This is a blog about the native conifers of the Pacific Northwest. It is a companion to the Northwest Conifers site. The blog will focus on timely and interesting details about our conifers, their connections to the rest of the environment, and our connection to them.

Sunday, September 20, 2020

Focus on Western White Pine

Western white pine doesn’t have the charm and stature of ponderosa pine with its golden bark and lofty height, but this white pine does have many subtle, attractive qualities. It grows straight and tall when given a chance, sometimes to a height of nearly 200 feet. The needles grow in bundles of five and have a blue-green color. The cones have a distinctive banana shape and are longer than any other Northwestern conifer except sugar pine cones. The gray bark breaks into rectangular plates on large trees. Another distinctive feature is the sticky resin on the cone scales. You will often see cones on the ground under a western white pine, and if you pick one up, don’t be surprised if you have sticky fingers. You were warned.

The scientific name of western white pine is
Pinus monticola, named by David Douglas after he found it growing on Mount St. Helens. The species name is Latin for “mountain dweller,” and that is where you can find it, growing throughout the mountains of the Pacific Northwest. It grows in the Cascades and in the Coast Range at elevations of 3000 to 5000 feet. In Washington and British Columbia, it grows right down to sea level. It also grows in northeast corners of Oregon and Washington, and in northern Idaho. It is the state tree of Idaho, where it’s sometimes called “Idaho pine.” In California, it grows in the Siskiyous and Sierras.

You may be surprised to find western white pines growing in the Coast Range of Oregon, but you can find some in the higher elevations. Some young ones grow in the Tillamook Forest near the top of the Storey Burn Trail, west of Storey Burn Road. In Portland, you can see several large western white pines at Hoyt Arboretum. They are growing along the Bristlecone Pine Trail. They are easy to identify by the labels on the trees and the banana-shaped cones on the ground. Again, don’t pick them up if you don’t want sticky fingers.

Western white pine was once abundant in its range, but disease and logging have greatly reduced its numbers. As with many other white pines, the bane of western white pine is white pine blister rust, a fungus introduced in North America from Europe over 100 years ago. Although the extensive stands of western white pine have been decimated by blister rust, the species has developed some resistance to the disease, and the Forest Service has a program for breeding rust-resistant trees. For more information, look here. Bark beetles also attack western white pine, especially after they have been weakened by blister rust.

Western white pine wood is described as nonresinous — no surprise, since it seems to send all that sticky resin to the cones. The wood is soft, straight and stable in character, which make it desirable for making moldings and window and door frames. The wood is light, attractive, and easy to work, making it ideal for wood carving. In the past, it was the primary source of match sticks.

Pollen cones

There appear to be few genetic differences between western white pines in different locations in the Pacific Northwest. So you can collect seeds from one habitat or elevation and successfully grow them elsewhere. The trees can readily adapt to different growing conditions. However, California populations do seem to be genetically distinct from those in the Northwest. The California trees are more resistant to white pine blister rust.


More info

Northwest Conifers
Gymnosperm Database 
USDA: Silvics of North America
Coniferous Forest


Wednesday, September 2, 2020

Alpine Conifers

The timberline in the mountains is a special place for conifers. Below the timberline, the trees grow tall. Visitors walk among the large trunks in deep shade under the canopy high above. However, at the timberline, the conifers are transformed into a completely different form. The timberline is often a park-like area that conifers share with grasses, shrubs and wildflowers. If the towering trees in the forests below remind us of the pillars of a great cathedral, the trees at the timberline elicit visions of heaven. Indeed, when the wildflowers bloom in summer, the streets there are paved with gold, as well as blue, red, and white wildflowers.
McNeil Point
McNeil Point on Mount Hood
Mountain hemlock

Yet, the beauty of these trees is forged in adversity. It is a wonder that conifers can survive at these high elevations where they can be completely covered in deep snow, where they can be blasted with ice crystals in fierce winds, and where their branches and even their roots can be frozen by severe winter temperatures. To survive here they must adapt. The short branches of subalpine fir and Pacific silver fir keep them from breaking when covered in snow. Mountain hemlock branches are bendable and small trees that are covered with snow bend to the ground and pop back up in summer. The drooping branches of Alaska cedar just don’t collect much snow. On the other hand, many species depend on deep snow to protect their roots from freezing. The snow also protects trees from high winds that would blast them with ice crystals.
Subalpine fir
The conifers that can survive these harsh conditions often grow in small clumps with just one or two larger trees, surrounded by a thicket of small trees. At the highest elevations, these conifers may grow in a stunted, krummholz form, often unrecognizable from their tall relatives below.
Mountain hemlock and whitebark pine

Whitebark pine
In his book, Timberline, Stephen Arno explains how these alpine conifers survive the extreme conditions at the timberline. Curiously, the winter conditions are not the limiting factor for these trees. Summer is the critical time when conifers must prepare for the winter. They must have enough time in the brief summer to put on new growth and for the new growth to become mature. Arno describes this maturation process as “hardening off of shoots.” This hardening enables the new growth to survive the winter. (Arno, p. 57)

Contrary to common sense, it is not only the cold of winter that is destructive to alpine conifers. It is also … wait for it … heat. Conifers prepare for cold weather in the fall when temperatures begin to drop below freezing. If needles do not mature in the summer, they can be damaged by frost. But warm weather can dry out the new growth in winter, especially when it is windy or sunny. This drying or “winter desiccation” can be fatal to needles that have not had a chance to mature in summer. This hardening protects the needles, enabling them to retain their moisture. You can look at damaged needles and tell whether they were damaged by frost or winter desiccation. Frost damaged needles shrivel and then turn black. Needles damaged by winter desiccation turn orange-brown. (Arno, p. 58)
Mount Rainier
The factor that determines the upper elevation limit for conifers is not how cold the winters are. Rather, it is how cold the summers are. Summer must be warm enough and long enough for new growth to become hardened to survive both frost and desiccation.

Late summer is a great time to visit alpine areas. The snows have melted, and wildflowers are taking advantage of their brief summer and blooming in abundance. These parklands of life living on the edge are unmatched in stunning beauty themselves. Also, the view there is often framed by picturesque, snow-capped mountain peaks.
Mount Hood
The most common conifers at the timberline are mountain hemlock, subalpine fir and whitebark pine. Look closely on the ground, too. You may see a mat of common juniper. To identify all the trees you find at the timberline, print this page: Alpine Conifers
Common juniper