نتایج جستجو برای: pine tree

تعداد نتایج: 184804  

2017
Hongxiang Wang Qianxue Wang Ling Liu

Inter-tree competition is considered one of the most important ecological processes of forest development. However, its importance in structuring the spatial patterns of plant communities remains controversial. We collected observational data from two plots in a natural Mongolian Scots pine forest to study the contribution of competition to tree growth, mortality, and size inequality. We used t...

2015
Martin Gutsch

The relationship between climate and forest productivity is an intensively studied subject in forest science. This thesis is embedded within the general framework of future forest growth under climate change and its implications for the ongoing forest conversion of pure pine forests into mixed oak-pine forests. My objective is to investigate future forest productivity at different spatial scale...

2016
Don C. Bragg

A major ice storm struck Georgia and the Carolinas in February of 2014, damaging or destroying hundreds of thousands of hectares of timber worth hundreds of millions of dollars. Losses were particularly severe in pine plantations in west-central South Carolina, including many on the Savannah River Site (SRS). An array of paired, mid-rotation loblolly (Pinus taeda L.) and longleaf (Pinus palustr...

Journal: :Proceedings of the National Academy of Sciences of the United States of America 2013
Charles C Rhoades James H McCutchan Leigh A Cooper David Clow Thomas M Detmer Jennifer S Briggs John D Stednick Thomas T Veblen Rachel M Ertz Gene E Likens William M Lewis

A current pine beetle infestation has caused extensive mortality of lodgepole pine (Pinus contorta) in forests of Colorado and Wyoming; it is part of an unprecedented multispecies beetle outbreak extending from Mexico to Canada. In United States and European watersheds, where atmospheric deposition of inorganic N is moderate to low (<10 kg⋅ha⋅y), disturbance of forests by timber harvest or viol...

2013
Tuula Kantola Mikko Vastaranta Päivi Lyytikäinen-Saarenmaa Markus Holopainen Ville Kankare Mervi Talvitie Juha Hyyppä

Forest disturbances caused by pest insects are threatening ecosystem stability, sustainable forest management and economic return in boreal forests. Climate change and increased extreme weather patterns can magnify the intensity of forest disturbances, particularly at higher latitudes. Due to rapid responses to elevating temperatures, forest insect pests can flexibly change their survival, disp...

2008
Don C. Bragg

By adapting data from national and state champion lists and the predictions of an existing height model, an exponential function was developed to improve tree height estimation. As a case study, comparisons between the original and redesigned model were made with eastern white pine (Pinus strobus L.). For example, the heights predicted by the new design varied by centimeters from the original u...

2009
DONALD M. GROSMAN STEPHEN R. CLARKE WILLIAM W. UPTON

Weevaluated the efÞcacy of systemic insecticides emamectin benzoate and Þpronil for preventing mortality of individual loblolly pines, Pinus taeda L., as a result of attacks by southern pine bark beetles (Coleoptera: Curculionidae, Scolytinae) for two consecutive years in Mississippi (2005Ð 2006) and Alabama (2006Ð2007). Trees were injected once in the spring of 2005 (Mississippi) or 2006 (Alab...

2004
Xiaowei Yu Juha Hyyppä Hannu Hyyppä Matti Maltamo

High-density airborne laser scanner data has been previously shown to provide great opportunities for individual tree detection and measurement of variables characterizing the detected trees. This paper evaluates the effect of laser flight altitude on the tree height estimation at individual tree level in the boreal forest area mainly consisting of Norway spruce, Scots pine and birch. The test ...

Journal: :Molecular ecology 2011
Sepideh M Alamouti Vincent Wang Scott Diguistini Diana L Six Jörg Bohlmann Richard C Hamelin Nicolas Feau Colette Breuil

Grosmannia clavigera is a fungal pathogen of pine forests in western North America and a symbiotic associate of two sister bark beetles: Dendroctonus ponderosae and D. jeffreyi. This fungus and its beetle associate D. ponderosae are expanding in large epidemics in western North America. Using the fungal genome sequence and gene annotations, we assessed whether fungal isolates from the two beetl...

Journal: :Applied sciences 2023

Tree-counting methods based on computer vision technologies are low-cost and efficient in contrast to the traditional tree counting methods, which time-consuming, laborious, humanly infeasible. This study presents a method for detecting seedlings images using deep learning algorithm with high economic value broad application prospects type quantity of seedlings. The dataset was built three type...

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