Crown lift too high?

[ QUOTE ]
I agree. With the hiker analogy, I liken it to my old favorite sport of trail running. When you take a corner you are less likely to fall over if you have weight in the middle as well as up high. Same for a vehicle; more tipsy with the roof rack packed.

I think "top-heavy" is a useful concept for hikers as well as trees. But I don't want this poor dead horse to get whupped up on any more either.

[/ QUOTE ]

Glad you mentioned that roof rack thing.

If we could use the same vehicle, keep the same frame structural strength, and remove weight only from the upper 3/4 or so, it may compare.

The lowest weight like the drive train would need to remain, as the closest representation of an anchored root system.

So we'd just be removing the window glass, headliner, gauges, seats, upper plastic trim, etc..

In the end, we'd have the heavy base, and a lighter upper vehicle. Although the load is on the rack, the upper vehicle would be lighter, and it would actually be less top heavy than before.

That's comparable to a hiker being less top heavy with just one backpack, than they would be with 2 packs (one on the back and one on the waist).

The illustration was not comparing the higher pack to the lower pack, but the matter of strength in relation to having one pack or two packs.

But the roof rack that you mentioned offers more versatility to thinking about weight and loads.
 
Mr Vaden and Mr Mayor, you guys are talking yourselves into a quandry especially you Mr Vaden. In fact you'd need to be a professor of english literature to try and decipher your last few posts.

Lets keep it simple.....

These trees are hideously over-lifted which puts them at significantly more risk of stem failure and windthrow because they have lost the dampening effect of the lower branches.

Maybe you guys should read this - http://joa.isa-arbor.com/request.asp?JournalID=1&ArticleID=91&Type=1

91057-crownlift.JPG
 
Damping

The energy from the wind is dissipated by the tree, using a complex damping mechanism. The tree's response to wind is to minimize the energy transferred from the wind to the main structure of the trunk. The energy is dissipated partly by the leaf drag, ... and partly by the complex branch sway mechanism.

The sway motion is heavily damped by three main factors:
..· mass damping: the interaction of the side branches attached to the main limb ...the sway motion in trees is damped because three main components: (1) interference of branches with those of neighbors, (2) aerodynamic drag on foliage, and (3) damping in the stem. This study estimated the importance of these three components to the overall damping was a ratio of 5:4:1 for a medium-sized tree.

**So branch dampening accounts for 1/2 of the total reduction in sway**

Thanks tockmal for leading us out of that quandary.
 
[ QUOTE ]

**So branch dampening accounts for 1/2 of the total reduction in sway**

Thanks tockmal for leading us out of that quandary.

[/ QUOTE ]

No problem Guy, you see it was simple really...remove those lower branches and we INCREASE the risk of stem snap or windthrow.
 
That's not a good practice, but I did see about 100 acres of Douglas fir in Beaverton cleared for logs, and the remnants either looked that way or got skinned-up that way. Murrayhill neighborhood. Even the remnants were a few hundred trees.

In the next 12 years or so - with some big Pacific NW storms - I don't recall seeing a single one of those 130' tall trees snapping or cracking a trunk. Several uprooted, but that was expected since most were interior trees - the perimeter and a lot of the middle protections was eliminated.

That's the sneaky part about trees sometimes. Its good to encourage people to avoid having their trees skinned-up into poodles, but then we are also faced with a lot of trees like this that don't exactly seem to prove our point sometimes.

Now, the attached image is a classic example in nature. These are evergreens on the Oregon Coast at Ecola State Park. These are right at the very edge of the land facing 80 to 100 mph winds virtually every winter. A couple of logs are laying on the ground for who knows what reason: not sure if they died first or not. But the bulk of the trees in the highly exposed grove, with their naturally skinned-up conopies, sway like a "mother", but they just hang in there.

99825-spruce.jpg
 

Attachments

  • 99825-spruce.webp
    99825-spruce.webp
    108 KB · Views: 27
And here is the flip side if you turn your back. This is basically what these trees are facing - no buffer...

The Pacific ocean with it's brute force winds...

This same grove endured the Columbus Day storm in 1963. Look on Wikipedia to see the winds for that storm. Stronger than the "storm of the century".

(Lighthouse is "Terrible Tilly" or Tillamook Rock Lighthouse.)

Ladies and Gentlemen, Allow me to present expert witnesses from nature...

99826-tilly.jpg
cool.gif
 

Attachments

  • 99826-tilly.webp
    99826-tilly.webp
    22.8 KB · Views: 57
Looks like a windy day in that lighthouse pic; it was a lot calmer last February.

Anyway, your expert witnesses were limbed up over a lifetime, forming reaction wood every minute of their lives. Suddenly exposed, perhaps, but still, how relevant is their testimony on the effects of sudden stripping?
 
[ QUOTE ]
Looks like a windy day in that lighthouse pic; it was a lot calmer last February.

Anyway, your expert witnesses were limbed up over a lifetime, forming reaction wood every minute of their lives. Suddenly exposed, perhaps, but still, how relevant is their testimony on the effects of sudden stripping?

[/ QUOTE ]

Over time yes.

But the ones in the neighborhood that did not break, were not limbed up over time.

Yes, it was a windy day at the lighthouse.

Probably 25 mph wind.

Did you know that the lighthouse was purchased and turned into a resting place for the deceased (probably cremation ashes).
 
i've seen trees like that in portland ore blow down in storms.... they slice a house in half!!!! it's my understanding also they will never develope trunk taper...or increase in trunk girth on the lower half?
 
[ QUOTE ]
i've seen trees like that in portland ore blow down in storms.... they slice a house in half!!!! it's my understanding also they will never develope trunk taper...or increase in trunk girth on the lower half?

[/ QUOTE ]

Exactly what I saw in Murrayhill and other neighborhoods near there where forests were cleared out leaving trees with top limbs only.

Never saw one snap, but they did blow over. In fact, I watched several blow over one day near Allen Blvd. in a big storm around 1989.

The inner trees never had taper anyway.

Some of the most sturdy trees I saw, were the full limbed trees sitting out in the open all by themselves for decades, which were never irrigated at any time.
 
[ QUOTE ]
they will never develope trunk taper...or increase in trunk girth on the lower half?

[/ QUOTE ]This cannot be true, but it's hard to argue with the observation that they will increase less without laterals.
 
i just read on another sight "excessive removal of lower branches should be avoided so that developement of taper is not affected" anyone want to correct me if it's wrong?!!!! Please comment.
 
the stand of trees in md vaden picture have not been "raised" . they appear to have no lower brances naturally. and they have may have adjusted in thier environment without any outside interference.
 
[ QUOTE ]
i just read on another sight "excessive removal of lower branches should be avoided so that developement of taper is not affected" anyone want to correct me if it's wrong?!!!! Please comment.

[/ QUOTE ]No it is not wrong. "Affected" does not mean "prevented". Taper always increases as long as the tree lives, but likely not as fast as with nearby laterals.
 
[ QUOTE ]
[ QUOTE ]
i just read on another sight "excessive removal of lower branches should be avoided so that developement of taper is not affected" anyone want to correct me if it's wrong?!!!! Please comment.

[/ QUOTE ]No it is not wrong. "Affected" does not mean "prevented". Taper always increases as long as the tree lives, but likely not as fast as with nearby laterals.

[/ QUOTE ]Guy...

Just for the sake of fun conversation, does the taper increase, or is the taper maintained as the tree elongates?

grin.gif
 
You must log in or register to reply here.

New threads New posts

Kask Stihl NORTHEASTERN Arborists Wesspur TreeStuff.com Teufelberger Westminster X-Rigging Teufelberger
Back
Top Bottom