The City of Lakewood is proposing to up-light the Garry oak trees adjacent the Colonial Plaza. This means putting lights under the trees, so as to create a cool, night-time effect. Unfortunately those making the proposal seem mainly concerned with surface appearances, and haven’t fully considered the science.
As we know, a major problem of modern living is light pollution. It is not just about not being able to see the stars, but it is also about the disruption of natural rhythms.
William Chaney, from Purdue University, wrote an article titled “Does night lighting harm trees?”. He pointed out that light effects both photosynthesis and photoperiodism – photoperiodism being the role of day length in growth and reproduction.
Chaney discussed some of the variables. Clearly the negative impact of the light is going to be worse if it is on all night rather than some of the night. You also have to consider the type of light – fluorescent, mercury vapor and metal halide lights have low impact, while incandescent and high pressure sodium are high impact.
There is also the question of where the lights are, and up-lighting should definitely be avoided. In fact, Chaney states “In all cases, up lighting and shining light over great horizontal distances should be avoided”.
So the City needs forget the up-lighting, because it is no good for the trees.
I should also mention the animals, including nesting birds, that would suffer because of the light pollution.
Finally, I think that there is something quite perverse about the idea of lighting up the Garry oaks. The City wants to give the impression that it cares about this special tree, yet in the process of signally its virtue it is damaging the very thing it is claiming to love and protect.