Remove small oak tree saplings in your garden or yard as quickly as possible, before they send down hard-to-eliminate taproots. These saplings can either grow from suckers shooting up from a mature oak tree's root system or from dropped acorns germinating and growing into separate plants. Kill these saplings without risking harm to the environment from chemical herbicides.
Soak the ground for two or three days with a slow-running garden hose to loosen the soil, especially during arid months. Once the ground is soft, grasp the stems with both hands and pull the saplings out evenly without jerking. You may be able to remove all the roots in one go. This method works well on young plants with stems less than an inch in diameter.
Dig out larger saplings by first soaking the ground and then loosening the soil surrounding the plant with a gardening fork; dig as deeply as possible and do not use a shovel or mattock as doing so can sever roots and leave some behind to grow back. Once the soil is loosened to a sufficient depth, pull the sapling free by applying steady upward pressure; sometimes it takes two people pulling together to dislodge larger saplings.
Cut off young seedlings level with the ground with a mower or a weed trimmer. Keep cutting them back as soon as new growth develops over the following months. This method works, but it may take a year or two to kill the remaining root network.
Rake up all of the fallen acorns you can find during fall and early winter to prevent new saplings from developing.