Geographic Source of Loblolly Pine Seed

The importance of the geographic source of seed used in forest planting has been stressed in American forestry literature for the past 30 years, but largely on theoretical grounds or on the basis of European experience. Douglas fir and ponderosa pine are practically the only American species for which definitive results of studies of geographic strains, based on plantations within the United States, have hitherto been published. The following article presents results obtained in plantations of loblolly pine established in eastern Louisiana in 1926 with seed from 4 geographic sources. At 15 years in plantation the local strain had produced more than twice as much pulpwood per acre as either of the 2 most distant strains. Conspicuous and economically important differences in resistance to disease also had appeared among the different strains, even between 2 from sources with almost identical climates.