RATE OF GROWTH. 27 



soil, moderately warm and moist (uot wet), in which the seeds are covered at a depth not 

 "exceedingtwice th*ir own diameter, and, further, protection of the young seedlings against the 

 hot sun and drying winds. Special attention is required in the nursery to avoid undue moisture 

 when the seedlings appear above the ground, as they are often attacked by a destructive disease 

 very common in propagating beds, known as "damping oil'." If, however, no adverse iulluences 

 have interfered with its normal development, the young plant presents itself after some mouths' 

 growth as a slender shoot, crowned by the persistent ^eed leaves, in the midst of which is the 

 terminal bud, the latter having already formed numerous short foliage leaves. No branches have 

 appeared, and the foliage leaves arise singly instead of in groups of five. The whole plant, as 

 it appears at this time, with its slender stem and long taproot, is represented, natural size, in PI. 

 IX, drawn from a specimen obtained in the pine woods of Michigan, in September, 1886. Earlier 

 and later stages of development of the seedlings are shown in the same plate (1, 2, 3, 4, 5, 6) drawn 

 from nursery specimens. 



For the first two or three years the growth of the seedling is slow, and is so greatly influenced 

 by its surroundings as to make it impossible to give averages that will fairly represent the yearly 

 increase in height and diameter. 



Thus, a healthy seedling, three years old, from the nursery TOW, measured 4.6 inches, while a 

 self sown specimen from Maine, four years old, measured only 2.7 inches in height. But, if the 

 circumstances are favorable, after the third year a growth of one to several inches is made each 

 year, and from this time on the yearly increase in height is clearly defined by alternating nodes 

 and internodes, a whorl of branches being formed at each node. 



The leading shoot is from the first the most conspicuous and the most important part of the 

 plant, branches being manifestly subordinate, dying off in later years as in other conifers. The 

 rate of growth being of most important practical interest, much space has been devoted to this 

 part of the developmental history. 



The tree rarely reaches a height of more than 160 feet and diameters of more than 40 inches, 

 more usually 30 inches. Occasionally these dimensions are exceeded; trees of 200 feet in height 

 and of 60 inches in diameter have been reported. The largest actually measured by the Division ot 

 Forestry was 48 inches in diameter breast high and 170 feet in height, with an age of about four 

 hundred and sixty years, containing 13* cubic feet of wood, standing in a group of similarly old 

 and large pines in Michigan. Another tree of this group, with 47 inches diameter and 162 feet 

 in height, contained 855 cubic feet, being less tapered. 



EXPLANATION OF PLATE IX. 



1. Seedling as it first appears with seed coat attached to seed leaves. 



2. Seedling with seed coat detached. 



3. Seedling with seed leaves and primary foliage leaves disposed singly on stem; five months old. 



4. Seedling in its second year, showing primary leaves and secondary leaves (mature form), the latter in clusters 



of fi ve. 

 5 and 6. Seedlings three to five years old. 



RATE OF GROWTH. 



The following statements regarding the progress and rate of growth of White Pine are based 

 mainly upon the very comprehensive data collected by the Division of Forestry in Maine, New 

 Hampshire, Massachusetts, Pennsylvania, Michigan, and Wisconsin. These data, involving meas- 

 urements and detailed analyses of over seven hundred trees grown under varying conditions, 

 together with records of the conditions under which they grew, and the amounts of timber which 

 were produced under such conditions per acre, are presented fully in the tables, with accompanying 

 notes, in the Appendix to this monograph. It appeared, however, desirable to present in the text 

 not only the generalizations and conclusions, but also some typical cases. Some other measure- 

 ments, made before this comprehensive investigation and recorded by the writer in his original 

 manuscript, are .also produced. 



HEIGHT GROWTH. 

 SEKDLING STAGE. 



The growth of the seedling is variable, according to the conditions under which it grows. In 

 the forest it is much slower than under cultivation, as would naturally be expected. The common 



