
Botanical Sexism Cultivates Home-Grown Allergies - LanceTaylor
https://blogs.scientificamerican.com/guest-blog/botanical-sexism-cultivates-home-grown-allergies/
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Alex3917
The only reason why we don't plant tons of edible fruit trees in city parks is
because they would make a huge mess and attract rodents. But now that we're
going to have self-driving robots that can clean up after the trees by the
time they're old enough to produce fruit, there really isn't any reason why
our park trees shouldn't be producing food for us.

~~~
klyrs
> ...there really isn't any reason why our park trees shouldn't be producing
> food for us.

The article does address that notion -- trees are really good at capturing
pollution, and a good amount of that pollution ends up in their fruit. Which
sucks. I grew up foraging urban food, and I'll still pick and eat berries and
stonefruits because they're too delicious to pass up, but it seems
irresponsible for governments to promote such a thing.

~~~
Alex3917
> The article does address that notion -- trees are really good at capturing
> pollution, and a good amount of that pollution ends up in their fruit.

Right, you wouldn't be able to do this with street trees for that reason, but
park trees are fine. The soil just needs to be tested on a regular basis for
heavy metals, but that isn't especially difficult; e.g. this has already been
done for a lot of community gardens in NYC. While fruit definitely contains
whatever pollution is in the environment, unlike many mushrooms it generally
doesn't hyper concentrate it.

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droningparrot
This is such an interesting insight into how urban planning decisions can
affect health.

What are the chances that airborne allergens increase rates of food allergies?

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EnderViaAnsible
As I understand it, very small.

Most allergens are denatured by acid and enzymes in the stomach. Many food
allergies, which typically are not the same kind of immunological reaction as
seasonal allergies/allergic rhinitis, are caused more by the failure of
epidermal barriers or acid attack than by mere exposure. don't become
sensitized because you ate something so much as because your body allowed bits
to get somewhere they are not allowed to be under any circumstances, which is
why the outsized anaphylactic reaction food allergies often cause.

(... _typically_. In some cases it is cross reaction, where an antigen in food
is too similar to some other antigen the body has previously identified as an
invader. See for example the temporary meat allergy that can be caused by some
Lone Star tick bites. And there are yet other causes of course...)

Seasonal allergies are usually mild because they are generally localized,
peripheral, and provoked in tissues that are designed to give this response as
a normal protective action.

(That is, your nose is correct to run or stuff in response to histamine
release caused by pollen. Frankly, I feel some foreboding about what sequelae
we will eventually discover to be caused by chronic H2 antagonist
administration over decades, drugs like Claritin/Zyrtec that people are taking
every day of their lives.)

So! While it is possible and some rare cross reactions have been observed
(particularly in fruiting trees/eating fruits), as a general rule your
seasonal allergies do not increase your food allergy risk.

Now, some people are at higher risk for both due to environmental or genetic
circumstances. But there it is a prior immune dysfunction that caused both
rather than one causing the other-- though it's an understandable intuition to
connect them as your question does. Having one or the other makes it more
likely you have both, but it one doesn't cause the other.

~~~
learc83
>So! While it is possible and some rare cross reactions have been observed
(particularly in fruiting trees/eating fruits), as a general rule your
seasonal allergies do not increase your food allergy risk.

If you're talking about oral allergy syndrome, it isn't really what I'd call
rare.

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manfredo
If by "batonical sexism" we mean the choice to use male trees instead of
female trees because it'd be a burden to clean up parts of the female tree
that drop to the ground seasonally. It's a straightforward tradeoff: use male
trees that produce pollen (and make it worse for allergies) or use female
trees that have to get cleaned up (or plant both, and deal with both
problems).

~~~
EnderViaAnsible
As the article notes, planting both actually reduces one of the problems:
pollen. Female plants attract and capture pollen. So you will slightly
increase litter while moderately reducing pollen.

Additionally, as the article also notes, all allergens are not created equal.
Pollen is mostly notable insofar as it is allergenic; planting trees with low
or nor allergenic pollen uncouples "pollen" and "pollen that causes allergies"
levels.

~~~
manfredo
> So you will slightly increase litter while moderately reducing pollen.

I don't see any indication that the increase in litter would at all be of
greater proportion than the decrease in pollen. Only that bit of pollen that
gets blown to a neighboring female tree would get absorbed. Not even all of
that, since presumably the majority would get blown off the tree. I can't see
how any more than a single digit percent of the pollen would be captured, so
people with allergies would still be affected.

The increase in litter would be significant if half the trees were female. On
my college campus there were parts of the year where certain types of trees
would drop seed pods and it littered the streets for the better part of a
week. It'd take a significant amount of manpower to clean it up - probably a
garbage-bag per tree - so we just left it outside and dealt with vegetation
litter for a couple weeks.

Unless the article backs up the claim that the pollen reduction would be
substantial and the increase in litter trivial it could still very well be
that a mix of female and male plants does not prevent allergic reactions to
such a degree that it's worth using a mix of plants.

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arkades
tl;dr

Male trees were planted disproportionate to female trees in urban settings
because they didn't shed messy seeds. The preponderance of male trees
increases the amount of pollen exposure. Author asserts this leads to an
epidemic of allergies/asthma. Author asserts this indirectly leads to cancer.

Author fails to apparently take into account that although we are exposed to
more male trees than female trees, our total tree (and therefore, pollen)
exposure is far lower than historic norms. If adverse consequences are due to
pollen over-exposure, we would still be net underexposed to pollen, so any
increase in adverse health consequences couldn't be explained by that.

Author also presents themselves as a "horticultural epidemiologist." Worth
noting that a google scholar search suggests this person is not an academic
and holds no academic credentials, but he does make his income flogging a pair
of books on this topic. I guess "Epidemiologist" isn't a protected title, but
I usually don't see it applied to someone that doesn't actually work in
epidemiology, or hold a degree in epidemiology.

~~~
droningparrot
One thing that isn't clear is how effective female trees are at removing
pollen from the air. Is it possible that even with a much higher population
but a more balanced sex ratio, there would still be a lower airborne pollen
count?

~~~
floatingatoll
Yes, that's the core premise made by the author: If we're going to plant male
plants, either we plant female plants (which have evolved to take up the
maximum amount of pollen possible) or our lungs take up the pollen (which
results in biological issues).

There's an inflection point where the amount of pollen left in the air by a
sparse male forest equals the amount of pollen left in the air by a dense
balanced-ratio forest. The article doesn't say where that inflection point is,
though — when you state that inflection point as "a balanced-ratio forest can
be XYZ as dense as a male-only forest with same or lower pollen counts", XYZ
could be 1.1x, 20x, 5000x. Extrapolating that to urban trees, with pollen
measured at human face heights, would be the holy grail of prove-or-disprove
the value of this approach.

It is very likely that trees evolved to pollinate no more than is necessary to
deliver the correct amount of pollen to the trees near them. I cannot find any
estimates of this percentage at all, so as with XYZ above, it could be 1%,
10%, or 99%. More science is definitely required in both forest-shaped
configurations and urban-shaped pockets.

~~~
im3w1l
I wonder how good trees really are at attracting pollen. Intuitively it sounds
like the forces should be small and the effect should be pretty marginal.

~~~
floatingatoll
Trees are 0.3 _billion_ years old, so presumably they are not just good at it,
but _best_ at it.

~~~
mrob
And birds are about 160 million years old, but they can't fly as high or as
fast as airplanes. Evolution doesn't plan ahead, so it easily gets stuck in
local maxima.

~~~
floatingatoll
Birds seem to fall out of the sky a lot less often. Could be the same is true
for pollen. I don’t know if I agree with the guy, but I think he’s right to
encourage more science time and money spent on it.

~~~
jeremysalwen
What? How could you think this is remotely true. It's international news when
a commercial aircraft crashes. Birds, not so much.

~~~
floatingatoll
Observer fallacy, though I’m kind of confused why I’ve never personally seen
it happen. I’ve seem one window strike but never a ground strike.

~~~
belorn
If you want to observe birds there are some great nest cams all over the
world.

The first days/weeks/months of flying is not perfect. A large predatory bird
needs a lot of training and exercise. Wildlife rehabilitation is an other good
source to hear about the work involved in getting wild birds to fly.

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michaelkeenan
Would it be feasible to genetically engineer trees to neither drop seeds nor
release airborne pollen?

~~~
ghjjjj
You don’t have to genetically engineer it. Just clone (known for millennia) a
barren plant.

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faissaloo
Great article, horrible title

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notjustanymike
You ever see one of those titles where individually you know all the words,
but don't know what they mean together?

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aaron695
The 10 people who died from the pollen storm in Melbourne was interesting.

[https://www.google.com.au/amp/amp.abc.net.au/article/9907120](https://www.google.com.au/amp/amp.abc.net.au/article/9907120)

It also interesting because it possibly only showed up because it hit the
media, but it should have been see-able before if proper stats were kept over
the long term.

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pvaldes
To use male trees in parks (when possible) is a technical choice, totally
unrelated with sexism. To link all things with female opression is unhealthy
and a mess leading to absurd dead ends.

Cities are full of "male symbols" in form of phallic shaped towers and square
high buildings. Should we remove all of them and start building round
hemispheric houses instead? Should we remove only the 50% of skyscrapers?

The term botanical sexism is unfair for garden designers (not always men) and
creates a non-existent problem

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robotron
I think you missed the point of the article.

~~~
pvaldes
Maybe the writer should have used a better title then. Less clickbaity and
annoying. That some pollens can trigger allergies when combined with diesel
particles is not exactly breaking news.

