Return to Native Trees of the Southern Rocky Mountains

Our course lay along the bank of Ham's Fork, through a hilly and stony, but not a rocky country; the willow flourished on the margin of the stream, and occasionally the eye was relieved, on scanning the plain, by a pretty clump of cottonwood or poplar trees. - John Kirk Townsend, Narrative of a Journey across the Rocky Mountains, 1834.

On the 18th we commenced the Fort which was a stockcade 80 ft square built of Cotton wood trees set on end sunk 2 1/2 feet in the ground and standing about 15 feet above with two bastions 8 ft square at the opposite angles. On the 4th of August the Fort was completed. And on the 5th the Stars and Stripes were unfurled to the breeze at Sunrise in the center of a savage and uncivilized country. - Osborne Russell, Journal of a Trapper, 1834.

 

The Narrowleaf cottonwood is the cottonwood found in the Rocky mountains proper, growing along streams, at elevations from 5000 feet to over 9300 feet, throughout the mountains of Wyoming, Colorado, and northern New Mexico. The Narrowleaf can grow to 60 feet in height and 3 feet trunk diameter, but rarely is more than 2 feet in diameter. The crown is somewhat tapering or pointed, unlike the broad crown of the Plains cottonwood. The branches tend to be more erect than the spreading thick limbs of the Plains cottonwood. The branches of the Narrowleaf cottonwood are more slender than those of Plains cottonwood, often with smooth pale bark, while the Plains cottonwood has gray furrowed bark right out to the twigs.

The narrow leaves are distinctive, in some cases like willow leaves in outline. There is a great variety in leaf form, sometimes very long and thin, other times rather broad like the leaves of the Lanceleaf cottonwood. Narrowleaf has short leaf stalks whereas Lanceleaf has long stalks.

The scientific name is Populus angustifolia , the narrowleaf poplar. Narrowleaf cottonwood was described by Lewis and Clark in 1805 on the Missouri River, as "a species of cottonwood with a leaf like that of the wild cherry." It was given its scientific name and first described for science by Edwin James, the naturalist on the Stephen Long expedition to Colorado, on July 4, 1820. James recognized it as a tree Lewis and Clark had encountered. The party was camped near Brighton, Colorado.

This tree looked down on the earliest fur trappers, and Fifty-niners seeking golden bonanza. It shaded the silver cities and the railroad towns, leaning over rushing streams in narrow canyons echoing to the sounds of narrow-gage steam locomotives freighted with ore and hopes. Silk-hatted mineral kings and struggling mineworkers strolled beneath Narrowleafs, the same trees growing today in Georgetown and other boom-time settlements. Many of the properties of the glory days of the early west are vanished and gone now, but the trees remain as they were.

Leaves Leaf blades variable in proportions, even on the same stem, but usually fairly slender, pointed at both ends, 1 to 5 inches long; usually over 2 inches long; sometimes reaching 6 inches or more on young sprouts. Width commonly 3/8 inch to 1.5 inch, occasionally more. The leaf edges are finely toothed, usually paer on underside.

Leaf stalks are short - 0.5 to 1 inch long - not over one third the length of the blade - and slightly flattened or even notched on the upper surface; otherwise round in cross section. Stalks may have reddish tinge. The short stalk distinguishes this leaf from the Lanceleaf cottonwood leaf which has a blade shape like some Narrowleaf cottonwood leaves, but a long stalk.

In late winter buds are dark brown and coated with a gummy resin with an aromatic odor; 1/4" to 1/2" long. In winter the resin is hard and yellow and can be chipped off, and the odor is not noticeable. The buds have five overlapping bud scales (willows only have one), and are sharp pointed and slender, not plump like those on Plains cottonwoods. The buds are only a little thicker than the twigs they grow from.

Leaves might be confused with the leaves of the Peachleaf willow, but other features are different.

Bark The bark is smooth, unbroken, and pale green or whitish in young trees, and gray and furrowed trunk like Plains cottonwood bark in large old trees. The bark furrows on mature Narrowleaf trees are not quite so deep and do not extend nearly so far along the branches as is the case for Plains cottonwood, leaving areas of smooth pale bark. The stipule scars (downward v-shaped lines on bark where branches emerge) are often prominent and dark.