LIFE HISTORY OF LODGEPOLE PINE IN ROCKY MOUNTAINS. lI] 
tive is very apt to be overestimated. One reason for this is that 
natural reproduction has often been credited to wind-sown seed, when 
in reality the seed was already present on the area in sealed cones. 
Hodson, as the result of a study on a large number of cut-over areas 
in Montana and Wyoming, concludes that “the largest amount of 
seed falls within a hundred feet of the seed tree, and the radius of 
effective reproduction is much less than is commonly supposed.” 
Clements states that the distance to which seed is carried by the 
wind “ was never found to exceed 164 feet.” Undoubtedly the dis- 
tances seeds are carried varies considerably with the topography and 
the situation of the seed trees. Trees on a ridge exposed to high winds 
will distribute seed the maximum distance. Until more definite in- 
formation is available, it is safe to assume that wind distribution 
~ should not be relied upon for distances of more than 150 to 250 feet, 
according to the character of the situation. 
REQUIREMENTS FOR NATURAL REPRODUCTION. 
Owing to its intolerance of overhead shade, lodgepole pine will not 
reproduce satisfactorily without considerable direct light. Although 
_the seed will germinate with a vary small amount of light, the young 
seedling soon dies without it. In mature stands a heavy thinning 
which reduces the crown density to about one-half is usually neces- 
sary to permit a fair amount of reproduction to start and thrive. 
Where the stand is opened by the removal of groups of trees on areas 
of 3 or 4 square rods or more, reproduction will usually start and 
erow well in the openings. Reproduction starting in this manner is 
more apt to be uneven aged and better divided into height classes, and 
consequently in less danger of stagnation, than in the dense, even 
aged stands of uniform height which so often follow fire. Vigorous 
young growth has been observed under stands in which a heavy and 
uniform thinning had been made, causing the forest to resemble one 
undergoing regeneration by the shelterwood method. In stands of 
only moderate density, however, seedlings are apt to be spindling and 
slow of growth. 
The most favorable seed bed for germination of lodgepole pine 
seed is a mineral soil with plenty of available heat and moisture. 
Needles and undecayed humus are apt to dry out rapidly in the 
spring, before the rootlets of most of the seedlings can reach the 
mineral soil. That mineral soil is not always necessary for germina- 
tion, however, is shown by the fact that on old cuttings in Montana 
where there has been no fire, seedlings apparently start indiscrim- 
inately on patches of mineral soil and in small clumps of pine grass 
1 Silvical Notes on Lodgepole Pine, by E. R. Hodson, in Vol. III, No. 1, of the Proceed- 
ings of the Society of American Foresters. 
