نتایج جستجو برای: diameter of roots

تعداد نتایج: 21169608  

1999
R. R. Ziemer

Root decay after timber cutting can lead to slope failure. In situ measurements of soil with tree roots showed that soil strength increased linearly as root biomass increased. Forests clear-felled 3 years earlier contained about one-third of the root biomass of oldgrowth forests. Nearly all of the roots < 2 mm in diameter were gone from 7-year-old logged areas while about 30 percent of the < 17...

The current research is based on the existing ecological conditions in the Zagros forests and knowledge of the response of forest trees to these conditions and the purpose of this study is to investigate the effect of topographic factors, tree characteristics on of fine roots biomass of gal oak (Quercus infectoria Oliv.) and also to compare the amount of nitrogen, phosphorus and potassium in th...

2002
KURT S. PREGITZER JARED L. DEFOREST ANDREW J. BURTON MICHAEL F. ALLEN ROGER W. RUESS RONALD L. HENDRICK

The fine roots of trees are concentrated on lateral branches that arise from perennial roots. They are important in the acquisition of water and essential nutrients, and at the ecosystem level, they make a significant contribution to biogeochemical cycling. Fine roots have often been studied according to arbitrary size classes, e.g., all roots less than 1 or 2 mm in diameter. Because of the siz...

Journal: رستنیها 2007
M. BARATI, M. BAZOOBANDI M. GHORBANLI

To characterize some important eco-physiological aspects of  Alhagi pseudalhagi growth, the present investigation was conducted at the farm of Khorasan Agricultural Research Center during 2004-2005. Various botanical characteristics including root structure and existence of starch in root were studied. Number of seeds per pod, pod length and test weight were recorded. A number of field and pot ...

X. Zeng Y. Peng,

Optimized nitrogen (N) management reduces total N application without sacrificing cropyield. However, the underlining mechanisms have not been well investigated, especially lackingthe evidence from roots. Here we performed a two-year field experiment with maize grownunder zero-N, conventional N and optimized N applications and examined grain yield, N,phosphorous (P) and potassium (K) uptake and...

Journal: :Tree physiology 2013
Bernhard Schuldt Christoph Leuschner Nicolai Brock Viviana Horna

It is generally assumed that the largest vessels are occurring in the roots and that vessel diameters and the related hydraulic conductance in the xylem are decreasing acropetally from roots to leaves. With this study in five tree species of a perhumid tropical rainforest in Sulawesi (Indonesia), we searched for patterns in hydraulic architecture and axial conductivity along the flow path from ...

Journal: :European journal of cardio-thoracic surgery : official journal of the European Association for Cardio-thoracic Surgery 2005
Axel Nötzold Michael Scharfschwerdt Lisa Thiede Michael Hüppe Hans-Hinrich Sievers

OBJECTIVE Stentless aortic valves are widely used due to their excellent hemodynamic properties. However, if the subcoronary implantation technique is used later dilatation of the sinotubular junction (STJ) can cause regurgitation. The aim of the study was to determine the dilatation tolerance of two commercially available stentless xenografts and fresh aortic and pulmonary roots against such d...

2010
S. P. Sah H. Jungner M. Oinonen H.-S. Helmisaari

To test the reliability of the radiocarbon method for determining root age, we analyzed fine roots (originating from the years 1985–1993) from ingrowth cores with known maximum root age (1–6 years old). For this purpose, three Scots pine (Pinus sylvestris L.) stands were selected from boreal forests in Finland. We analyzed root C age by the radiocarbon method and compared it with the abovementi...

Journal: :Tree physiology 2004
Christoph Leuschner Heinz Coners Regina Icke

The spatial heterogeneity of water uptake by fine roots under field conditions was analyzed in situ with miniature sap flow gauges in a mature beech-oak-spruce mixed stand. Sap flow rate (J), sap flow density (Jd), and root surface-area-specific flow rate (uptake rate, Js) were measured for eight to 10 small-diameter roots (3-4 mm) per species in the organic layer (superficial roots) and in the...

نمودار تعداد نتایج جستجو در هر سال

با کلیک روی نمودار نتایج را به سال انتشار فیلتر کنید