نتایج جستجو برای: forests

تعداد نتایج: 39403  

2005
Mark Vellend

Many forest herbs show reduced frequency in forests growing on former agricultural land (secondary forests) relative to forests that were never cleared for agriculture (primary forests). To explain this pattern, studies of secondary forest colonization by forest herbs have stressed the role of limited seed dispersal, though environmental conditions may also limit colonization. Here I demonstrat...

Journal: :Mycological research 2009
Anthony Amend Sterling Keeley Matteo Garbelotto

Examining the fine-scale spatial structure of fungal populations can tell us much about how individual species reproduce and disperse throughout natural landscapes. Here we study the fine-scale genetic structure of Tricholoma matsutake, a prized edible and medicinal mushroom, by systematic sampling of mycorrhizas within fairy rings in 50-y-old and old-growth forests in two villages. Using singl...

Journal: :Proceedings of the National Academy of Sciences of the United States of America 2009
Heather Keith Brendan G Mackey David B Lindenmayer

From analysis of published global site biomass data (n = 136) from primary forests, we discovered (i) the world's highest known total biomass carbon density (living plus dead) of 1,867 tonnes carbon per ha (average value from 13 sites) occurs in Australian temperate moist Eucalyptus regnans forests, and (ii) average values of the global site biomass data were higher for sampled temperate moist ...

2013
Feifei Zhu Muneoki Yoh Frank S. Gilliam Xiankai Lu Jiangming Mo

Elevated nitrogen (N) deposition to tropical forests may accelerate ecosystem phosphorus (P) limitation. This study examined responses of fine root biomass, nutrient concentrations, and acid phosphatase activity (APA) of bulk soil to five years of N and P additions in one old-growth and two younger lowland tropical forests in southern China. The old-growth forest had higher N capital than the t...

2011
Lado KUTNAR Dragan MATIJAŠIĆ Rok PISEK

An example of the possible use of selected forest-stand based indicators for evaluation of conservation status was shown in case of the Natura 2000 forest habitats of Slovenia, and the potential threats to habitat types were identified. Using the existing forest-management system, and two levels of ICP Forests monitoring as sources of data on the size of habitat, tree composition, developmental...

2016
Yisen Wang Qingtao Tang Shu-Tao Xia Jia Wu Xingquan Zhu

Random forests are one type of the most effective ensemble learning methods. In spite of their sound empirical performance, the study on their theoretical properties has been left far behind. Recently, several random forests variants with nice theoretical basis have been proposed, but they all suffer from poor empirical performance. In this paper, we propose a Bernoulli random forests model (BR...

2015
Feifei Zhu Xiankai Lu Lei Liu Jiangming Mo

Elevated nitrogen (N) deposition may constrain soil phosphorus (P) and base cation availability in tropical forests, for which limited evidence have yet been available. In this study, we reported responses of soil inorganic nutrients to full factorial N and P treatments in three tropical forests different in initial soil N status (N-saturated old-growth forest and two less-N-rich younger forest...

2015
Xin Xiao Xiaohua Wei Yuanqiu Liu Xunzhi Ouyang Qinglin Li Jinkui Ning Eric J. Jokela

Carbon stock is an important indicator of cumulative ecosystem productivity. Using this indicator, and based on field sampling data, this paper compared the long-term difference in carbon stocks between aerial seeding (AS) and natural regeneration (NR) forests of Pinus massoniana in sub-tropic forests, China, in order to assess the effectiveness of AS in a highly degraded forest landscape. The ...

2009

Over the last two and half decades, strong evidence showed that the terrestrial ecosystems are acting as a net sink for atmospheric carbon. However the spatial and temporal patterns of variation in the sink are not well known. In this study, we examined latitudinal patterns of interannual variability (IAV) in net ecosystem exchange (NEE) of CO2 based on 163 site-years of eddy covariance data, f...

2016
MARK GREEN

Mr. GREEN of Wisconsin. Mr. Chairman, I submit the following resolutions for the RECORD. Whereas, our National Forests were established in the 1920’s for multiple use including soil and water protection, recreation, and timber production, and; Whereas, harvesting is an integral component of multiple-use management of forest lands, and; Whereas, it is not in the best interest of sustainable ecos...

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