AMOUNT AND DURATION OF GROWTH OF VARIOUS SPECIES OF TREE SEEDLINGS

Abstract

Shoot growth was measured for 11 spp. of tree seedlings grown together in the field at Durham, N. Carolina. The spp. were balsam fir (Abies balsamea), loblolly pine (Pinus taeda), shortleaf pine (P. echinata), slash pine (P. caribaea), red pine (P. resinosa), white pine (P. strobus), white ash (Fraxinus americana), eastern red oak (Quercus borealis maxima), white oak (Q. alba), yellow poplar (Liriodendron tulipifera), and black walnut (Juglans nigra). White ash and yellow poplar made twice as much growth as red and white oak and black walnut. Of the conifers, loblolly pine made the most growth, shortleaf and slash pine made 2/3 as much, and red and white pine and balsam fir made only 1/6 as much growth as loblolly pine. All spp. resumed growth within a few days of each other in late Mar. or early Apr., but various spp. ceased growth at different times from July to Oct. White ash, red oak, white oak and black walnut made about half their growth by May 1 and ceased growth in July or early Aug. Growth of yellow poplar was fairly evenly distributed over every month from Apr. through July and finally ceased in Sept. Growth of loblolly, short-leaf and slash pine was fairly evenly distributed over every month from Apr. through Aug. and finally ceased in Oct. Red and white pine resumed growth little sooner than the southern pines, but made 65% of their growth by May 1, 90% by June 1 and ceased growth in July or Aug. Tree seedlings grew longer in N. Carolina than the same spp. did in New England, but the northern spp. made poor growth and the mortality was high in N. Carolina. In spite of the difference in length of growing season the seasonal distribution of growth for a spp. was similar in New England and N. Carolina. Most spp. resume growth in the spring before danger of frost is past and cease growth in mid or late summer, after growing only 1/2-3/4 of the frost-free season.