Common Insect Pests and Diseases of Shore Pine on the Oregon Coast (Pinus Contorta Douglas Ex
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EM 9008 • September 2010 Common insect pests and diseases of shore pine on the Oregon coast (Pinus contorta Douglas ex. Louden var. contorta) James E. Reeb and David C. Shaw hore pine (figure 1) is a subspecies of Shore Pine in Oregon lodgepole pine that inhabits the coastal Lodgepole pine has the widest range of Sstrip in Oregon. Insect pests, diseases, environmental tolerance of any North American and nonbiological (abiotic) factors may have conifer. Because of this, the species is widely an impact on growth, visual appearance, and distributed throughout western North America. productivity of trees. However, shore pine is Lodgepole pine is a two-needled pine that is quite a vigorous tree and tolerates conditions characterized as a hard pine or a yellow pine. most other trees could not. Perhaps the most Lodgepole pines can be found growing in the Rocky commonly observed problems of shore pine are Mountains, Sierra Nevada, and the mountains and salt damage and shade (lack of full sun), both coasts of Oregon. Their range extends from Alaska factors that may be confused with insect or to Mexico. It is the only conifer that is native to both disease damage. Biotic problems such as the pitch Alaska and Mexico. Lodgepole pines vary in growth masses of the sequoia pitch moth, the roundish rate and form, depending on location. Lodgepole swellings (caused by western gall rust), reddish pine has four geographic varieties: P. contorta var. needles and poor needle retention (caused by contorta, the coastal form known as shore pine, foliage diseases) and the smaller pitch masses beach pine, or coast pine; P. contorta var. bolanderi, a at the base of the tree (caused by red turpentine Mendocino County White Plains form in California beetle) are commonly observed but rarely kill the called Bolander pine; P. contorta var. murrayana tree. In this publication, we review the general in the Sierra Nevada, called Sierra lodgepole pine nature of shore pine in Oregon and the common or tamarack pine; and P. contorta var. latifolia, the nonbiological, insect pest, and disease problems inland form often referred to as Rocky Mountain that impact tree health. lodgepole pine or black pine. Although the coastal form grows mainly between sea level and 2,000 ft (610 m), the inland form is found from 1,600 to 12,000 ft (490 to 3,660 m). James E. Reeb, Extension forester, Lincoln County Extension, Oregon State University. David C. Shaw, Extension forest health specialist, Department of Forest Engineering, Resources, and Management, Oregon State University. Unless otherwise noted, photos are by one of the authors, © Oregon State University. Figure 1. Shore pine on Battle Rock in Port Orford, Oregon. In much of its range lodgepole pine is an important commercial timber species. Lodgepole gets its name from the fact that Native Americans used its straight slender boles as poles for their teepees. It is an aggressive and hardy tree capable of restocking cutover land in a short time. These trees often reach heights of 80 ft and diameters of 30 in. They are characterized by long clear boles and short, narrow open crowns. Bark beetles and dwarf mistletoe are major damage agents of lodgepole pine outside the coastal areas, while the thin bark of lodgepole pine makes it easily killed by wildfire. Along the coast, bark beetles, dwarf mistletoe, and fire are not very important. Figure 2. Shore pine at the coastal edge, near Gold Beach, Shore pine Oregon. Lodgepole pines growing along the coast of the Pacific Northwest are called shore pine and sometimes beach pine or coast pine. Shore pine (Pinus contorta Douglas ex. Louden var. contorta) is a small tree that rarely exceeds 60 ft in height. Shore pine can vary from a shrub form on exposed coastal bluffs (figure 2), a dwarf tree planted on sand dune areas (figure 3), or tall trees growing in protected sites (figure 4). It is characterized by a short, often “contorted” bole with a dense irregular crown of twisted branches. In maturity, the crown becomes conical. The Latin word contorta means contorted or twisted and refers to the irregular crown of the typical, scrubby shore pine. They have little to no commercial timber value; however, the trees are Figure 3. Shore pine planted in sand dunes, near Dune greatly prized for their aesthetic characteristics City, Oregon. and are important ornamental yard trees. They are important trees for wildlife, because the pine nuts are a favorite food of squirrels and songbirds. Shore pines are often found on histosols (peat bogs or muskegs) in southeastern Alaska, British Columbia, and western Washington, and on dry, sandy, or gravelly sites in western Oregon and farther south along the coast on inceptisols, alfisols, and ultisols. Shore pine can be found growing with Douglas fir, Sitka spruce, western hemlock, western red cedar, redwood, and Port Orford cedar. On protected sites, shore pine will be replaced by these species, whereas on dune and bluff sites, it is the only tree that can grow there. Shore pine needles occur two to a bundle and are typically 1 to 3 in long (2.5 to 7.5 cm), stout and somewhat flattened, and often appear twisted along Figure 4. Tall stature trees in Honeyman State Park, their length. Shore pines start producing cones when Oregon. 2 they are between 5 and 10 years old. Shore pines are die from shade after canopy closure. The result is a monoecious; that is, they have both male and female thick dense stand with dead limbs extending from flowers on the same tree. Male flowers are yellow, the ground level to the upper canopy, where live cylindrical and clustered at branch tips, while female limbs still support needles capable of gathering flowers are reddish purple at branch tips and appear sunlight for photosynthesis. Under this closure, very in the upper crown. Female flowers become prickly little other vegetation can survive. Many older shore cones that are 1 to 2 in long (2.5 to 5 cm) and egg- pine stands, however, have even-sized trees that are shaped. These cones are attached to the branches in widely spaced, each tree with a distinctive rounded pairs without stalks and measure 0.8 to 2.4 in long crown and contorted branches. The understory may (2 to 6 cm). They are brownish orange when ripe be thick with evergreen shrubs (salal, evergreen and tend to point backward toward the main trunk. huckleberry, and rhododendron; figure 6). Most Some cones will open and release seed soon after insects and diseases go unnoticed in natural stands, maturing, while others can remain unopened for whereas the slightest impact on a specimen tree or several years. The winged seeds are about 0.2 in long on a yard tree may cause worry. (5 mm). Because lodgepole pine occupies such a variety of sites, when planting shore pine trees it is important that the seed or seedling source matches the site where the pines are being planted. A study of shore pines on Vancouver Island found that seed should not be transferred more than 500 ft in elevation. It could be moved 1.5° north or south but only a short distance east and west. The researchers concluded that seed used at their research site should come only from sites within the narrow rain shadow of Vancouver Island (Ying and Liang 1994). Sorensen (1992) and Stoneman (1984) both concluded that Sierra lodgepole pine in Oregon could be moved over large geographical areas, but should Figure 5. Shore pine in a yard, Port Orford, Oregon. be restricted to narrow elevation differences. If a lodgepole seedling from the Blue Mountains in eastern Oregon is moved and planted on the Oregon coast, its chances of survival are minimal. Even our native shore pines can be damaged and sometimes killed when large storms move large amounts of salt spray inland. An imported lodgepole seedling does not stand a chance in our coastal environment. Landscape vs. natural settings Shore pine in the landscape is an important ornamental tree for homeowners (figure 5). As a yard tree, shore pine can attain heights of 40 ft or more. Even as a yard tree, its form is very often not straight, or it is purposely formed into contorted shapes. Some yard trees are pruned and may not have limbs for much of the length up the trunk. In contrast, natural shore pine can occur in dense stands along the coast. Canopy closure may happen Figure 6. Shore pine and understory of salal, evergreen when the trees are very short, often less than 20 ft huckleberry, and rhododendron, Honeyman State Park, tall. The lower branches extend to the ground and Oregon. 3 Common problems of shore pine Salt damage In the following section, we discuss major Salt damage to shore pine is a common nonbiological problems of shore pine, followed by phenomenon along the Oregon coast in certain insects, and then diseases. Nonbiological problems years. Violent storms and high winds along the such as shading or salt spray may appear as insect or coast pick up salt spray (usually in winter) and can disease damage, or one may find a biotic agent on a blow this material inland a considerable distance. tree because it is stressed by abiotic factors. Salt interferes with normal biological function of the needle and will kill part or all of a shore pine Major Nonbiological Problems of needle. The needle reddens and dies, or portions Shore Pine (see table 1) of the needle die, depending on how much salt is deposited. This can give the tree crowns a singed Table 1.