We hate to say “do the math” because math reminds us of the budget, and budgets make us want to climb a tall tree and not come down.
But this not about the budget (whew!). It IS about trees! Citizens, environmentalists, the city arborist, and the council – particularly councilmember Colleen Clay – have been crunching numbers, trying to find some way to compare the relative environmental worth of trees vs solar power.
Trees won out in the council’s view – except maybe for councilmember Josh Wright who wanted to make the ordinances more flexible. The majority decided not to create any exceptions for solar panels. The benefits of leaving a live tree in place outweigh those of solar power, they said.
Clay found a way to compare numbers from a real-life situation – a controversial one in which a city tree was removed for solar panels. She had estimated power-production numbers for the solar array site when it was blocked by a tree, and from after the removal. The kilowatt hours produced by a solar panel after the tree was removed were LESS than the projected kilowatt hours produced by solar panel partially blocked by a tree – once she added in the kilowatt hours the tree saves.
Solar power offsets coal pollution and environmental damage from mining, but trees soak up storm water, filter the air, provide shade, and increase property values for an entire neighborhood. They do it for a hundred years or more, and take decades to replace.
The council, which is discussing proposed revisions to the city tree ordinances, mulled the solar exception, and tree replacement pre-plantings during their Jan. 10 and Jan 18 work sessions. They put aside the solar exception as a nonstarter, but liked the idea of pre-plantings.
The system now requires property owners who want to take down a living tree (not a dead, dying, or a hazardous one) to plant a surprisingly large number of replacement saplings – up to a score or more. The large number takes into account the size of the tree canopy the city loses, and how many small trees it will take to eventually replace it – reckoning in how many will likely survive into the next century.
Rather than wait until a tree removal, the suggestion has been made, property owners could plant trees before, which would not only offset the cost (saplings are expensive, especially by the dozen), but get a jump-start on replacing the urban forest.
The city arborist Todd Bolton thought it might work out, and that he could keep track of planting records without too much extra staff time. So, the council will discuss that further.
Lasers in the Air
The arborist has cool maps. He showed the city council a series of them created by airborne lasers. They show various data about the tree canopy that he showed singularly or in combination as he punched his computer buttons.
Old imagery, taken in 2001, indicated that the city had only 38% canopy cover, but new, higher-resolution imagery shows 59% cover. God news, but the way we’re going, the city arborist projects that will drop to 54% in ten years. Even with its tree replacement requirement, the city is losing more than it is gaining. The dead or hazardous trees that get wavered don’t get replaced.
Bolton told the council that Takoma Park has few “teenage” trees, so there will be a period when the canopy declines before they become mature and the “baby” trees of this generation get to adolescence.
Some of our trees, particularly the white and chestnut oaks, are 150 years old. They were part of our post-Civil War reforestation. During the Civil War (1861-1865) the capitol region was denuded of forests, says Bolton. Photos of Takoma Park in the 1880s show mostly young, 15-year-old trees. Those grew up to be the venerable oaks that shower acorns on your roof every fall, Dear Readers.
Fortunately, much of the city was built from the 1880s to the 1940s when trees around new houses were left standing. Starting in the 50s developers’ standard practice has been to clear-cut and grade entire tracts – the results of which can be seen in surrounding communities where there is no mature canopy.
Bolton showed laser images that revealed lines of 100+ year old mature trees that were left standing behind Ward 5 houses built in the 40s.
Councilmember Dan Robinson asked if oaks were the preferred replacement trees. Bolton replied that white oaks sometimes are – when he can get them. He’d prefer to offer chestnut oaks because they do well in Takoma Park’s “poor” soil, but he said they are not commercially available.
So, Dear Reader, if you’re looking for a good stocking stuffer for Mr. Bolton next Christmas, plant all the chestnut oak acorns you can find!