significant increases in 

 timber yields often can be 

 achieved by application of 

 nitrogen, phosphorus, 

 potassium, or trace ele- 

 ments, and that yields of 

 forage for livestock and 

 wildlife can be similarly 

 enhanced. Related research 

 on use of sewage sludge 

 for fertilization of forests 

 showed this to be effective 

 in increasing growth of 

 loblolly and Virginia pines 

 on depleted soils such as 

 mine banks (e.g., Berry and 

 Marx 1977). Criteria have 

 been developed, as in the 

 case of slash pine, for 

 evaluating potential re- 

 sponses from use of differ- 

 ent fertilizers, along with 

 recommendations for rates 

 and timing of applications 

 (Stone 1983, p. 86). 



Nutrient cycling has likewise 

 received considerable atten- 

 tion from forest scientists. 

 This has been due in part 

 to increased interest in 

 making use of forest 

 biomass for energy as well 

 as conventional logs and 

 boltwood, with consequent 

 questions of nutrient deple- 

 tion (e.g., Wells 1977). 

 Studies have shown, for 

 example, that normal har- 

 vesting of tree boles results 



in nutrient losses that 

 approximate nutrient inputs; 

 but with harvesting on very 

 short rotations and total 

 use of biomass, nutrient 

 losses may exceed the 

 natural supply. Better under- 

 standing of the physical 

 and chemical properties of 

 forest soils also has resulted 

 from the work of scientists 

 such as W.F. Miller at 

 Mississippi State University 

 (1976). 



The profitability of forest 

 fertilization has been a 

 matter of much uncertainty, 

 in large part because of 

 wide variations in forest 

 conditions and responses 

 to fertilization. Nevertheless, 

 studies of slash pine stands 

 in the Southeast (e.g., Fight 

 and Dutrow 1981) have 

 indicated that proper appli- 

 cation of fertilizers at the 

 right time could yield returns 

 as high as 27 percent on 

 investments in this practice. 



Hardwood management 

 has also been of much 

 significance in the South. 

 Hardwood types cover 

 more than half the forest 

 area of the region, including 

 bottomlands with many 

 valuable species and high- 

 producing sites. The upland 



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