There has been a lot of viral press lately about the unique relationship between Wi-Fi and trees. A recent study in the Netherlands claimed that the radiation emitted from Wi-Fi radios might be making trees sick. When I first read about this study about Wi-Fi’s environmental impact, I was reminded about American poet Joyce Kilmer’s famous poem, “Trees”:
“I think that I shall never see
A poem lovely as a tree.
A tree whose hungry mouth is prest
Against the earth’s sweet flowing breast;
A tree that looks at God all day,
And lifts her leafy arms to pray;
A tree that may in summer wear
A nest of robins in her hair;
Upon whose bosom snow has lain;
Who intimately lives with rain.
Poems are made by fools like me,
But only God can make a tree.”
As soon as that study was released late last year, the story went viral and the panic began. Based on what I read in the blogosphere, Wi-Fi signals were propagating to every nearby forest and not a single tree was safe. I am starting to believe there might be some truth to the hysteria. Last August, I looked outside the window of my house to observe a lovely tree in my back yard. All the leaves were green and glistening. I did however notice that in late September and October, the leaves on my tree began to turn yellow and red. Even worse, by November all leaves had fallen completely off the tree in my back yard!
Years ago, I remember a similar report that claimed that the honeybee population in North America was dwindling due to a phenomenon known as Colony Collapse Disorder (CCD). Guess what the culprit was? You guessed it: Wi-Fi. Of course this honeybee disorder was occurring when 802.11b (802.11bee) radios were only available. Once everyone upgraded to 802.11g radios, the honeybees got much better. (For the record, Aerohive has always been a very bee-friendly company.)
Can we get serious for just a moment? Wi-Fi is killing trees and bees? And maybe the sky is falling Chicken Little? What would happen if we took a typical indoor AP and placed it in the middle of the forest? Let’s just say a 2.4 GHz AP at full transmit power of 100 mW combined with a +3dBi omni-directional antenna. The amount of radiated power that would emit from the head of the antenna would be 200mW. The laws of physics still apply in the forest and therefore Free Space Path Loss (FSPL) would immediately begin to attenuate the Wi-Fi signal. A rock’n’roll received signal from a client perspective is -40 dBm which converts to 1/10,000th of a milliwatt. A -60 dBm received signal converts to one-millionth of one milliwatt. In other words, we are talking very low received amplitude even from the perspective of a tree.
I am not a scientist, but something tells me that Wi-Fi is not the reason for leaves falling off trees; I believe the real cause is a seasonal phenomenon known as Autumn.
As a matter of fact, I blame trees for the negative effects that they have on Wi-Fi. If a tree’s body weight is 75 percent water, think about how much a tree attenuates the amplitude of a 2.4 or 5 GHz Wi-Fi signal as it propagates through the tree. Trees are Wi-Fi killers!
All kidding aside, I love trees just as much as the next guy, but I think it is safe to say that our trees and Wi-Fi can live together harmoniously. Now if someone put a WLAN controller in the forest, I might be worried. Luckily, Aerohive uses a cooperative control wireless LAN Architecture, that provides all of the benefits of a controller-based architecture, but is easier to deploy and expand, lower cost, more reliable, more scalable, more ubiquitously deployable, higher performing and more suitable for voice over wireless LAN than today’s controller-based architectures. So with all due respect to Joyce Kilmer:
“I think that I shall never see
A WLAN controller as lovely as a tree.
Poems are made by fools like me,
But only Aerohive can make a controller-free HiveAP.”
A healthy side note on Wi-Fi’s environmental impact: As Global Training Manager, I am often asked in the training classes that I teach about any possible negative health effects on humans that could be caused by Wi-Fi. Numerous studies have shown that there is no convincing scientific evidence that weak RF signals will cause adverse health effects.
The Wi-Fi Alliance takes any concern about the alleged health impact of Wi-Fi technology seriously. More information about WLANs and Health can be found on the Wi-Fi Alliance website.
