Very strange tree behavior....

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Very strange tree behavior....

#1  Postby Macdoc » Jun 05, 2017 1:14 am

DAILY NEWS 2 June 2017
The strange Cook pine trees that always lean towards the equator

Matt Ritter at California Polytechnic State University in San Luis Obispo was writing up a description of the Cook pine (Araucaria columnaris) for a book on the urban trees of California when he realised that the pines always leaned south. So he rang up a colleague in Australia to see if that was the case there. It turned out it was – but this time the pines leaned north.

“We got holy-smoked that there’s possibly a tree that’s leaning toward the equator wherever it grows,” says Ritter.

He and his colleagues studied 256 Cook pines scattered across five continents. They collected tree data at 18 locations between latitudes of 7 and 35° north, and 12 and 42° south. The team estimated that the trees tilt by 8.55 degrees on an average – about double the tilt of the Leaning Tower of Pisa.

The trees also slant more the further they are from the equator in both hemispheres. “It’s a shockingly distinct pattern,” says Ritter. One tree in South Australia slants at 40 degrees.

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https://www.newscientist.com/article/21 ... e-equator/

:scratch: coriolis ???
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Re: Very strange tree behavior....

#2  Postby felltoearth » Jun 05, 2017 1:55 am

Sunlight
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Re: Very strange tree behavior....

#3  Postby Weaver » Jun 05, 2017 2:04 am

felltoearth wrote:Sunlight

Exactly.
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Re: Very strange tree behavior....

#4  Postby Macdoc » Jun 05, 2017 3:22 am

The trees also slant more the further they are from the equator in both hemispheres.


and this is explained by sunlight?? Must be very naive researchers were it so simple.
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Re: Very strange tree behavior....

#5  Postby Weaver » Jun 05, 2017 3:44 am

Macdoc wrote:
The trees also slant more the further they are from the equator in both hemispheres.


and this is explained by sunlight?? Must be very naive researchers were it so simple.

If, as the photo appears to show, they preferentially grow their branches on the equator-side of the tree, then yes, it is not surprising that the effect is more pronounced further from the equator, as the Sun position is more biased throughout the year in high latitudes. Once above the 23 degree line, there is no time during the year when the Sun isn't to the equator side of the tree, so all branch growth might happen on the equator side - causing the tree to lean more and more to expose the pole-side to sunlight during the midday.
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Re: Very strange tree behavior....

#6  Postby Weaver » Jun 05, 2017 3:50 am

From your OP article, Macdoc:
Trees normally correct for such asymmetry in their growth, but for some unknown reason the Cook pine is unable to do so, says Ritter. “We could be just dealing with an artefact of its genetics that we are seeing now when we have spread it all over the world,” he says. Alternatively, it could be an adaptation to catch more sunlight at higher latitudes.
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Re: Very strange tree behavior....

#7  Postby Weaver » Jun 05, 2017 3:51 am

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Re: Very strange tree behavior....

#8  Postby theropod » Jun 05, 2017 11:58 am

Phototropism.

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Re: Very strange tree behavior....

#9  Postby juju7 » Jun 05, 2017 12:24 pm

theropod wrote:Phototropism.


I think you can get a cream for that
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Re: Very strange tree behavior....

#10  Postby felltoearth » Jun 05, 2017 2:28 pm

I've seen Ash trees planted on the north side of buildings lean northward to capture more light. Doesn't surprise me that there are trees that will do this at different latitudes.
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The weirdness that is the Cook Pine

#11  Postby Calilasseia » Jun 07, 2017 12:46 am

New Scientist has just presented me with this article featuring Araucaris columnaris, a coniferous tree that is originally an endemic of the New Caledonia flora, but which has been transplanted to a range of locations around the world.

This is a tree that leans toward the Equator. Plant it south of the Equator, and it grows leaning north. Plant it north of the Equator, and it grows leaning south.

A scientific paper documenting this can be found here.

From the paper (citation: Worldwide Hemisphere-Dependent Lean In Cook Pines by Jason W. Johns, Jennifer M. Yost, Dean Nicolle, Boris Igrc & Matt K. Ritter, Ecology, 0(0): 1-3 (2017)):

Johns et al, 2017 wrote:Under most conditions, trees grow vertically in response to the opposing influences of light and gravity (Wyatt and Kiss 2013). In challenging environments, where competition for light or mechanical stress is intense, trees may grow non-vertically (Loehle 1986). Here we describe a novel hemisphere-dependent leaning habit in Araucaria columnaris (Cook pine) (J.R. Forst.), a widely cultivated conifer endemic to New Caledonia. Specifically, in a large sample of individuals from around the world, we demonstrate that the Cook pines’ lean is non-random: trees in the northern hemisphere lean south, and those in the southern hemisphere lean north. Additionally, the magnitude of the lean is more pronounced at higher latitudes in both hemispheres. Our data and the pattern that we describe here elucidate the fact that plants are responding to their global environment in a way not yet fully understood.

A tree’s form is determined by the complex interactions of genetics and environmental stimuli (Braam 2005). Under most conditions, trees grow vertically in response to the opposing influences of light and gravity (Loehle 1986). In challenging environments, where competition for light or mechanical stress is intense, trees may grow in a non-vertical fashion (Braam 2005, Telewski 2006). Although the growth responses contributing to vertical growth have been studied for over 100 yr, the mechanisms driving them remain only partly elucidated (Darwin and Darwin 1880, Sinnott 1952, Wyatt and Kiss 2013). Never before has a hemisphere-dependent leaning pattern been documented across a tree species.

Araucaria columnaris (J.R. Forst.) Hooker, the Cook pine, is a New Caledonian endemic conifer, which has been planted in temperate, subtropical, and tropical areas throughout the world (Fig. 1; Kershaw and Wagstaff 2009). 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 (Farjon and Filer 2013). While the common lean of A. columnaris has been anecdotally observed, its hemisphere-dependent leaning pattern has not been described in the literature. We first noticed A. columnaris leaning south in California and Hawaii, where it is a common horticultural plant. Our observation from Australia, though, suggested that A. columnaris lean north in the southern hemisphere.

We measured 256 trees on five continents in 18 different regions (distinct areas more than 500 km from each other), spanning 7°–35° N and 12°–42° S latitude, including the species’ native range in New Caledonia (21° S). For each tree, we recorded height, trunk diameter at 1.5 m above ground, azimuth direction of lean, and the extent of lean (see Appendix S1). We defined the extent of lean as the horizontal distance on the ground from directly beneath the apical meristem to the base of the trunk. The magnitude of lean is the extent of the lean divided by the tree’s height (Appendix S1). We used magnitude of lean for downstream analyses. The median lean for all trees measured is 2.42 m away from the base, and the median tree height is 18 m, resulting in an 8.05° lean angle (95% CI 7.50°–8.50°).

We uncovered a surprisingly consistent pattern of hemisphere-dependent directional leaning in A. columnaris. In the northern hemisphere, trees lean south (median azimuth of 151°, 95% CI 144°157°), and in the southern hemisphere they lean north (median azimuth of 0°, 95% CI 15°10°; Fig. 2). Fewer than 9% of individual trees lean away from their predicted direction. This pattern is consistent across all regional samples (18/18; sign test, P << 0.001).

We also examined the relationship between magnitude of lean and latitude (Fig. 3). For these analyses, we used only the north-south axis component (scalar) of lean azimuth, or “axial lean” (Appendix S1). We found that a simple linear regression explains 54% of the variance, suggesting that trees lean more the further they are from the equator (R2 = 0.543, F1,254 = 304.4, P << 0.001).

The cause of directional lean in this species is unclear. Vertical growth in shoots is generally maintained by a negative relationship with gravity (negative gravitropism; Hashiguchi et al. 2013) and a positive relationship with their light source (positive phototropism; Darwin and Darwin 1880, Loehle 1986, Christie and Murphy 2013). Non-vertical shoot growth can be caused by mechanical perturbation from wind or snow or by a phototropic response to a light source that is not directly above the shoot (Tomlinson 1983, Telewski 2006). Mechanistic studies in Arabidopsis thaliana have identified several gene families whose regulation effects phototropic and gravitropic growth in plants. However, the mechanisms controlling the expression of these genes and the interactions between them are not well understood, especially for woody species (Wyatt and Kiss 2013).

The leading hypothesis for the molecular mechanism of gravitropism is that sedimentation of amyloplasts on actin microfilaments activates a signal transduction pathway resulting in asymmetric transport of auxin in the stem, causing it to straighten itself parallel with the gravity vector (Hashiguchi et al. 2013). This hypothesis, like phototropism, is supported by the identification of genes whose proper expression is necessary for observing a gravitropic phenotype.

Phototropism acts principally during primary growth in shoot tips to maintain an upright form in trees (Speck and Burgert 2011). Once secondary growth begins in stems, trees correct asymmetrical growth by forming reaction wood (Sinnott 1952, Du and Yamamoto 2007). Reaction wood results from asymmetric growth in the vascular cambium and can cause a leaning stem to correct itself to vertical. Although the mechanisms are different in gymnosperms (compression wood) and angiosperms (tension wood), trees can reestablish vertical growth after external forces cause leaning (Plomion et al. 2001).

forces cause leaning (Plomion et al. 2001). The mechanisms underlying directional lean of Araucaria columnaris may be related to an adaptive tropic response to the incidence angles of annual sunlight, gravity, magnetism, or any combination of these (Loehle 1986, Christie and Murphy 2013). It is interesting that the pronounced lean in A. columnaris is rare in other species, including other Araucaria native to New Caledonia. It is possible that the biophysical constraints of leaning for a tall tree ultimately prevail over any benefits of additional light interception gained by leaning (Read and Stokes 2006). Another possibility is that the lean is non-adaptive, or even harmful. Even though A. columnaris is one of the most widespread Araucaria species in New Caledonia, and the only one to express a lean, the species may nevertheless have small effective population sizes, and suffer fixation of deleterious alleles.

Regardless of which causal processes give A. columnaris its characteristic lean, this unique phenomenon needs further study. A better understanding of the dramatic leaning pattern in this species may lead to discoveries regarding the underlying mechanisms linking plant responses to environmental cues.
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Re: Very strange tree behavior....

#12  Postby aban57 » Oct 06, 2017 2:34 pm

Macdoc wrote:
DAILY NEWS 2 June 2017
The strange Cook pine trees that always lean towards the equator

Matt Ritter at California Polytechnic State University in San Luis Obispo was writing up a description of the Cook pine (Araucaria columnaris) for a book on the urban trees of California when he realised that the pines always leaned south. So he rang up a colleague in Australia to see if that was the case there. It turned out it was – but this time the pines leaned north.

“We got holy-smoked that there’s possibly a tree that’s leaning toward the equator wherever it grows,” says Ritter.

He and his colleagues studied 256 Cook pines scattered across five continents. They collected tree data at 18 locations between latitudes of 7 and 35° north, and 12 and 42° south. The team estimated that the trees tilt by 8.55 degrees on an average – about double the tilt of the Leaning Tower of Pisa.

The trees also slant more the further they are from the equator in both hemispheres. “It’s a shockingly distinct pattern,” says Ritter. One tree in South Australia slants at 40 degrees.

Image

https://www.newscientist.com/article/21 ... e-equator/

:scratch: coriolis ???


I was under the impression that Coriolis force only acted on significant masses, was I wrong ?
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Re: Very strange tree behavior....

#13  Postby zulumoose » Oct 06, 2017 2:44 pm

A strange phenomenon worldwide is that wherever solar panels are planted, they also tend to lean towards the equator. Must be something to do with gravity or the phases of the moon.
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Re: Very strange tree behavior....

#14  Postby DavidMcC » Oct 06, 2017 2:51 pm

zulumoose wrote:A strange phenomenon worldwide is that wherever solar panels are planted, they also tend to lean towards the equator. Must be something to do with gravity or the phases of the moon.

Nicwe one, 'moose! :thumbup:
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Re: Very strange tree behavior....

#15  Postby CdesignProponentsist » Oct 06, 2017 8:26 pm

aban57 wrote:

I was under the impression that Coriolis force only acted on significant masses, was I wrong ?


It's extremely difficult to measure the Coriolis effect even with a large pool of water moving towards a drain. I doubt the slow moving sap moving through the tree could have any effect on growth behavior.


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Re: Very strange tree behavior....

#16  Postby The_Piper » Oct 07, 2017 12:34 pm

Macdoc wrote:
DAILY NEWS 2 June 2017
The strange Cook pine trees that always lean towards the equator

Matt Ritter at California Polytechnic State University in San Luis Obispo was writing up a description of the Cook pine (Araucaria columnaris) for a book on the urban trees of California when he realised that the pines always leaned south. So he rang up a colleague in Australia to see if that was the case there. It turned out it was – but this time the pines leaned north.

“We got holy-smoked that there’s possibly a tree that’s leaning toward the equator wherever it grows,” says Ritter.

He and his colleagues studied 256 Cook pines scattered across five continents. They collected tree data at 18 locations between latitudes of 7 and 35° north, and 12 and 42° south. The team estimated that the trees tilt by 8.55 degrees on an average – about double the tilt of the Leaning Tower of Pisa.

The trees also slant more the further they are from the equator in both hemispheres. “It’s a shockingly distinct pattern,” says Ritter. One tree in South Australia slants at 40 degrees.

Image

https://www.newscientist.com/article/21 ... e-equator/

:scratch: coriolis ???
It appears as though The Angel of Death is in that picture. :shock:
I read in a very old book about finding south by looking at tree branches, they should have more growth on the south side. I took that to mean in a clearing.
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Re: Very strange tree behavior....

#17  Postby DavidMcC » Dec 01, 2017 10:25 am

Post withdrawn - someone actually DID argue that it was the Coriolis force! :roll:
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