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Vol. II

Evergreens of Colorado. By Burton 0.

Longyear, State Forester. 1914*
First Biennial Report of the State

Forester of the State of Colarado.

Second Biennial Report of the State

Forester of the ttate of Colorado.


" D




Evergreens of Colorado


p*of*e*inr opoiviSioN of










HEN the first settlers in Colorado staked their claims along
the streams that issue from the canyons in the foothills or
penetrated the mountain fastnesses in search of grazing land,
they found vast forests of evergreen trees clothing the rugged
mountain sides and reaching down the gulches to the very
border of the plains. The development of this country during
the past fifty years, however, has worked great changes in
these forests. The laying of railways, the construction of bridges, the
development of mining and the building of houses, fences and telephone
lines, have all made their legitimate demands upon them. But other
forces of purely destructive character have also been at work. Insect
pests have killed a great many trees and led the way for the attacks of
such fungi as bring about the decay of timber. Storms of wind, wet
snow or sleet have sometimes uprooted the trees or crushed them to
the earth.

The heaviest toll, however, that has been levied upon our forests in
Colorado has been here, as elsewhere, by forest fires. These have either
consumed the timber, often laying bare the very rock, or licked the
foliage from the trees and left their naked trunks to slowly whiten in
the sunshine and storms of the years that have followed. Some of the
older residents of our state tell of forest fires that burned for forty days
without any attempt being made to check them. Forest fires in the
mountains were to be expected with the coming of dry weather and as
timber was more plentiful than labor, these fires were free to burn them-
selves out. Today much of the magnificence of our mountin scenery is
sadly marred by the ghastly pole patches which mark the location of
these fires where the bare rocks often show like tombstones to com-
memorate the disaster.

In spite of all these drains upon our forest resources, the forests of
pine and cedar, of spruce and fir which remain are still the glory of our
mountains in Colorado. New generations of trees, moreover, are coming
up in many cases to take the place of those that have disappeared and
some future period will see again perhaps the evergreen mantle spread
over the scars that now appear. Moreover, the real worth of our forests
in this country is now being recognized as never before and State and
Nation are uniting their efforts to protect and to utilize in more con-
servative ways the timber that yet remains. No more are fires allowed
to burn and spread through the forests, that have required centuries to
grow, without heroic efforts being made to check them. Throughout
every part of our forest lands today are men whose duties are concerned
with the control of the worst enemy of the forest, the fires. The people
who visit the mountains for pleasure and recreation, too, are becoming
imbued with the true sentiment of forestry so that the menace to our
woodlands from this source is being lessened year by year. It is now

< ' , * *



common knowledge that campfires should be put out instead of being left
to jeopardise the timber and every true sportsman and woodsman can
but take pride in practicing such methods in the mountains as shall not
endanger the forests, in whose shelter lie the pleasures that he seeks.

There are richer pastures, however, to be gained from contact with
the forests than to make them merely a place in which to hunt or fish
or camp. The trees which compose the forests are themselves worthy of
our acquaintance. To know the different species by sight or to be able
to identify them through careful study is an accomplishment that can
but deepen the joy of an outing in the forests of our mountains through
the feeling of intimacy and friendliness which comes to us from the trees.

In the following pages such descriptions of our native evergreens
are given as should enable almost anyone to learn their names and char-
acteristics. This work is not prepared as a scientific treatise of the
subject, but is intended primarily to enable the person without a technical
knowledge of botany to become familiar with our trees and thus gain
that sympathetic attitude toward them which usually accompanies such


Our true forests in Colorado are composed entirely of trees com-
monly called Evergreens. By this term we are accustomed to think of
such trees as the pines, spruces, cedars, firs, and other of similar botanical
characters, but in the southern and tropical forests are to be found trees
of widely different characters from these except that they also retain
green foliage the year around and in this respect they too are Evergreens.
The native evergreen trees of our state, however, all belong to one great
and important family, the Coniferae or Pine Family. Most of the mem-
bers of this family are trees in stature, comparatively few being shrubs.
Among lumbermen they are classed as soft woods, although the hardest
woods among them are much harder than some of the so-called hard-
woods among the broad-leaf trees. With very few exceptions, the foliage
of the trees in the Pine family consists of needle, or awl, or scale-shaped
leaves which remain on the twigs during several years, so that the trees
are never without living foliage. Exceptions to this rule are found in
the bald cypress of the southern states, in the larches of the north and
in the Ginkgo or maidenhair fern tree of Japan. But as none of these
trees are native to Colorado, all of our trees of the Pine family are true

Another characteristic of the trees in this family is the resinous
juice or sap which they possess, and which exudes especially from
wounds made in the bark and sap wood of the branches or trunks. This
is well illustrated in the blazing of pine or spruce trees in which case
the pitch which oozes out, gradually hardens on exposure to the air and
forms the material sometimes used as chewing gum.

The process of turpentine orcharding as practiced in the southern
states consists in cutting box-like cavities into the sides of the trunks
of certain species of pines and wounding the bark and sapwood for

i-:vi-:iMJiiKENs or COLORADO

FiK. 2. I'.ristlc coin- I'inc. ii. (Ii-ovc on Pike's IV;ik. 1>. Small
showing the whitish h;ii'k. . Ti'uiik of an old tree. |. ("ones and
-s, \ i...


some distance above them. The crude turpentine or pitch runs down
into these cups from which it is dipped out when a sufficient quantity
has collected. By a process of distillation, this pitch gives off the spirits
of turpentine, which is volatile, while the common resin or rosin of
commerce is left behind as a solid residue. The wood of some of our
pines often becomes nearly or quite saturated with its own pitch and in
this condition possesses great durability. The so-called pitch posts are
formed in this way and command a high price as compared with the
common type of fence posts.

The most distinctive characters of the members of the Coniferae,
however, are found in the flowers and fruits which they bear. The
flowers are of two kinds, staminate and pistillate. The staminate flowers
are those which produce the pollen. They appear in spring^ aboul the
time that the new foliage pushes out, and are borne in small catkins or
cone-like clusters near the ends of the twigs. Each cluster of stamen-
flowers usually consists of numerous small stamens crowded together
upon a short axis which they completely hide. 'In some species these
staminate cones are about one-half or two-thirds of an inch long and
contain a hundred or more stamens, while in others they are much
smaller and have but few stamens. Each stamen of the cluster con-
sists of a minute double sac filled with the pollen in the form of a yellow-
ish powder. As the tree comes into bloom each little stamen sac splits
open in such a way that the pollen is allowed to sift out into the air.
When in this condition, a light breeze is sufficient to waft the pollen
powder away continuously, while a sudden gust of wind will shake it
out in visible quantity in appearance like sulphur dust. In regions where
large forests of pine occur, this pollen dust is often so abundant, during
the blossoming period, as to lend the impression that a shower of sulphur
has occurred. When seen under the high power of a microscope, the
pollen is found to consist of little grains each of which is composed of
three rounded cells. Two of these cells are air sacs and serve to buoy up
the grains in the air, while they are being wafted along. The shedding
of pollen usually lasts but a few days after which the staminate flower
clusters dry up and fall off, hence are not commonly noticed except bj
the unusually observant person.

The pistillate cones, which are later to bear the seeds, are usually
produced at the ends of very short lateral branches in the upper part of
the tree. Each cone consists of a little axis covered with flattened scales.
These little scales differ in shape considerably in different species, es-
pecially when the cone is mature, and furnish some of the characters by
which the species may be distinguished. Each scale represents a pistil,
that part of a flower which bears the seed. At the base of each pistil,
upon its upper side, are two minute rounded bodies called ovules. These
are the rudimentary seeds and instead of being enclosed by the pistil, as
in most other families of plants, in the Coniferae or pine family, they
are naked or exposed while the tree is in bloom. During the period of
blooming, the pistillate flower-cones stand erect upon the twigs which
bear them, with the tips of the scales spread outward. Some of the



'i 1 1'iin-. n. Tn-c with n i n. - i in-h li'inik. l>. An old
I iHM-illcs, \'._.. il. Muturc. opfii coiK 1 . . Si'cds.


pollen grains, with which the air is at this time filled, are caught upon
these scales and slip downward, thus coming in contact with the ovules
at the base. This constitutes the process of pollination. Soon after
the pistillate cones have been pollinated, the pistil scales close together
tightly to await the process of fertilization. Fertilization in the mem-
bers of the pine family is similar to that in other plants, except that it
is much slower in some of them. During this process, the pollen grains
that have come in contact with the ovules each send out a microscopic
tube which finds its way through a minute opening in the coat of the
ovule. In this way the cell contents of the pollen grain is enabled to
unite with the contents of an egg cell within the ovule. From this union
an embryo plant is formed, and the ovule develops into a seed.

In the spruces and firs the cones are full grown and their seeds are
mature at the end of the first season after blooming. But in the pines
the cones make but little growth during the first season, but grow
rapidly during the second summer and mature their seeds at the close of
the second season after blooming.

In the junipers the pistillate scales, which are few in number, be-
come fleshy and grown together as they mature and thus form the berry-
like fruits characteristic of these plants.

The pine family in Colorado contains at least thirteen species which
grow to the stature of trees, while two more are merely shrubs. These
are grouped into five subdivisions or genera which may be distinguished
from each other by the characters given in the following key.

Coniferae PINE FAMILY.
Key to the Genera Found in Colorado

I. Foliage leaves needle-shaped, single or in bundles of two to five; fruit
a dry, scaly cone; seeds usually furnished with a thin wing.

1. Needles (leaves) in tufts or bundles of two to five, surrounded at
the base by a small sheath of thin scales and placed just above a
little scale-like leaf or bract; scales of the mature cones thick,
hard and woody.

1. Genus Pinus The Pines.

2. Needles (leaves) single, without a sheath at the base, not seated
just above a bract; scales of the mature cones thin, leathery or

A. Needles (leaves) in our species stiff and four-angled, each
one jointed to a small, hard, brownish, stem-like base;
branchlets from which the leaves have fallen rough with the
leaf-bases which remain after the upper part has fallen off;
mature cones hanging or pendulous, the scales persistent.

2. Genus Picea The Spruces.

B. Needles (leaves) flat, falling entirely away and leaving
small rounded scars on the branchlets, which are quite

smooth after the needles have fallen.

a Needles \\iih narrowed stalk-like bast', needle-sears
small ami elliptical across tlie branchlets; mature cones
hanging or pendulous. 1'eathered with three-pointed,
projecting bracts, the scales persistent.

::. (Ji nils I'xi-mlntxitiitt Tin- hou.iilas Firs.

Needles not much narrowed at the base, sears quite
large, circular in outline: mature cones erect, green,
dark purple or blackish, the scales falling separately
fr< >ni the axis.

C.i-iius Ahirn Tlif Malsani Firs.

II. Foliage la\es a u 1-sha ped or scale-shaped, in the latter case entirely
covering the twigs; fruit berry-like, more or less juicy; seeds hard
and bony, without a thin wing.

7,. (J.'inis .1, ',,;/> r.x The .Junipers jiinl CVdars.

i. <;I:M s /'/////* TIII: PINKS.

The pint's form the most important group among the lumber produc-
ing trees. As indicated in the key, they are most easily recogni/ed among
the other members of the Cnnifi rd< by ha\ ing their needles in bundles of
to Ihe with a short sheath at the base. This sheath is composed of
a number of thin, translucent scales attached to a very short stem. This
littb- stem represents a very short branch which bears the bundle of
needles at its apex. This can be easily seen by pulling one of the
bundles of needles from a twig of a pine tree when the little stem,
together with the sheath, comes off with it. Kach of these little branches,
moreover, grows in the angle or axil of a small bract or scale-like leal'
on the twig, which is the normal place for a branch to stand. The
nes of staminate (lowers grow in crowded clusters around the base
ew growth of the season and after they have dried up and fallen
hey leave a bare space on this part of the branch. The pistillate
ones occur singly or in whorls of two to three around the base
present season's growth. They are small and inconspicuous at
d are easily overlooked. After the blossoming period, they de-
very slowly and ha\e only about doubled in size by the end of the
I'urin:,' the second spring, however, they grow rapidly and
sixe i y midsummer, although they retain their green color until
. Toward the close of autumn the color has changed to a
nd the cone scales begin to dry and spread apart. The
are now mature, loosen and begin to drop out. the wind
for many rods from the parent tree. It is possible in some
ns oi three different ages upon the same twig: first those
wering stage, second those which are maturing the seeds,
v, hicli ha\e lost their seeds but still cling to the branch.
of all the pines are thick, hard and woody and in some
ipped with a sharp, curved prickle or spine. Two seeds are
at the base of each scale. The wing of the seed is not
the seed, hut is derived from the upper part of the scale


to which the seeds are attached. When the seeds reach the ground and
become wet with dew or rain, the wings readily separate from them and
leave them to germinate quietly as conditions may favor. Five species
of pines are native to the foothills and mountains of Colorado.


I. Needles, five in a bundle.

A. Scales of the cones tipped with curved prickles.

1. Pinus aristata.

B. Scales of the cones without prickles.

2. Pinus flcxilis.

II. Needles, two or three in a bundle.

A. Needles two and three in a bundle, 3 to 6 inches long.

3. Pinus ponderosa scopulorum.

B. Needles usually two in a bundle, seldom over 2 y 2 inches long.

a. Needles 1^4 to 2% inches long; seeds small, winged.

4. Pinus contorta murrayana.

b. Needles % to 1% inches long; seeds large, apparently

5. Pinus editUs.


Pinus aristata Kiigelm.

The bristle-cone pine is a tree of the high altitudes in the mountains
of Central and Southern Colorado, in Utah, Nevada, and in Southern
California and Arizona. It is a small or medium sized tree of rather
bushy habit, which seldom reaches a height of fifty feet, and with a short,
branched trunk one to three feet in thickness. The bark on young trees
is smooth and greyish white, but on old trunks it becomes broken into
flat ridges covered with small scales of a dark brownish grey color. The
needles are short and are borne in bundles of five. They are crowded
along the branchlets in such a manner as to produce an elongated brush-
like appearance, from which is derived the common name of ''foxtail
pine." The cones are about three inches long and each scale is tipped
with a slender, curved bristle. The wood, which is soft and light with
brownish colored heart wood, is possessed of but little strength and is
seldom used except occasionally for mine timbers and fuel.

In Colorado this tree is only occasionally met with. It grows in
somewhat open groves of rather limited extent and is of but little im-
portance either as a lumber tree or for planting. Above Manitou, on the
slopes of Pikes Peak, are to be found a few small groves of this pine.
In the San Juan Forest of Southern Colorado it occurs in sufficiently large
areas to be cut for railway ties to a limited extent.

Tin- limner pin*- occurs almost throughout the Rocky .Mountain

-ion in ill.- higher elevations, also in Western California on the western

op.~ ot til.- Sierre \e\ada raime. In Colorado it commonly i;rows

t -.\ceii Mi" elevations of 7, .".on and 1 l,u<io feet. It is the piiu 1 which one

mmonly mi'.'is w}i-n approaching timber line and is almost sure

IK- found upon exposed, wind-swept slopes and ridges at !),()()() to

It dci-ivcs its name from the lon^ lateral branches whicth


are so flexible as to enable them to bend readily without breaking. In
general it closely resembles the bristle-cone pine, both in its altitudinal
range and in habit of growth. It commonly possesses the same bushy
form and branching trunk as the foregoing species, although occasional
specimens may be found which possess a tall, straight, unbranched trunk.
It is much more abundant in this state and reaches a greater size than
the bristle-cone pine. The needles of this pine are also borne in bundles
of five, but are about one-half longer than those of the bristle-cone pine
and instead of remaining on the branchlet for twelve to fifteen years as
in that species, in the limber pine they remain only from three to five
years. This gives the branches the appearance of being covered with
short tufts of needles at the ends of the twigs.

In this pine the sheath of each bundle of needles is composed of long,
thin scales which fall away almost before the foliage has reached full
size. Thus in looking at the bundles of needles, the sheath is apparently
wanting except during the early part of the season, when the new growth
is just coming out. The cones are commonly three to five inches in
length, although in some parts of the range of this tree, they are much
larger than this. The cone scales are broadly oval and are entirely des-
titute of prickles. This feature readily distinguishes the limber pine
from the bristle-cone pine. The seeds are about one-third of an inch in
length and ordinarily are wingless.

The bark of young stems and branches is light grey or silvery white.
On old trunks it reaches a thickness of one to two inches and is of a
blackish brown color. In such cases, it is broken into broad ridges by
deep fissures which are often crossed by smaller fissures which separate
the ridges into rectangular plates covered by small scales. The wood is
rather light, soft, fine grained, with pale yellow sap wood and reddish
heart wood. Commercially this tree is of relatively little importance in
this state. It is occasionally used in the manufacture of lumber, mine
posts, railway ties and for fuel. Occasional specimens may be found which
possess straight, unbranched trunks, suitable for posts or for sawn lumber.

Pin us pondcrosa scorpulorum Engelm.

This is the Rocky Mountain form of Pinus ponderosa, commonly
known as bull pine and western yellow pine, a tree which extends from
the western Rocky Mountain region to the Pacific slope and from British
Columbia to western Texas and Mexico. It is the common pine of the
foothills and lower mountain slopes in Eastern Colorado. In some places,
for example along the Divide which extends eastward for many miles
between Denver and Colorado Springs, this pine reaches well into the
plains region. West of the Continental Divide the yellow pine occurs
principally in the southwestern quarter of the State, where it reaches its
best development as a lumber tree. Among the mountains, the rock pine
commonly leaves off at an altitude of about 8,500 feet, although occasional



Fig-. 5. Yellow Pine. Mature tree, open-grown type, 50 feet tall, trunk
25 inches in diameter.


specimens may be found much higher than this. It is capable of growing
in drier situations than most of our other conifers, and is therefore the
common type of tree found upon southern and western slopes. Upon dry
and rocky ridges this pine grows in low rounded form with short, stocky
trunk, but when more favorably situated as to soil and moisture, it
reaches a height of 80 to 100 feet and a trunk diameter of two to four
feet. In such cases, the trunk loses its lower limbs in early age and
forms clear trunks adapted to the better class of lumber. The needles
are dark green in color and are borne in bundles of two to three on the
same twig. Their length is from three to six inches.

The bark on trees of moderate age is broken into rounded ridges,
covered with small brownish or nearly black scales. In this condition,
the tree is often known as Black Jack among lumbermen. In trees that
have reached two feet in diameter, the bark usually divides into broad
plates which extend up and down the trunk and are covered with cinna-
mon red scales, due to the disappearing of the outermost layers. Under
such conditions, the bark acquires a thickness of from one to three inches.
The sap wood is nearly white, while the heart wood takes on a light red
color. It is heavy and strong, but differs much in quality and is apt to
be quite knotty unless sawn from very large clear trunks. The botanical
name, ponderosa, refers to the great size and heavy weight of this timber.

The cones in our region are usually 2 % to 3 inches in length and
the thick, hard scales are tipped with slender prickles, which become
easily broken off after the cones have opened to discharge the seeds.
The seeds are about one-quarter inch long with wings about one inch in
length. The seeds germinate readily and the seedlings are able to with-
stand the direct sunlight, making this one of the easiest of our native
evergreens to raise from seed. This is our most important native lumber
tree in Colorado and produces the best quality of lumber in the matter
of strength and durability. While it is still common throughout the
eastern foothills of the state, the most extensive forests of this tree were
at one time to be found in the southwestern portion of the state in the
Mesa Verde region where extensive lumbering operations have been
carried on. Much of this cut-over land is now being reforested, however,
by a natural growth of this tree.

contort a mnrrat/an(t Engelm.

The lodge pole pine, also improperly called white pine, derives its

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Online LibraryBritish Museum (Natural History). Dept. of ZoologyPamphlets on forestry in Colorado (Volume 2) → online text (page 1 of 10)