نتایج جستجو برای: individual tree height model

تعداد نتایج: 2652299  

2007
AN JIN CHANG JUNG OK KIM KIYUN YU YONG IL KIM

The main objective of this study was to compare methods to estimate the number of trees and individual tree height using remote sensing data. A Korean pine tree study area for these techniques was selected. the methods of watershed segmentation, region-growing segmentation, and morphological filtering were compared to estimate their accuracy. The algorithm was initiated by developing a normaliz...

Journal: :Theoretical population biology 1998
H Lischke T J Löffler A Fischlin

Individual based, stochastic forest patch models have the potential to realistically describe forest dynamics. However, they are mathematically intransparent and need long computing times. We simplified such a forest patch model by aggregating the individual trees on many patches to height-structured tree populations with theoretical random dispersions over the whole simulated forest area. The ...

2004
Xiaowei Yu Juha Hyyppä Hannu Hyyppä Matti Maltamo

High-density airborne laser scanner data has been previously shown to provide great opportunities for individual tree detection and measurement of variables characterizing the detected trees. This paper evaluates the effect of laser flight altitude on the tree height estimation at individual tree level in the boreal forest area mainly consisting of Norway spruce, Scots pine and birch. The test ...

Journal: :Brazilian journal of biology = Revista brasleira de biologia 2011
C S Gonçalves M A Batalha

Savannas are tropical formations in which trees and grasses coexist. According to the "honeycomb rippling model", inter-tree competition leads to an effect of trees growing and dying due to competition, which, at fine spatial scale, would resemble honeycomb rippling. The model predicts that the taller the trees, the higher the inter-tree distances and the evenness of inter-tree distances. The m...

2007
Guoqing Sun Dawei Liu Jon Ranson Benjamin Koetz

The height of scattering phase center retrieved from InSAR data is considered to be correlated with tree height and the spatial structure of the forest stand. Though some researchers have used simple backscattering models to estimate tree height from the height of scattering center, the effect of forest spatial structure on InSAR data is not well understood yet. A three-dimensional coherent rad...

2010
Matthew B. Russell Ralph L. Amateis Harold E. Burkhart

This study uses two regionwide data sets, one exemplified by intensive management and the other by nonintensive management, to investigate whether including regional locale and thinning response improves the loblolly pine height– diameter relationship. Results showed that including geographic coordinates as scaled variables, in addition to including a thinning response modifier, reduces the var...

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه فردوسی مشهد - دانشکده علوم تربیتی و روانشناسی 1391

the purpose of this study was to examine the status of supervision on departments’ heads at ferdowsi university of mashhad (fum) and realize some applied themes to provide a fit model for supervising departments’ heads in fum. the method was case study under a research category aimed for applied one. using purposive sampling, interviews were conducted with top fum managers, head departments, an...

Journal: :Remote Sensing 2010
Xiaowei Yu Juha Hyyppä Markus Holopainen Mikko Vastaranta

Approaches to deriving forest information from laser scanner data have generally made use of two methods: the area-based and individual tree-based approaches. In this paper, these two methods were evaluated and compared for their abilities to predict forest attributes at the plot level using the same datasets. Airborne laser scanner data were collected over the Evo forest area, southern Finland...

2017
Ville Luoma Ninni Saarinen Michael A. Wulder Joanne C. White Mikko Vastaranta Markus Holopainen Juha Hyyppä

Forest resource information has a hierarchical structure: individual tree attributes are summed at the plot level and then in turn, plot-level estimates are used to derive stand or large-area estimates of forest resources. Due to this hierarchy, it is imperative that individual tree attributes are measured with accuracy and precision. With the widespread use of different measurement tools, it i...

2015
Zhugeng Duan Dan Zhao Yuan Zeng Yujin Zhao Bingfang Wu Jianjun Zhu

Topography affects forest canopy height retrieval based on airborne Light Detection and Ranging (LiDAR) data a lot. This paper proposes a method for correcting deviations caused by topography based on individual tree crown segmentation. The point cloud of an individual tree was extracted according to crown boundaries of isolated individual trees from digital orthophoto maps (DOMs). Normalized c...

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