yields. The best of such 

 trees have produced about 

 twice as much gum as 

 average trees and signifi- 

 cantly more wood volume 

 than woods-run trees. 



Other research with slash 

 pine, conducted by R.J. 

 Dinus, F.F. Jewell, H.R. 

 Powers, P.V. Siggers, G.A. 

 Snow, P.C. Wakeley, and 

 O.O. Wells, for example, 

 found significant genetic 

 variation in resistance to 

 fusiform rust related to 

 geographic origin and tree 

 parents. Field tests showed 

 the feasibility of sizable 

 improvements in survival 

 and growth by selection of 

 seed from the more resistant 

 parents. 



Because of its many desir- 

 able properties for wood 

 products and oleoresin, 

 slash pine became the 

 popular choice in many 

 tree-planting programs. 

 Some of the widespread 

 plantings failed, however, 

 and this fact stimulated 

 investigations relating to 

 site relationships, fertiliza- 

 tion, drainage, and seed 

 sources. Based on results 

 of studies of such factors, 

 foresters can now make 

 intelligent decisions as to 



where slash pine can best 

 be established. 



Studies of the genetics of 

 loblolly pine also showed 

 much genetic variation in 

 growth and resistance to 

 disease, both by geographic 

 area and by individual trees 

 (Sluder 1980). These genet- 

 ic studies have notably 

 involved a Southwide seed- 

 source study, begun in 

 1951 under the sponsoring 

 of a committee on southern 

 forest tree improvement. 

 Committee work, such as 

 cone and seed testing 

 services and publication of 

 proceedings of confer- 

 ences, has provided much 

 guidance and stimulation 

 both to genetics research 

 and to reforestation pro- 

 grams of southern forestry 

 agencies (e.g., University of 

 Georgia 1983). 



Several industry -university 

 cooperative tree- 

 improvement programs 

 also have been developed 

 in the South, at North 

 Carolina State University, 

 the University of Florida, 

 and at Texas A. and M. 

 University. Loblolly pine 

 seed orchards established 

 in the North Carolina State 

 Cooperative, for example, 



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