Fertilizing oak trees.

[The Fishman]

I don't think it was clear that they were specifically testing nitrogen fertilizer. The conclusions they draw make it sound like they determined fertilization in general does not affect acorn production.

Additionally, I don't understand why they wanted to test nitrogen specifically. If nitrogen is most beneficial to new growth, then it stands to reason they should have studied the affects of additional P and K instead of N.

Basically, the paper is a bit misleading in its conclusions. And if they specifically intended to only show the affect of nitrogen on acorn production, then the experiment doesn't really give me any helpful information at all, as I would never apply nitrogen specifically to encourage acorn production.

I misread what they did. Here is what they did with P and K. "Application rates of actual phosphorus (monocalcium phosphate; CaH4P2O8) and potassium(potassium chloride; KCl) differed between sites and years based on soil test results. We added enough phosphorus and potassium each year to maintain 101 kg/ha of phosphorus and 269 kg/ha of potassium in the soil (Savoy and Joines, 2009). We calculated the amount of fertilizer needed for each tree by measuring the crown area (i.e., surface area from the trunk of the tree to the edge of the crown) of each tree." So they did a soil test and added enough P and K to bring the level up to the P and K recommendations of Savoy and Joines (2009).

 

[The Fishman]

From the study:

"
Wolgast and Stout (1977) reported an increase in bear oak (Quercus
ilicifolia) acorn production following fertilization of young stands in
New Jersey. Callahan et al. (2008) and Bogdziewicz et al. (2017) re-
ported increased acorn production in small plots that contained red
oaks following 15 and 25 years of nitrogen additions, respectively "

You left out this portion of that paragraph where it states "none of the studies on other oak species considered the influence of individual variation in production capacity." As shown in this study and Greenberg (2000) and Healy et al. (1999), about half of oak trees are poor acorn producers. In this study, 41% of trees classified as poor producers accounted for only 17% of all acorns produced. If you do not account for the individual variation of each tree in your survey design, you cannot accurately state what effect fertilizer had on acorn production. This study did five years of prior research to determine each tree's masting characteristics before the study began. The analysis can then use this information to help determine fertilizer impacts.

 

[Telemark]

Go to https://droughtmonitor.unl.edu/Maps/MapArchive.aspx and please let me know if the study area was impacted beyond an abnormally dry period for more than a month during the study time period

The study area was impacted beyond an abnormally dry period for more than a month during the study period, with much of 2007 and 2008 being in "severe drought". Also, I don't see why we are using one month and "abnormally dry" as the threshold. I would think any extended period of abnormally dry conditions could affect plant growth, especially when you consider the first sentence of the quote I posted: "The Southeast region generally receives substantial precipitation and is often considered water-rich." It stands to reason that any extended period of "abnormally dry" conditions would impact plant growth in an area generally "considered water rich."

The study ended in 2015, so I am not sure why a high impact drought in 2016 is relevant.

You seem to be ignoring the part before it where it mentioned "record-breaking droughts of 2006–2008 and 2010–2012" The summer of 2007 and 2008 was especially bad in Eastern Tennessee as per the map in the link you posted. The webpage mentions a drought in Tennessee specifically because it's a page dealing specifically with Tennessee. that does not exclude Tennessee from the other 6 years of record-breaking drought in the Southeast mentioned in the previous sentence.

 

[Telemark]

You left out this portion of that paragraph where it states "none of the studies on other oak species considered the influence of individual variation in production capacity." As shown in this study and Greenberg (2000) and Healy et al. (1999), about half of oak trees are poor acorn producers. In this study, 41% of trees classified as poor producers accounted for only 17% of all acorns produced. If you do not account for the individual variation of each tree in your survey design, you cannot accurately state what effect fertilizer had on acorn production. This study did five years of prior research to determine each tree's masting characteristics before the study began. The analysis can then use this information to help determine fertilizer impacts.

I think you are over-generalizing by saying "The analysis can then use this information to help determine fertilizer impacts". If they were specifically testing the effects of nitrogen fertilizer then it is important to make that distinction.

 

[Telemark]

I misread what they did. Here is what they did with P and K. "Application rates of actual phosphorus (monocalcium phosphate; CaH4P2O8) and potassium(potassium chloride; KCl) differed between sites and years based on soil test results. We added enough phosphorus and potassium each year to maintain 101 kg/ha of phosphorus and 269 kg/ha of potassium in the soil (Savoy and Joines, 2009). We calculated the amount of fertilizer needed for each tree by measuring the crown area (i.e., surface area from the trunk of the tree to the edge of the crown) of each tree." So they did a soil test and added enough P and K to bring the level up to the P and K recommendations of Savoy and Joines (2009).

Right. But none of that contradicts what i said in the text you quoted there.

 

[TreeDaddy]

I kinda skimmed through the thread. Here is my take on fertilizing oak.

1. I am only doing it to young trees that I just planted or are less than 4 years old. Combine this with a GOOD weed mat and some mulch and they take right off.
2. It really helps getting the young trees growing. I'm not that worried about older trees. They are in God's hands.
3. Cutting down their competition will help them immensely. The sun is a powerful thing.
4. There is no way in hell to have an accurate study UNLESS you took acorn size and weight into consideration. I plant my corn at much lower population than my neighbors. We end up getting similar yields. Their kernel size is way smaller than mine. Same could be true for acorns.
5. Highly unlikely that it would be cost effective to fertilize oaks for more/bigger acorns. Better to stick with the small ones. They really respond.
6. If you wanna get some fertilizer in the ground pick up the shovel and make a slot, throw in some triple 19 at 10-12" deep and reclose the hole. I do it all the time. It goes quick on young trees. I try to place it approximately 16" from the central leader. You wanna promote the root growth to find the fertilizer and also dont want it too hot in closer to the leader.
View attachment 62337

another wolverine tree spade brother

I knew you were a good man,Buck

bill

 

[Teeder]

There's no way in hell I'm lugging hundreds of lbs of fertilizer into the woods for my mature oaks every year. Much easier to release their crowns. If they can increase the crown area, they will drastically increase the ability to produce acorns.
I used to fertilize my young trees, but stopped because it caused them to grow too fast. I tube my little trees and if they grow too fast, they'll shoot up and be too whippy, especially red oak varieties and sawtooth.
The additional benefit of crown release is getting more sunlight to the ground which drastically adds browse.

 

[omicron1792]

I can only speak for myself on this one, I won't ever attempt to fertilize an oak tree in an effort to increase acorn production.

You’re too logical for that.

 

[omicron1792]

It's an interesting concept to consider. If what you are saying is true, then the addition of nitrogen can be detrimental, while the addition K is beneficial.

"N negatively affects the plant’s physical defense along with the production of antimicrobial compounds"

"Potassium (K) is an essential plant nutrient, when it is present in adequate concentration, it can certainly increase the plant’s polyphenolic concentrations, which play a critical role in the defense mechanism"

Frontiers | Plant mineral nutrition and disease resistance: A significant linkage for sustainable crop protection

Complete and balanced nutrition has always been the first line of plant defense due to the direct involvement of mineral elements in plant protection. Minera...

www.frontiersin.org

"Nutrients like Phosphorus, Potassium, Manganese, Zinc, Boron and Silicon have been proven by research to boost plant immunity."

"Potassium and Boron strengthen the cell wall and cell structure which prevents fungi and other pathogens from entering the cell"

What can improve disease resistance in my crops? - Dhanashree Agro

Nutrients like Phosphorus, Potassium, Manganese, Zinc, Boron and Silicon have been proven by research to boost plant immunity. Similarly Salicylic Acid and Jasmonic Acid play an active role in defending the plant against pathogens. Phosphorus is responsible for root development, a healthy root...

dhanashreecropsolutions.com

There are studies that show early nitrogen DEFICIT helps oak trees produce acorns earlier. In humans caloric restriction increases health and life expectancy.

Things in nature are often a lot different than what my mind thinks they will be.

 

[omicron1792]

another wolverine tree spade brother

I knew you were a good man,Buck

bill

I’m in the club too!

 

[omicron1792]

Go to https://droughtmonitor.unl.edu/Maps/MapArchive.aspx and please let me know if the study area was impacted beyond an abnormally dry period for more than a month during the study time period. The study ended in 2015, so I am not sure why a high impact drought in 2016 is relevant.

Also they say droughts happen on a regular basis in the area. You couldn’t do a 15 year study in this area, or any, without wild swings in those things. It would make the study less valid to exclude it.

 

[omicron1792]

In Craig we trust.

https://fwf.tennessee.edu/wp-content/uploads/sites/24/2020/07/Fertilizing-oaks-for-acorns-Wildlife-Trends.pdf

 

[The Fishman]

The study area was impacted beyond an abnormally dry period for more than a month during the study period, with much of 2007 and 2008 being in "severe drought". Also, I don't see why we are using one month and "abnormally dry" as the threshold. I would think any extended period of abnormally dry conditions could affect plant growth, especially when you consider the first sentence of the quote I posted: "The Southeast region generally receives substantial precipitation and is often considered water-rich." It stands to reason that any extended period of "abnormally dry" conditions would impact plant growth in an area generally "considered water rich."

You seem to be ignoring the part before it where it mentioned "record-breaking droughts of 2006–2008 and 2010–2012" The summer of 2007 and 2008 was especially bad in Eastern Tennessee as per the map in the link you posted. The webpage mentions a drought in Tennessee specifically because it's a page dealing specifically with Tennessee. that does not exclude Tennessee from the other 6 years of record-breaking drought in the Southeast mentioned in the previous sentence.

The trees were not being treated with fertilizer before 2011. They were only looking at acorn production amongst the trees. The 2010-2012 "record breaking drought" didn't occur in the study area. You can generalize across the entire southeastern U.S., but it didn't occur in the study area. The fertilizer treatments did not start until 2011. So please explain how a drought in 2007 and 2008, that impacted all trees equally, affected the fertilizer treatments that occurred in 2011-2015?

I get it. You don't like the results of this 10-year study on 120 trees across three different sites conducted by seven professional forestry researchers from three universities and three forestry agencies. As people have stated, it probably doesn't hurt to fertilize oaks. This study does show that if acorn production is your goal, crown release will produce more acorns than fertilization.

 

[FarmerDan]

Where's Yoder?

 

[BuckSutherland]

Where's Yoder?

I think he passed on from one too many corona boosters. Suddenly just stopped posting and he was drinking the kool aid

 

[jsasker007]

Think Yoder got the boot here. I see he's on another habitat forum pretty regular.

 

[Angus 1895]

I just looked up the California guidelines for walnuts , and Pecans.

They recommend a petiol test. As in testing the leaves. If the leaf is under 2.1% nitrogen then yields will be affected on the down side by as much as 20%. ( I think). If over 3.5 % nitrogen added should be re evaluated.

It had guidelines for other nutrients also.

Anyways I think if it’s affordable a petiol test makes perfect sense for gaining knowledge. Soil tests would seem less important.

Another thing is to remember nutrients can also be applied foliar, to bypass the roots.

 

[Telemark]

The trees were not being treated with fertilizer before 2011. They were only looking at acorn production amongst the trees.

Right. There were extreme weather events during the baseline years. That should have been considered and discussed extensively.

I get it. You don't like the results of this 10-year study on 120 trees across three different sites conducted by seven professional forestry researchers from three universities and three forestry agencies.

That was an unnecessary and inappropriate ad hominem attack. I won't respond any further to it.

This study does show that if acorn production is your goal, crown release will produce more acorns than fertilization.

Not quite. This study suggests that crown release will produce more acorns then nitrogen fertilization. I think it is an important distinction to make, and I have never disputed this conclusion. In fact, I specifically said I would never consider using nitrogen specifically to increase acorn production. I was, and remain, completely convinced that crown release is beneficial to acorn production in oak trees, and skeptical to the idea that nitrogen fertilization is significantly beneficial to increased acorn production.

I believe the confusion came from the conclusion that "fertilizer does not increase acorn production" came from a study that tested only nitrogen fertilizer. That is not an appropriate conclusion to draw from the referenced study.

 

[Teeder]

Another thing is to remember nutrients can also be applied foliar, to bypass the roots.

That's not easy to do to an oak that's large enough to produce acorns, especially a natural grown tree that's already in the woods which is probably 60 feet tall.

 

[omicron1792]

That's not easy to do to an oak that's large enough to produce acorns, especially a natural grown tree that's already in the woods which is probably 60 feet tall.

Yeah. Lot of reaching (get it!) going on now.