of high air polkition. Eckert believes Since the 1970s, disposal of sew- 

 that acid rain resulting from air pollu- age sludge has been of environmental 

 tion causes a release of aluminum into concern and an important problem 

 the soil solution, and that since alu- faced by many New Hampshire com- 

 minum is toxic to some plant roots, munities, one being disease-causing 

 tree growth is inhibited. His laboratory organisms. Municipal sewage, treated 

 experiments suggest that soil alumi- properly however, is not a health 

 num can indeed affect uptake of es- hazard to humans. Sludge, particu- 

 sential nutrients, cause trees to grow larly that of industrial origin which 

 more slowly and become more sus- may contain inorganic constituents, 

 ceptible to stresses such as drought, such as lead, copper, chromium, nickel 

 fungi, insects, and air pollution. Thus and cadmium, could pose a poten- 

 acid rain may predispose trees to de- tially serious threat to plant, animal 

 cline from other stresses. He is now and human health. Applying a method 

 using isozyme analysis to determine developedby the U.S.D.A.. Beltsville, 

 the genetics of individual red spruce Maryland, R. D. Harter, soil chemist, 

 trees, rather than seedlings, and evalu- and George Crombie, then Durham 

 ate the impact of air pollution and public works director, perfected an 

 other forms of stress on tree health. economical procedure for composting 



, , sludge. Since sludge can be consid- 



Hardwood species such as oak, ^^^^ ^ complete fertilizer, except for 



beech, birch and maple are plentiful m ^^^^^^^^^ ^he material is now used 



New Hampshire forests. But accord- fo^ compost for flower beds by both the 



ing to J. L. Hill, wood technologist, ^^^^ ^^^ residents of Durham. When 



products made of hardwoods require ^^ ^^^^ ^^^ ^^^ Hampshire 



lowmoisture wood obtained by dry mg ^^^^^ ^^^^ analyzed for several inor- 



inkilns,acriticalprocessrepresenting elements, half contained poten- 



a major production cost in the manu- ^.^^j^ ^^^.^ elements, lead being most 



facture of hardwood products^ A re- ^^^^^^^ 

 search team consisting ot Hill, a 



graduate student and two scientists Harter, along with a large team of 

 from the College of Engineering and soil scientists from the Northeast, are 

 Physical Sciences have devised a cooperating on a research project en- 

 practical solution to the drying pro- titled, "Soil properties affecting sorp- 

 cess. The procedure has been auto- tion of heavy metals from waste." His 

 mated by use of a personal computer to interest here is in more basic problems 

 control iciln temperature and moisture in soil chemistry. This research has 

 and thus reduce drying time and avoid practical applications because, ac- 

 damage to the lumber. When kiln cording to Harter, "the ability of a soil 

 drying costs as much as one dollar per to hold a retained ion against leaching 

 board foot of lumber, accurate control or plant uptake is crucial, and impor- 

 of the process is essential to reduce tant in land areas to be used for 

 degrading and produce high quality disposal of potentially toxic wastes." 

 lumber. Thus automated control of the ^^^^^^ ^.^^ ^^^^^^ ^^^ .^^^^^._ 

 kiln drying process reduces cost, im- ^^^ ^^^^ ^^ ^^^^^^ ^^. j^ .^ ^^^^.^_ 

 proves quality and provides a proce- f ^^^^.^^^^ ^^^^ clear-cutting, and 

 dure which should be useful to the ^^^ ^^^^^^ ^^ ^.^^ ^^ ^^^^^^ ^^.^ ^^^ 



wood processing industry. ^ • x i- 



t^ o J nutrient cycling. 



72 



