Hermaphroditic flowers blooming unseasonably on an oak tree (»the green oak«) of uncertain hybrid origin prompted a detailed investigation into the biology of the flowering, and the morphology of various traits of the tree, which is growing in an urban area near Zadar, northern Dalmatia, Croatia. Hermaphroditic flowers were also detected on one holm oak tree from Weihenstephan, Germany. Since t...

Efforts inEurope to convertNorway spruce (Piceaabies) plantations tobroadleaf ormixedbroadleaf-conifer forests could be bolstered by an increased understanding of how artificial regeneration acclimates and functions under a range of Norway spruce stand conditions. We studied foliage characteristics and leaflevel photosynthesis on 7-year-old European beech (Fagus sylvatica) and pedunculate oak (...

A recent lengthening of the growing season in mid and higher latitudes of the northern hemisphere is reported as a clear indicator for climate change impacts. Using data from Germany (1951-2003) and Slovenia (1961-2004), we study whether changes in the start, end, and length of the growing season differ among four deciduous broad-leaved tree species and countries, how the changes are related to...

Anthracnose is one of the most common and important foliage diseases of shade trees in Iowa. Symptoms of anthracnose are often referred to as “leaf blights” or “leaf spots” and are most serious on sycamore, ash, maple, white and bur oak, and walnut. Linden, hickory, elm, red and black oak, and other deciduous trees also are susceptible, although anthracnose is less common and damaging on these ...

By creating or modifying habitats used by other organisms, physical ecosystem engineers can influence local patterns of biological diversity. However, there have been very few empirical studies quantifying engineering effects in different biological systems. In this study, we examined the effect of shelter-building caterpillars on the species richness and guild structure of leaf-chewing herbivo...

The responses of Aedes albopictus to sources of oviposition attractants and stimulants were evaluated with a behavioral bioassay in which females attracted to odorants emanating from water were trapped on screens coated with an adhesive. Gravid mosquitoes were attracted to volatiles from larval-rearing water and soil-contaminated cotton towels. Bacteria were isolated from these substrates and f...

Anthracnose is one of the most common and important foliage diseases of shade trees in Iowa. Symptoms of anthracnose are often referred to as “leaf blights” or “leaf spots” and are most serious on sycamore, ash, maple, white and bur oak, and walnut. Linden, hickory, elm, red and black oak, and other deciduous trees also are susceptible, although anthracnose is less common and damaging on these ...

In the Mediterranean evergreen oak woodlands of southern Portugal, the main tree species are Quercus ilex ssp. rotundifolia Lam. (holm oak) and Quercus suber L. (cork oak). We studied a savannah-type woodland where these species coexist, with the aim of better understanding the mechanisms of tree adaptation to seasonal drought. In both species, seasonal variations in transpiration and predawn l...

The diversity of plant neighbors commonly results in direct, bottom-up effects on herbivore ability to locate their host, and in indirect effects on herbivores involving changes in plant traits and a top-down control by their enemies. Yet, the relative contribution of bottom-up and top-down forces remains poorly understood. We also lack knowledge on the effect of abiotic constraints such as sum...