Douglas J. Frederick

Combining constructed wetlands and aquatic and soil filters for reclamation and reuse of water

Abstract Reclamation and reuse of water and nutrients at their source provide the opportunity to use simple, less costly technologies and lessens potentials for catastrophic effects due to centralized treatment system failures. The combination of multiple treatment environments within constructed wetlands can provide water quality suitable for reuse. A current project in rural Chatham County, NC, uses simple, aesthetically pleasing treatment components constructed both outdoors and indoors to reclaim domestic sewage for toilet flushing, landscape irrigation and aesthetic water features. A courtyard containing constructed wetlands and a solarium with modular soil filter components and aquatic chambers are designed to treat sewage from within a small business facility and to provide recreational space for its 60 employees. The combination of vertical flow and horizontal flow constructed wetlands with fill and draw controls provides the necessary environments for nitrification–denitrification, removal of organic materials and phosphorus adsorption reactions. The system is designed to treat and reuse 4500 l day −1 (1200 gal day −1 ) of domestic sewage from the business. Some of the plants used are selectively bred or genetically engineered to maximize their water reclamation potential. Utilization of simple treatment and reuse technology has permitted the business owner to renovate an abandoned and deteriorating school building into a home for two thriving and internationally based businesses and to protect the water quality of a nearby reservoir.

Field trials of a short-rotation biomass feller buncher and selected harvesting systems

A continuous-speed felling and bunching prototype machine was evaluated in harvesting a three-year-old, short-rotation sycamore plantation. A small tractor, grapple skidder, and large chipper were evaluated along with the prototype machine as complete harvesting systems. Prediction equations, production rates, and costs were developed for each component of the systems. Production of the feller buncher was about 850 stems an hour (17·3 green Mg), and felling cost for the test was

Nutrient content and distribution in natural southern Coastal Plain hardwoods.

3·29 green Mg−1. Total system cost was about

Influence of site condition, fertilization and spacing on short rotation hardwood coppice and seedling yields

11·50 green Mg−1. However, cost could be reduced with a smaller chipper. A survey of stump damage showed little damage from the feller buncher when it was operating properly. The tractor caused minimal skidding damage, less than that of the large skidder.

Nutrient content prediction equations for wetland trees in the US Southern Coastal plain

Abstract Nutrient pools in Atlantic and East Gulf Coastal Plain hardwood forests were studied to determine contents and distributions of N, P, K, Ca and Mg. Bottomland, wet flat and swamp stands aged 10, 20, 40 and 60 years were examined. Results show that tree component nutrient concentrations were relatively stable across site types except for somewhat lower concentrations in 60-year-old stands. Site types did not differ greatly in their biomass and nutrient contents for most age classes. In all sites, tree boles comprised the largest single aboveground biomass pool by age 40, while relative contributions by saplings and litter generally decreased with age. These stands were productive and accumulated biomass at 4·6 t ha −1 year −1 over 60 years.

Aboveground energy production and distribution of southeastern hardwood swamp forests

Abstract Coppice and seedling biomass was superior on a relatively more fertile old field (OF) site compared with yields on forest cleared and fertilized (CF) and forest cleared not fertilized (C) sites, and followed the order OF>CF.C. Biomass production ranged from 1·6 dry-28·6 Mg ha −1 for four-year-old seedlings, and 0·9–12·4 Mg ha −1 for two-year-old coppice on the C and OF sites, respectively. Coppice sprout height was generally not related to number of sprouts per stump but was significantly greater as basal diameter of the cut stump increased. Narrower planting spacings generally resulted in greater biomass yields for four-year-old seedlings but trends were less defined for coppice. Seedling yields were greater for four-year-old water-willow oak ( Quercus sp.) with 28·6 Mg ha −1 at a 0·6 × 3·1 m spacing of the OF site. However, biomass yields of four-year-old oak, sycamore ( Platanus occidentalis L.) and sweetgum ( Liquidambar styraciflua L.) seedlings were not significantly different at a 0·6 × 3·1 m spacing on the OF site. Coppice yields at two years were greater than same age seedlings on the OF site for all species. Failure to refertilize on the CF site after initial seedling harvests may have resulted in lower two-year coppice yields compared with seedlings of the same age.

Weight, Volume, and Physical Properties of Major Hardwood Species in the Gulf and Atlantic Coastal Plains

Abstract Nutrient content prediction equations are presented for blackgum, green ash, red maple, sweetgum, water tupelo, hickory, laurel oak, water oak, and baldcypress growing on wetland sites in the southern United States from Virginia to Mississippi. In all, 495 trees from 19 locations on the Coastal Plain were sampled for N, P, K, Ca, and Mg concentrations and biomass of foliage, branches, bole wood, and bole bark. The ranking of nutrient concentrations in tree components was N>Ca>K>Mg>P for foliage and Ca>N>K>Mg>P for branches, bole wood, and bole bark. Individual species equations developed to predict nutrient contents for the total-bole and total-tree had coefficients of determination (R2 values) ranging from 0·87 to 0·99. These equations make it possible to compare the nutrient losses associated with total-tree and conventional bole wood harvesting on wetland sites.

Weight, Volume, and Physical Properties of Major Hardwood Species in the Upland-South

Abstract Energy production and distribution were examined in fully stocked, even-aged 10-, 20-, 40- and 60-year-old southeastern swamp forests. Maximum intraspecies energy value differences were small within a given tissue. Mean energy values (kJ g−1 dry weight) ranged as follows: foliage (18·76-21·17) >stem wood (19·04–20·34)>branch (19·11–19·85)>stem bark (16·72-20·33). Total live aboveground biomass and energy content in these swamp forests increased with stand age, as follows: 41·4, 108·8, 208·9 and 297·5 Mg ha−1 and 81·7, 209·0, 416·4 and 593·6 MJ m−2, respectively. Depending upon stand age, whole-tree harvest energy yields exceeded energy yields derived in a conventional harvest by 21–96%.