Austrian pine (Pinus nigra)

Synonyms: Pinus austriaca, Pinus nigricans

Common Names: European black pine, black pine

Description:

Austrian pine (Pinus nigra) is a large evergreen conifer from Europe and western Asia, widely planted in North America as an ornamental, street tree, and windbreak [1]. It readily escapes those plantings and has naturalized in New England and the Great Lakes region, seeding itself into open, sandy, and disturbed ground [1]. MISIN tracks it as a non-native species to map where it is spreading beyond where it was planted [1].

Habit:

Austrian pine is a medium-to-large pine, usually pyramidal when young and rounded with age, that can grow well over 60 feet tall [1]. Its needles grow two to a bundle, are stiff and sharp-tipped, dark green, and about 3 to 5 inches long, staying on the tree for several years [1]. The bark is thick and dark gray-brown to nearly black, deeply grooved and broken into scaly plates [1]. Its woody cones are oval and brown, about 2? to 3 inches long, with each scale tipped by a small blunt prickle [1]. Being evergreen, it stands out year-round; escaped seedlings and young trees are easiest to notice in open fields, dunes, and prairies where other trees are sparse [1].

At-a-glance cues:

1. Stiff, sharp, dark green needles in bundles of two, about 3 to 5 inches long [1]
2. Thick, dark gray-brown to blackish bark, deeply grooved into scaly plates [1]
3. Oval brown cones about 2? to 3 inches long, each scale tipped with a small blunt prickle [1]
4. Seedlings and young pines appearing in open, sandy, or disturbed ground near planted trees [1]

Leaves:

1. Needles borne two per bundle (fascicle) [1]
2. About 3 to 5 inches (8?12 cm) long, stiff, with sharp points [1]
3. Dark green; stay on the tree about 4 to 8 years [1]
4. When bent sharply, the needles bend rather than snapping cleanly [2]

Stems:

1. A large woody tree, pyramidal when young and broad-topped with age, often well over 60 feet tall [1]
2. Bark thick, dark gray-brown to nearly black, deeply grooved and broken into scaly plates and ridges [1]
3. Buds whitish and resinous; twigs stout [2]

Flowers:

1. Conifers do not have true flowers; Austrian pine reproduces with cones [1]
2. Small pollen cones cluster at the bases of new spring shoots and release yellow pollen on the wind [2]
3. Separate seed cones form at the branch tips and take about two years to ripen [1]
4. Pollen and seed cones are borne on the same tree [2]

Fruit and seeds:

1. The "fruit" is a woody seed cone, oval, brown, about 2? to 3 inches long, with scales tipped by a small blunt prickle [1]
2. Each scale holds winged seeds that are carried on the wind [1]
3. Trees begin producing cones at about 15 to 40 years old, with good seed crops every 2 to 5 years [1]
4. Wind-blown seed is the only way the tree spreads to new ground [1]

Habitat:

Austrian pine is planted across the northern United States and escapes into open, sunny places ? old fields, sand dunes, sandy prairies, roadsides, and forest edges [1]. It is tough and adaptable, tolerating poor and sandy soils, drought, road salt, and air pollution, which is part of why it was so widely planted and why it establishes on harsh, disturbed sites [1]. It is native to central and southern Europe and western Asia, from Spain and Morocco east to Turkey and Crimea [1]. In North America it has naturalized in New England and the Great Lakes region, where it spreads from plantings into surrounding open ground [1][2].

Reproduction:

Austrian pine spreads only by seed [1]. Its cones release winged seeds that blow on the wind, so a planted tree in a yard, park, or shelterbelt can seed itself into open fields and natural areas downwind [1]. A tree starts bearing cones at about 15 to 40 years old and then produces good seed crops every few years [1]. There are no runners or root-sprouts ? new trees come only from these wind-blown seeds landing on bare or open ground [1].

Because the tree grows only from seed and does not resprout, control is straightforward in principle: pull or cut the seedlings and young trees before they mature and start making their own seed, and remove or avoid planting seed-source trees next to open natural areas [1].

Impact and Damage:

Austrian pine is not poisonous to people or pets, and it is valued as a hardy ornamental and windbreak tree [1]. Its concern is as an escapee: it is considered moderately invasive in the northeastern United States, where it spreads out of plantings and naturalizes in forests and open ground [1]. The bigger problem is in open, sunny habitats where pines are not naturally part of the community ? sand dunes, sandy prairies, savannas, and old fields [1]. There, escaped Austrian pines grow into the open ground, casting shade and gradually converting sunny, low-growing native plant communities toward closed pine woodland, which crowds out the grasses and wildflowers adapted to open conditions [1][2]. Because it tolerates poor, sandy, and disturbed soils so well, it can establish on exactly the kinds of open sites that many native open-habitat species depend on [1].

Similar species:

Austrian pine is one of several two-needle pines that are mixed up with one another. The long, stiff, dark green paired needles and the dark, deeply furrowed bark are the best clues.

Red pine (Pinus resinosa) is a native two-needle pine of similar size and is the most common point of confusion. Its needles snap cleanly when bent sharply, while Austrian pine's needles bend without breaking, and its bark is reddish rather than dark gray-brown [2].

Scots pine (Pinus sylvestris) is another non-native two-needle pine that also escapes plantings. It has shorter, twisted, blue-green needles and a distinctive orange-red flaky bark on the upper trunk, unlike Austrian pine's longer dark green needles and dark bark [2].

Jack pine (Pinus banksiana) is a native two-needle pine of sandy ground, but its needles are much shorter (about 1 inch) and twisted, and its small cones are curved and often stay closed on the branches [2].

Japanese black pine (Pinus thunbergii) is a planted two-needle pine that resembles Austrian pine, but it has conspicuous white, pointed end buds and is most often planted in coastal settings [2].

Monitoring and rapid response:

Signs to watch for:

1. A pine with stiff, sharp, dark green needles in bundles of two, about 3 to 5 inches long [1]
2. Thick, dark gray-brown to blackish bark, deeply grooved into scaly plates [1]
3. Oval brown cones about 3 inches long with a small blunt prickle on each scale [1]
4. Young pines or seedlings turning up in open fields, dunes, prairies, or roadsides near planted trees [1]

What you can do:

1. Pull seedlings by hand while they are small ? they come up easily, especially in sandy or moist soil [1]
2. Cut saplings and small trees off at the base; pines do not resprout from the stump, so cutting kills them [1]
3. Avoid planting Austrian pine near open natural areas, and consider removing seed-bearing trees that are seeding into nearby fields, dunes, or prairies [1]
4. Return to check the area for new seedlings, since nearby cone-bearing trees keep dropping wind-blown seed [1]
5. Natural area crews can cut escaped trees across an open site, prioritize isolated outliers and the seed-source trees first, and repeat as new seedlings appear [1]

When to call a professional:

1. Large trees that need to be felled safely, especially near buildings, roads, or power lines [1]
2. Extensive stands of escaped pines spreading across a dune, prairie, or other open natural area [1]
3. For chemical control options, contact a licensed applicator or your local cooperative extension office.

Report sightings to MISIN. Help track this species' spread by submitting observations through the MISIN web site or the MISIN mobile app (Android, iOS, Windows, and macOS). Photos at multiple angles paired with a precise GPS location are the most valuable data for confirming new occurrences and triggering rapid-response review.

Credits:

1. Carey JH (1993). Pinus nigra. In: Fire Effects Information System (FEIS), U.S. Department of Agriculture, Forest Service. research.fs.usda.gov
2. Native Plant Trust, Go Botany. Pinus nigra (Austrian pine). gobotany.nativeplanttrust.org

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