نتایج جستجو برای: oak trees decline

تعداد نتایج: 187710  

2007
IAN A. DICKIE S. E. HOBBIE

1 Multiple factors are known to influence tree seedling establishment, yet the degree to which these factors depend on each other and on spatial context is largely unknown. We examined the influence of herbaceous competition and water and nitrogen limitations on tree seedling establishment as functions of distance from trees (within-site spatial context) and site history (between-site spatial c...

2017
Jongbum Jeon Ki-Tae Kim Hyeunjeong Song Gir-Won Lee Kyeongchae Cheong Hyunbin Kim Gobong Choi Yong-Hwan Lee Jane E Stewart Ned B Klopfenstein Mee-Sook Kim

The fungus Raffaelea quercus-mongolicae is the causal agent of Korean oak wilt, a disease associated with mass mortality of oak trees (e.g., Quercus spp.). The fungus is vectored and dispersed by the ambrosia beetle, Platypus koryoensis Here, we present the 27.0-Mb draft genome sequence of R. quercus-mongolicae strain KACC44405.

2001
DAVID W. PETERSON PETER B. REICH

Although it is well known that fire can exert strong control on stand structure, composition, and dynamics in savannas and woodlands, the relationship between fire frequency and stand structure has been characterized in few of the world’s savanna and woodland ecosystems. To address this issue in temperate oak-dominated ecosystems, we studied the effects of fire frequency on stand structure and ...

2016
anastasia pantera

Background and purpose: Valonia oak (Quercus ithaburensis subsp. macrolepis (Kotschy) Hedge & Yalt.) is an east Mediterranean endemic, xerothermic and deciduous tree of particular interest in forestry. There has been a growing demand lately to include the species in reforestations in Greece which also increased the interest to investigate its response to climate change. The main purpose of this...

2014
Yong-Bok Lee Su Jung An Chung Gyoo Park Jinwoo Kim Sangjo Han Youn-Sig Kwak

Microorganisms have many roles in nature. They may act as decomposers that obtain nutrients from dead materials, while some are pathogens that cause diseases in animals, insects, and plants. Some are symbionts that enhance plant growth, such as arbuscular mycorrhizae and nitrogen fixation bacteria. However, roles of plant pathogens and diseases in natural ecosystems are still poorly understood....

2016
Dorota Wrońska-Pilarek Władysław Danielewicz Jan Bocianowski Tomasz Maliński Magdalena Janyszek

Pollen morphology of three parental Quercus species (Q. robur L., Q. petraea (Matt) Liebl, Q. pubescens Willd.) and two spontaneous hybrids of these species (Q. ×calvescens Vuk. = Q. petraea × Q. pubescens and Q. ×rosacea Bechst. = Q. robur × Q. petraea) was investigated in this study. The pollen originated from 18 natural oak sites and 67 individuals (oak trees). Each individual was represente...

Journal: :Tree physiology 1996
N T Edwards P J Hanson

Stem respiration was measured throughout 1993 on 56 mature trees of three species (Quercus alba L., Quercus prinus L., and Acer rubrum L.) in Walker Branch Watershed, Oak Ridge, Tennessee. A subset of the trees was remeasured during 1994. Diameter increments, stem temperatures and soil water were also monitored. Respiration rates in the spring and summer of 1993 tracked growth rate increments, ...

2014
Anna O. Conrad Luis E. Rodriguez-Saona Brice A. McPherson David L. Wood Pierluigi Bonello

Over the last two decades coast live oak (CLO) dominance in many California coastal ecosystems has been threatened by the alien invasive pathogen Phytophthora ramorum, the causal agent of sudden oak death. In spite of high infection and mortality rates in some areas, the presence of apparently resistant trees has been observed, including trees that become infected but recover over time. However...

Journal: :Computers, Environment and Urban Systems 2003
Nina M. Kelly Karin Tuxen

Tanoak (Lithocarpus densiflorus), coast live oak (Quercus agrifolia), black oak (Q. kelloggii), and some shreve oak (Q. parvula var. shreve) trees in coastal California are affected by a new disease called ‘‘Sudden Oak Death.’’ These tree communities are extremely important for habitat provision, recreation, and aesthetics. Research of and community interest in this new disease is very high. We...

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