A science-based tree fertilization question

Well said, bermie.

We need a plant biochemist/physiologist !

I'm not so sure about that "using stored starch reserves" concept in association with nitrogen application. Here are my untrained thoughts on this:

Nitrogen is the key element to plants manufacture of proteins, amino acids, DNA & RNA, etc. Carbon is extracted from the air, possibly the soil, and is combined by the plants to form these complex organic molecules. The whole process is driven by burning stored energy, which in turn is created by photosynthesis. Relative abundance of any of the starting materials alone is not sufficient, it takes an actively growing plant to utilized the starting materials.

I have always presumed that the stored energies are used to repair lost tissue and to perform cellular functions when photosynthesis is not available. I have always presumed that growth spurts are powered by the optimal conditions in fertility, moisture, temperature, and sunlight.

I have never thought that rapid growth would USE stored energy faster than it generated energy , as I always thought it would be powered by sunlight in optimal conditions.

Any thoughts on this, by the well educated plant biochemists among us?

All trees have an optimal mass:energy ratio.
That is, that it should be able to generate enough energy to maintain its mass and generate enough to store to fuel future normal seasonal demand and increases in mass. Obviously photosynthesis is the mechanism by which the energy is generated.
Trees will store that energy in the form of starch at the end of its 'seasonal cycle' in order to fuel the next season's spurt of leaf flush, and growth in other meristematic areas. The tree generates, uses and stores enough energy to maintain the mass it has and fuel future growth.

Pruning makes demands on those energy reserves to create callus tissue, and initiate compartmentalization, that is why we prune according to size, season and requirements/capabilities of the species. Other things use energy, root and twig extention, secondary growth, ect. and add nauseum...

If a tree is 'languishing' or 'sickly', it generally reduces its demands on stored energy because of the reduced ability to produce it in the first place and settles on maintaining the current mass achieved, and not forcing much addition to its mass that it would then have to obtain the additional energy to maintain. Such trees even reduce their mass - twig and branch dieback come to mind. This is as well what overmature trees do naturally as they decline into veteran status.

Now some might say, well if you fertilize such a tree with N based products and encourage new leaf growth, surely that will enable to tree to produce more sugars/starch and 'reinvigorate'.

What can happen, is that yes, initially the tree flushes new leaves, extends twigs, etc. BUT at what demand on the stored energy? You have now increased the overall mass, gone into an energy 'deficit' as stored energy reserves, being saved for maintaining the previous status quo, have been used to fuel this unexpected flush.

Can the new flush generate enough additional energy to restore the deficit AND add to the reserves necessary to maintain the now increased mass??

This is the question that must be asked, in light of the tree species, age, problems, site, climate, etc... N based fertilization may not be the way to go, OTHER formulations may be better, and indeed the one that certainly will do no harm, is forking in composted mulch.

Thus endeth the lesson...:jester:

Really good post

Very interesting.
Anybody ever watch Bill Nye The Science Guy?
He has a more grown up show on Discover, its called " STUFF HAPPENS"

Its true, it does. Science is the study of this stuff happening and also naming the stuff happening. Some stuff is natural and other stuff is not, you gotta watch out for both.

When it comes down to it you have to observe and judge each case by itself because there is a lot of stuff happening out there with a lot of different names effecting lots of other stuff. Maybe use some fertilizer, maybe not. what does it look like? what will happen if you do and what if not? Take a look at all the stuff in each case and see what is happening there. It might be different some where else. ( not usually by much though)

Sadly, I suspect that the tree fertilization nuts will not be reading any of this, or won't be able to see past the dollar signs when they find out we are not talking about tactics for selling more fertilization.

pdqdl said:

Sadly, I suspect that the tree fertilization nuts will not be reading any of this, or won't be able to see past the dollar signs when they find out we are not talking about tactics for selling more fertilization.

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This nut is I have been actively studying this topic lately so this topic has broadened my perspective. I have been forking in mulch well really spreading carefully with my skid steer around my trees. After a year I noticed less chlorosis leaf color and even healing of trunk wounds. I feel it to be directly related to my efforts because other trees not mulched have the same symptoms of chlorosis poor vigor etc. My soil is high in clay so my mulching is shallow like 2 inch in depth. I have contemplated mulching by drilling and back filling with wood chip mulch. I like to test stuff on my trees lol. On my trees that were mulched the leaves stay on longer in fall and this years drought did not even seem to reach permanent wilting point. I wish we could train home owners in the value of composed wood chip mulch as I have seen it's benefits at my property. I don't feel inorganic fertilizer can produce the same result and should be more used in temporary solution's to deficiencies and after prescribed fertilization pinpoints the need. I actually got in this thread looking for a good soil testing lab to send samples to!

Rope, check this out before you drill and backfill with chips.
http://www.puyallup.wsu.edu/~Linda ...ral Myths_files/Myths/Wood chip pathogens.pdf

Ed Roland said:

Rope, check this out before you drill and backfill with chips.
http://www.puyallup.wsu.edu/~Linda ...ral Myths_files/Myths/Wood chip pathogens.pdf

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Ok good read, but composted are ok right? I have an area I spread chips out and then push up in a pile and re-spread over a year period would not the uglys be gone in that time period? I also have rotten log piles that under neath are pure composted black sludge. I was thinking the aeration combination in heavy soil clays would be a benefit!

There are so many things going on in the soil that it is often hard to tell what is going on. We can read one study that will show that adding a certain treatment will be effective, then in a similar site another study shows no effect or a contraindication.


One thing all my reading has shown me is that by simply improving the bulk density, in the basal root zone, most trees will show some improvement. Composts have a wide spectrrum of minor and trace nutrients, they often will buffer pH, they hold moisture better.....

I think Russ Carson posted an anecdotal observation on the Knot Hole many years ago, where he found an eight fold increase in macro-biota in the mulched areas compared to the "lawn" a few feet away.

Recent studies by TCoT and Bartlett have shown total soil replacement with mixed composts and topsoil, in a 3-4 foot radius, will improve compaction stressed plants.

Another study i have read ( a few years ago) found that replacing with only composted "black dirt" retained too much water.

With the chlorosis, I'm reading a compilation book on Fe in crop plants, the causal conditions can be high levels of Ca in the soil, which can lead to elevated levels of bicarb. Compaction, to the extent that tire ruts in fields will be chlorotic, and outside them will be fine. Too much or too little water in the soil. Low Sulfur in the soil, seems that S is an integral component to moving the Fe from the roots to the transport mechanism of the xylem. Rather dry reading but some interesting stuff that supports my long held belief that soil samples are needed only after improving the soil does not solve the problems.

If it is an "improved" urban/exurban site then the soil is more then likely depleted, so say the least.

John Paul Sanborn said:

There are so many things going on in the soil that it is often hard to tell what is going on. We can read one study that will show that adding a certain treatment will be effective, then in a similar site another study shows no effect or a contraindication.


One thing all my reading has shown me is that by simply improving the bulk density, in the basal root zone, most trees will show some improvement. Composts have a wide spectrrum of minor and trace nutrients, they often will buffer pH, they hold moisture better.....

I think Russ Carson posted an anecdotal observation on the Knot Hole many years ago, where he found an eight fold increase in macro-biota in the mulched areas compared to the "lawn" a few feet away.

Recent studies by TCoT and Bartlett have shown total soil replacement with mixed composts and topsoil, in a 3-4 foot radius, will improve compaction stressed plants.

Another study i have read ( a few years ago) found that replacing with only composted "black dirt" retained too much water.

With the chlorosis, I'm reading a compilation book on Fe in crop plants, the causal conditions can be high levels of Ca in the soil, which can lead to elevated levels of bicarb. Compaction, to the extent that tire ruts in fields will be chlorotic, and outside them will be fine. Too much or too little water in the soil. Low Sulfur in the soil, seems that S is an integral component to moving the Fe from the roots to the transport mechanism of the xylem. Rather dry reading but some interesting stuff that supports my long held belief that soil samples are needed only after improving the soil does not solve the problems.

If it is an "improved" urban/exurban site then the soil is more then likely depleted, so say the least.

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Yeah it seems the more you read the more complicated it becomes. I sometimes wonder if even the most noted scientist have a clue lol. My trees that were showing mild chloritic signs were in heavily compacted and poor soil conditions hardly any top soil more shale and city pit. They seem to respond well to wood chips likely as much for increased moisture and lessened compaction than lack of minerals. They also before mulching were used for target practice and had terrible wounding to the cambium with minimal callousing. I actually mulched so I did not have to mow or worry about getting bit by a venomous snake going to my car! I got a profound secondary benefit from my admitted laziness, the tree is definitely responding in a most favorable manner!

My observations would suggest trees that are over fertilized are structurally weaker than unfertilized. Plenty of studies have proven this. J Of Arbor
i observed trees in the same area that were not fertilzed with less or no failure.
Why else this may have happened, may be these same trees also recieved more watering and had been pruned incorrectly in the past.
I think the trees that are over loved(fertilized, watered, Lions tailed etc) fail more than trees left alone or with minimal culturing.

The rates given in texts on the bag/bottle IMo are more than double than what is necessary.
Same thing is true with method of application. No proof that the resource intensive practice of soil injection is better than good ol broadcast.

Over fertilized trees do produce vigorous growth that will out compete a leader and/or show poor structure( point of attachment) this Also has been studied completely with Nursery grown trees

I guess that this thread is pretty much over my head, because i am not in the business.

I have a little to add if all of you will allow me.

I lived on a piece of property 30 years ago, and my Dad and I kept a potato garden on one piece of ground. it has not been in active cultivation for more than 20 years now.

This past summer, I went out to cut some firewood on the property, and came to see that a Tamarack tree had been hit by lightning and was dead.

Now, this tree was HUGE for a normal Tamarack in this northern climate.

It grew at the edge of the Potato garden. It had grown to about 24" at dbh. When I cut it down and counted the rings that were about 1/2" apart ,,,I counted 25. It had grown that big in only 25 years. It most certainly was not there when we were gardening there, or I would have remembered.

I can tell you for sure that fertilization is a big factor in tree growth.

bobt said:

I can tell you for sure that fertilization is a big factor in tree growth.

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I don't think anyone will argue with that. The point is, at what cost to defense or anchorage, longevity, or structural strength. Getting the plant correct for the soil its placed in should be the first objective imo.

ropensaddle said:

I don't think anyone will argue with that. The point is, at what cost to defense or anchorage, longevity, or structural strength. Getting the plant correct for the soil its placed in should be the first objective imo.

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Well, like I said in my previous post, I was hesitant to contribute to this thread.

However, this particular tamarack tree sprouted and grew all on its own through at least 25 seasons and when it was finally killed by lightning, had attained quite significant size for it's age. I have no idea how it would have fared against years of wind, ice, or insect damage. None of the other Tamarack trees on the property have suffered any noticeable problems from insects or disease, they are simply smaller.

There is another of the same species that lives about 50 feet from this tree that is of similar size and looks darn healthy. It too must certainly have benefited from the fertilizer we used on the Potatoes. If you know anything about raising potatoes, the fertilizer is not high in Nitrogen, but heavy in P and K. Now I wonder how much bigger, (if any) these trees would have grown if they had benefitted from a high Nitrogen diet.

Maybe in 40 more years or so if I am still alive, I can let you know how it is still doing.

Bob

bobt said:

Well, like I said in my previous post, I was hesitant to contribute to this thread.

However, this particular tamarack tree sprouted and grew all on its own through at least 25 seasons and when it was finally killed by lightning, had attained quite significant size for it's age. I have no idea how it would have fared against years of wind, ice, or insect damage. None of the other Tamarack trees on the property have suffered any noticeable problems from insects or disease, they are simply smaller.

There is another of the same species that lives about 50 feet from this tree that is of similar size and looks darn healthy. It too must certainly have benefited from the fertilizer we used on the Potatoes. If you know anything about raising potatoes, the fertilizer is not high in Nitrogen, but heavy in P and K. Now I wonder how much bigger, (if any) these trees would have grown if they had benefitted from a high Nitrogen diet.

Maybe in 40 more years or so if I am still alive, I can let you know how it is still doing.

Bob

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Lol I wonder who fertilized the 5000 year old redwoods

You said it has not been actively cultivated for twenty years I would think the fertilizer was long gone a year after the garden stopped. It could be the trees benefited more from loosened soil and adequate light and if they were growing during the gardening may have got a boost. It would be a stretch to believe they benefited all that time though.

pdqdl said:

THANK YOU BERMIE! That is what I was asking about!





The part about reduced lignin should translate to weaker structure and more storm damage.

Perhaps someone else will pipe in with more good info?

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Photosynthate is diverted from defense(production of allelochemicals) to increased growth of succulent tissues. Increased growth without corresponding increase in photosynthesis may cause stress in the plant.

ropensaddle said:

Lol I wonder who fertilized the 5000 year old redwoods

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The facilitators under redwoods convert nitrogen to nitrates, breakdown of coarse woody debris and even fog water.

Ed Roland said:

The facilitators. legumes growing under redwoods convert nitrogen to nitrates.

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So how were they applied?

ropensaddle said:

Yeah it seems the more you read the more complicated it becomes. I sometimes wonder if even the most noted scientist have a clue lol.

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I would say that they have a clue, often a general understanding. One will notice that the more expert a person is, them ore qualifying statements they will use. "generally" "More often then not"....

As with anyone, the more educated we become, the more we know how little we actually know.

The problem, which I was alluding to, is the law of confounding variables; there are so many things going on that we may not be able to know the exact problem.

Bulk density seems to be the biggest limiting factor in any nutrient-uptake problem, so I lean towards addressing it before anything else.

On "improved" properties, the two factors with bulk density are compaction and dirth of organics. Both can be addressed with amending or replacing. Quite often replacing is easier then trying to excavate and mix amendments into native soils. I will just mix a little natives into the outer area for transition.

My trees that were showing mild chloritic signs were in heavily compacted and poor soil conditions hardly any top soil more shale and city pit. They seem to respond well to wood chips likely as much for increased moisture and lessened compaction than lack of minerals. They also before mulching were used for target practice and had terrible wounding to the cambium with minimal callousing. I actually mulched so I did not have to mow or worry about getting bit by a venomous snake going to my car! I got a profound secondary benefit from my admitted laziness, the tree is definitely responding in a most favorable manner!

Click to expand...

Something to revisit is my objection to the industries tendency to talk about mulch while applying fresh chip. True mulch needs a of compost, and dumping fresh chip onto an old chip ring often does not do the job.

I will not get into my diatribe against landscrapers who have commoditized the practice of "mulching"....