Leaf disks of oak (Quercus petraea (Matt.) Liebl.) trees were subjected to rapid dehydration in air in the dark. Optimal photochemical efficiency of PS II (F(v)/F(M)), photochemical (q(P)) and nonphotochemical (q(NP)) quenchings of chlorophyll a fluorescence, and relative conductivity (C(r)) of leaf disk diffusate were measured in leaf disks with different water deficits (D). No effect of dehyd...

Early season leaf growth requires a large amount of nitrogen, and the amount of N provided for new leaf development has been well tested. Although shoot position within the crown strongly influences leaf properties, little is known about absorbed and remobilized nitrogen allocation in the tree crown. Thus, we investigated differences in the allocation of recently absorbed nitrogen in the tree c...

The intensive foraging of insectivorous birds and bats is well known to reduce the density of arboreal herbivorous arthropods but quantification of collateral leaf damage remains limited for temperate forest canopies. We conducted exclusion experiments with nets in the crowns of young and mature oaks, Quercus robur, in south and central Germany to investigate the extent to which aerial vertebra...

Although fungi, bacteria, and specific bacterial taxa, such as the actinomycetes, have been studied extensively in various habitats, few studies have examined them simultaneously, especially on decomposing leaves in streams. In this study, sugar maple and white oak leaves were incubated in a stream in northeastern Ohio for 181 days during which samples were collected at regular intervals. Follo...

Northern red oak (Quercus rubra L.) seedlings and trees differ in their response to ozone. Previous work reported reductions in net photosynthesis, carboxylation efficiency and quantum yield of mature tree leaves, whereas seedling processes were unaffected by the same ozone exposure. To further characterize differences in ozone response between seedlings and mature trees, we examined carbon par...

We evaluated the importance of epiphytic lichens in the nutrient cycling of a blue oak (Quercus douglasii) woodland in California. Each oak tree contained an average of 3.8 kg lichen biomass, totaling 590 kg per ha. For comparison, oak leaf biomass was 958 kg per ha. We compared tree growth, volume and composition of throughfall (rainfall falling though the tree canopy), litterfall, and soil nu...

citation: Choberka, E.G., M.R. Penskar, and P.J. Higman. 2001. Special plant abstract for Gymnocarpium robertianum (limestone oak fern). Michigan Natural Features Inventory, Lansing, MI. 2 pp. fern and lacks the pronounced, extended tips of the main leaf segments so evident in well-developed fronds of G. robertianum. Best survey time/phenology: Gymnocarpium robertianum is recognizable whenever ...

To elucidate changes in the defensive traits of tree seedlings under global environmental changes, we evaluated foliar successional trees, such as beech, oak, and magnolia grown a natural-light phytotron. Potted were combination two CO2 concentrations (360 vs. 720 ppm) nitrogen (N) treatments (4 15 kg N ha?1 yr?1) for growing seasons using quantitative chemical analyses anatomical method. We hy...