نتایج جستجو برای: forests

تعداد نتایج: 39403  

2005
David A. King S. Joseph Wright Joseph H. Connell

Maximum height was assessed for tree species from seven temperate deciduous forests, one subtropical forest and one tropical forest and combined with published tree heights for three other tropical forests. The temperate deciduous forests showed a strong concentration of canopy species and a dearth of subcanopy species. In contrast, the four tropical forests showed more uniform distributions of...

Journal: :Statistics and its interface 2009
Heping Zhang Minghui Wang

Random forests have emerged as one of the most commonly used nonparametric statistical methods in many scientific areas, particularly in analysis of high throughput genomic data. A general practice in using random forests is to generate a sufficiently large number of trees, although it is subjective as to how large is sufficient. Furthermore, random forests are viewed as "black-box" because of ...

Journal: :Environmental management 2014
Sandra Sotomayor Carla Barbieri Sonja Wilhelm Stanis Francisco X Aguilar Jordan W Smith

This study explores the importance of different motivations to visit three types of recreational settings--farms, private forests, and state or national parks. Data were collected via a mail-back questionnaire administered to a stratified random sample of households in Missouri (USA). Descriptive and inferential statistics reveal both similarities and discontinuities in motivations for visiting...

2011
Camilla Sandström Anna Lindkvist Karin Öhman

Changing and competing land use, where we make use of a growing share of resources, potentially undermines the capacity of forests to provide multiple functions such as timber, biodiversity, recreation and pasture lands. The governance challenge is thus to manage trade-offs between human needs and, at the same time, maintain the capacities of forests to provide us with these needs. Sweden provi...

2012
Hyontai Sug

Random forests are known to be robust for missing and erroneous data as well as irrelevant features. Moreover, even though the forests have many trees, they can utilize the fast building property of decision trees, so they do not require much computing time. In this paper an efficient procedure that utilizes random forests to predict the cylinder bands in rotogravure printing is shown. Even tho...

2013
Warren G. Abrahamson Michael R. Weaver

This week’s exercise explores the fundamentals of sampling theory using virtual forests. Two Pennsylvania old-growth forests were digitized enabling you to employ haphazard, systematic, and random sampling methods while investigating sampling protocols based on sampling areas versus distances. As you sample these virtual forests, you will discover that the efficiencies of sampling methods vary ...

2016
Fangyuan Hua Xiaoyang Wang Xinlei Zheng Brendan Fisher Lin Wang Jianguo Zhu Ya Tang Douglas W. Yu David S. Wilcove

Reforestation is a critical means of addressing the environmental and social problems of deforestation. China's Grain-for-Green Program (GFGP) is the world's largest reforestation scheme. Here we provide the first nationwide assessment of the tree composition of GFGP forests and the first combined ecological and economic study aimed at understanding GFGP's biodiversity implications. Across Chin...

2013
Yong Luo Han Y. H. Chen

Understanding climate change-associated tree mortality is central to linking climate change impacts and forest structure and function. However, whether temporal increases in tree mortality are attributed to climate change or stand developmental processes remains uncertain. Furthermore, interpreting the climate change-associated tree mortality estimated from old forests for regional forests rest...

Journal: :The Journal of Ecology 1913

Journal: :Nature 1927

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