Does deadwood sap strength?

[Mike Corazzi]

Sorry. During my last repot, my roots got too dry and it has made seasonal quips very weak.

 

[Potawatomi13]

I have this dead and peeled end of a limb on a procumbens.

View attachment 410658

My question is should I lop it off? I have seen deadwood I like but it never leads to foliage.
Is this limb end keeping flow from the foliage higher on the same branch?
There's another on the tree but the light is too poor to get a pic of it.

The limbs in question are ones that have died off up to the dead part.

??

Is this rhetorical question?

 

[Wires_Guy_wires]

You made a comment about juniper foliage needed to draw resources into a juniper branch. That much is true. Before you jinned the end of that branch, the foliage on it was actively drawing water and other resources into the branch. Conversely, the branch was generating energy via photosynthesis, and also generating hormones to tell the tree "more roots needed - more vascular development needed".

If you remove 50% of the foliage on a branch and jin the tip (removing all live layers or bark), you are "weakening" the branch to the extent that suddenly the branch is not drawing up the same amount of water and resources, or generating the same amount of energy or growth hormone. When damage like this happens, the tree will balance and reallocate resources. The growth at the base of the branch might get stronger... or depending on the circumstances you may find that the growth lower down the branch may weaken or die back.

However the bottom line is that once you "kill" part of the tree by pruning, jinning, creating shari, or whatever, that part of the tree is "dead" and plays no further role. The tree will create a border of healing tissue, and will seal off the wound. The deadwood neither draws resources from the tree, nor contributes anything to it.

FWIW - the core of the trunk of a tree is deadwood. It is not living tissue and aside from providing structural support plays no further role in the growth of a tree.

I think this covers most of it. I agree.

I would however, would like to comment on the drop in sap pressure. A tree, or any plant for that matter, blows itself with water up like a balloon to reach turgor pressure. The foliage evaporates and draws water, the roots sip, pressurize and push water upwards. This (and a lot of other processes) creates a balance of evaporation and thus 'breathing' and drinking.
However, if a large branch is lopped off and the branch is jinned, this balance can take some time to restore. Some herbaceous plants can show this effect very seriously and look weak for days or even weeks after being cut. Either because they're slow to close the gaps, or because their internal pressure is so high that it physically can't close said gaps until it has proverbially run out of steam - lost so much water that the lack of pressure just stops the bleeding.
Grapevines can bleed out - as a kid I spent at least two spring weekends of my life slapping raw sliced potatoes on grapevine wounds trying to close them (the sap is delicious and sweet!) after the vine was cut at the wrong time. I've seen that pines can bleed pretty heavily too, due to their naturally high root pressure at certain times in a season.

I see fresh jins and fully undamaged branches as two different things: the jin can be compared to a pipe system with a tap on the end (open wound), and a tap somewhere in the middle (foliage). Whereas an undamaged branch can be seen as a pipe system with just a single tap on the end (foliage).
You can fill a bathtub with water from the first tap, while the other tap is running into an open sink.. But logically it's running at just half the pressure. It will be slower than a pipe system with a single tap at full pressure. It'll also be slower than the first system, with the end tap fully closed. Because the latter would just be similar to the second.
Until the tap is closed, there will be a difference in "time it takes to fill the tub" and in this analogy it also explains the difference in "the amount of water and solutes a branch receives in a given timespan". It works both in the 'draw water' direction as well as the 'push water' direction. Flowing water as we know it, always goes for the path of least resistance.. In a closed system, it's pushed by the roots and drawn by the foliage. In an closed system with open ends, that's not always the case.
In a sense, the plant vascular system is nothing more than a bunch of connected tubes that transport water through a membrane. There's an entire maple syrup industry leaning on the principle that if you pierce that system, you'll get free syrup until it closes. Now I'm a big fan of bacon and syrup! But I'm convinced that that same syrup could've fed a bunch of branches, and that drawing too much of it, can severely weaken a tree. There's probably a Canadian who can tell us more about that. I heard it's kind of their thing!

I think that's sort of what Mike is asking.
Sealing the jin isn't always helpful, but it you really want to keep the foliage close to it alive and thriving.. It might be a wise move to do so, until you actually see that the foliage is back on its feet.

The question that remains, I believe, is how much a wound actually hurts a branch near it. I think five is a good number. On a scale of somewhere between some numbers.