147 



PINE BREEDING IN THE UNITED STATES 



J. W. DUFFIELD, PALMER STOCKWELL 



Trees fit into the general rule that 

 the plants and animals which nature 

 gave us have not been considered quite 

 good enough. For millions of years, it 

 is true, nature has developed a breath- 

 taking variety of forms, each wonder- 

 fully adapted to its surroundings. 

 Changes in climate or the conforma- 

 tion of the earth's surface have caused 

 the extinction of some forms and the 

 development and migration of others. 

 But during the long development of 

 civilization man has learned to alter 

 some of the myriad forms of life about 

 him, making them better suited to his 

 needs. 



Centuries of breeding have devel- 

 oped livestock and plants that have 

 special value, but only recently has man 

 applied his knowledge of breeding to 

 the development of better forest trees. 

 Much of this work has been done with 

 pines because of their wide distribu- 

 tion and their value for many wood 

 products. Today pine-breeding re- 

 search has progressed to the point that 

 promising pine hybrids exist for each 

 of the major timber-producing regions 

 in the United States. 



How has this point been reached? 

 And what are the results now ready for 

 trial? 



As long as man used only an occa- 

 sional tree he was not concerned with 

 replacing it. But when he began to 

 fell sizable sections of the forest, he 

 observed that the succeeding cover 

 was often different from the one he 

 had removed. To insure another tree 

 crop of the type harvested, he often 

 found it necessary to sow seeds or plant 

 young trees. This practice foreshad- 

 owed the beginning of forest-tree im- 

 provement, perhaps 500 years ago. In 

 his early planting operations, the for- 

 ester soon learned that certain local 

 races of trees surpassed the average. 



American foresters, influenced in 

 their early work by European forestry, 



were quick to import one of Europe's 

 leading timber trees, the Scotch pine, 

 a species that, despite its name, extends 

 from the British Isles into Siberia and 

 from the Arctic Circle as far as south- 

 ern Austria and the Iberian Peninsula. 

 Foresters in New York State found 

 that Scotch pine from the shores of the 

 Baltic Sea made a respectable tree in 

 their plantations, while the same spe- 

 cies grown from south German seed 

 produced gigantic corkscrews and 

 other bizarre and useless forms. Forest- 

 ers in almost every European country 

 have studied Scotch pine from various 

 sources and have come to recognize an 

 almost limitless number of local races, 

 each fitted by natural selection into 

 the mold of the local climatic and soil 

 conditions. 



In the past few years, several workers 

 in the Forest Service, notably R. H. 

 Weidman, T. T. Munger, and W. G. 

 Morris, have completed studies of local 

 races of ponderosa pine and Douglas- 

 fir, two of our most widespread and 

 important western conifers. An inter- 

 esting study of altitudinal races of pon- 

 derosa pine in the Sierra Nevada of 

 California was initiated by L. Austin, 

 also of the Forest Service. Work of 

 this kind has led foresters to the realiza- 

 tion that careful comparative studies of 

 climate and soils and of the growth of 

 local races should enable them to pro- 

 ceed with more certainty in their work 

 of reforestation. 



In recent years most spectacular re- 

 sults have been achieved by this analyt- 

 ical approach in parts of Italy, South 

 Africa, Australia, and New Zealand 

 regions that have rather meager na- 

 tive conifer forests and only moderate 

 rainfall, most of which falls in the win- 

 ter. Such a climate resembles that of 

 coastal California, where a few small 

 patches of natural Monterey pine sur- 

 vive. The fossil record shows that this 

 pine once occupied a much larger area, 



