By-products of stump grinding

By-products of stump grinding

Depending on exactly where the stump grinder is positioned relative to the stump, the resulting stump grindings will vary in both size and color.
The portions of the stump originally above ground will be almost entirely “wood-colored” and will be as long as 7” and the diameter of your index finger.
From there the particles will get smaller, right down to 1/4” x 1/4 “ and even sawdust-sized.
As the stump grinder reaches further down into the ground, it will “cut” more soil, resulting in a change of color to the pile as the dirt, darker in color, gets intermingled with the wood chips.


Volume of stump grindings relative to the original size of the stump-

Even after 15 years and over 13,000 ground stumps, it still is hard for me to say it –
The larger the stump, the more the stump grindings.
I’ve had many 20’ diameter stumps that produced 3 wheelbarrows full of grindings. On the other end of the scale, I’ve had some
large stumps that produced  10 cubic yards of stump grindings. How much is 10 cubic yards? Think large dump truck.
For a rough rule of thumb, when you look at a stump, take the volume of what you see and
multiply it by ten (10) to arrive at the volume of grindings produced by the stump grinding
process.
Many is the client who has been left with 2 to 4   cubic yards of mulch.
( A cubic yard measures 3’ x 3’ x 3’)


Where do all the grindings go as they are being made?

The vast majority of stump grinders throw the grindings underneath the stump grinding machine..
While this is a good thing relative to the property that the grinder is on, it often creates problems for doing a good job.
On almost any job where the stump is larger than 30” in diameter, the machine will generate so many ships that that the operator can no longer “see” where the stump actually is. The
best way to maintain visual certainty, and job integrity, is to then back the machine off the stump and move the ship pile off of the stump. Depending on the machine, this pile removal cycle can occur after  every 15 minutes of gringing time.
With the completion of a grind, any chips that have gone “rogue” and flown away from the larger pile must be mechanically brought back to the pile.
 


What's to be done with the hole where the stump was and all the grindings?

Unfortunately, there's no away around it.
There is no machine out there that can just vacuum up this material and cart it off.
And, stump grinding piles are so varied in consistency that they do not respond well  to being scooped up by machine.
In the end, roughly half of the grindings from any grinding job must be hand loaded into whatever vehicle will carry them off.

On the bright side is their usefulness. Although not uniform in color or size like commercially available screened mulch,
they can be put to the same purpose . In addition, these wood chips can absorb up to 7 times their own weight in water,
which renders them as great material for wet garden paths and landing areas.

There are multiple solutions to filling up the hole left from the stump grinding process.
The ideal solution is to removed all the grindings from the hole, which is usually 6" to 8" deep, and the
filling the hole with fresh soil. This insures that the new plant material , whether grass or ornamentals, will have
a good shot at thriving.

For those less concerned, the "dirtier" part of the grindings pile can be used to fill in the hole up to 2" below finished grade,
with a 2 " veneering of fresh soil spread out on top like icing on a cake.
Finally, for roughest resulting look, the grindings can be used to fill the hole completely, the top layer is then spring raked
to remove the larger woody portions. Grass can be started on this but it will extremely weedy, if not barren,  for at least a couple of years
after wards.