نتایج جستجو برای: trees canopy

تعداد نتایج: 102028  

2008
Raita Säynäjoki Petteri Packalén Matti Maltamo Mikko Vehmas Kalle Eerikäinen

The aim was to use high resolution Aerial Laser Scanning (ALS) data and aerial images to detect European aspen (Populus tremula L.) from among other deciduous trees. The field data consisted of 14 sample plots of 30 m × 30 m size located in the Koli National Park in the North Karelia, Eastern Finland. A Canopy Height Model (CHM) was interpolated from the ALS data with a pulse density of 3.86/m2...

2011
DAVID D. BRESHEARS JOHN A. LUDWIG

Solar radiation directly and indirectly drives a variety of ecosystem processes. Our aim was to evaluate how tree canopy architecture affects near-ground, incoming solar radiation along gradients of increasing tree cover, referred to as the grassland–forest continuum. We evaluated a common type of canopy architecture: tall trees that generally have their lowest level of foliage high above, rath...

Journal: :CoRR 2017
Hamid Hamraz Marco A. Contreras

Airborne discrete return light detection and ranging (LiDAR) point clouds covering forested areas can be processed to segment individual trees and retrieve their morphological attributes. Segmenting individual trees in natural deciduous forests however remained a challenge because of the complex and multi-layered canopy. In this chapter, we present (i) a robust segmentation method that avoids a...

2003
E. J. Sayer D. M. Newbery

Leafing phenology of two dry-forest sites on soils of different depth (S = shallow, D = deep) at Shipstern Reserve, Belize, were compared at the start of the rainy season (April–June 2000). Trees 2.5 cm dbh were recorded weekly for 8 wk in three 0.04-ha plots per site. Ten species were analysed individually for their phenological patterns, of which the three most common were Bursera simaruba, M...

The present study eas aimed to evaluate the potential of ALS data in estimation of individual canopy cover area and tree heights for the part of Shast Kalate of Gorgan. In this study 117 tree that located in dominant forest story and without overlay with adjacent trees, were selected. Center coordinates of sample trees were determined using DGPS system. Individual canopy area and tree heights w...

2003
E. J. Sayer D. M. Newbery

Leafing phenology of two dry-forest sites on soils of different depth (S = shallow, D = deep) at Shipstern Reserve, Belize, were compared at the start of the rainy season (April–June 2000). Trees 2.5 cm dbh were recorded weekly for 8 wk in three 0.04-ha plots per site. Ten species were analysed individually for their phenological patterns, of which the three most common were Bursera simaruba, M...

2017
Tim van Emmerik Susan C. Steele-Dunne Rolf Hut Pierre Gentine Marceau Guerin Rafael S. Oliveira Jim Wagner John S. Selker Nick van de Giesen

Trees play a crucial role in the water, carbon and nitrogen cycle on local, regional and global scales. Understanding the exchange of momentum, heat, water, and CO 2 between trees and the atmosphere is important to assess the impact of drought, deforestation and climate change. Unfortunately, ground measurements of tree properties such as mass and canopy interception of precipitation are often ...

Journal: :جنگل و فرآورده های چوب 0
مجتبی آذریان دانشجوی کارشناسی ارشد جنگل شناسی و اکولوژی جنگل، دانشکدة منابع طبیعی، دانشگاه تهران، کرج، ایران محمد رضا مروی مهاجر استاد گروه جنگل داری و اقتصاد جنگل دانشکدة منابع طبیعی، دانشگاه تهران، کرج، ایران وحید اعتماد استادیار گروه جنگل داری و اقتصاد جنگل دانشکدة منابع طبیعی، دانشگاه تهران، کرج، ایران انوشیروان شیروانی استادیار گروه جنگل داری و اقتصاد جنگل دانشکدة منابع طبیعی، دانشگاه تهران، کرج، ایران سید محمد معین صادقی دانشجوی دکتری جنگل شناسی و اکولوژی جنگل، دانشکدة منابع طبیعی، دانشگاه تهران، کرج، ایران

the aim of study was to evaluate qualitative and quantitative characteristics of old trees in pattom and namkhaneh districts in the nowshahr, northern iran. the trees quantitative characteristics of dbh, total height, slenderness coefficient, trunk height, crown length, buttress height, and canopy cover area and qualitative characteristics of crown and trunk, i.e., health, vitality, and concurr...

ژورنال: علوم آب و خاک 2018

Trees crown can be regarded as main factor contributing to the conservation and support of soil in many ecosystems including semiarid forests in Zagross. The aim of this study was to find out the effect of tree crown of pictachio (Pistacia atlantica Desf) on N, OC, P, pH, EC and the texture of the soil. Soil samples were collected in and outside the crown of 5 single pistachio trees on four dir...

Journal: :Conservation biology : the journal of the Society for Conservation Biology 2009
Nalini M Nadkarni Willam A Haber

Tropical pastures present multiple barriers to tree regeneration and restoration. Relict trees serve as "regeneration foci" because they ameliorate the soil microclimate and serve as safe spots for dispersers. Here, we describe another mechanism by which remnant trees may facilitate pasture regeneration: the presence of seed banks in the canopy soil that accumulates from decomposing epiphytes w...

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