When it comes to stump grinding, the industry standard is to grind the stump until there is no longer a log. Generally, tree stump milling experts will grind stumps to 4-6 inches below ground level, but some machines can go even deeper. Vertical stump grinders, for example, can reach a depth of up to 62.5 inches below ground level. Some machines can even grind stumps up to 18 inches on the ground.
The depth of the stump depends on the size of the tree. Generally, a white oak trunk is deeper than that of a sycamore tree, and a sycamore trunk is deeper than an aspen. Your local arborist can estimate the depth of the trunk when they come out to grind it. Standard regulations state that only a stump 200 to 300 mm can be ground below the level of the surrounding ground.
If you need deeper grinding, it can be ordered, although the price may increase. It takes more time and labor to grind larger stumps, and the blade of the shredder must be large enough to remove small pieces for safety and maintenance purposes. Removing a stump can help prevent disease or pests from spreading if you have removed a diseased or pest-riddled tree. It also prevents the tree from growing back and eliminates an eyesore or tripping hazard.
You may choose to rent a stump grinder and do it yourself, but it may be cheaper to hire a professional woodland service. When stumps are against retaining walls, fences or buildings, it is very difficult to get the machine close enough to completely crush it. You may also decide to simply ask the tree service company that is shredding your stump to get rid of them. Stump grinders are a fantastic tool for removing ugly or unwanted tree stumps, but they can be dangerous in the wrong hands.
It's best to hire a professional who knows how far to dig and how to grind in order to get that stump out easily and save you money and time in the process.