The influence of thinning and tree size on the sapwood area / leaf area ratio in coigue

2005 ◽  
Vol 35 (7) ◽  
pp. 1679-1685 ◽  
Author(s):  
Pablo A Gajardo-Caviedes ◽  
Miguel A Espinosa ◽  
Urcesino del T González ◽  
Darcy G Ríos
Keyword(s):  
Leaf Area ◽  
Specific Leaf Area ◽  
Regression Models ◽  
Area Ratio ◽  
Destructive Sampling ◽  
Cross Sectional ◽  
Sapwood Area ◽  
Nothofagus Dombeyi ◽  
The Relationship ◽  
Best Fit

The effect of thinning and crown class on the projected leaf area, specific leaf area, and projected leaf area / sapwood area ratio was evaluated in a 48-year-old even-aged stand of coigue (Nothofagus dombeyi (Mirb.) Oerst.). The data were collected through destructive sampling of 27 trees and analyzed with analysis of variance and regression models. The projected leaf area was greater in trees from more intensely thinned stands. The specific leaf area and the projected leaf area / sapwood area ratio did not vary between treatments. The sapwood cross-sectional area at breast height (1.3 m) and at the base of the live crown provided the best fit for the relationship between projected leaf area and sapwood area. The current sapwood area provided the worst fit, suggesting that at an early age, coigue sapwood does not present permeability problems associated with tyloses.

A leaf area – sapwood area ratio developed to rate loblolly pine tree vigor

1985 ◽  
Vol 15 (6) ◽  
pp. 1181-1184 ◽  
Author(s):  
C. A. Blanche ◽  
J. D. Hodges ◽  
T. E. Nebeker
Keyword(s):  
Leaf Area ◽  
Loblolly Pine ◽  
Dry Weight ◽  
Area Ratio ◽  
Cross Sectional ◽  
Sapwood Area ◽  
Breast Height ◽  
Pine Tree ◽  
Individual Trees ◽  
The Relationship

Stem cross-sectional sapwood area was linearly related to leaf area in loblolly pine. A better relationship was obtained using cross-sectional sapwood area taken at crown base than at breast height. The relationship was affected by time of sampling, with time of maximum needle biomass giving the best correlation. Specific leaf area (area in square centimetres per gram dry weight) was variable, but the mean of 95.32 cm2/g is comparable to reported values for other species. The leaf area – sapwood area ratio at breast height varies only slightly among individual trees so that a mean ratio of 0.29 can be utilized to accurately predict leaf area. The ratio between curent-year or previous-year sapwood production and leaf area (grams per square metre of foliage) was used as an indicator of tree vigor. Tree vigor values varied greatly (21 – 180 g/m2), but were normally distributed within this range.

The relationship between tree height and leaf area: sapwood area ratio

Oecologia ◽  
2002 ◽  
Vol 132 (1) ◽  
pp. 12-20 ◽  
Author(s):  
N. McDowell ◽  
H. Barnard ◽  
B. Bond ◽  
T. Hinckley ◽  
R. Hubbard ◽  
...  
Keyword(s):  
Leaf Area ◽  
Tree Height ◽  
Area Ratio ◽  
Sapwood Area ◽  
The Relationship

scholarly journals Online News and Protest Participation in a Political Context: Evidence from Self-Reported Cross-Sectional Data

2021 ◽  
Vol 7 (1) ◽  
pp. 205630512098445
Author(s):  
Nora Kirkizh ◽  
Olessia Koltsova
Keyword(s):  
Digital Media ◽  
Regression Models ◽  
Online News ◽  
Political Context ◽  
Government Control ◽  
Multilevel Regression ◽  
Traditional Media ◽  
Cross Sectional ◽  
Internet Media ◽  
The Relationship

Availability of alternative information through social media, in particular, and digital media, in general, is often said to induce social discontent, especially in states where traditional media are under government control. But does this relation really exist, and is it generalizable? This article explores the relationship between self-reported online news consumption and protest participation across 48 nations in 2010–2014. Based on multilevel regression models and simulations, the analysis provides evidence that those respondents who reported that they had attended a protest at least once read news online daily or weekly. The study also shows that the magnitude of the effect varies depending on the political context: surprisingly, despite supposedly unlimited control of offline and online media, autocratic countries demonstrated higher effects of online news than transitional regimes, where the Internet media are relatively uninhibited.

scholarly journals The Association Between Patients' eHealth Literacy and Satisfaction With Shared Decision-making and Well-being: Multicenter Cross-sectional Study (Preprint)

2020 ◽  
Author(s):  
Richard Huan Xu ◽  
Ling-Ming Zhou ◽  
Eliza Lai-Yi Wong ◽  
Dong Wang
Keyword(s):  
Decision Making ◽  
Shared Decision Making ◽  
Regression Models ◽  
Well Being ◽  
Shared Decision ◽  
Background Characteristics ◽  
Cross Sectional ◽  
Ehealth Literacy ◽  
High Level ◽  
The Relationship

BACKGROUND Although previous studies have shown that a high level of health literacy can improve patients’ ability to engage in health-related shared decision-making (SDM) and improve their quality of life, few studies have investigated the role of eHealth literacy in improving patient satisfaction with SDM (SSDM) and well-being. OBJECTIVE This study aims to assess the relationship between patients’ eHealth literacy and their socioeconomic determinants and to investigate the association between patients’ eHealth literacy and their SSDM and well-being. METHODS The data used in this study were obtained from a multicenter cross-sectional survey in China. The eHealth Literacy Scale (eHEALS) and Investigating Choice Experiments Capability Measure for Adults were used to measure patients’ eHealth literacy and capability well-being, respectively. The SSDM was assessed by using a self-administered questionnaire. The Kruskal-Wallis one-way analysis of variance and Wilcoxon signed-rank test were used to compare the differences in the eHEALS, SSDM, and Investigating Choice Experiments Capability Measure for Adults scores of patients with varying background characteristics. Ordinary least square regression models were used to assess the relationship among eHealth literacy, SSDM, and well-being adjusted by patients’ background characteristics. RESULTS A total of 569 patients completed the questionnaire. Patients who were male, were highly educated, were childless, were fully employed, were without chronic conditions, and indicated no depressive disorder reported a higher mean score on the eHEALS. Younger patients (SSDM<sub>≥61 years</sub>=88.6 vs SSDM<sub>16-30 years</sub>=84.2) tended to show higher SSDM. Patients who were rural residents and were well paid were more likely to report good capability well-being. Patients who had a higher SSDM and better capability well-being reported a significantly higher level of eHealth literacy than those who had lower SSDM and poorer capability well-being. The regression models showed a positive relationship between eHealth literacy and both SSDM (<i>β</i>=.22; <i>P</i>&lt;.001) and well-being (<i>β</i>=.26; <i>P</i>&lt;.001) after adjusting for patients’ demographic, socioeconomic status, lifestyle, and health status variables. CONCLUSIONS This study showed that patients with a high level of eHealth literacy are more likely to experience optimal SDM and improved capability well-being. However, patients’ depressive status may alter the relationship between eHealth literacy and SSDM. CLINICALTRIAL

scholarly journals Exploring Spatiotemporal Variation in Hourly Metro Ridership at Station Level: The Influence of Built Environment and Topological Structure

2018 ◽  
Vol 10 (12) ◽  
pp. 4564 ◽  
Author(s):  
Zhuangbin Shi ◽  
Ning Zhang ◽  
Yang Liu ◽  
Wei Xu
Keyword(s):  
Built Environment ◽  
Topological Structure ◽  
Regression Models ◽  
Closeness Centrality ◽  
Spatiotemporal Variation ◽  
Spatial And Temporal Variation ◽  
Structure Factors ◽  
The Relationship ◽  
Best Fit

Reliable and accurate estimates of metro demand can provide metro authorities with insightful information for the planning of route alignment and station locations. Many existing studies focus on metro demand from daily or annual ridership profiles, but only a few concern the variation in hourly ridership. In this paper, a geographically and temporally weighted regression (GTWR) model was used to examine the spatial and temporal variation in the relationship between hourly ridership and factors related to the built environment and topological structure. Taking Nanjing, China as a case study, an empirical study was conducted with automatic fare collection (AFC) data in three weeks. With an analysis of variance (ANOVA), it was found that the GTWR model produced the best fit for hourly ridership data compared with traditional regression models. Four built-environment factors, namely residence, commerce, scenery, and parking, and two topological-structure factors, namely degree centrality and closeness centrality, were proven to be significantly related to station-level ridership. The spatial distribution pattern and temporal nonstationarity of these six variables were further analyzed. The result of this study confirmed that the GTWR model can provide more realistic and useful information by capturing spatiotemporal heterogeneity.

scholarly journals Fitness Cost of Imazamox Resistance in Wild Poinsettia (Euphorbia heterophylla L.)

Agronomy ◽  
2020 ◽  
Vol 10 (12) ◽  
pp. 1859
Author(s):  
Saeid Hassanpour-bourkheili ◽  
Mahtab Heravi ◽  
Javid Gherekhloo ◽  
Ricardo Alcántara-de la Cruz ◽  
Rafael De Prado
Keyword(s):  
Growth Rate ◽  
Leaf Area ◽  
Specific Leaf Area ◽  
Dry Weight ◽  
Area Ratio ◽  
Fitness Cost ◽  
Seed Plant ◽  
Growth Indices ◽  
Relative Growth ◽  
Net Assimilation

Wild poinsettia (Euphorbia heterophylla L.) is a difficult-to-control weed in soybean production in Brazil that has developed resistance to herbicides, including acetolactate synthase inhibitors. We investigated the potential fitness cost associated to the Ser-653-Asn mutation that confers imazamox resistance in this weed. Plant height, leaf and stem dry weight, leaf area and seed production per plant as well as the growth indices of specific leaf area, leaf area ratio, relative growth rate and net assimilation in F2 homozygous resistant (R) and susceptible (S) wild poinsettia progenies were pairwise compared. S plants were superior in most of the traits studied. Plant heights for S and R biotypes, recorded at 95 days after planting (DAP), were 137 and 120 cm, respectively. Leaf areas were 742 and 1048 cm2 in the R and S biotypes, respectively. The dry weights of leaves and stems in the S plants were 30 and 35%, respectively, higher than in the R plants. In both biotypes, the leaves had a greater share in dry weight at early development stages, but from 50 DAP, the stem became the main contributor to the dry weight of the shoots. The R biotype produced 110 ± 4 seed plant−1, i.e., 12 ± 3% less seeds per plant than that of the S one (125 ± 7 seed plant−1). The growth indices leaf area ratio and specific leaf area were generally higher in the S biotype or similar between both biotypes; while the relative growth rate and net assimilation rate were punctually superior in the R biotype. These results demonstrate that the Ser-653-Asn mutation imposed a fitness cost in imazamox R wild poinsettia.

scholarly journals The relationship of leaf photosynthetic traits -VcmaxandJmax- to leaf nitrogen, leaf phosphorus, and specific leaf area: a meta-analysis and modeling study

2014 ◽  
Vol 4 (16) ◽  
pp. 3218-3235 ◽  
Author(s):  
Anthony P. Walker ◽  
Andrew P. Beckerman ◽  
Lianhong Gu ◽  
Jens Kattge ◽  
Lucas A. Cernusak ◽  
...  
Keyword(s):  
Leaf Area ◽  
Specific Leaf Area ◽  
Meta Analysis ◽  
Leaf Nitrogen ◽  
Relationship Of ◽  
The Relationship ◽  
Photosynthetic Traits ◽  
Modeling Study

scholarly journals Morphological and moisture availability controls of the leaf area‐to‐sapwood area ratio: analysis of measurements on A ustralian trees

2015 ◽  
Vol 5 (6) ◽  
pp. 1263-1270 ◽  
Author(s):  
Henrique Furstenau Togashi ◽  
Iain Colin Prentice ◽  
Bradley John Evans ◽  
David Ian Forrester ◽  
Paul Drake ◽  
...  
Keyword(s):  
Leaf Area ◽  
Area Ratio ◽  
Ratio Analysis ◽  
Sapwood Area ◽  
Moisture Availability

Production ecology of Thuja occidentalis

2010 ◽  
Vol 40 (6) ◽  
pp. 1155-1164 ◽  
Author(s):  
Philip V. Hofmeyer ◽  
Robert S. Seymour ◽  
Laura S. Kenefic
Keyword(s):  
Leaf Area ◽  
Light Exposure ◽  
Tree Height ◽  
Growth Efficiency ◽  
Analysis Of Covariance ◽  
Stem Volume ◽  
Sapwood Area ◽  
Thuja Occidentalis ◽  
Production Ecology ◽  
The Relationship

Equations to predict branch and tree leaf area, foliar mass, and stemwood volume were developed from 25 destructively sampled northern white-cedar ( Thuja occidentalis L.) trees, a species whose production ecology has not been studied. Resulting models were applied to a large sample of 296 cored trees from 60 sites stratified across a soil gradient throughout northern Maine. Nonlinear regression analysis was used to assess alternative forms of the relationship between volume increment (VINC) and projected leaf area (PLA); analysis of covariance was used compare stemwood growth efficiency (GE) among soil-site classes, light exposure classes, and the presence of decay. Stem volume was estimated with Honer’s equation ( T.G. Honer. 1967. Forest Management Research and Services Institute ) with refitted parameters. PLA was best predicted with Maguire and Bennett’s nonlinear model ( D.A. Maguire and W.S. Bennett. 1996. Can. J. For. Res. 26: 1991–2005 ) using sapwood area or crown length and the ratio of tree height to diameter at breast height. A sigmoid model form captured the relationship between VINC and PLA more precisely and with less bias than the simple power function; this implies that the relationship between GE and PLA reaches a peak rather than decreases monotonically. At PLAs >50 m2, GE gradually declined with increasing crown size and was significantly influenced by site and light exposure. With PLA, site, and light held constant, decayed trees had a significantly lower (by 11%) GE than sound stems, a finding not previously reported for other tree species.

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