ed a number of poles that
averaged two inches in diameter at the ground and one and one half
inches fifteen feet above it. These poles averaged forty feet high and
were sixty-seven years of age. Others of my notes read: "9728 trees
upon an acre. They were one hundred and three years of age, two to six
inches in diameter, four and a half feet from the ground, and from
thirty to sixty feet high, at an altitude of 8700 feet. Soil and
moisture conditions were excellent. On another acre there were 4126
trees one hundred and fifty-four years old, together with eleven young
Engelmann spruces and one _Pinus flexilis_ and eight Douglas firs. The
accumulation of duff, mostly needles, averaged eight inches deep, and,
with the exception of one bunch of kinnikinick, there was neither
grass nor weed, and only tiny, thinly scattered sun-gold reached the
brown matted floor."

After self-thinning has gone on for a hundred years or so, the ranks
have been so thinned that there are openings sufficiently large to
allow other species a chance to come in. By this time, too, there is
sufficient humus on the floor to allow the seeds of many other species
to germinate. Lodge-pole thus colonizes barren places, holds them for
a time, and so changes them that the very species dispossessed by fire
may regain the lost territory. Roughly, the lodge-pole will hold the
ground exclusively from seventy-five to one hundred and fifty years,
then the invading trees will come triumphantly in and, during the next
century and a half, will so increase and multiply that they will
almost exclude the lodge-pole. Thus Engelmann spruce and Douglas fir
are now growing where lodge-pole flourished, but let fire destroy this
forest and lodge-pole will again claim the territory, hold it against
all comers for a century or two, and then slowly give way to or be
displaced by the spruces and firs.

The interesting characteristic of holding its cones and hoarding seeds
often results in the cones being overgrown and embedded in the trunk
or the limbs of the trees. As the cones hug closely the trunk or the
limbs, it is not uncommon for the saw, when laying open a log at the
mill, to reveal a number of cones embedded there. I have in my cabin a
sixteen-foot plank that is two inches in diameter and six inches wide,
which came out of a lodge-pole tree. Embedded in this are more than a
score of cones. Probably most of these cones were of the first crop
which the tree produced, f