The Austrian pine (Pinus nigra) is also commonly referred to as black pine. This evergreen tree grows best in U.S. Department of Agriculture plant hardiness zones 4 through 8A. You can recognize the Austrian pine tree by its dark green, and rather long needles. Its shape resembles that of a pyramid — with a typical Christmas-tree shape when young, maturing to a flat-topped, broader silhouette.
Pinus nigra, the Austrian pine or black pine, is a moderately variable species of pine, occurring across Southern Europe from the Iberian Peninsula to the eastern Mediterranean, on the Anatolian peninsula of Turkey, Corsica and Cyprus, as well as Crimea and in the high mountains of Northwest Africa. It is found at elevations ranging from sea level to 2,000 m (6,600 ft), most commonly from 250–1,600 m (820–5,250 ft).
The world’s oldest black pine, located in the Banaz district of Uşak, Türkiye, is estimated to be 1000 years old. This makes it significant in the country, which is known for a very dry climate, inhospitable for most trees. It has a length of 11 meters, a diameter of 3 meters and a circumference of 9.60 meters.
Pinus nigra is moderately fast growing, at about 30–70 cm (12–28 in) per year. It usually has a rounded conic form, that becomes irregular with age. The tree can be long-lived, with some trees over 500 years old. The trees are often used as windbreaks and for erosion control due to their sturdy nature and deep root system. They are effective in stabilizing soil and reducing wind erosion.
In both the US and UK most of the specimens planted are from Austrian sources, the P. nigra subsp. nigra and P. nigra subsp. nigra var. nigra seed selections. In the late 1950s and early 1960s, when demand for natural trees was extremely high, its rapid growth, deep green color and low cost made it briefly a popular Christmas tree, but the extreme length of the needles (making it very difficult to decorate) soon led to its fall from favor, and it has long since been abandoned in the US for that purpose.
Characteristics of Austrian Pine (Pinus nigra)
- Austrian Pines can grow to a height of 20 to 55 meters (66 to 180 feet) at maturity. They spread to a width of 6 to 12 meters (20 to 39 feet).
- They have a moderate to fast growth rate, growing about 30 to 70 centimeters (12 to 28 inches) per year.
- The needles are dark green, often curved and slightly twisted. They are 8 to 15 centimeters (3 to 6 inches) long and occur in bundles of two.
- The bark is thick, gray to yellow-brown, and becomes increasingly fissured with age. It is widely split by flaking fissures into scaly plates.
- Austrian Pines have a deep and extensive root system that helps them anchor firmly and access deep water sources. This root system allows them to thrive in various soil types, including clay and sandy soils.
- It thrive in USDA hardiness zones 4 to 7. They are well-suited to a range of temperate climates and can tolerate cold winters and hot summers.
- The cones of the Austrian Pine are ovoid to conical, measuring 5 to 10 centimeters (2 to 4 inches) in length. They are typically brown and have a woody texture. The cones take about two years to mature from pollination. Once mature, they release seeds that are dispersed by wind.
- They’re are long-lived trees, with some individuals reaching up to 500 years old. They are known for their durability and resilience.
- They prefer well-drained soils. They can tolerate a variety of soil types, including sandy, loamy, and clay soils. They are also adaptable to slightly acidic to neutral pH levels. While they prefer well-drained soils, Austrian Pines can tolerate occasional periods of drought once established.
Austrian Pine (Pinus nigra) Distribution
Geographic Range
- Native Range: Austrian Pine is native to southern Europe and Asia Minor. It is found in countries such as Austria, Italy, Spain, France, Greece, Turkey, and the Balkans.
- Introduced Range: This pine has been widely planted outside its native range, including in North America, where it is used for landscaping, windbreaks, and reforestation.
Habitat
- Soil and Topography: Austrian Pines are highly adaptable and can grow in a variety of soil types, including sandy, loamy, and clay soils. They prefer well-drained soils but can tolerate poor, rocky, and dry soils.
- Elevation: They are found at elevations ranging from sea level to about 2,000 meters (6,560 feet) in their native range.
- Climate: Austrian Pines thrive in temperate climates with cold winters and hot summers. They are tolerant of drought and can withstand harsh environmental conditions.
Ecological Importance
- Biodiversity: Austrian Pine forests provide habitat for various plant and animal species. They are important for soil stabilization and preventing erosion in mountainous regions.
- Fire Adaptation: These pines are moderately fire-resistant due to their thick bark, which protects them from low-intensity fires.
Uses
- Landscaping: Austrian Pines are popular in landscaping due to their attractive appearance and adaptability. They are often used as ornamental trees, windbreaks, and for erosion control.
- Timber: The wood of Austrian Pine is used for construction, furniture, and paper production. It is valued for its strength and durability.
Conservation Status
- Threats: In some regions, Austrian Pine populations are threatened by pests, diseases, and habitat loss. Conservation efforts are focused on protecting natural populations and promoting sustainable forestry practices.
Austrian Pine (Pinus nigra) Cultivation
Soil Requirements
Austrian Pines prefer well-drained soils. They can tolerate a variety of soil types, including sandy, loamy, and clay soils. They are also adaptable to slightly acidic to neutral pH levels.
Sunlight
These pines thrive in full sun. Ensure they receive at least 6 hours of direct sunlight daily for optimal growth.
Watering
Young Austrian Pines need regular watering to establish their roots. Water deeply but infrequently to encourage deep root growth. Once established, they are moderately drought-tolerant.
Planting Time
The best time to plant Austrian Pines is in the spring or fall when temperatures are mild. This allows the roots to establish before the extreme heat of summer or the cold of winter.
Spacing
When planting multiple Austrian Pines, space them at least 6 to 8 meters apart to allow for their mature spread and to ensure good air circulation.
Mulching
Apply a layer of mulch around the base of the tree to retain soil moisture, regulate soil temperature, and suppress weeds. Keep the mulch a few centimeters away from the trunk to prevent rot.
Fertilization
Austrian Pines generally do not require much fertilization. If the soil is poor, you can apply a balanced, slow-release fertilizer in the spring. Avoid over-fertilizing, as this can lead to excessive growth and weaken the plant.
Pruning
Prune Austrian Pines annually in late winter or early spring to maintain their shape and size. Remove any dead, damaged, or diseased branches. For a more compact growth habit, you can also pinch back the new growth (candles) in the spring.
Pest and Disease Management
Austrian Pines are relatively pest and disease-resistant. However, they can occasionally be affected by pests like pine beetles, aphids, or fungal diseases. Regularly inspect your plants and treat any issues promptly with appropriate measures.
Winter Protection
In colder climates, young Austrian Pines may benefit from some winter protection. Apply a layer of mulch around the base and consider using burlap to shield them from harsh winds and heavy snow.
Subspecies
Pinus nigra subsp. nigra
Varieties:
- Pinus nigra var. nigra: Found in Austria, northeast and central Italy, east to the Crimea and Turkey. The needles are stout and rigid, with 3–6 layers of thick-walled hypodermal cells.
- Pinus nigra var. pallasiana: Found in the eastern Mediterranean, including Turkey and the Crimea. It has similar characteristics to var. nigra but is adapted to slightly different climatic conditions.
- Pinus nigra var. caramanica: Found in the Anatolian peninsula of Turkey. It is adapted to the dry climate of the region.
Pinus nigra subsp. salzmannii
Varieties:
- Pinus nigra var. salzmannii: Found in the western Mediterranean, including Spain and southern France. It has thinner and more flexible needles compared to subsp. nigra.
- Pinus nigra var. corsicana: Found in Corsica. It has similar characteristics to var. salzmannii but is adapted to the specific conditions of the island.
- Pinus nigra var. mauretanica: Found in the high mountains of Northwest Africa. It is adapted to the dry and harsh conditions of the region.
How to Plant Austrian Pine
- Locate a spot in your yard that receives full sun. This spot must also be able to accommodate the Austrian pine after it grows to maturity. Keep in mind that the tree has a 20- to 40-foot spread and can reach heights as high as 60 feet.
- Measure the root ball of the Austrian pine seedling and dig a hole that is equal in depth and at least 2 inches wider all the way around. Gently remove the root ball from the container it came in. Simply tap the edges and you should be able to wiggle the root ball right out.
- Remove any burlap that is surrounding the root ball and place the root ball directly in the center of the hole. Austrian pines can handle almost any type of soil, including sand, clay, loam, alkaline, acidic as long as it drains well.
- Mix the soil you dug out of the hole with some compost. Use this combination to fill in the remaining space around the root ball. You need enough of the mixture so that the root ball barely moves when you tug on it.
- Water the soil around the root ball until it becomes moist, but not sopping wet. Regular waterings are necessary for the first two years once you have finished planting your Austrian pine. After that, rain water will be sufficient.
- Spread a 3-inch layer of mulch around the top of the Austrian pine seedling. Mulch helps keep weeds at bay, as well as keeps the soil moist.