Light fluctuations and crown traits were studied for saplings of four tree species in a Costa Rican rain forest. Light fluctuations (1988–1994) were assessed by annual light estimations above saplings, using a visual crown position index. Crown traits in 1994 and growth between 1994 and 1995 were measured. Crown position values varied between 1.5 and 2.5. Of the 70 saplings only four were found...

Growth and survival of young European beech (Fagus sylvatica L.) is largely dependent on water availability. We quantified the influence of water stress (measured as Available Soil Water Storage Capacity or ASWSC) on vitality of young beech plants at a dry site. The study site was located in a semi-natural sessile oak (Quercus petraea (Mattuschka) Liebl.) stand adjacent to beech stands on a roc...

The aim of this study was to develop a relatively rapid, simple and repeatable method to characterize the crown architecture of Queensland maple (Flindersia brayleyana F. Muell.) by vertical hemispherical photography. Calibration scales were developed to provide horizontal planes of measurement at heights from 15 to 40 m above the camera. Hemispherical images of tree crowns were merged with the...

Zinc (Zn) deficiency is one of the leading nutrient disorders in rice (Oryza sativa). Many studies have identified Zn-efficient rice genotypes, but causal mechanisms for Zn deficiency tolerance remain poorly understood. Here, we report a detailed study of the impact of Zn deficiency on crown root development of rice genotypes, differing in their tolerance to this stress. Zn deficiency delayed c...

The dynamics of a water jet on a flat free surface are investigated using a nanosecond pulsed laser for creating an oscillating bubble with different depths beneath the free surface. A thin jet is shown to deform a crater surface resulted from surface depression and cause a circular ring-shaped crater on the connection surface between the crater of surface depression and the thin jet. The colla...

always on kingdom history of the world a king without a crown is unconceivable. the persian kings were not exception of this rule. iranian ancient kings crown as one of the aspects of the monarchy and power, the image of king while makes he distinguishes from other persons is visible in various artistic works. one of the important artistic works that image of iran’s kings with their power symbo...

introduction : to achieve success in treatment, one cannot ignore the knowledge of pulp anatomy. mandibular premolars are considered to be the most difficult teeth for endodontic therapy due to high variability in their canal morphology. it is possible that a relation exists between the crown size and the number of extra canals in these teeth, so this in vitro study aims to investigate the rela...

Daily and seasonal net photosynthesis (Anet), transpiration (E), absorbed photosynthetically active radiation (Qa) and light-use efficiency (epsilonc) in a red maple container nursery were simulated with MAESTRA, a three-dimensional canopy model. Effects of canopy heterogeneity were simulated by imposing changes in crown spacing. The light transfer sub-model, a distribution model of incident, d...

A method to measure tree crown dimensions is introduced in this article. The method is based on terrestrial images, which are captured from two different directions. Image orientation is registered during the image acquisition and this geometrical information is utilized in image pre-processing. In pre-processing images are corrected from distortion errors and rectified to plane parallel to tre...

Efficient forest management requires detailed, timely information on forests. The increasing availability and affordability of high spatial resolution remotely sensed imagery provides viable opportunities for developing automatic forest inventories at fine scale. Individual tree crown detection and delineation has become increasingly important for forest management and ecosystem monitoring. Exi...