Decomposition of three leaf species (Alnus glutinosa, Eucalyptus globulus and Quercus robur) were examined in a headstream. During two months decomposing leaves were periodically analysed for nutrient content, soluble sugars, phenols, protein precipitation capacity, total fiber, weight loss, microbial and macroinvertebrate colonisation. The leaves of the three species showed similar patterns in...

Freshwater ecosystems are positioned at low levels in the landscape and receive large inputs of diverse plant-based detritus, a major source of energy for consumers in aquatic ecosystems. We conducted Þeld experiments in Urbana, IL to determine the independent and combined effects of leaves of common tree species including thenorthern redoak (Quercus rubraL.), sugarmaple (Acer saccharumMarshall...

Short-term effects of ozone (O(3)) on phyllosphere fungi were studied by examining fungal populations from leaves of giant sequoia (Sequoiadendron giganteum (Lindl.) Buchholz) and California black oak (Quercus kelloggii Newb.). Chronic effects of both O(3) and sulfur dioxide (SO(2)) were studied by isolating fungi from leaves of mature Valencia orange (Citrus sinensis L.) trees. In this chronic...

Timely and accurate identification of tree species by spectral methods is crucial for forest and urban ecological management. It has been proved that traditional methods and data cannot meet such requirements. In this study, a total of 394 reflectance spectra (between 350 and 2500 nm) from foliage branches or canopy of 11 important urban forest broadleaf species were measured in the City of Tam...

Within the eastern deciduous forest region, forest composition varies, with some areas dominated by a mix of oaks (Quercus spp.) and other areas dominated by a mix of sugar maple (Acer saccharum) and other tree species. Prescribed fire is being used on an experimental basis to assess its effectiveness in restoring and maintaining oak-dominated forests. Maple-dominated forests are susceptible to...

Leaf miners typically show non-random distributions both between and within plants. We tested the hypothesis that leaf miners on two oak species were clumped on individual host trees and individual branches and addressed whether clumping was influenced by aspects of plant quality and how clumping and/or interactions with other oak herbivores affected leaf-miner survivorship. Null models were us...

An afforestation system which utilizes the pioneer species eastern cottonwood (Populus deltoides Bartr. ex Marsh.) as a nurse for slower growing, disturbance-dependent species is under evaluation as a forest rehabilitation tool on former agricultural land in the Lower Mississippi River Alluvial Valley, USA. The primary objectives of this study were to quantify understory light availability in t...

The enzyme, ß-glucogallin: 1,2,3,6-tetra-O-galloyl-ß-D-glucose 4-O-galloyltransferase, which catalyzes the last common step in the biosynthesis of the two subclasses of hydrolyz­ able tannins, i.e. gallotannins and ellagitannins, was purified 868-fold from leaves of peduncu­ late oak ( Quercus robur, syn. Q. pedunculata) to apparent homogeneity. Polyclonal antibod­ ies against this pivotal enzy...

Leaves exhibit a wide range of form and function: as well as the flattened photosynthetic organs we are most familiar with, modifications of leaf morphology produce the rigid spines of cacti, the cup-shaped insect traps of pitcher plants, colorful flower parts such as petals and some of the tendrils used for attachment by climbing plants. One fundamental choice in leaf architecture is whether t...