# Aluminum toxicity in trees



## Linda (Sep 7, 2017)

Posts from all over the world are showing the decline of trees. Even after the wettest year on record, trees in Oregon are drought stressed. There is the possibility that aluminum toxicity could be the problem. Aluminum prevents the uptake of water and disrupts other nutrient absorption. If this is true, how might homeowners (or even those near natural forests) address this issue? I understand that measuring for aluminum in the soil is very difficult, but meaning the pH is an indirect method. If the pH is below 5.5 most plants have difficulty with normal growth, and aluminum toxicity may be the issue (aluminum lowers pH). It is complicated in the Pacific Northwest because soils are naturally more acidic already. Is pH the only test we can use? What is the best way to counteract the toxicity of the aluminum? I have read that lime raises the pH and might solve the problem. I appreciate your help.


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## JeffGu (Sep 7, 2017)

Aluminum is the third most prevalent element, and the _most_ prevalent metal in the earth's crust. In soil, it becomes bound up with other elements and isn't found in it's pure form. You can make it barely soluble by changing the pH of whatever medium it is in, but trying to change the soil pH to make it _less_ soluble is a fool's erand. Since the aluminum toxicity inhibits uptake of calcium by roots when the Al reacts with the Ca it would seem that adding more Ca to the soil only increases the reaction with the Al present, and doesn't increase root uptake. The only thing that I know of that may reduce aluminum toxicity (and it's extremely controversial whether it's even true) is silicon.

I'm not sure what you're hoping for. Something we can spray on the entire Pacific Northwest that will neutralize aluminum toxicity? How about pressuring politicians to require all new housing construction to use steel framing, now that some standards for structural elements have been worked out and the steel studs suitable for house framing are available. That would reduce forest decline a hell of a lot more than trying to ammend soil to reduce aluminum toxicity.

Just sayin'...


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## ATH (Sep 7, 2017)

Wait....what??? So letting the trees over-mature without active management and replacing that building material with a non-renewable resource is a better choice? As a nation we grow FAR more timber than is harvested. The healthiest trees tend to be in managed forests. The primary motivation for management in many circumstances is the promise of a future pay off - why would we want to stop that?

As to the OP's question: Here is a good article on Aluminum toxicity. Without a baseline, it would be difficult to say whether this is a 'new' landscape level problem or not. We have very high pH where I am, so that is not an issue here in NW Ohio.


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## Linda (Sep 8, 2017)

ATH said:


> Wait....what??? So letting the trees over-mature without active management and replacing that building material with a non-renewable resource is a better choice? As a nation we grow FAR more timber than is harvested. The healthiest trees tend to be in managed forests. The primary motivation for management in many circumstances is the promise of a future pay off - why would we want to stop that?
> 
> As to the OP's question: Here is a good article on Aluminum toxicity. Without a baseline, it would be difficult to say whether this is a 'new' landscape level problem or not. We have very high pH where I am, so that is not an issue here in NW Ohio.


Thank you! This is the best article I have seen. I will use that information to test tree soil in my area and if of benefit, I'll let others know too. I am grateful for your help. If you run into any other articles I will be interested in them as well! Again, thank you.


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## Jason Douglas (Sep 8, 2017)

Read KT Smith's work on forest acidification and it's affect on Ca and I believe Mg uptake.

Generally attributed to anthropogenic reasons. The real solution is addressing the crap that is getting pumped into the air before we lose our unmanaged native forests. Not a problem everywhere but the effects of acid rain have been documented and studied for decades now. Emissions are down significantly since the 70s and 80s but the negative effects are clearly long lasting.

Small scale, it's easier to raise pH and provide plant available base nutrients than it is to lower it. Doing this on a huge geographic area isn't realistic however. If Al is at toxic levels, other metals may also be.


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## ATH (Sep 8, 2017)

It has been a long time, but when I read quite a bit about acid rain impacts in the Adirondacks. It killed many lakes and ponds, but the forest soils were well buffered, and relatively minimal impacts except higher elevation areas with less soil. Not that this is _good_ news, per say...but not as bad as it could have been. Like you said, though, emissions are way down and acid rain isn't continuing to be the problem it was - we are just living with the legacy of the past.


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## arborcure (Sep 10, 2017)

The aluminum in the soil is only going increase. Thanks to geoengineering. Aluminum is a main ingredient in it. Geoengineering is not new its been going on since the 50s it was just called chem trails until the past year or two. Nano particles of aluminum is one of the main ingredients that they spay everyday. Just look at the horizon and you'll notice a gray haze that's not smog but metal particulates in the air. There is a history channel program about cloudseeding and harp that proves chem trails aren't conspiracy. putting aluminum In the atmosphere and blasting it with microwaves can cause droughts. That program stated they should be able to control the weather by 2020 but watching these hurricanes i would say they are ahead of schedule.


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## JTM (Sep 10, 2017)

How does aluminum lower pH? It would exist as a hydroxide in nature.


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## JTM (Sep 10, 2017)

Acid rain releases phosphates.


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## ATH (Sep 10, 2017)

JTM said:


> How does aluminum lower pH? It would exist as a hydroxide in nature.


I think he has the cause/effect mixed up. Lower pH leads to more Al+++ in the soil...leading to toxcity.


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## JTM (Sep 10, 2017)

ATH said:


> I think he has the cause/effect mixed up. Lower pH leads to more Al+++ in the soil...leading to toxcity.


So the acid reacts with the hydroxide to produce the salt , Al++. Okay, but help me understand here. In an agricultural setting calcium fixes nitrogen in the soil so that plants can utilize it, is that correct? So how does aluminum affect this process or does it? If low pH is a factor wouldn't Mt. Saint Helens still be a wasteland? The amount of sulfur dioxide put out by that volcano when it blew its top would have definitely lowered the pH.


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## Linda (Sep 11, 2017)

Have your soils tested. Many areas of the country (world) have excess AL++++ in the soils. This causes the pH to be lowered and plants cannot absorb water and phosphorous. I am seeking to test that idea and find a solution. Thanks to ATH above for at least one good article!


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## JTM (Sep 11, 2017)

ATH said:


> Wait....what??? So letting the trees over-mature without active management and replacing that building material with a non-renewable resource is a better choice? As a nation we grow FAR more timber than is harvested. The healthiest trees tend to be in managed forests. The primary motivation for management in many circumstances is the promise of a future pay off - why would we want to stop that?
> 
> As to the OP's question: Here is a good article on Aluminum toxicity. Without a baseline, it would be difficult to say whether this is a 'new' landscape level problem or not. We have very high pH where I am, so that is not an issue here in NW Ohio.


informative article but I don't like how how they paint a broad stroke to imply that aluminum concentrations in soil is proportional to overall concentrations in earth's crust. That is just stupid BS. Take a gander here: https://pubs.usgs.gov/pp/1270/pdf/PP1270_508.pdf


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## Jason Douglas (Sep 12, 2017)

I think the OP's concern is Al toxicity in certain area with pretty acidic soils and I was pointing out potential problems in those soil types.


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## JTM (Sep 12, 2017)

Amazon rainforest forest soils have a pH below 5. The article ATH refers to is talking about crops. Does free Aluminum affect trees?


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## ATH (Sep 12, 2017)

JTM said:


> So the acid reacts with the hydroxide to produce the salt , Al++. Okay, but help me understand here. In an agricultural setting calcium fixes nitrogen in the soil so that plants can utilize it, is that correct? So how does aluminum affect this process or does it? If low pH is a factor wouldn't Mt. Saint Helens still be a wasteland? The amount of sulfur dioxide put out by that volcano when it blew its top would have definitely lowered the pH.


Soil science class was a long time ago....and that wasn't an "A+" class for me! But regarding Mt. St. Helens - I think a big factor is that it is very difficult to lower soil pH - most soil is very well buffered (see comment above regarding acid rain).

Calcium doesn't fix nitrogen...bacteria and other microorganisms (or lightning...) do. Aluminum doesn't impact that process (that I know of...): it is either directly toxic or it binds with phosphorous or sulfur making those unavailable to the plant.


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## ATH (Sep 12, 2017)

JTM said:


> informative article but I don't like how how they paint a broad stroke to imply that aluminum concentrations in soil is proportional to overall concentrations in earth's crust. That is just stupid BS. Take a gander here: https://pubs.usgs.gov/pp/1270/pdf/PP1270_508.pdf


Agreed...that is a terrible illustration to imply that any given acre of soil contains 140,000 lbs of Al...


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## ATH (Sep 12, 2017)

JTM said:


> Amazon rainforest forest soils have a pH below 5. The article ATH refers to is talking about crops. Does free Aluminum affect trees?


My assumption is that every species will react differently. Crops are studied in detail by hundreds of universities and hundreds more private entities (seed companies, for example). Trees...not quite so much. That is why the Tree Fund is so important...


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## JTM (Sep 12, 2017)

ATH said:


> My assumption is that every species will react differently. Crops are studied in detail by hundreds of universities and hundreds more private entities (seed companies, for example). Trees...not quite so much. That is why the Tree Fund is so important...


Thanks. I'll check that out.


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## JeffGu (Sep 13, 2017)

Nearly all of the studies on the toxicity of trivalent aluminum have been carried out in relation to food crops. The bulk of the studies and articles, like THIS one, are in relation to areas with a soil pH of less than 5.5 such as occurs in the tropical rainforests of South America, Africa, and Southeast Asia where there are a lot of people to feed. Note that we're talking about land that has been deforested to accomodate crop production. It seems to me that if you're trying to raise goldfish in a swamp full of alligators, and after removing the alligators the algae in the water is killing your goldfish, it doesn't really make sense to study the effect of the algae on the alligators. Clearly, the alligators were doing just fine with it. Maybe it's just a bad place to raise goldfish, eh?

Heavy liming of the soils in these areas has had very short term success... when the whole farm turns into laterite, the farmers clearcut more land and start again. It's very hard to lime the subsoils, and dumping tons of _anything_ on them isn't going to come without its own price tag, down the road. Again, the question still remains... what exactly is the OP hoping for? A magic powder, known only to online arborists, that she can sprinkle over the Old Growth Forests to protect them from aluminum? Help with picking up beer cans in the Pacific Northwest?


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## Jason Douglas (Sep 14, 2017)

I think a problem is arising with species that arent adapted to such low pH where metal ions can become toxic. 

Not a problem here as we're still pretty limey and alkaline where the metals are much much less available.


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## Jason Douglas (Sep 15, 2017)

Attached is some of Kevin's and other's papers regarding acid deposition and it's effects.

There's a lot more available at the Forest Service website.


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## JeffGu (Sep 15, 2017)

Most excellent reading, Jason. Managing even small tree lines and woodlots on agricultural land and leaving pruned/fallen deadwood in brush/wood piles is not only good habitat for the wildlife, but helps to build healthy forest floors. K.T. Smith and the others point out an interesting benefit that plays directly to this thread's subject... the rotting wood increases exchangeable Ca, while decreasing exchangeable Al, to the surrounding trees.

Unfortunetly, the number of landowners around here that would place any significance on the value of doing this is vastly overwhelmed by the number who use tractors and bulldozers to clear anything that is roughly perpendicular to the ground, pile it up and burn it, and plant corn and soybeans.


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