By Norma Kline, OSU Extension Forester for Coos and Curry Counties

Shore pine (Pinus contorta var. contorta), is a common and extremely hardy native tree of Oregon’s coast. Shore pine can occur in solid stands or in mixed stands along with Sitka spruce, Port-Orford-cedar, western hemlock and Douglas-fir. Shore pine is adapted to our long summer dry periods and rainy winters. The characteristic twisted growth form on rocky bluffs near the beach, attesting to its ability to withstand our harsh windy coastal weather (Figure 1). It may seem surprising that our coastal shore pine is a variant of the straight, tall lodgepole pine found throughout central and eastern Oregon. The scientific name of lodgepole is Pinus contorta while Shore pine is Pinus contorta var. contorta. You can confirm the two are very similar by taking a close look at the needles and cones. Both lodgepole and shore pine have needles in bundles of two, and small woody cones that are 1-2 inches long. These cones can remain closed for years. The bark is thin and flaky. While lodgepole pine is used for a number of commercial wood products, shore pine is mainly appreciated for its ecosystem function and beauty in the landscape.

Despite shore pines’ reputation for being a tough and hardy native conifer, it can still succumb to a number of common forest health issues. In the home landscape, a common stressor includes watering mature trees during the summer. This can occur if a lawn or garden has been developed around existing trees. Overwatering can cause a suitable environment for pathogens to infest the root system which eventually causes tree decline. On the other hand, a newly planted shore pine seedling will require periodic watering until it is established, see Selecting, Planting and Caring for a New Tree, in references below.

Shore pine is shade intolerant, in other words it does best in full sun. Shore pines that are overtopped or shaded by other trees will eventually become spindly and exhibit poor growth. Another hazard in home landscapes is root damage or compaction caused by trenching or road construction. Injury to limbs or the tree trunk (bole) through equipment damage or incorrect pruning can also create a route for insects or pathogens to gain entry. Avoid damaging the branch collar or tree trunk while pruning (Figure 2). Pruning should be completed from October to February. Pruning outside this time period can attract Sequoia pitch moth, which create unsightly globs of pitch on the tree trunk. For a comprehensive description of forest health considerations for shore pine, see Common Insect Pests and Diseases of Shore Pine on the Oregon Coast, in references below.

References

Selecting, Planting, and Caring for a New Tree: https://extension.oregonstate.edu/catalog/pub/ec1438

Common Insect Pests and Diseases of Shore Pine on the Oregon Coast: https://extension.oregonstate.edu/catalog/pub/em9008