The applicability of the pipe model theory for the prediction of foliage biomass in trees from natural, untreated black spruce stands

1992 ◽  
Vol 22 (8) ◽  
pp. 1118-1123 ◽  
Author(s):  
Edgar Robichaud ◽  
Ian R. Methven
Keyword(s):  
Model Theory ◽  
Black Spruce ◽  
Strong Relationship ◽  
Cross Sectional Area ◽  
Social Classes ◽  
Regression Equations ◽  
Sectional Area ◽  
Cross Sectional ◽  
Pipe Model ◽  
Pipe Model Theory

Trees were sampled from 26 black spruce (Piceamariana (Mill.) B.S.P.) stands across New Brunswick and within the boreal forest of Quebec to test the validity of the pipe model theory for sampling purposes. Trees were sampled from a wide range of ages, site qualities, densities, and social classes for determination of foliage biomass and sapwood cross-sectional areas at breast height and at the base of the live crown. A strong relationship was found between sapwood cross-sectional area and foliage biomass across the range of conditions. The y-intercepts for these regression equations, based on the untransformed data, were not significantly different from zero (P < 0.05). Partial correlation analysis indicated no significant relationship between the foliage biomass and tree age, site quality, or stand density but confirmed the strong relationship with sapwood cross-sectional area. Suppressed and intermediate social classes followed a similar relationship as dominant trees. Regression equations developed from this study were similar to those determined for spruce species and supported the use of sapwood cross-sectional area as a predictor of foliage biomass for black spruce.

Application of the pipe model theory to predict canopy leaf area

1982 ◽  
Vol 12 (3) ◽  
pp. 556-560 ◽  
Author(s):  
R. H. Waring ◽  
P. E. Schroeder ◽  
R. Oren
Keyword(s):  
Leaf Area ◽  
Model Theory ◽  
Large Fraction ◽  
Cross Sectional Area ◽  
Unit Weight ◽  
Sectional Area ◽  
Cross Sectional ◽  
Sapwood Area ◽  
Pipe Model ◽  
Pipe Model Theory

The pipe model theory presents the idea that a unit weight of tree foliage is serviced by a specific cross-sectional area of conducting sapwood in the crown. Below the crown, a large fraction of the tree bole may be nonconducting tissue, so the sapwood area would have to be known to estimate foliage. We applied the pipe model theory to the analysis of several western coniferous species to learn whether the distribution of canopy leaf area could be accurately estimated from knowledge of the sapwood cross-sectional area at various heights, including breast height (1.37 m). Results are excellent, but taper in the conducting area must be considered when sapwood area is measured below the crown.

scholarly journals Effects of tree size and position on pipe model ratios in Scots pine

2005 ◽  
Vol 35 (6) ◽  
pp. 1294-1304 ◽  
Author(s):  
Frank Berninger ◽  
Lluis Coll ◽  
Petteri Vanninen ◽  
Annikki Mäkelä ◽  
Sari Palmroth ◽  
...  
Keyword(s):  
Scots Pine ◽  
Area Ratio ◽  
Cross Sectional Area ◽  
Sectional Area ◽  
Relative Height ◽  
Cross Sectional ◽  
Tree Diameter ◽  
Pipe Model ◽  
Absolute Height ◽  
The Relationship

We investigate how the foliage mass to wood area ratios depend on tree and stand characteristics of previously collected data from Scots pine (Pinus sylvestris L.). Our analysis allowed a separation of the relationship between stem and branch cross-sectional areas and the relationship between the branch cross-sectional area and foliage mass. We studied how these relationships varied within and between stands. The lowest site fertility class had a higher foliage mass to stem area ratio than better sites. The relative height of a tree in the stand (Φ) was the major factor that determined the variation in the relationship between the branch cross-sectional area and the stem cross-sectional area. Models based on absolute height or tree diameter were usually weaker. Models based on Φ were simpler, since no other variables were able to explain between-stand variation in the presence of Φ. We were able to predict changes in the branchiness of the tree but not in the foliage mass supported per unit of branch area.

Scots pine and Norway spruce foliage biomass in Finland and Sweden — testing traditional models vs. the pipe model theory

2020 ◽  
Vol 50 (2) ◽  
pp. 146-154 ◽  
Author(s):  
Aleksi Lehtonen ◽  
Juha Heikkinen ◽  
Hans Petersson ◽  
Boris Ťupek ◽  
Eero Liski ◽  
...  
Keyword(s):  
Norway Spruce ◽  
Scots Pine ◽  
Accurate Method ◽  
Cross Sectional Area ◽  
Sectional Area ◽  
Tree Crown ◽  
Cross Sectional ◽  
Pipe Model ◽  
Biomass Models ◽  
Model Approach

The pipe model approach was compared with foliage biomass models by using the cross-sectional area at the tree crown base for predicting foliage biomass of Scots pine (Pinus sylvestris L.) and Norway spruce (Picea abies (L.) Karst.). We evaluated the impacts of site type, fertilization, and climate on the relationship between foliage biomass and cross-sectional area at the tree crown base, referred as to the pipe model ratio. Our hypotheses were that (i) the pipe model approach is a more precise and accurate method for foliage prediction than the traditional biomass models and (ii) the pipe model ratio for foliage does not explicitly depend on any single environmental driver. Data used here consisted of felled trees from Finnish and Swedish biomass studies. These data were analyzed by linear mixed models with different covariates, and the uncertainties of different modelling approaches were evaluated. The pipe model outperformed other models for Scots pine but not for Norway spruce. Results showed larger pipe model ratios for Scots pine in herb-rich forests compared with those of trees in subxeric heath forest. Results from fertilized trees indicated that the addition of nitrogen temporarily increased foliage biomass.

scholarly journals EFFECT OF ROOTSTOCK ON LONGEVITY AND FRUIT AND TREE CHARACTERISTICS OF PLUM

HortScience ◽  
1995 ◽  
Vol 30 (3) ◽  
pp. 431d-431
Author(s):  
J.D. Norton ◽  
G.E. Boyhan ◽  
J.A. Pitts
Keyword(s):  
Multiple Regression ◽  
Shoot Growth ◽  
Cross Sectional Area ◽  
Regression Equations ◽  
Sectional Area ◽  
Cross Sectional ◽  
Nutrient Analysis ◽  
Tree Survival ◽  
Foliar Nutrient ◽  
Tree Characteristics

The dwarfing characteristics of St. Julien and Pixy rootstocks as measured by shoot growth and trunk cross-sectional area (TCSA) was evident. Tree survival was significantly reduced after 3 years on Nemaguard and Pixy rootstocks. None of the elements measured by foliar nutrient analysis were below the minimum for plums; however, significant multiple regression equations for total shoot growth, TCSA, and survivability were evident with R2 of ≈0.30 in all three cases.

Pelvic Canal Narrowing Caused by Triple Pelvic Osteotomy in the Dog

1994 ◽  
Vol 07 (03) ◽  
pp. 110-113 ◽  
Author(s):  
D. L. Holmberg ◽  
M. B. Hurtig ◽  
H. R. Sukhiani
Keyword(s):  
Postoperative Complications ◽  
Pelvic Osteotomy ◽  
Cross Sectional Area ◽  
Sectional Area ◽  
Cross Sectional ◽  
Canal Width ◽  
Operative Complications ◽  
Post Operative Complications

SummaryDuring a triple pelvic osteotomy, rotation of the free acetabular segment causes the pubic remnant on the acetabulum to rotate into the pelvic canal. The resulting narrowing may cause complications by impingement on the organs within the pelvic canal. Triple pelvic osteotomies were performed on ten cadaver pelves with pubic remnants equal to 0, 25, and 50% of the hemi-pubic length and angles of acetabular rotation of 20, 30, and 40 degrees. All combinations of pubic remnant lengths and angles of acetabular rotation caused a significant reduction in pelvic canal-width and cross-sectional area, when compared to the inact pelvis. Zero, 25, and 50% pubic remnants result in 15, 35, and 50% reductions in pelvic canal width respectively. Overrotation of the acetabulum should be avoided and the pubic remnant on the acetabular segment should be minimized to reduce postoperative complications due to pelvic canal narrowing.When performing triple pelvic osteotomies, the length of the pubic remnant on the acetabular segment and the angle of acetabular rotation both significantly narrow the pelvic canal. To reduce post-operative complications, due to narrowing of the pelvic canal, overrotation of the acetabulum should be avoided and the length of the pubic remnant should be minimized.

DETERMINATION OF THE FUNCTION OF THE ROD’S CROSS-SECTIONAL AREA USING VIBRATION EIGENFREQUENCIES

2020 ◽  
Vol 0 (4) ◽  
pp. 19-24
Author(s):  
I.M. UTYASHEV ◽  
◽  
A.A. AITBAEVA ◽  
A.A. YULMUKHAMETOV ◽  
◽  
...  
Keyword(s):  
Cross Sectional Area ◽  
Variable Cross ◽  
Sectional Area ◽  
Longitudinal Vibrations ◽  
Cross Sectional ◽  
Method Error ◽  
Various Boundary Conditions ◽  
Elastic Fixation ◽  
Crosssectional Area

The paper presents solutions to the direct and inverse problems on longitudinal vibrations of a rod with a variable cross-sectional area. The law of variation of the cross-sectional area is modeled as an exponential function of a polynomial of degree n . The method for reconstructing this function is based on representing the fundamental system of solutions of the direct problem in the form of a Maclaurin series in the variables x and λ. Examples of solutions for various section functions and various boundary conditions are given. It is shown that to recover n unknown coefficients of a polynomial, n eigenvalues are required, and the solution is dual. An unambiguous solution was obtained only for the case of elastic fixation at one of the rod’s ends. The numerical estimation of the method error was made using input data noise. It is shown that the error in finding the variable crosssectional area is less than 1% with the error in the eigenvalues of longitudinal vibrations not exceeding 0.0001.

Changes in the parameters of nasal breathing and parameters of the upper respiratory tract during orthognathic operations in patients with II and III skeletal class of jaw anomalies

2020 ◽  
pp. 22-27
Author(s):  
S.Sh. Gammadaeva ◽  
M.I. Misirkhanova ◽  
A.Yu. Drobyshev
Keyword(s):  
Respiratory Tract ◽  
Nasal Cavity ◽  
Nasal Septum ◽  
Cross Sectional Area ◽  
Upper Respiratory Tract ◽  
Sectional Area ◽  
Nasal Breathing ◽  
Cross Sectional ◽  
Skeletal Class ◽  
Upper Respiratory

The study analyzed the functional parameters of nasal breathing, linear parameters of the nasal aperture, nasal cavity and nasopharynx, volumetric parameters of the upper airways in patients with II and III skeletal class of jaw anomalies before and after orthognathic surgery. The respiratory function of the nose was assessed using a rhinomanometric complex. According to rhinoresistometry data, nasal resistance and hydraulic diameter were assessed. According to the data of acoustic rhinometry, the minimum cross-sectional area along the internal valve, the minimum cross-sectional area on the head of the inferior turbinate and nasal septum and related parameters were estimated. According to the CBCT data, the state of the nasal septum, the inferior turbinates, the nasal aperture, the state of the nasal cavity, and the linear values of the upper respiratory tract (nasopharynx) were analyzed. The patients were divided into 4 groups according to the classification of the patency of the nasal passages by

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