Wide roots most stable
After a windstorm we can learn about tree root systems -- bad
root systems, especially.
A tree that stands up to wind does so by virtue of wide roots.
The same physics apply that make us steadier when we take a wide
stance.
Most tree roots are not particularly stiff -- some species'
roots have historic uses as rope and bindings because they're so
flexible. So their wide base isn't stiff like the foot of a goblet.
It has the flex of our knees. The top can rock in the wind without
snapping roots.
Grass and water to blame
This spruce's root system should have been about 18 inches deep,
with 4 - 11 large diameter flare roots, each ranging as wide as the
tree is tall and giving rise to many branching roots along the
way.
Instead, it was shallow and restricted, unable to win
against grass and poor drainage.
Competition slows root growth, especially when the tree species
involved is one that never had to develop ways to co-exist with a
greedy, chemically off-putting groundcover like Kentucky bluegrass.
Roots stall, too, where oxygen's been displaced by water. Here, the
soil is so compacted that water's still puddled just below ground
30 hours after a storm.
There's a large root, its broken end just above the pointing
shoe. It's one of only two of that size we found at this root
system's perimeter. With just two flare roots spread wide, the tree
had no chance once its top became large and the wind
strong.
Keep your spruce standing tall
Write a different story for your spruce so you'll never see its
roots. At planting, create a well-drained, grass-free ring at least
a few feet wider than the tree's widest branch tips, and expand it
as the tree grows. Keep the soil aerated within its rightful
root zone -- a circle as wide across as the tree is tall. You tree
will be more stable and also resist its other pests.