Tag: Mountain Pine Beetle

Limber Pine—Branches Flexible Enough You can Tie them in Knots

The tree grows under conditions which may prove too harsh for other species.

Limber pine (Pinus flexilis) is another species which may be susceptible to damage from the pine beetle. Like most other trees, this species has a number of alternate names, including Rocky Mountain pine. This conifer is native to the western states as well as the two westernmost Canadian providences.

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Trunk of the limber pine

In Colorado, it is found from elevations of 5000′ to 12,000′.  It is also native to Utah where it is reported to grow from elevations of 4000′  to 11000′. Limber pine in North Dakota grow below 3000′. The groves of trees in North Dakota are thought to have arisen from seeds carried to the area by various Native Americans.

Limber pine survive stressors which may prove too harsh for other species. For instance, it is able to grow under dry conditions. The bendable property of its branches may allow it to survive in avalanche prone areas and this trait may help with slope stabilization as well as runoff control. Limber pines also have deep taproots, which help with resistance to wind. This species provide food for rodents and birds, such as the Clark’s Nutcracker. In turn the seeds are too large to be blown far by the wind; birds, then are a means of distribution. OLYMPUS DIGITAL CAMERA

Although lumber from Pinus flexilis is of little commercial value today, in the past it was used in mines, as railroad ties, and as firewood. In herbal medicine the resin may be used like that of other pines—as an antiseptic and to help with respiratory conditions. The seeds can also serve as a food source for humans.

Limber pines are a long-lived species, which may not reach maturity until 200 years. (North American Trees, Preston and Braham.) Some of the oldest trees may be well over 1500 years. Even though some members of this species grow on windy ridges causing  twisting and stunting, others may approach sixty feet in height.

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Leaves of the limber pine

Pinus flexilis belongs to the the group of pines with their needles in bundles of five. These leaves grow to be between 2.5 and 3.5 inches in length. The female cones are green prior to maturity and may grow as long as seven inches.

Like many conifers of the mountain west, the limber pine may be affected by climate change and damage by various pests, including mountain pine beetles; a fungus which causes white pine blister rust; and drawf mistletoe. The fungus spread from Asia to Europe in the 1860s. It made its appearance in Wyoming on limber pines in 1970 and by the late 1990s was found in Colorado as well.

To find the tagged LIMBER PINE (Pinus flexilis) in the arboretum, C182, start near the SE corner of Sheldon Drive and City Park. A row of trees, including ashes and conifers, runs more or less parallel to City Park Drive. The limber pine is in the middle of a small cluster of conifers. In the middle of an open area is a park bench which is west of this small grove of trees. Another landmark might be the exercise station near this same corner. You could walk from there along the row of trees to find the pine. 

This specimen was planted in 1981 when it had a diameter of 8″. In the flesh it does not appear quite as scraggly as it does in the winter photo.

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Limber pine in the snow

 

 

 

 

 

 

 

 

Ponderosa Pine—Or maybe you call it Bull Pine, Black Jack, Western Yellow Pine, or One of Many Other Names

Three subspecies have been identified through-mitochondrial DNA.

What a surprise! The ponderosa pine is one of the first trees with a distribution in most of the WESTERN part of the US and part of Canada! According to National Audubon Society Field Guide to North American Trees (Western Region,1980) this is the most widely distributed pine in the United States. Its range includes British Columbia. In Colorado the species covers about 2 million acres. The Colorado State Forest Service website, also says this is about 8 % of the forested area of the state. Ackerman mentions the tree grows from about 4600-9600 elevation. (Flora of Colorado, 2015.)

Like many of the other trees discussed in this blog, the ponderosa pine appears to be a  complex species. Even its “discovery” may be controversial with some sources citing 1820 and others mentioning 1805 passages from Lewis & Clark Expedition. According to the Gymnosperm Database, three subspecies have been determined through mitochondrial DNA. The three varieties appear to have geographic distinctions, too. The groupings include the northernmost trees, Pacific trees, and the more interior trees. Chris Earle, the author of conifers.org, indicates there does not seem to be interbreeding where the northern family shares habitat with the Pacific group.

This species are normally tall, straight trees with the trunk free of lower branches. OLYMPUS DIGITAL CAMERA

The Ponderosa pine is one of the three highest producing lumber species in the western United States. Its wood is used for everything from veneer to construction. Apparently the trunks were sometimes used as flagpoles as at least one story of the origin of the name Flagstaff in Arizona, involves a ponderosa pine displaying the US flag.

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Ponderosa pine needles showing length and the bundles of two

The ponderosa pine provided Native Americans with food, medicine, and transportation in the form of canoes or snowshoes, as well as construction material and dyes. Almost the entire plant could be eaten. The many medicinal uses included the usual ointment for infections, skin conditions, and pain control. A less commonly mentioned use of tree parts in medicine was needles being tools for dermatological and gynecological reasons. The rosin left over after turpentine distillation is used on violin bows.

Male seed cones on Ponderosa pine
Female cones on Ponderosa pine with male cones in the background

Monumental Trees lists the oldest ponderosa, located in Yosemite, to be more than 1020, although a 1914 record of a tree in southwest Colorado was measured at 1047 years. As might be expected for a tree that is only native to North America, the United States also has the widest and tallest trees. The record for height is a tree in Oregon measured to be over 268 feet tall.

At least four species of Ips beetle can infect ponderosa pines. These beetles normally attack dying or stressed trees, but when there are excess beetles they may attack and kill healthy trees. For the eighteen years from 1996 to 2014, the mountain pine beetle damaged over 3 million acres of trees in  Colorado alone. Although these beetles have always destroyed some trees, according to the National Park Service recent outbreaks had become more severe. According to the Colorado State Forest, though, the problem may have begun to abate in 2017. In the past, long term cold snaps killed off many of the noxious beetles, but with warmer winters, good forestry management techniques must be employed, including thinning of trees, and solar treatment of logs from downed trees to help control the destructive insects. With climate change, the forests of the West, as well as the rest of the world, may be changing.

The Ponderosa pines on the Fort Collins Self-guided Tree Tour are easy to find. They still sport the rustic signs first used to identify the trees.

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The appearance of the bark changes as the tree ages

To find  C152 Ponderosa Pine (Pinus ponderosa), drive to the west end of Oak Street, just east of the intersection with Bryan Street. The trees are in front of the pottery studio.