نتایج جستجو برای: sap flux density

تعداد نتایج: 494422  

Journal: :Tree physiology 2012
Xingyuan Chen Gretchen R Miller Yoram Rubin Dennis D Baldocchi

The heat pulse method is widely used to measure water flux through plants; it works by using the speed at which a heat pulse is propagated through the system to infer the velocity of water through a porous medium. No systematic, non-destructive calibration procedure exists to determine the site-specific parameters necessary for calculating sap velocity, e.g., wood thermal diffusivity and probe ...

2006
Yao-Li Chuang Ram Oren Andrea L. Bertozzi Nathan Phillips Gabriel G. Katul

Linking sap flow in tree boles to plant transpiration continues to be a fundamental and practical research problem in physiological ecology and forest hydrology. Many models have been proposed to describe water movement within trees with varying degrees of success. The prevailing resistance–capacitance (RC)-circuit models have the advantage of being easy to implement. However, RC models are ord...

2004

Land devoted to plantation forestry (50millionha) has been increasing worldwide and the genus Eucalyptus is a popular plantation species (14millionha) for its rapid growth and ability to grow well on a wide range of sites. Fertilization is a common silvicultural tool to improve tree growth with potential effects on stand water use, but the relationship between wood growth and water use in respo...

Journal: :Tree physiology 2004
Chelcy R Ford Carol E Goranson Robert J Mitchell Rodney E Will Robert O Teskey

We monitored the radial distribution of sap flux density (v; g H2O m(-2) s(-1)) in the sapwood of six plantation-grown Pinus taeda L. trees during wet and dry soil periods. Mean basal diameter of the 32-year-old trees was 33.3 cm. For all trees, the radial distribution of sap flow in the base of the stem (i.e., radial profile) was Gaussian in shape. Sap flow occurred maximally in the outer 4 cm...

2013
V. Hernandez-Santana M. S. Alvarado-Barrientos C. M. Rodriguez-Dominguez A. Perez-Martin A. Díaz-Espejo

Knowledge of temporal variations in radial profiles of sap flux density (Js) and its relation to canopy water vapour exchange would help to improve our understanding of plant water relations. In this study we aimed to test if there is a consistent radial profile of Js in olive trees under optimal soil water availability and severe water stress conditions. Furthermore, if the radial profile of J...

Journal: :Tree physiology 2015
Maurits W Vandegehuchte Stephen S O Burgess Alec Downey Kathy Steppe

While natural spatial temperature gradients between measurement needles have been thoroughly investigated for continuous heat-based sap flow methods, little attention has been given to how natural changes in stem temperature impact heat pulse-based methods through temporal rather than spatial effects. By modelling the theoretical equation for both an ideal instantaneous pulse and a step pulse a...

Journal: :Advances in Civil Engineering 2023

Introducing superabsorbent polymer (SAP) into white fair-faced concrete can achieve the purpose of internal curing, which is beneficial to popularization and application concrete. The effects SAP mixture curing water content on properties were investigated macroscopically through indexes, including slump, electric flux, standard cube compressive strength, tensile splitting strength. mechanism t...

حسین زاده, فاطمه , ززولی, محمدعلی, منظم, محمدرضا, یزدانی چراتی, جمشید,

Introduction: The power transmission lines are the emission source of extremely low frequency (ELF) electromagnetic fields that are considered to have an adverse impact on human health. Therefore the aim of this study was to evaluate the amount of magnetic flux with extremely low frequencies (ELF) around high voltage power transmission lines in the western areas of Tehran in 2012. Material a...

Journal: :Tree physiology 2011
Marykate Z Black Kevin J Patterson Peter E H Minchin Kevin S Gould Michael J Clearwater

Whole vine (K(plant)) and individual root (K(root)) hydraulic conductances were measured in kiwifruit (Actinidia chinensis Planch. var. chinensis 'Hort16A') vines to observe hydraulic responses following partial root system excision. Heat dissipation and compensation heat pulse techniques were used to measure sap flow in trunks and individual roots, respectively. Sap flux and measurements of xy...

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