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Pinus nigra

Austrian Pine

(Pinaceae - Pine Family)

Form

• large evergreen specimen tree
• maturing at about 40' tall by 20' wide in urban situations, but can reach much larger dimensions under optimum conditions with extreme maturity
• upright oval to upright pyramidal growth habit in youth, becoming rounded and flat-topped with maturity
• medium growth rate

Culture

• full sun to partial sun
• performs best in full sun in moist, well-drained soils, but very adaptable to adverse soil conditions (including clay, compacted, poor, and/or alkaline soils), moderate to heavy Winter salt spray, heat, drought, and pollution
• propagated primarily by seeds
• Pine Family, with Diplodia Tip Blight (Diplodia pinea, also known as Sphaeropsis sapinea) being the overwhelmingly serious disease (specifically fungal) problem, and Pine Sawfly Larvae being an occasional pest problem (but not nearly as severe as in Mugo Pine)
• abundantly available in ball and burlap form
• terminal foliage and stems are very subject to Diplodia Tip Blight, which slowly but surely kills entire branches (and entire trees in a group planting if left unchecked for several years); however, the death of these terminal stems (usually exposed to the sun) is sometimes confused with interior branch dieback, a natural occurrence in all trees due to self-shading
• the inexpensive and thoroughly preventive early care for Diplodia Tip Blight is to annually inspect each tree in a given area, and snip off the infected stems anytime between late Summer and late Winter at 1' below the point of dieback, as repeated infection by fungal spores is transmitted each Spring (primarily to the newly emerging candles, primarily by splashing rainwater); more expensive treatments are chemical or fungicidal in nature as the new candles expand in growth, and have a narrow window of application in order to yield an effective result for the entire year

Foliage

• two evergreen needles per bundle, to 5" long and stiff
• dark green, radiating from the very stout stems, and persisting for about five years on the stems

Flowers

• monoecious, flowering in late April and early May, and while noticeable they are ornamentally insignificant
• staminate flowers are in clustered orange-yellow catkins, while the pistillate flowers appear as small immature yellow-green "cones"

Fruits

• 2" brown cones

Twigs

• chartreuse and stout when emerging from the large terminal buds as upright "candles", becoming gray, rough, needle-scarred, and very stout with age

Trunk

• gray-brown furrows and ridges are often hidden by the lower branches, unless the tree is limbed up with age
• upon prolonged exposure to sunlight, the outer bark on mature trees becomes chalky white, and the inner bark darkens to almost black, creating a platy zebra-like pattern with maturity; however, only Austrian Pines that are limbed up and of old age exhibit this trait

ID Summary

• the bold, upright, broadly pyramidal growth habit in youth is highlighted by long, stiff, dark green, dense needles on stout ascending branches, with prominent light green vertical candles in Spring
• the flat-topped crown of extreme age (over 50 years) is composed of many spreading but ultimately ascending upper branches, with sparse branching from the mid- and lower trunk, whose exposed bark takes on the composition of chalky white platy ridges contrasting with deep dark furrows

Function

• evergreen tree used either as a single specimen, or in group or mass plantings as a visual screen or windbreak, and casting dense shade with maturity

Texture

• bold texture in youth (becoming very bold-textured with age as the branches develop a semi-contorted character, the trunk becomes bare, and the bark develops plates and a bicolored pattern)
• thick density in youth (with regions of mature trees either becoming sparse or remaining dense with age)

Assets

• probably the most urban-tolerant pine for the Midwestern United States
• Winter salt spray tolerant (one of the few Pines)
• very bold texture
• emerging stems and foliage in Spring are the attractive white-green "candles" that contrast well with the background dark green foliage
• ornamental white-and-black checkerboard bark with extreme age (if the tree is limbed up and exposed to full sun)

Liabilities

• Diplodia Tip Blight is a very severe potential disease problem
• Pine Sawfly Larvae are an occasional needle-eating pest problem

Habitat

• zones 4 to 7
• native to various regions of Europe, including Austria

Variants

• the species form is practically the only available choice
• however, Bosnian Pine (Pinus heldreichii leucodermis), which is slower-growing but strikingly similar in its bold, dark-green foliaged, broadly pyramidal appearance and salt spray tolerance as compared to Austrian Pine, may become its substitute in the future, IF Bosnian Pine does not develop Diplodia Tip Blight in landscape plantings

Purpose

• Austrian Pine is a bold-textured and urban-tolerant (including Winter salt spray) Pine, having a broad-pyramidal growth habit with ascending branches and showy Spring candles, and often developing a flat-topped crown and ornamental bark with extreme age.

Summary

• Pinus nigra is a bold-textured, long-needled, and dark green Pine tree that is ideal for Midwestern soils and climates, but is plagued by a combination of being over planted and being very susceptible to the fungal infection known as Diplodia Tip Blight.

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