Oak Quercus spp

Zinc concentrations in forest plants vary considerably. In oaks (Quercus spp.), for example, some species are accumulators, whereas others may be termed discriminators. For individual species, zinc concentrations tend to follow the pattern of roots > foliage > branch > trunk (Van Hook et al. 1980). Small lateral roots accumulate Zn to much greater levels than other vegetation components and are probably most sensitive to changes in zinc inputs. Half-time persistence of zinc in forest ecosystems varies from about 3 years in organic matter components to >200 years for large soil pools (Van Hook et al. 1980). 

From oak (Quercus spp.) forest sprayed aerially with 70.75 g diflubenzuron/ha to control gypsy moth instars samples collected 3 days prior to spraying, and up to 21 days after spraying... 

Chart 8.1.S Shikimates (skeletons) widespread on land (5max=57, av=43 5//ftnax=0.48, av=0.39). Tannins lignans epigallocathechin gallate (Asian black tea. Camellia sinensis L.) Kuntze, Theaceae, Ang. MI) procyanidins and prodelphinidins (widespread in plants) soluble hydrolyzable tannins gallotannin (myrobalan. East Indian trees, Terminalia spp., oak, Quercus spp., Lithocarpus spp., and sumac, Rhus spp.) ellagitannin (Myrtaceae). 

Tannins are abundant in many different plant species, in particular oak (Quercus spp.), chestnut (Castanea spp.), staghorn sumac (Rhus typhina), and fringe cups (Tellima grandiflora). Tannins can be present in the leaves, bark, and fruits, and are thought to protect the plant against infection and herbivory. 

Triazine herbicides are primarily effective in controlling herbaceous weeds. A notable exception is the use of granular hexazinone for controlling woody invaders such as oaks (Quercus spp.) or aspen (Populus tremuloides) in conifer stands on medium- and fine-textured soils in the South or in boreal forests. Hexazinone also is used in the Maritime Provinces of Canada for controlling woody and herbaceous growth in natural Christmas tree stands (Townsend, 1995a). The impact of herbaceous plant cover is somewhat different from that of woody plant competitors, so control strategies on various forest conifer sites may differ. 

Three-ply triplicate wood panels of dimensions 500 x 300 x 14 mm and of 400 X 400 X 6 mm were prepared. The former were composed of pine wood Pi-nus sylvestris) veneers of, respectively, 3.5 mm and 7 mm thicknesses for the two lower plys and of an oak (Quercus spp.) veneer of 3.5 mm thickness for the upper veneer giving 14 mm total plywood thickness. These panels were suitable for floor covering. The second type of plywood panels were composed of three 2 mm thick beech (Fagus sylvatica) veneers. 

D-Quercitol, a pentahydroxycyclohexane, is found in the bark of Quercus suber and Tiliacora acuminata and roots of Cissampelos pareira, Legnephora moorii and Cyclea burmanni (see 137). It appears to be uniformly present in the bark of oak (Quercus spp.). 

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