Scots pine (Pinus sylvestris) is a native Eurasian pine plant that grows on nutrient-poor, dry, rocky soils. Given the name, it should come as no surprise that scots pine is the national tree of Scotland. It is also important within the forestry industry due to its use for wood pulp and timber.
I. Appearance and Characteristics
Pinus sylvestris, the Scots pine (UK), Scotch pine (US), Baltic pine, or European red pine is a species of tree in the pine family Pinaceae that is native to Eurasia. It can readily be identified by its combination of fairly short, blue-green leaves and orange-red bark.
Pinus sylvestris is an evergreen coniferous tree growing up to 35 meters (115 feet) in height and 1 m (3 ft 3 in) in trunk diameter when mature, exceptionally over 45 m (148 ft) tall and 1.7 m (5+1⁄2 ft) in trunk diameter on very productive sites. The tallest on record is a tree over 210 years old growing in Estonia which stands at 46.6 m (153 ft). The lifespan is normally 150–300 years, with the oldest recorded specimens in Lapland, Northern Finland over 760 years.
The bark is thick, flaky and orange-red when young to scaly and gray-brown in maturity, sometimes retaining the former on the upper portion. The habit of the mature tree is distinctive due to its long, bare and straight trunk topped by a rounded or flat-topped mass of foliage.
The shoots are light brown, with a spirally arranged scale-like pattern. On mature trees the leaves (‘needles’) are a glaucous blue-green, often darker green to dark yellow-green in winter, 2.5–5 centimeters (1–2 inches) long and 1–2 millimeters (1⁄32–3⁄32 in) broad, produced in fascicles of two with a persistent gray 5–10 mm (1⁄4–3⁄8 in) basal sheath. On vigorous young trees the leaves can be twice as long, and occasionally occur in fascicles of three or four on the tips of strong shoots. Leaf persistence varies from two to four years in warmer climates, and up to nine years in subarctic regions. Seedlings up to one year old bear juvenile leaves; these are single (not in pairs), 2–3 cm (3⁄4–1+1⁄4 in) long, flattened, with a serrated margin.
The seed cones are red at pollination, then pale brown, globose and 4–8 mm (5⁄32–5⁄16 in) in diameter in their first year, expanding to full size in their second year, pointed ovoid-conic, green, then gray-green to yellow-brown at maturity, 3–7.5 cm (1+1⁄8–3 in) long. The cone scales have a flat to pyramidal apophysis (the external part of the cone scale), with a small prickle on the umbo (central boss or protuberance). The seeds are blackish, 3–5 mm (1⁄8–3⁄16 in) in length with a pale brown 12–20 mm (1⁄2–13⁄16 in) wing and are released when the cones open in spring 22–24 months after pollination. The pollen cones are yellow, occasionally pink, 8–12 mm (5⁄16–15⁄32 in) long; pollen release is in mid to late spring.
II. How to Grow and Care
Sunlight
Plant it in a location where it gets at least 6 hours of full sun each day, and make sure to give it plenty of space, as this is a tree that will get very large.
Temperature and Humidity
Scots pine is native to northern Europe and Central Asia. It can thrive in many climates, though it does not do well in subtropical or tropical regions.
Watering
Young trees need about 1 inch of water per week. Mature trees only need water during hotter days and only if the tree has not received rainfall recently.
Soil
Pinus sylvestris prefer a well-drained porous gravelly subsoil, overlaid with a light sandy loam. They seem to be particularly happy in a soil underlaid with a porous glacial drift. In cultivation, however, they succeed very well in ordinary well-drained soil. When the plants are set in clay soil, which is often done, the soil should be thoroughly loosened by trenching or subsoil plowing, and well under-drained. Any available humus, wood ashes, and well-rotted manure incorporated in the soil greatly aid in rendering it friable and porous for the roots.
Fertilizing
Fertilizer is not necessary, but if you do feed it, only give it fertilizer once a year in the spring just before it comes out of dormancy, using a 15-5-10 slow-release fertilizer. Spread the fertilizer in a band just under the outer perimeter of the pine’s canopy, raking it into the top layer of the soil. Water the tree thoroughly immediately after feeding. Mulch the area around the base of the tree to a depth of 3 to 4 inches, and reapply mulch every 1 to 2 years. Once established, this tree requires little care.
Pruning
Removal of the lower branches of Scots Pine is a serious mistake, and, if healthy, they should be retained to the base. Pruning or disbudding can be intelligently performed to add much to the natural symmetry. The extraction or removal, early in spring, of the central or terminal bud, will tend to compel the branches which start from the side buds to spread apart and form a much denser growth. Cutting back the previous year’s terminal growth to a strong bud or branchlet on the main limbs over the tree, if the plant is inclined to be thin in its branching, always produces a much denser lateral growth.
Propagation
Scots pine is grown from planting seeds or stem cuttings. Stem or branch cuttings are a good way to grow new plants from pruned branches or new growth. Here’s how to propagate Scots pine from stem cutting:
- You will need a pot with ample holes, moistened potting soil, pruners, plastic wrap, and rooting hormone.
- Take 4- to 6-inch cuttings from healthy branches with new growth. Dip the cut end in the rooting hormone.
- Pull off the pine needles from the cut-end side, leaving only the top half of the pine needles intact on the stem.
- Plant the cut-end in moistened soil, such as peat or perlite mixed with sand in a pot with ample holes for good drainage.
- Cover the pot with plastic to keep the humidity up, also place the cutting in a warm, brightly lit spot.
- Remove the plastic for about one hour each day to allow the cutting some fresh air. Remove the plastic completely once new growth appears. It may take up to one year for cuttings to take root. New growth is proof the cutting is establishing new roots. Replant the cutting in the ground or a new pot after it has developed several more inches of growth.
How to Grow From Seed
For germination success, consider stratifying (tricking seeds they’ve gone through winter) or putting them in potting soil in a container in the refrigerator for at least four weeks.
Next, sow the seeds indoors by placing them in individual pots with well-drained potting soil. Push each seed just beneath the soil surface with the pointy end of the seed facing downward.
Place the pots in a sunny window and water thoroughly, always keeping the seeds moist (but not too soggy). Germination may take about three to four months.
Potting and Repotting
Plant newly rooted or young seedlings in the ground in the spring. If repotting new saplings, only repot every two or three years in the late fall or early spring. Do not repot too much, since repeated transplanting can shock and potentially kill the plant. Cut back on the water before repotting, keeping the soil slightly dry.
To transplant, remove the root ball from the pot, keeping it whole. Prune away old roots from the bottom and sides. Remove some old soil from the middle of the soil ball and replace it with new soil in the new pot. Cover the root ball with new soil. Do not make it too big of a pot, since a deep pot may get soggy soil, which can lead to root rot.
Overwintering
Mature Scots pines can handle winter without a problem. Seedlings and saplings are more sensitive to cold winters and will need some protection. Use a layer of mulch to insulate the soil around the seedling about 4 to 6 inches thick. Also, water the young tree thoroughly at least twice a month throughout fall and winter.
Protect the young tree trunk from winter winds and foraging animals with chicken wire and a burlap wrap until its root system is well established. The tree will need several years to establish a strong root system.
Pests and Diseases
Common Pests and Diseases
When a Scots pine develops yellowing needles along a single branch, this may be a sign of a pine wilt fungal disease, called Cyclaneusma needle cast. Consult an expert for confirmation. The tree will need to be removed and destroyed since it is incurable. Western gall rust and Lophodermium needle cast are also common in some areas.
Several insects are known to affect Scots pine, sucking pine sap, which can kill or severely affect these trees, including:
- Pine spittlebug (Aphrophora parallela)
- European pine sawfly (Neodiprion sertifer)
- Pine root collar weevil (Hylobius radicis)
- Giant conifer aphid (Cinara spp.)
- Pine needle scale (Chionaspis pinifoliae)
- White pine weevil (Pissodes strobi)
- Pine root tip weevil (Hylobius rhizophagus)
- Zimmerman pine moth (Dioryctria zimmermani)
To treat these pests, try an insecticidal soap first. Also, horticultural oil applied in early spring is another good solution. Only move on to chemical pesticides if these organic solutions prove unsuccessful.
Porcupines and birds, especially pine grosbeak, can also cause damage to the tree.
Common Problems
Scots pine trees are tough trees that can handle many climates and soils. They like full sun and can withstand a frigid winter. The rule of thumb to keep these plants thriving is to protect them in their early years.
Yellowing Pine Needles
This condition can be caused by the soil being too wet and poor drainage. Soggy soil leads to root rot and needle yellowing. Another potential cause is needle scorch when the soil is too dry on hot days. Insufficient light, ventilation, or pines shocked by too much sunlight can also cause yellowing needles. Also, in fall, when deciduous trees lose their leaves, Scots pines may also experience seasonal yellowing and needle drop; usually, they’ll drop their old needles every three years.
Evaluate the conditions of your Scots pine to determine what’s affecting your tree. Adjust the watering schedule accordingly. If your tree is not getting enough light or is too crowded by other trees, you might want to consider replanting it in a better location.
Tree Appears to Be Dying
If the plant’s bark is wrinkling, peel back a bit of the branch bark. If the inner layer of the bark is dry and brown, it’s dead. If it’s still green underneath it still has life. If the tree is low on water, give it water, but do not overdo it; it can shock the tree.
If pine needle yellowing only occurs on the old needles, the tree can bounce back. If yellowing occurs on old and new growth, the tree may be more difficult to revive. Remove the lower branches of a pine tree that are dead, dying, or damaged to reinvigorate the tree.
Swollen, Soft Trunk, and Red Needles
If a tree’s bark starts to appear swollen or soft, it can be a sign of Cronartium ribicola or rust. If you notice a lot of yellowish-whitish sores on the lower part of the trunk, and the tree develops red needles, it likely has this fungal infection. If it appears on branches, remove the branches. Cut down and destroy diseased branches. Infected parts that are cut out, should be layered with pine tar as a salve for the cuts.
Oozing Sap
A little bit of sap is no reason to worry. However, if the sap is steadily streaming from the tree, it is likely injured from physical breakage, insects, or disease. Cankers are fungal growths that spread under the bark and affect the tree, sometimes causing sap to ooze. These growths can kill a tree if not handled early on. Chemicals can’t control cankers, but if you prune it out early, it can eliminate the problem from spreading.
III. Uses and Benefits
- Ornamental uses
The mighty but graceful Scots pine (Pinus sylvestris) is a tall evergreen tree that is prized for its attractive needles which offer year-round appeal. This fast-growing tree makes for an appealing specimen tree in landscapes, rock gardens, and coastal gardens. This species is also commonly grown as a Christmas tree. Good companion plants include asters, lawson cypress, and butterfly bush.
- Other uses
Pinus sylvestris is an important tree in forestry. The wood is used for pulp and sawn timber products. A seedling stand can be created by planting, sowing, or natural regeneration. Commercial plantation rotations vary between 50 and 120 years, with longer rotations in northeastern areas where growth is slower.
In Scandinavian countries, the pine was used for making tar in the preindustrial age. Some active tar producers still exist, but that industry has almost ceased. The pine has also been used as a source of rosin and turpentine.
The wood is pale brown to red-brown, and used for general construction work. It has a dry density around 470 kg/m3 (varying with growth conditions), an open porosity of 60%, a fibre saturation point of 0.25 kg/kg, and a saturation moisture content of 1.60 kg/kg. The pine fibres are used to make the textile known as vegetable flannel, which has a hemp-like appearance, but with a tighter, softer texture.