Wednesday, June 26, 2013

How to kill an oak tree #973: Killing me slowly with backfill

God, this is disheartening.  Stopped for gas in Paso Robles, CA on Friday afternoon (Paso Robles = Oak Tree Pass in English - the most recent and perhaps most ill-fitting language of the area) and I saw this:

(Click to enlarge)
This tree is dying. It is a massive California white oak/valley oak (Q. lobata) with a crown spread of about 80 feet or so.

And therein lies the problem.  A crown spread of 80 feet equals a root system spread of more than 80 feet.  But when the gas station was built the grade was raised around the tree, save for a 10 foot diameter dish right around the trunk that was left at the original grade.

The grade wasn't raised by much - 6 inches in most places, maybe 12 to 18 inches farther away from the tree.  But that's enough, especially if (as I suspect) construction equipment compacted the soil in the drip line root zone.  Roots that were inches below the surface poised to swallow precious moisture from the rare Paso Robles cloudbursts and which had plenty of pores of air space in which to breath, are now several times farther from the hard packed surface, with no air space to breath and no water to drink.

The sad parts are:

1. Someone actually made an effort to help the tree by leaving a dish at original grade.  They just didn't know (I prefer that to thinking they knew and just didn't care) that the most valuable roots are way out below the drip line or beyond.  They didn't know that even a minor change in grade, especially when combined with soil compaction, can suffocate the fine feeder roots that are the lifeblood of any tree, no matter how huge.  The knowledge gap on construction sites is still, after all these years, immense.

2. The tree is dying so slowly - this gas station was built several years ago - that by the time it dies no one will connect its death to the damage that was done during construction.  Instead its death will be blamed on old age (Ha! This tree would live another 150 years left to its own devices) or on the insect and/or disease pests that aren't the primary cause of death but are only the secondary and opportunistic beneficiaries of the tree's stress and struggles.

The third and saddest part?

 (Click to enlarge)

3.  There's another tree right next door behind a car dealership that is dying in exactly the same slow way.


Obey the drip line people.  And if you're not going to - or can't - obey the drip line, then do the tree the honor of harvesting it and putting it to use, rather than leaving it to die a slow, drawn-out death that will leave its wood rotten and its spirit ruined.

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