نتایج جستجو برای: hyrcanain forests

تعداد نتایج: 39403  

2002
Yi Lin Yongho Jeon

In this paper we study random forests through their connection with a new framework of adaptive nearest neighbor methods. We first introduce a concept of potential nearest neighbors (k-PNN’s) and show that random forests can be seen as adaptively weighted k-PNN methods. Various aspects of random forests are then studied from this perspective. We investigate the effect of terminal node sizes and...

Journal: :Science 2008
Gordon B Bonan

The world's forests influence climate through physical, chemical, and biological processes that affect planetary energetics, the hydrologic cycle, and atmospheric composition. These complex and nonlinear forest-atmosphere interactions can dampen or amplify anthropogenic climate change. Tropical, temperate, and boreal reforestation and afforestation attenuate global warming through carbon seques...

Journal: :J. Applied Mathematics 2012
Hyontai Sug

Random forests are known to be good for data mining of classification tasks, because random forests are robust for datasets having insufficient information possibly with some errors. But applying random forests blindly may not produce good results, and a dataset in the domain of rotogravure printing is one of such datasets. Hence, in this paper, some best classification accuracy based on clever...

        The prevalence of Corona disease as one of the most critical infectious diseases has increased the risks of food security in different parts of the world. Local communities, especially in rural areas, are highly dependent on natural resource-based ecosystem service strategies to manage global food security and meet livelihood needs. Forests and pastures can also provide goods and servic...

2014
Enqing Hou Huimin Xiang Jianli Li Jiong Li Dazhi Wen

Remnant forests in urban areas provide vital ecosystem services but are susceptible to many human activities including heavy metal emissions. In this study, we collected 192 samples of mineral soils at depths of 0–3, 3–13 and 13–23 cm in 16 remnant forests (eight natural forests and eight plantation forests) in the urbanized Pearl River Delta, China. We assessed the potential risks of soil Cu, ...

2014
Rebecca Ostertag Faith Inman-Narahari Susan Cordell Christian P. Giardina Lawren Sack

The potential influence of diversity on ecosystem structure and function remains a topic of significant debate, especially for tropical forests where diversity can range widely. We used Center for Tropical Forest Science (CTFS) methodology to establish forest dynamics plots in montane wet forest and lowland dry forest on Hawai'i Island. We compared the species diversity, tree density, basal are...

ژورنال: :مجله گیاهشناسی ایران 2015
حبیب زارع طیبه امینی اشکوری مهرآسا زارع

گونه .phyllanthus tenellus roxb به عنوان گزارش جدید، از غرب مازندران نام برده می شود، این گونه به صورت بومی شده در اغلب مناطق کم ارتفاع و در حاشیه باغ ها و مزارع دیده شده و به علت برخورداری از برگ های بیضی شکل با آرایش غیر مارپیچی که بیشتر دورج به نظر رسیده، همراه با گلهای بسیار کوچک در کنار دمبرگ ها شناخته می شود.

Journal: :journal of ornamental plants 2014
achar devaraja am jakhar mamta jakeer p shetty kpv

in the present study, randomly amplified polymorphic dna (rapd) markers were used to analyze the genetic diversity in 20 varieties of philodendron. the polymerase chain reaction was performed with 60 rapd primers, out of which 21 primers showed clear amplification as well as more polymorphism. in total, 354 scorable rapd loci with 348 polymorphic bands (98%) were observed. percentages of polymo...

2006
Petteri Muukkonen Raisa Mäkipää Raija Laiho Kari Minkkinen Harri Vasander Leena Finér

In the present study, the aboveground biomass of the understorey vegetation of boreal coniferous forests was modelled according to the percentage cover. A total of 224 observations from 22 stands in upland forests and 195 observations from 14 different studies in peatland forests were utilized for the present analyses. The relationships between biomass and percentage cover can be used in ecosys...

2014
Dennis C. Odion Chad T. Hanson André Arsenault William L. Baker Dominick A. DellaSala Richard L. Hutto Walt Klenner Max A. Moritz Rosemary L. Sherriff Thomas T. Veblen Mark A. Williams

There is widespread concern that fire exclusion has led to an unprecedented threat of uncharacteristically severe fires in ponderosa pine (Pinus ponderosa Dougl. ex. Laws) and mixed-conifer forests of western North America. These extensive montane forests are considered to be adapted to a low/moderate-severity fire regime that maintained stands of relatively old trees. However, there is increas...

نمودار تعداد نتایج جستجو در هر سال

با کلیک روی نمودار نتایج را به سال انتشار فیلتر کنید