Trunk movement in young vs mature fir's?

[amatbrewer]

While hiking in the mountains this weekend and observing trees for inspiration, I was struck by something that maybe someone could help explain.

I was focusing on sub-alpine firs (I love sub-alpine firs) and noticed most of the young trees had lots of really nice movement to the trunk (and most of the ones that were not 'nice' still had lots of movement). But then when I looked for examples of what this looks like as mature trees in the same area, I was surprised to find that it was hard if not almost impossible to find mature trees that I could envision starting as those same young ones?!?! Most of the mature trees had very little moment to the trunks and the few that did were not all that pleasing and most were from obvious causes (e.g. a large down hill bow near the base from rock or heavy snow loading on the hill).

Now I am familiar with the dramatic shapes I see in these when they are on ridge tops or cliff faces. How they get to become what they are is obvious from the extreme conditions they experience. But I am not sure how in the less extreme areas, why most of the young trees would have such dramatic (and often very pleasing to the eye) movement in the trunk, but it is almost nonexistent in the mature trees.

What am I missing?

Fop reference below is a young stand of sub-alpine firs that I found inspirational.

 

[Wires_Guy_wires]

Imagine a garden hose coiled up, having drastic bends.
You then turn on the tap, and the pressure inside the hose will increase. This evens out most bends. This happens in seconds.

Now imagine a piece of wood, and decades of water flowing through that wood. The pressure to get water a few feet up in the air can be quite high, but still just a drop a minute or so. Multiply that by a few decades, and over time you'll have enough force to bend wood. The path of least resistance.
In herbs like tomatoes, this can take just a few hours (or months) and it's a fun thing to try at home. Wire them down for a day or two, and or even pinch the stem so you can give a branch a 45 degree angle. Within a week it'll be back up again, or at least trying to. Over time, these angles will decrease, even in wood. Sometimes internal structures stay intact and the rest of the tree just grows around it, but straight up none the less.

 

[amatbrewer]

Makes total sense. Thanks!

 

[AJL]

Could it also be a long term result of repeated livestock and deer browsing damage when they are young. Here in Britain I find sites with a high deer or sheep population often have some wonderful 'naturally' stunted 'instant bonsai' where young saplings have been repeatedly browsed over the years.
If the browsing pressure is reduced for example when sheep grazing is stopped by fencing them out of an area, or if the deer population is reduced, then the stunted trees react by growing away rapidly. Perhaps in USA and Canada this might happen due to increased predation of grazing animals by wolves? Only a theory!!!....

 

[just.wing.it]

Could be that the curvy ones get shaded out by the straight ones....if its dense woods.

 

[0soyoung]

I'm not clear on how 'interesting ones' came to be. I've seen contorted trees in the forest.
Sometimes it is clear that they are in an avalanche zone and get laid flat during the winter - then they curve up when the snow melts. Sometimes it is clear that the seedling grew horizontally to reach light (followed the gradient in light intensity), then it grew upward following a path that rendered the foliage getting maximal light. In these cases, the continued growth of the bigger/older neighbors shutters off the light and the little guy dies.
Other times I see trees with lots of trunk movement and cannot, for the life of me, conceive of how/why it got to be that way. It is sheltered from wind, it isn't subject to snow pack sliding, it isn't under or even near the big guys in any meaningful sense. This is more of a mystery to me that why the big guys always go straight up. There are an abundant number tropisms that tend to make the trunk straight vertical.

 

[amatbrewer]

Other times I see trees with lots of trunk movement and cannot, for the life of me, conceive of how/why it got to be that way. It is sheltered from wind, it isn't subject to snow pack sliding, it isn't under or even near the big guys in any meaningful sense. This is more of a mystery to me that why the big guys always go straight up. There are an abundant number tropisms that tend to make the trunk straight vertical.

This is one of the things that I assumed that few if any besides me geek out over.
I love finding trees with aspects where the cause is not obvious and then see if I can figure out the what/why behind it.
Being involved with trail maintenance I have seen many cases where we end removing the cause such as cutting and clearing a downed trunk or upturned root ball. In other cases I have determined that the trunk or rocks that were the cause have been removed by natural conditions (e.g. a bolder had been up against the trunk but then erosion cause it to move). Much of this is pure speculation on my part based on what little evidence is left and I am probably wrong often, but I find it an enjoyable mental exercise.

 

[River's Edge]

I'm not clear on how 'interesting ones' came to be. I've seen contorted trees in the forest.
Sometimes it is clear that they are in an avalanche zone and get laid flat during the winter - then they curve up when the snow melts. Sometimes it is clear that the seedling grew horizontally to reach light (followed the gradient in light intensity), then it grew upward following a path that rendered the foliage getting maximal light. In these cases, the continued growth of the bigger/older neighbors shutters off the light and the little guy dies.
Other times I see trees with lots of trunk movement and cannot, for the life of me, conceive of how/why it got to be that way. It is sheltered from wind, it isn't subject to snow pack sliding, it isn't under or even near the big guys in any meaningful sense. This is more of a mystery to me that why the big guys always go straight up. There are an abundant number tropisms that tend to make the trunk straight vertical.

When collecting sub-alpine fir i have noted the contorted specimens are that way due to heavy snow load repeatedly throughout growing areas. The straighter ones tend to be in areas that heavy snow does not accumulate as much due to density of the forest. In other words the more interesting specimens tend to be in areas exposed to the elements rather than protected by denser forest. This is the same for Mt. Hemlock, we deliberately target the exposed sides of the high alpine that are facing the prevailing winds and heavy storm paths.

 

[parhamr]

In my time wandering the alpine forests, I’ve noticed the same as most reports above:

• Edges of forests
• Exposed gaps between tall trees
• Edges of rock faces
• Large lower bends often occur from large trees landing on small ones
• Wiggles relate to snow—it may fall to one depth, then shift in a melt, then the next storm comes, blowing a different direction
• 90-degree and greater sharp corners are breaks from animals or tree fall that then heal over

 

[Shibui]

Now imagine a piece of wood, and decades of water flowing through that wood. The pressure to get water a few feet up in the air can be quite high, but still just a drop a minute or so. Multiply that by a few decades, and over time you'll have enough force to bend wood. The path of least resistance.

I don't think this is the real process. As a lumber miller I get to see the insides of many trees. I see plenty where the core of the log (which was once the immature sapling) is bent but the outside of the older log is now straight. I take this to meant that the tree did not bend itself straight. You are correct about the quickest path being a straight line so I'm confident from what I see that the tree simply grows more on the inside of bends so eventually the trunk ends up straight. When we slice through a log you can see that the growth rings are wider on the inside of many bends and narrower on the outsides.

In plantation grown softwoods here younger trees sometimes get bends like the picture above, even though we have no snow or other adverse environmental factors. These bends in our trees are known as 'speed wobble' caused by the sapling growing faster than it can harden up so the new growth can't support itself and bends over to various degrees. Bad wobbles will not grow out but minor bends will disappear as the trunk thickens (not by actually straightening but by thickening more inside the bends.
I have no idea whether any of these factors could be at play in the firs referred to in sub alpine environment. Maybe it is just a case of straighter ones winning the competition and bendy ones not surviving because they don't get a fair share of light quick enough?

 

[River's Edge]

Competition for sunlight, and other resources is sound reasoning for survival. The bent, stunted, damaged trees rarely recover to match the other trees. Collection is often challenged by the weakened condition of the " collectable" or desired forms that show character and age due to the trials they have endured. It often takes three seasons for adequate recovery before any Bonsai work can commence.