d (_Populus angustifolia_) crowds
the water's edge, here and there mingling with red-fruited hawthorns
and wild plums (_Prunus Americana_). A short distance from the stream
the sumac stands brilliant in the autumn, and a little farther away
are clumps of greasewood and sagebrush and an occasional spread
of juniper. Here and there are some forlorn-looking red cedars and a
widely scattered sprinkling of stunted yellow pines (_Pinus scopulorum_).

At an altitude of six thousand feet the yellow pine acquires true tree
dignity and begins to mass itself into forests. When seen from a
distance its appearance suggests the oak. It seems a trifle rigid,
appears ready to meet emergencies, has a look of the heroic, and
carries more character than any other tree on the Rockies. Though a
slender and small-limbed tree in youth, after forty or fifty years it
changes slowly and becomes stocky, strong-limbed, and rounded at the
top. Lightning, wind, and snow break or distort its upper limbs so
that most of these veteran pines show a picturesquely broken top, with
a towering dead limb or two among the green ones. Its needles are in
bundles of both twos and threes, and they vary from three to eight
inches in length. The tree is rich in resin, and a walk through its
groves on an autumn day, when the sun shines bright on its clean
golden columns and brings out its aroma, is a walk full of contentment
and charm. The bark is fluted and blackish-gray in youth, and it
breaks up into irregular plates, which on old trees frequently are
five inches or more in thickness. This bark gives the tree excellent
fire-protection.

The yellow pine is one of the best fire-fighters and lives long. I
have seen many of the pines that were from sixty to ninety feet high,
with a diameter of from three to five feet. They were aged from two
hundred and fifty to six hundred years. Most of the old ones have
lived through several fires. I dissected a fallen veteran that grew
on the St. Vrain watershed, at an altitude of eight thousand feet,
that was eighty-five feet high and fifty-one inches in diameter five
feet from the ground. It showed six hundred and seventy-nine annual
rings. During the first three hundred years of its life it averaged an
inch of diameter growth every ten years. It had been through many
forest fires and showed large fire-scars. One of these it received at
the age of three hundred and thirty-nine years. It carried another
scar which it received