[lookout bob]

we saw this tree on the Kautz Creek trail at Mount Rainier and I wonder what causes a tree to grow like this

[ThinAir]

Aliens

[IanB]

Western Red cedar is actually closest in relation to the cypress genus, which are among the trees most prone to develop alternate leaders if the circumstances favor such. I'd have been curious looking at that tree to see what was going on up above on the main trunk - such examples are often like puzzles where the history of the situation can be deduced. From what shows in your picture, some situation higher on the main trunk encouraged the low branch to turn upward. It then looks like it fused with itself (another thing Red cedar is prone to do), but then the shortest path for the live wood eventually skipped past the loop. At this point the whole assembly doesn't look like it is very robust as the main trunk seems fully dominant.

[Owler]

not related really but this is pretty cool...https://en.wikipedia.org/wiki/Trail_trees "Trail trees, trail marker trees, crooked trees, prayer trees, thong trees, or culturally modified trees are hardwood trees throughout North America that Native Americans intentionally shaped with distinctive characteristics that convey that the tree was shaped by human activity rather than deformed by nature or disease. A massive network of constructed pre-Columbian roads and trails have been well documented across the Americas, and in many places remnants can still be found of trails used by hunters and gatherers. One unique characteristic of the trail marker tree is a horizontal bend several feet off the ground, which makes it visible at greater distances, even in snow. "

[PowderPawn]

The loop I would think that maybe it grew around something which is no longer there... another tree etc. But looking at the way that it grew off of the side as well this does look even stranger. Maybe something to do with genetic mutation in the tree.

[Chief Joseph]

Is it possible that at the bottom of the branch that the round area with the hole might actually be one of those very large and old mushroom-growth type items? They normally grow upon dead trees but I have seen them on live varieties as well. Probably not, but might be a possibility?

[freshstart]

Ghost of a nursing log was my first thought, fits with most observations offered here so far (sorry aliens) I wonder if there might even be some of the very last remnants of the decayed nurse log laying alongside the tree trunk, any ground pictures? Edit: Found it, kind of https://goo.gl/maps/jnDL9U1ri8kS4k9w8 https://goo.gl/maps/XYhAmnSJrwMaL2jB7 https://goo.gl/maps/wm82VzgTEhHh2Xoz5

[IanB]

Thanks freshstart! Those pictures show that the entire tree is a dead snag, so it suggests that the original leader failed (maybe from lightning, or whatever) and then two lower limbs turned upright as replacements and did well for a number of years before dying too. Simple elbows like the upper limb are typical, but very contorted configurations like the lower one can readily occur also. If you think of how that lower branch was probably one of the last remaining, very droopy limbs near the bottom of the tree. When it was recruited into becoming a leader it had to do some serious repositioning. (You can see how much thicker the lower part of the loop is where it was laying down compression wood to assist in righting itself.) It's even possible that the tree failed in stages, with the upper secondary living for some time before failing, and then the lower one coming into play as a last gasp. A story like that could be explained by the tree slowly dying from root rot. As less root system is available over time, it becomes harder for the tree to service water to the upper canopy, and thus the secondary and then tertiary leaders were each attempts to struggle on with less before finally succumbing. Trees each have personal histories just like people. Learning to read their body language can add another whole dimension to our appreciation of their lives.