Where pine trees grow?

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Pine trees are an excellent choice for someone looking for an attractive addition to their garden that generally grows quickly. The pine tree is evergreen – meaning it will retain its green foliage throughout the year. This makes it a beautiful addition to a garden for the winter, and also adds to the festive atmosphere around the holiday season. It also makes it a good option for those looking for fast-growing trees for either privacy or wind protection, along the perimeter of their garden. There are about 100 species of pine to choose from, with variable growth rates.

How fast do pine trees grow?

Pine trees grow at an average rate of just under 1ft to 2ft per year. Pine trees are divided into three subcategories in terms of growth: fast-growing, medium-fast growing, and slow-growing. Slow growing pines will grow a maximum of 1ft annually. Medium-fast will have growth rates of 1ft to 2ft. Fast-growing species can achieve growth rates of over 3 feet per year.

Read Pine tree trimming cost guide here.

What are the longest living trees?

The longest living trees on Earth are the slow-growing Bristlecone pine or Pinus aristata. These trees can live for thousands of years. The Bristlecone can retain its needles for over 30 years before renewing them, unlike the average 2-year cycle of most pine species. In the White Mountains, New Hampshire, The Tree-Ring Research group has discovered a Bristlecone with a confirmed age of 5,062 years.

There are three sub-types of Bristlecone. Pinus longaeva, the most long-lived of the three, and what makes up most of the famous examples of ancient Bristlecones. There are also the Rocky Mountain Bristlecone, which has the largest population, and the Foxtail pine, which forms the thickest groves.

How long do pines take to reach maturity?

Pine trees can vary significantly by species in how long they take to reach full size and maturity. Their life stages can be indicated by the leaves. In the first stage of life, young seedlings will produce seed leaves for about a year. Then they will produce juvenile leaves from six months up to 5 years, which are indicated by their spiral arrangement. These will then change to scale leaves in the same arrangement, but small and brown. Finally, the adult ‘leaves,’ i.e. the needles, will grow out from the scale leaves on the mature tree.

In terms of when they reach full height, this is usually between 50 and 145 feet, though dwarf species, such as the Siberian Dwarf, only reach a maximum of 10ft.

Pine is considered mature enough for wood harvest at around 25 to 30 years. Sometimes they are left to grow for up to 50 years as the value of the wood will increase with age.

What’s the tallest species of pine?

The Sugar Pine, or Pinus lambertiana, is the tallest known species of pine tree. The sugar pine can exceed heights of 200ft and lives for around 500 years. This species is native to North America, and can commonly be found in the mountainous regions of Oregon and California, and also northwestern Mexico.

Can I make my pine tree grow slower?

The best way to slow down the growth of your pine tree is to trim periodically. You should first wait until the tree has already grown as high as you want it. Then use a suitable tree saw to cut off between 6 and 12 inches from the central stem at the top. Make your cut at a 45-degree angle, so that the moisture doesn’t settle on top of the cut and cause rot.

When that’s done, you can use loppers to cut the branches below the top down a few inches, making sure it’s even around each side of the tree. Cut the rest of the limbs in proportion to maintain the cone shape. Repeat this process on the top and sides of your tree annually to maintain the height that you want.

Types of Fast-Growing Pines:

Monterey Pine (Pinus radiata): Can grow up to 3 feet per year, and up to 160ft tall. The widespread, cultivated version is desirable for its wood and pulp. It’s the most planted pine on the planet. Despite this, it’s only native to some small areas in California and Mexico, and the natural species are endangered and not suitable for harvesting. Its needles have a dark green hue, and bark can be red-brown or gray. They tolerate many soil conditions and its rapidly spreading roots can be used to stabilize erosion.

Eastern White Pine (Pinus Strobus): It tree can grow over three feet per year and reach up to 80ft tall. Commonly used in colonial times as British ship masts, it’s native to the Eastern US, and can commonly be found growing along the Appalachian mountains. These can easily be cut back and shaped into hedges, making them a great option as a wind barrier.

Lobolly Pine (Pinus taeda): The second most common species in the USA, it can grow over 3 feet per year and up to 100ft tall. Used widely for its timber and naturally native to the southeast US. Its bark has a red-brown color with light green needles. This species is suitable for shade or ornamental use.

Page 4. Growing and harvesting the forest

Forest management

Managing plantations involves thinning and pruning, depending on whether the trees are being grown for high-value saw logs, or as lower-quality logs.

Thinning

With a harvest age of 25–35 years, and final tree numbers of around 300 stems per hectare, two thirds of the trees planted are usually cut down during the early stages of the growing cycle to make more room for the others. The felled trees are either left on the ground to rot, or sometimes harvested as posts, poles or pulpwood.

Pruning

About five years after planting, the best trees are usually pruned up to a height of 4 metres. At around seven years, the trees may be pruned up to 6.5 metres. At around nine years, when the trees are 16 metres high, all the unpruned trees are felled to allow the remainder room to grow. This system is designed to produce a substantial yield of valuable knot-free wood in the lower part of the trunk.

Some forest management systems aim to grow a high yield of logs with small knots – suitable for structural timber such as house frames, roof trusses and poles. In this case the trees aren’t pruned, and they are grown closer together (450 stems per hectare) to limit branch growth and keep the knots small.

Types of log

No matter what kind of management system is followed, the forest will yield a range of log types. For example, large pruned logs are used for clear timber and veneer, large knotty logs for structural timber, and small logs from the top of the trees for wood chips, wood pulp, fibreboard and particleboard.

Logging

Logging is done by teams who:

  • fell the trees using chainsaws or mechanical shears
  • pick up and move the logs using crawler tractors, wheeled skidders or overhead cable haulers
  • cut the branches off the logs
  • use cranes to load the logs onto trucks for transport to log depots, mills or ports for export.

The logs are carefully sorted into categories according to their intended use and value.

Production

The amount of wood a hectare can produce depends on the rotation (lifespan) of the trees, how many are grown to maturity, and the productivity of the site, which is related to soil depth and fertility, and climate. Under very good conditions, such as a deep pumice soil and mild climate, a hectare of trees may produce 840 cubic metres of wood when harvested at 28 years. This would give a mean annual growth increment of 30 cubic metres per hectare per year; the national average is around 23.

How Fast Do Pine Trees Grow?

Pine trees are grown for beautifying the landscape, creating privacy screens, and also, for collecting timber. This Gardenerdy article deals with how fast pine trees grow, and provides some helpful information on quick-growing pine varieties that are used for landscaping projects.

Did You Know?

The slow-growing bristlecone pine (Pinus aristata) are the oldest living trees, with one of them present in the Great Basin National Park, in Nevada, which is about 4,600 years old. They grow in USDA hardiness zones 4 through 8.

Trees are generally slow growers, and take a few decades to attain their maximum size. However, some cultivars develop at an exceptionally slow rate. For those of you who have recently shifted to a new place and plan to starting landscaping right from scratch, planting fast-growing trees is a practical solution.

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One such tree that grows fast and makes an attractive specimen in the landscape is none other than the pine. They are the most common coniferous trees grown all over the world, having about 100 species. They look amazingly attractive during winters, and are mostly used as Christmas trees, especially the Scotch pine trees, during the festive season. Let us find out the growth rate of some species of pine trees.

How Much Do Pine Trees Grow in a Year?

Different types of pines are used for different purposes in landscaping. They have evergreen foliage―the green leaves are retained throughout the year. This feature makes them perfect for creating privacy screens, protecting properties, and windbreak (barriers against winds). They also look adorable with their needle-shaped foliage. But one thing that concerns landscapers is the rate at which they grow. Well, the answer differs from species to species and the growth conditions that are provided to them.

On an average, the yearly growth rate of pine trees is less than a foot to more than two feet. Thus, according to the growth rate per year, they are broadly grouped into three types, viz. slow-growing pines, medium-fast growing pines, and fast-growing pines. Examples of slow-growing pine trees are Virginia pine and longleaf pine. They grow to a maximum of one foot a year. The medium-fast growing pine trees grow about 1-2 feet per year, and examples are red pine and Austrian pines. Lastly, the fast-growing pines grow up to two feet and more annually.

Types of Fast-growing Pine Trees

Talk about pine trees that grow rapidly, and the Australian pine is commonly included in the list. Despite the name, this straight-growing, tall tree is not a true pine species. But, it belongs to the Casuarina genus, and is not related to evergreen conifers. The needle-shaped structure that resembles pine foliage is composed of jointed branchlets, while true leaves are reduced in the form of scales. If you want to plant rapid-growing pines, then check out the following varieties below:

Afghan Pine

Scientific Name: Pinus eldarica
Alternative Name: Mondell pine
USDA Hardiness Zones: 6-10

This fast-growing, drought-tolerant pine is grown for its evergreen foliage. It adapts well in full sun and alkaline soil having pH 7.9-8.5. At maturity, it attains a maximum height of 80 feet and spreads to approximately 30 feet. When planted in a row, this pine variety is excellent for marking garden borders. But, make sure that you leave a spacing of 15 feet or slightly more between two Afghan pine trees.

Aleppo Pine

Scientific Name: Pinus halepensis
Alternative Name: Jerusalem pine
USDA Hardiness Zones: 9-10

The Aleppo pine grows to a maximum height of 40 feet with an almost equal spread. This pine cultivar is suited for planting in a wide range of soil conditions, and can tolerate slightly acidic to mildly alkaline soil. It requires less water after establishment, which is why it is preferred for planting in xeriscapes. The lower tree trunk is deeply fissured and is bright orange in color, while the upper portion is flaky in texture.

White Pine

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Scientific Name: Pinus strobus
Alternative Name: Eastern white pine and northern white pine
USDA Hardiness Zones: 3-8

A very hardy pine variety, white pine is grown as windbreak in the landscape. When planted with proper care, it grows with an annual growth rate of three feet, and attains 50-80 feet height and 20-40 feet width. You can plant it in garden sites that remain exposed to full sun. It can be grown in nearly all soil types. Besides this, the oval canopy shape is another desirable attribute of this species of pine. Therefore, it is highly prized for growing in formal gardens.

Loblolly Pine

Scientific Name: Pinus taeda
Alternative Name: Southern yellow pine
USDA Hardiness Zones: 6-10

The loblolly pine is a huge tree, prized for its valuable timber. It grows up to 115 feet in height and is a type of southern pine that secretes a yellowish resin. Thus, the name southern yellow pine is given to this pine species. This cultivar requires clay soil with acidic pH (6.1-6.5) and full sunlight for optimal growth. In short, this fast-growing species should be planted with special care.

Slash Pine

Scientific Name: Pinus elliottii
Alternative Name: Swamp pine, yellow slash pine
USDA Hardiness Zones: 7-11

Humid climate, full sun, and adequate soil moisture are necessary for growing this pine cultivar. The identifiable trait of this pine tree is the extraordinarily long leaves, which are borne in clusters of 2-3 foliage. The height of a matured slash pine averages 75-100 feet, and its spread ranges from 30-50 feet. This tree is commercially planted for deriving superior quality timber.

Scotch Pine

Scientific Name: Pinus sylvestris
Alternative Name: Scots pine
USDA Hardiness Zones: 3-7

Besides its attractive, orange-colored scaly bark, and bluish-green foliage, this evergreen tree grows at a fast rate. It spreads to about 30 feet, and requires sufficient space for optimal growth. The scotch pine is susceptible to pine wood nematode, which in severe infestation cases, kills the tree. Hence, prior to planting scotch pine, see to it that you can include this pine variety in your landscape.

While selecting fast-growing evergreen trees for your landscape, compare the growth factors of each variety with the prevailing climatic conditions in your zone. For easy maintenance, preferably choose native cultivars, or at least the ones that can tolerate soil and growth conditions in your area.

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Loblolly pine

Pinus taeda
Family: Pinaceae

Natural History
Needles and cones of loblolly pine
Photo credit: Larry Korhnak, University of Florida

The word “loblolly” originally meant a thick porridge or gruel served to English sailors. When Europeans first came to settle the southeastern United States, they used that word to describe some of the local swamps where they found mud with the same thick, gooey consistency. The term also came to be applied to some of the plants that commonly grew in these areas, which is how loblolly pine (Pinus taeda) and loblolly bay (Gordonia lasianthus) got their common names.

Today loblolly pine, also called oldfield pine, is the most important commercial timber in the southeastern United States. Over 50% of the standing pine in the southeast is loblolly. The specific epithet, taeda, comes from the Latin word for torch and refers to the resinous wood.

This is an easily-seeded, fast-growing member of the yellow pine group and is an aggressive invader in fallow fields. It is widely grown in plantations for commercial timber production, but also has been planted to help stabilize soil and reduce erosion or as a noise and wind barrier. Loblolly has also been planted in mine reclamation areas and due to its high litter and biomass productivity, loblolly pine is being studied as a possible alternative source for energy.

Habitat & Range

Loblolly pine prefers acid soils and full sun, but will adapt to a variety of sites, including fertile, upland fields, moist forests, or with mixed hardwoods. It is often found in association with shortleaf pine (Pinus echinata). Loblolly pine is widely scattered throughout the forests of the coastal plains and lower Piedmont plateau. It is very vigorous on fallow fields and cutover lands. It will often fully restock such areas in a relatively short time.

Loblolly pine is found throughout much of the southeastern United States from New Jersey to central Florida and west into Tennessee, Kentucky, Texas, and Oklahoma. It is not found in the lower Mississippi Valley.

Wildlife Use

Loblolly pine stands are important for numerous wildlife species. The trees provide habitat for many animals, including white-tailed deer, wild turkey, gray squirrels, rabbit, quail, and doves. Many songbirds feed on the seeds and help propagate the trees through seed dispersal. Red crossbills depend on loblolly pine seeds for up to 50% of their diet. Other birds who frequent the trees include pine warblers, Bachman’s warblers, and brown-headed nuthatches. Osprey and bald eagles often nest in tall loblolly pines. Two endangered species that also use these pines are fox squirrels, which eat the cones, and red-cockaded woodpeckers, which will sometimes nest in old growth trees.

Human Use

The wood of this tree, which is marketed as southern yellow pine, is of lower quality than that of longleaf or shortleaf pines in terms of lumber and is therefore primarily used for pulp and paper products. However, it is possible for use as lumber or plywood. Loblolly pine wood may be sold interchangeably with shortleaf pine. Loblolly pine is the state tree of Arkansas.

Identifying Characteristics

Size/Form: Loblolly pine is a large evergreen tree that reaches heights of 40 meters, with a trunk about a meter in diameter. It has a long, clear bole that is occasionally buttressed, ascending limbs, and a rounded, spreading crown. Young trees retain lower branches much longer than slash or longleaf pines.
Leaves: Pines have long needle-like leaves that are held in bundles called “fascicles” with a sheath holding the needles together at the base. The first steps toward identifying each species are 1) measuring the length of the needles, 2) counting the number in a fascicle, and 3) measuring the length of the sheath. Be sure to check a few branches to get an average for the whole tree.

On loblolly pine, the needles are 10 to 17 cm long, and borne in fascicles of 3 or occasionally 2. They are dark yellowish green or sometimes grayish green, thick but flexible, and sometimes slightly twisted. The sheath is 1-1.5 cm long. The needles are often persistent through the end of the second season.

Twigs: The twigs are thin, yellowish- to reddish-brown, and scaly. The buds are slightly resinous.
Bark: Young bark is yellowish-gray or a light reddish-brown. Mature bark is dark grayish-brown. Furrows in the trunk break it into elongated, broad, irregular plates.
Cones: All pines are gymnosperms, which means that they reproduce with seeds but do not bear flowers or fruits. All pines are also monoecious, meaning that they bear both seed and pollen cones in separate structures on the same plant. The seeds cones can be “serotinous” (meaning that they remain closed at maturity and only open in response to a fire) or they can be “nonserotinous” (meaning that they open to release the seeds as soon as they are mature).

On loblolly pine, the pollen cones are 2-4 cm long and yellowish brown, sometimes with a hint of red.

The young seed cones are yellow turning to green and generally appear in clusters of 2 or 3 (rarely solitary). Mature seed cones are 6-10 cm long and anywhere from light to dark brown. The cones are egg-shaped to cylindrical and either sit directly on the branch or on very short stalks. The exposed part of each scale forms a diamond shape that is crossed by a distinct ridge with a stout, sharp spine in the middle. Loblolly pine produces a large number of cones and there are usually many cones on the tree at any time of year. The cones are nonserotinous and usually fall soon after maturity.

Seeds: The seeds of loblolly pine are 5-7 mm, with an attached wing adding 15-23 mm.
Similar Trees on the Florida 4-H Forest Ecology Contest List:
There are four pine species on our list.

  • Loblolly Pine has needles in fascicles of 3. The needles are 4 to 9 inches long.
  • Longleaf Pine has needles in fascicles of 3 or occasionally 4. The needles are 8 to 18 inches long.
  • Pond Pine has needles in fascicles of 3 or occasionally 4. The needles are 4 to 8 inches long.
  • Slash Pine has needles in fascicles of 2 or occasionally 3. The needles are 5 to 12 inches long.

Images

Click on any thumbnail to see a photo. Use left and right arrows to navigate. Use “esc” to exit the lightbox.

Photo credit: Larry Korhnak
University of Florida
Photo credit: Larry Korhnak
University of Florida
Photo credit: Erich G. Vallery
USDA Forest Service – SRS-4552
Bugwood.org
Photo credit: Franklin Bonner
USFS (ret.)
Bugwood.org

Learn More

  • USDA Forest Service Fire Effects Information System (FEIS) – Pinus taeda
  • UF/IFAS EDIS Fact Sheet
  • USDA/NRCS Fact Sheet

Loblolly Pine

This tree is one of the fastest growing southern pines. One of the meanings of “loblolly” is mud puddle, where these pines often grow.
Pinus taeda (Loblolly Pine), also called Arkansas pine or North Carolina pine, is a large evergreen tree and the largest of the southern pines. It reaches heights of 90′ to 110′ with a diameter of 1 to 5′ with exceptional specimens reaching160′. The tallest Loblolly Pine currently known stands at 169′ in Congaree National Park. Loblolly Pine has a long, clear trunk, ascending limbs, and a rounded, spreading crown. It is one of several pines native to the Southeastern United States, from central Texas east to Florida, and north to Delaware and Southern New Jersey. Over 50% of the standing pine in the southeast is loblolly.
The word loblolly means “low, wet place”, but these trees are not limited to that specific habitat. Loblolly Pines grow well in acidic clay soil, which is common throughout the South, and are thus often found in large stands in rural places. Other old names, now rarely used, include oldfield pine, due to its status as an early colonizer of abandoned fields; bull pine, due to its size (several other yellow pines are also often so named, especially large isolated specimens); and rosemary pine, due to loblolly’s distinctive fragrance compared to the other southern pines.
For the scientific name, Pinus is the Latin name for pines and taeda refers to the resinous wood.
With the advent of wildfire suppression, Loblolly Pine has come to prevalence in some parts of the Deep South that were once populated with greater numbers of Longleaf Pine. The rate of growth is rapid, even among the generally fast-growing southern pines.
The famous “Eisenhower Tree” on the 17th hole of Augusta National Golf Club is a Loblolly Pine. U.S. President Dwight D. Eisenhower, an Augusta National member, hit the tree so many times that, at a 1956 club meeting, he proposed that it be cut down. Not wanting to offend the President, the club’s chairman, Clifford Roberts, immediately adjourned the meeting rather than reject the request outright.
Its needles are in bundles of three, sometimes twisted, and measure 4” to 9” long, an intermediate length for southern pines. They have a slight bluish-green tinge, are stiff, and sometimes slightly twisted. The needles usually last up to two years before they fall, which gives the species its evergreen character. Although some needles fall throughout the year, most needles fall during the autumn and winter of their second year.
Loblolly pine produces a large number of cones every year. The seed cones are green, ripening pale buff-brown and 3” to 6” in length. They are ¾” to 1 ¼” broad when closed but open to 1 ¾” to 2 ½” wide. Each scale bears a sharp spine. They remain on the trees for several seasons.
The bark is grayish-brown and furrowed with elongate, broad, irregular plates. Young twigs are reddish-brown and scaly. Buds at the ends of branches are much thinner than associated slash and longleaf pine.
The wood, which is marketed as southern yellow pine, is primarily used for pulp and paper but also for lumber and plywood. It may be sold interchangeably with shortleaf pine. This tree is commercially grown in extensive plantations.
Loblolly pine stands are important for numerous wildlife species. The trees provide habitat for many animals, including white-tailed deer, wild turkey, gray squirrels, rabbit, quail, and doves. Many songbirds feed on the seeds and help propagate the trees through seed dispersal. Red crossbills depend on loblolly pine seeds for up to 50% of their diet. Other birds that frequent the trees include pine warblers, Bachman’s warblers, and brown-headed nuthatches. Osprey and bald eagles often nest in tall loblolly pines.
Two endangered species that also use these pines are fox squirrels, which eat the cones, and red-cockaded woodpeckers, who will sometimes nest in old growth trees.

How Tall Pine Trees Get

Pine Trees image by Antonio Oquias from <a href=’http://www.fotolia.com’>Fotolia.com</a>

Depending on the species, pine trees grow to greatly varying heights. From a dwarf tree at a short height of 4 feet to a variety that reaches 100 feet in maturity, there are several options for your landscape. Identify different species, their features, growth rates and expected heights for a broad selection.

Care for Appropriate Growth

Provide excellent care to pine trees so they reach their full potential height. Plant pine trees in areas exposed to full sun. Grow pines in preferred moist, slightly acid, well-drained soil with good fertility. Add mulch to the area surrounding trees for increased water retention and to prevent problematic weeds, according to the Clemson University Extension.

Dwarf Pine Trees

Dwarf cultivars of the mugo pine tree (Pinus mugo) reach a height range of 2 to 5 feet. Cultivars include Gnom, which reaches a height of 2 feet with a spread of 3 feet, and Compacta, which reaches a height of 4 feet with a width of 5 feet. Mugo pines are slow growers, averaging under 1 foot of growth annually. Foliage is needle-like and evergreen, fading to a yellow-green color during the winter season. Cones measure up to 2 inches in length.

Short Pine Trees

Virginia pines (Pinus virginiana), also referred to as scrub pines, reach a height of 15 to 40 feet with a spread of 10 to 30. These short evergreen pine trees display dark green to yellow-green needle-like foliage that yellows during the winter months. Exhibiting a slow growth rate of less than 1 foot annually, Virginia pines produce cones that measure 2 to 3 inches in length. Standard mugo pines also grow to a height range of 15 to 20 feet with a spread of 20 to 25.

Medium Pine Trees

Medium pines include spruce pines (Pinus glabra) that reach a height of 50 to 90 feet. Longleaf pines (Pinus palustris) are another medium pine species with a height range of 55 to 80 feet. Spruce pines display dark green needle-like foliage with a twisted appearance as well as cones that reach up to 2 1/2 inches. Spruce pines are known for their fast growth rate. Longleaf pines display dark green needle-like foliage and cones that reach 6 to 10 inches long. Growth rate is variable, beginning as a slow process within the first 10 years of life and progressing to a faster rate of 2 feet of new growth annually.

Tall Pine Trees

Tall pines reach 100 feet or more. Though white pine (Pinus strobus) may remain at a height of 50 to 80 feet, it has the potential to reach 150-plus feet in maturity, according to the Clemson University Extension. White pines display blue-green needles at a rapid growth rate of over 2 feet every year. Slash pines (Pinus elliottii) are a more reliably tall variety with an ultimate height of 100 feet. Slash pines display dark green needle-like foliage and glossy brown cones that measure 3 to 6 inches in length; slash pine grows quickly at more than 2 feet of new annual growth.

Scientists Just Solved The Strange Case of Pine Trees That Always Lean Towards The Equator

You can find them in many places around the world – tall, lean conifers that can’t seem to grow straight. And now scientists have figured out that the direction these Cook pines (Araucaria columnaris) lean is always towards the equator, but they’re not quite sure why.

Scientists have measured these trees across five continents and, for the first time, documented a species with a leaning pattern that appears to be hemisphere-dependent.

Cook pines originally come from New Caledonia, a tropical archipelago in the southwest Pacific Ocean. The trees were first classified during Captain James Cook’s second mission to circumnavigate the globe.

These stately pines are a popular choice for parks and gardens in many parts of the world. They can grow up to 60 metres tall (197 feet), and due to their short branches, they have a characteristic narrow appearance.

But even more characteristic is a propensity for a drunken-looking slant.

“When grown outside of its native range, this species has a pronounced lean so ubiquitous that it is often used as the identifying characteristic for the species,” the researchers write in their paper.

Leaning pines on the campus of the University of California, US. Photo: Johns et al., Ecology (2017)

It started out as an anecdotal observation – one of the researchers, botanist Matt Ritter from California Polytechnic State University, noticed that in California and Hawaii, the pines all seemed to be leaning south.

But A. columnaris are also commonly grown in Australia, where one of them has even become an infamous leaning Christmas tree in the town of Lismore.

And weirdly enough, colleagues told him that the tilt in the southern hemisphere is directed towards the north.

To investigate this, Ritter and his team gathered measurements from 256 trees across 18 regions on five continents, including the species’ native range in New Caledonia.

The researchers excluded any trees whose growth could be impacted by another object, such as a building or electricity pole.

They recorded the height of each tree, trunk diameter, as well as the compass direction and extent of the lean, and to their surprise, Cook pines turned out to be more systematic in their leanings than anyone could have expected.

“We uncovered a surprisingly consistent pattern of hemisphere-dependent directional leaning in A. columnaris,” the team reports.

On average, the pines tilt by 8.05 degrees, leaning south in the northern hemisphere, and the opposite direction in the southern hemisphere. Less than 9 percent of the trees measured didn’t conform to this pattern.

And latitude makes a difference, too – the further away the trees grew from the equator, the greater the slant. So instead of labelling them drunks, it could have something to do with sunlight.

Many plants, including conifers like these pines, are known for their propensity to lean towards a light source when it’s not directly above the shoot – a characteristic known as phototropism.

But there’s a different plant characteristic that helps trees stay upright – their ability to detect gravity at a molecular level, and therefore direct roots and shoots in the correct directions (towards and away from the ground, respectively).

Even if a baby tree develops a tilt towards the sun, as the plant matures it tends to correct this asymmetry and grow upwards, unless there’s an environmental force preventing this, such as really strong prevailing winds in one direction.

But for some reason, A. columnaris just keep on tilting, no matter how tall they grow. And they even appear to be unique in this regard, because other Araucaria species from New Caledonia can stand up straight no matter where in the world you plant them.

It’s possible that Cook pines have a genetic quirk that allows them to lean, seeking out more sunlight in latitudes other than their native range. But scientists think that gravity and even Earth’s magnetic field could be playing a role, too.

“The mechanisms underlying directional lean of A. columnaris may be related to an adaptive tropic response to the incidence angles of annual sunlight, gravity, magnetism, or any combination of these,” they write.

Of course, the researchers are hoping to investigate further. They think that further studies of the species could even lead to discovery of little-known mechanisms that plants use to respond to environmental cues.

The study was published in Ecology.

Pinus taeda / Loblolly pine

Description. Loblolly pine is an evergreen coniferous species of tree that grows to mature heights of 100 to – 125 feet (30 – 35 m) with a trunk up to 1.3 to 5 feet (0.4 – 1.5 m) in diameter measured at breast height. Exceptional specimens may reach 160 feet (50 m) tall, the largest of the southern pines. Trees mature with a broadly conic to rounded crown.

  • Bark is red-brown in color, forming square or irregularly rectangular, scaly plates, with no present resin pockets.
  • Branches grow spreading and ascending.
  • Twigs are moderately slender at circa 0.4 inch (1 cm) thick, orangish to yellow-brown in color, aging darker brown with a rough texture.
  • Foliar buds are lance-cylindric shape, colored pale red-brown, measuring 0.4 to 0.48 inch (1 – 1.2 cm) long, mostly less than 0.4 inch (1 cm) broad. They are slightly resinous, with ; scale white-fringed margins and acuminate apices
  • Leaves (needles) are borne in fascicles of three, growing sometimes twisted, measuring 4.8 to 8.8 inches (12 – 22 cm) long — an intermediate length for southern pines, shorter than those of the Longleaf pine (P. palustris) or slash pine (P. elliotii), but longer than those of the Shortleaf pine (P. echinata) and Spruce pine (P. glabra). The needles usually persisitt up to two years before falling, which gives the species its lush, evergreen character. Although some needles fall throughout the year due to severe weather, insect damage, and drought, most needles fall during the autumn and winter of their second year.
  • Pollen cones are cylindric, measuring 0.8 to 1.6 inches (20 – 40 mm) long, yellow to yellow-brown in color.
  • Seed cones are green in color, ripening pale buff-brown, measuring 2.8 to 5.2 inches (7 – 13 cm) in long, by 0.8 to 1.2 inches (2 – 3 cm) broad when closed, opening to 1.6 to 2.4 inches (4 – 6 cm) wide.
  • Seed scales bear a sharp 0.12 to 0.24 inch (3 – 6 m) long prickle.

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