Seeing as a lot of people around the world urinate against trees it came to mind that I never thought about how the tree responds to this. Is it detrimental for a tree if people urinate against them?

When looking on the internet, I found this explanation about urine:

Human urine consists primarily of water (91% to 96%), with organic solutes including urea, creatinine, uric acid, and trace amounts of enzymes, carbohydrates, hormones, fatty acids, pigments, and mucins, and inorganic ions such as sodium (Na+), potassium (K+), chloride (Cl-), magnesium (Mg2+), calcium (Ca2+), ammonium (NH4+), sulfates (SO42-), and phosphates (e.g., PO43-). What Is the Chemical Composition of Urine?

Of course, it is possible that the small amounts present in urine are negligible in contrast to the amounts a tree absorbs on a daily basis. What I am wondering: is the chemical composition of urine detrimental or beneficial for a tree?

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    $\begingroup$ Tom, this is a wonderful improvement from your previous [now deleted] post, and I'm glad you took the time to do some of your own research and include it here. Really great to see the newly added effort! Thanks! +1 $\endgroup$ Commented Mar 7, 2019 at 20:12
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    $\begingroup$ related. Also, my +1 to this question and @theforestecologist comment was not enough to express how much the improvement in this question is appreciated. I wish I could upvote again... $\endgroup$
    – De Novo
    Commented Mar 9, 2019 at 0:15
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    $\begingroup$ In most instances, plants benefit from animal litter, which is why it is sprayed in fields, and used to get bigger crops. Everything in moderation obviously, there is an optimum influx of animal litter which increases plant growth, which in the case of humans weeing, is much lower proportion than cows. other human activities are a lot more detrimental to trees, i wouldn't worry about weeing on them. a big tree can probably benefit from about 1 cubic meter of wee before it got detrimental. ideally you have to keep the pH at about 6.4 $\endgroup$ Commented Apr 17, 2019 at 0:55
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    $\begingroup$ a large tree can probably benefit from about 1 cubic meter of wee for a year before it gets detrimental, but not in the same place at the same time. $\endgroup$ Commented Apr 17, 2019 at 0:56
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    $\begingroup$ Indeed. for cow urine here is a study: scielo.br/img/revistas/hb/v27n4/06t01.gif $\endgroup$ Commented Apr 18, 2019 at 8:59

2 Answers 2


Here is a book about dry-matter production of urine treated plants. If we consider that trees are large plants, it's fair to apply the study to trees too:

The findings of the study suggested that urine and urine products are equally as effective as mineral fertilizer especially in sandy soil and that splitting the application is a useful strategy to manage urine and urine products for optimum dry matter production.

Some plants do live in harsh environments with chalky pH and other specifics, and they may weakened by it. It's safe to say most trees are unaffected or improved by some urine, although the biggest trees are because of rain and steady underground streams (groundwater).

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    $\begingroup$ but just like anything in biology amounts matter, if enough people urinate against a tree it can cause salinity issues. But you need a ridiculous number of people to cause that. Note dog urine is far more concentrated so it can reach the problem levels much faster, trees visited by dozens of dogs in a day suffer for it. $\endgroup$
    – John
    Commented Apr 18, 2019 at 13:47
  • $\begingroup$ @com.prehensible I am sorry, I completely forgot this question (multiple SE's sometimes clutter my mind). If I understand correctly (correct me if I am wrong), it depends on the kind, size and (in the case of dogs) the concentration of the urine and its amount are all important factors. $\endgroup$
    – Tom Sol
    Commented Aug 23, 2019 at 19:59
  • $\begingroup$ And the rainfall too. Sorry am in car can't answer. $\endgroup$ Commented Aug 28, 2019 at 6:27

Speaking specifically about blueberry bushes as a perhaps extreme example, they thrive in acidic soil and nitrogen-laden soil. However, dog urine is bad for blueberries, as the high nitrogen content overwhelms the plant and damages fruit production. Dog urine is only slightly acidic (pH 6-6.5) and can often be alkaline, which also changes the soil acidity in the direction that is not good for blueberries. The acidity and nitrogen content of dog urine can depend on diet.

If there's a plentiful supply of rainwater and the soil has the right nutrient balance and acidity for the plants and trees living in it, then urine will disturb that balance, strictly speaking, however marginally. More urine could damage plants if it changes the soil constitution outside the comfort zone of what is growing in that soil.


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