نتایج جستجو برای: dbh of trees

تعداد نتایج: 21171343  

2017
Lingxiu Chen Wenhua Xiang Huili Wu Pifeng Lei Shengli Zhang Shuai Ouyang Xiangwen Deng Xi Fang

Wood density (WD) is not only an important parameter to estimate aboveground biomass but also an indicator of timber quality and plant adaptation strategies to stressful conditions (i.e., windthrow, pests, and pathogens). This study had three objectives: (1) to compare WD among seven subtropical tree species; (2) to determine how tree growth traits may influence possible differences in WD betwe...

2012
Xugao Wang Liza S. Comita Zhanqing Hao Stuart J. Davies Ji Ye Fei Lin Zuoqiang Yuan

Tree survival plays a central role in forest ecosystems. Although many factors such as tree size, abiotic and biotic neighborhoods have been proposed as being important in explaining patterns of tree survival, their contributions are still subject to debate. We used generalized linear mixed models to examine the relative importance of tree size, local abiotic conditions and the density and iden...

One of the effective steps for the sustainable forest development is the recognition of habitat condition and silvicultural characteristics of the rare species. Accordingly, this study investigated the aut ecology of Sorbus lorestanica as a rare species of Zagros. For this purpose, the exclusive natural habitat of Sorbus lorestanica in Lorestan province (Gahar rood protected area) was selected ...

Journal: :Ecology 2007
Daniel C Nepstad Ingrid Marisa Tohver David Ray Paulo Moutinho Georgina Cardinot

Severe drought episodes such as those associated with El Niño Southern Oscillation (ENSO) events influence large areas of tropical forest and may become more frequent in the future. One of the most important forest responses to severe drought is tree mortality, which alters forest structure, composition, carbon content, and flammability, and which varies widely. This study tests the hypothesis ...

2007
Jeffrey Pine D. W. Johnson

Thinning utilizing cut-to-length and whole-tree harvesting systems with subsequent underburning were assessed for their influence on stand productivity and mensurational variables in uneven-aged Jeffrey pine (Pinus jeffreyi Grev. & Balf.) on the Tahoe National Forest. Both intermediate and a combination of dominant and codominant crown class trees were selected within each treatment to evaluate...

2009
Mikko Vastaranta Timo Melkas Markus Holopainen Harri Kaartinen Juha Hyyppä Hannu Hyyppä

Remote-sensing (RS) methods, such as airborne laser scanning (ALS), are capable of acquiring tree-level forest information with high accuracy. However, these methods need more detailed reference data from sample plots than standwise mean characteristics. Field-measured treewise characteristics must be matched with ALS data on the measured position of the tree. In addition to tree position and s...

Journal: :international journal of advanced biological and biomedical research 2013
maziar haidari hamid jalilvand hamed aghajani mehran nasiri

any defects in street trees may cause injuries to human, vehicles and buildings. this research was investigated in the babol city, mazandaran province, in the northern state of iran.used the perfect inventory methods and measured the diameter at breathe height (dbh), height and hazardous criteria (dead woods, cracks or seams, decay, wound or cankers, root problems, weak branch unions and skew f...

2003
Jouni Siipilehto Juha Siitonen

The degree of naturalness was assessed in 37 mature (stand age 80−198 yrs) Norway spruce dominated stands located in southern Finland by measuring the number (0−610 ha–1) and basal area (0−33 m2ha–1) of cut stumps. The Johnson’s SB distribution was fitted for living spruce trees to describe the dbh-frequency and basal area-dbh distributions. Regression models were constructed for predicting the...

Journal: :Remote Sensing 2017
Ivar Oveland Marius Hauglin Terje Gobakken Erik Næsset Ivar Maalen-Johansen

Airborne laser scanning is now widely used for forest inventories. An essential part of inventory is a collection of field reference data including measurements of tree stem diameter at breast height (DBH). Traditionally this is acquired through manual measurements. The recent development of terrestrial laser scanning (TLS) systems in terms of capacity and weight have made these systems attract...

2016
Daud J. Kachamba Terje Gobakken Eric J. Jokela

In this study we present general (multiple tree species from several sites) aboveand belowground biomass models for trees in the miombo woodlands of Malawi. Such models are currently lacking in the country. The modelling was based on 74 trees comprising 33 different species with diameters at breast height (dbh) and total tree height (ht) ranging from 5.3 to 2 cm and from 3.0 to 25.0 m, respecti...

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