[Roelven]

Just browsing the papers linked in the article you can find some relevant things:

[Effects on trees and plants]

The microwaves may affect vegetables. In the area that received radiation directly from “Location Skrunda Radio Station” (Latvia), pines (Pinus sylvestris) experienced a lower growth radio. This did not occur beyond the area of impact of electromagnetic waves. A statistically significant negative correlation between increase tree growth and intensity of electromagnetic field was found, and was confirmed that the beginning of this growth decline coincided in time with the start of radar emissions. Authors evaluated other possible environmental factors which might have intervened, but none had noticeable effects [103]. In another study investigating cell ultrastructure of pine needles irradiated by the same radar, there was an increase of resin production, and was interpreted as an effect of stress caused by radiation, which would explain the aging and declining growth and viability of trees subjected to pulsed microwaves. They also found a low germination of seeds of pine trees more exposed [104]. The effects of Latvian radar was also felt by aquatic plants. Spirodela polyrrhiza exposed to a power density between 0.1 and 1.8 μW/cm2 had lower longevity, problems in reproduction and morphological and developmental abnormalities compared with a control group who grew up far from the radar [105].

[source] https://www.pathophysiologyjournal.com/article/S0928-4680(09...

[Junk_Collector]

My immediate problem with this study is that they personally selected a sample of 60 damaged trees near radio transmitters to compare to a selected sample of healthy trees away from radio transmitters. The conclusions is effectively built into their sampling.

[montenegrohugo]

Huh. This does sound bad and honestly quite scary. Is there any theorizing made on how these plants get affected by radar? What exactly is the biological mechanism at play here?

[ddebernardy]

This article from a separate comment lists a few candidate mechanisms, plus another few preoccupying effects for millimeter wavelengths:

https://twin.sci-hub.tw/6759/4e3bc086c40841aacf40b068776dc0f...

> 3.3.1. Oxidation mechanism of cellular harm

> A well-studied potential mechanism of harm from radiofrequency radiation is one of cellular oxidation. Healthy biological systems require a balance of oxidation and antioxidation to fight infection and prevent disease (44, 45, 46). A review of the literature by Yakymenko et al. (2016) confirmed that in 93 of 100 studies, non-ionizing radio- frequency radiation caused a cellular stress response with excessive reactive oxygen species. He concluded, “oxidative stress induced by RFR exposure should be recognized as one of the primary mechanisms of the biological activity of this kind of radiation.”

[dr2chase]

How do you get mm-wave radiation to an aquatic plant? Skin depth at that frequency is tiny. Are they doing studies on duckweed? (Look up the plant, indeed, they are.) And I can see how pine needles might be more affected, what with size and pointy tips.

[posterboy]

> a lower growth radio

Lol, freudian slip?

You didn't post any causal explanation, just correlation.

Assuming the correlation was significant, maybe low magnetic fields along the radar are responsible, or transient spikes, high frequency (dys-)harmonics - because it says "pulsed" but I don't know whether it means square pulse or rather probably not. Might latvias Equip is slightly out of tune, who knows. Noisy relais is no rarity at all.

[ovi256]

Before conducting controlled experiments (which can verify causality) it's usual to conduct compared studies, which find the experimental factor occuring in a population and study its outcome. It's enough to establish correlation, much cheaper, and you can do it today instead of waiting however long it takes for the experiment (years if you have to grow trees while exposing them to microwave radiation)

[bluGill]

True, but when you find a lot of random change correlations that are not really there.

[st26]

It's known in the ham community that pine needles diminish the range of UHF radios, so it fits with pre-existing knowledge.

Reportedly needles are about the same length as a UHF antenna, and so they tend to absorb the radiation.

5G is, I believe, somewhere in the UHF spectrum.

[Junk_Collector]

Trees are quiet good at scattering RF mostly do to the water in them, their density of leaves/needles and the random orientation that they grow in. This leads to significant attenuation of the signal even if it isn't absorbed by anything. It's also worth noting that dried wood is almost RF transparent.