Out on a Limb

Emerald Ash Borer adultBrian Thomas’ latest – Do People Live Longer among Trees? – has to be seen to be believed:

Could living near trees possibly affect human health? Increasingly, studies indicate that trees can improve human health. Evolution doesn’t expect this, but biblically speaking, trees and people have close ties.

Even for Brian this article is breathtaking. The subject is a recent paper, called The relationship between trees and human health (pdf), which set out to investigate a potential “relationship between the natural environment and improved health outcomes.” This was done by looking at changes in mortality in US counties that had been invaded by the emerald ash borer, which wipes out ash trees. Controlling for other variables – something which Brian describes as taking “steps to demonstrate that living longer was not linked to living among trees” – they discovered that there really was a correlation between tree death and human death.

Correlation does not prove causation, but it does still suggest that this might be the case (or at least that there may be a common cause). As such I take great comfort in these results, as it is quite impossible to go for more than a few steps in a straight line here without finding yourself in an increasingly dense forest. Despite this, according to Mr Thomas I should be worried that a connection between trees and health doesn’t fit with evolution!

What is the real cause of these phenomena? The researchers don’t know, but the data fit with the strange idea that broken trees may lead to broken hearts.

In the evolutionary mindset, what survival advantage would people have from just seeing strong trees? And how can evolution explain people’s health deteriorating when trees wither?

I don’t know if that’s just poorly worded or if Brian really believes that for evolution to be true there would need to be a “survival advantage … from just seeing strong trees,” given these results. But what is the ‘biblical’ explanation that he seems so fond of? This:

In contrast to evolutionary origins myths, trees play a surprisingly strong role in actual human history. The book of Genesis uses the word “tree” 28 times, for example. Its fourth instance occurs in Genesis 2:9: “And out of the ground made the LORD God to grow every tree that is pleasant to the sight, and good for food.” So, right from the beginning, trees were identified as sources of food and of beauty.

A footnote adds:

This biblical link deepens when one considers that the resurrection of the Lord Jesus, “whom they slew and hanged on a tree” (Acts 10:39), is mankind’s only hope of eternal pleasure. “In thy presence is fulness of joy; at thy right hand there are pleasures for evermore” (Psalm 16:11).

The article concludes:

The Bible also says about the believer, “His branches shall spread, and his beauty shall be as the olive tree, and his smell as Lebanon.” [Hosea 14:6] Clearly, God made trees for the purpose of bringing pleasure to people. [Footnote: “Of course, the right response to this provision of pleasure is to praise God.”] Are researchers uncovering evidence of this God-made link between man and trees?

A glaring omission from this list of bible trivia are the Tree of Knowledge (from which the apple was plucked, causing original sin and death) and the Tree of Life (which God fears Adam will also eat from, granting him eternal life, and thus banishes him from Eden to prevent this). Ditto the fig tree Jesus kills, along with various mentions of trees in the parables. This is strange, because Brian’s argument effectively distils to the claim that “the bible mentions trees, often in non-trivial and symbolic ways, so anything old nonsense I say about them must be biblical and also true.” Meanwhile he leaves any actual mechanism to the unexplained and/or supernatural.

Given this exceptionally low bar for a potential explanation, what can we come up with that would do the same from an evolutionary standpoint? As everyone should know, the colonisation of the land by plants was an important step in making the continents habitable by animals – trees thus play “a surprisingly strong role” in the evolutionary history of the planet. You hurt the trees, you hurt the Earth. A more evolutionary psychology-type explanation would probably involve a reduction in stress due to the subconscious thinking that it was able to escape into the trees from leopards.

Hmm, stress… There’s an idea – what were all those extra people dying from again? From the press release: (emphasis added)

In an analysis of 18 years of data from 1,296 counties in 15 states, researchers found that Americans living in areas infested by the emerald ash borer, a beetle that kills ash trees, suffered from an additional 15,000 deaths from cardiovascular disease and 6,000 more deaths from lower respiratory disease when compared to uninfected areas.

Maybe having living trees helps with air pollution, and sweeping up leaves provides exercise? Actually, while we’re looking at the actual findings of the study rather than engaging in pseudoscientific speculation, what do they say about this?

[Our] results do not provide any direct insight into how trees might improve mortality rates related to cardiovascular and lower-respiratory-tract illness. However, there are several plausible mechanisms including improving air quality, reducing stress, increasing physical activity, moderating temperature, and buffering stressful life events. Future research could fruitfully investigate the possible mechanisms linking the natural environment and health.

It’s probably something boring like that. Of course, Brian would likely say that it was still an example of God’s grace and foresight – in which case he needs to compare and contrast the definitions of “function” and “by-product.”

One thought on “Out on a Limb

  1. “In contrast to evolutionary origins myths, trees play a surprisingly strong role in actual human history.”

    Er — what about our arboreal origins, “Down from the Trees”, etc.? (don’t forget that Ardipithecus shows that we evolved bipedality in the trees rather than on the ground.)

    I declare this new information on trees to be positive proof of evolution (but a little damning to the Aquatic Ape hypothesis).


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