of age. Tensile strength calculated per unit cross-sectional area of collagen increased with age, the maximal value in the oldest group (5.5 kg/mm2 collagen) being about three times that in the youngest. The quantity present per unit area of surface also increased with age. An estimate of the total "surface mechanical resistance" obtained by multiplying collagen per unit area of skin and tensile strength rose continuously about twentyfold between the youngest to oldest of the groups. Application of a load produces after a time an elongation at constant rate ( K). Extensibility, measured by the ratio of this rate to length at zero time ( l0) obtained by extrapolation, and corrected to constant load of 100 g/mm2 cross-sectional area of collagen, was found to fall with age, the range being about eightyfold.

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