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Ecological classificafion systems range over a variety of scales and reflect a variety of scientific viewpoints. They incorporate or emphasize varied arrays of environmental factors. Ecological classifications have been developed for marine, wetland, lake, stream, and terrestrial ecosystems. What are the benefits of ecological classification for natural resource management planning and implementation?

Pistillate flower development and acorn production were observed in small populations of white oak (Quercus alba L.) and black oak (Quercus velurina Lam.) in central Missouri from 1990 to 1997. There were significant year-year differences in the size of flower crops for both species and significant tree-tree differences in black oak. About 7% of the white oak flowers matured into acorns: most flowers aborted by early July just after fertilization. About 12% of the black oak flowers matured into acorns, but some individual trees never or rarely produced a mature acorn. The number of...

We measured vegetation at shrub patches used for nesting by Yellow-breasted Chats (Icteria virens) to evaluate the importance of nesting habitat patch features on nest predation, cowbird parasitism, and nest site selection. Logistic regression models indicated that nests in small patches (average diameter 10 cm dbh) nearby. Patches used by chats for nesting had larger average diameters than unused patches and tended to contain more small stems. Chats appeared to prefer large patches and experienced lower nest predation there. Although they might experience higher brood parasitism frequencie...

Results showed a moderate to high susceptibility of Pinus sylvestris to western gall rust Peridermium barknessii, from Pinna sylvestris in Michigan and Pinna banksiana in Minnesota. In general, Pinus sylvestris seed sources were more susceptible to aeciospores collected from Pious sytvestris than, aeciospores collected from Pinus banksiana.

Stem tissue of resistant and susceptible genotypes of Poyulus tremuloides Michx, wounded or woundinoculated with Entoleuca mammata (Wahlenberg: Fr.) J.D. Rogers & Y.M. Ju was prepared for histochemical and microspectrophotometric analysis. Samples were collected over a 96-h period. Parenchyma cell walls associated with the response zone of infected resistant and susceptible genotypes accumulated phenolic substances having lignin-like properties. Features of the lignified zone distinguished resistant from susceptible genotypes. This zone in the resistant genotype was uniformly lignified,...

With the increased use of variables such as canopy cover photosynthetically active radiation (PAR) and overstory leaf area index (LAI) in forestry research, relationships between these variables and traditional forestry variables must be defined before recommended levels of these research variables can be achieved by forestry practitioners on the ground. We measured basal area, canopy cover, Ozalid percent full light, PAR, and overstory LAI in thinned and unthinned plots within oak and pine stands with the objectives of: 1) determining the relationships between these variables in two...

Roads and road building on the US national forests have become the focus of intense public debate in recent years. Timber companies and others argued that forest roads are an essential transportation system for the production of commodities that society needs. Environmentalists and others reply that national forest roads constitute ecologically destructive "corporate welfare." Recreation is the main use of national forest roads (Coghlan and Sowa 1998), but recreationists sharply disagree about their appropriate role. For enthusiasts of motorized recreation, forest roads are an integral...

Nurient storage is an important aspect of resprouting potential and production of Salix viminalis L., a pioneer species used for biomas production in weden. Seasonal dynamics of nitrogen (N), protien, soluble arbohydrates, starches, and lipids were studied in roots, cutting, stems, and leaves during a full growth cycle induced by varying photoperiod and temperature in growth chamber. Nitrogen was supplied at two rates. Both season and N availability significantly affected storage of N and carbohydrates. Reserves peaked in dormancy, and plants grown at a higher N availability were able to...

This study repersents a first step in gaining awareness of what people think about ecological and related concepts. Forty-one undergraduate nonscience majors at a liberal arts college in chicago were asked to define, explain, or illustrate the follong four terms: "forest preserves," "natural area," "ecological restoration," and "biodiversity." Analysis involved repeated reading of responses and identification of common themes. Forest preserves held a variety of meaning for people whiel natural areas often were equated with bature inits most pristine form. The term ecological restoration...

Many applied and theoretical investigations require information on how productivity varies in time and space (Temple and Wiens 1989, DeSante 1995). Examples include studies of habitat quality, population trends, life-history tactics, and metapopulation dynamics. From a demographic perspective, reproductivity is the number of young, counted at a given time of year, produced per adult (e.g. Caswell 1989). Various measures have been used to estimate productivity. One of the most attractive is mist neting during the summer after young have left the nest, but ideally before they have left the...