A new forest disease called Sudden Oak Death, caused by the pathogen Phytophthora ramorum, occurs in coastal hardwood forests in California and Oregon. In this paper, we analyzed the spatial–temporal patterns of overstory oak tree mortality in China Camp State Park, CA over 4 years using the point patterns mapped from high spatial resolution remotely sensed imagery. Both univariate and multivar...

Ancient trees are considered one of the most important habitats for biodiversity in Europe and North America. They support exceptional numbers of specialized species, including a range of rare and endangered wood-living insects. In this study, we use a dataset of 105 sites spanning a climatic gradient along the oak range of Norway and Sweden to investigate the importance of temperature and prec...

Tree decline is a physiological phenomenon resulting from climatic disturbances that involves damage to forest ecosystems. This study examined the effects of tree on nutrient concentrations in leaves, bark, and wood Persian oak (Quercus brantii) trees. Trees were categorized by severity (healthy, slight, moderate, severe decline). Leaves collected middle outer parts crowns. Bark samples taken a...

Oak and birch trees belong to Fagales order. Specific IgE to pollen allergens of both trees are frequently found in Korea pollinosis patients. Oak trees which comprise 40% of forest area are common in Korea. However, birch trees are sparse. We compared the allergenicity of pollen extracts of white oak, sawtooth and Mongolian oaks which are prevalent species in Korea, with the pollen extract of ...

We conducted a case-control study to examine the role of water stress and various other factors on the development of Phytophthora ramorum cankers in symptomatic (case) and symptomless (control) coast live oak (Quercus agrifolia) and tanoak (Lithocarpus densiflorus). Midday stem water potential (SWP) in Q. agrifolia subject trees ranged from – 0.25 to –3.1 megapascals (MPa). SWP was higher (ind...

In forests, the vulnerable seedling stage is largely influenced by the canopy, which modifies the surrounding environment. Consequently, any alteration in the characteristics of the canopy, such as those promoted by forest dieback, might impact regeneration dynamics. Our work analyzes the interaction between canopy neighbors and seedlings in Mediterranean forests affected by the decline of thei...

A total of 62 coast live oaks (Quercus agrifolia) were monitored since they were initially boxed for transplantation in 1993. At that time, only branches injured during the moving process and deadwood were removed, leaving the entire canopy intact. This was a departure from the usual transplanting methodology that traditionally removes up to 70 percent of the canopy in order to compensate for t...

Oak-dominated forests in northwestern Arkansas have recently experienced an oak mortality event associated with an unprecedented outbreak of a native insect, the red oak borer, Enaphalodes rufulus (Haldeman). To determine whether prior drought was associated with increased E. rufulus infestation level of Quercus rubra L. trees, we employed a suite of dendrochronological measurements from Q. rub...

Recent mortality in coast live oak (Quercus agrifolia), California black oak (Q. kelloggii), and tanoak (Lithocarpus densiflorus) exceeds historical levels in forests affected by the pathogen Phytophthora ramorum. We assessed the balance between recent mortality and seedling populations in these species to examine the status of regeneration in stands with varying levels of mortality caused by P...