Tools for Tree Core Sampling
Dendrologists--individuals who study tree-ring records--use a variety of tools to study a core sample of a tree. These tools are designed to do as little damage to the tree as possible while gathering the sample. A core sample is a cylindrical section extracted from the tree. It can be used to determine important information regarding the tree, including its age, growth rate and overall soundness.
An incremental borer is a tool used to bore into the tree to extract the core sample. It is a compact tool that can easily fit into a vest pocket or backpack. The tool consists of a handle, a borer bit and an extractor. Forestry Suppliers suggests when choosing an incremental borer that you consider the length of the borer bit, the core diameter and thread style. The borer bit length determines the maximum depth that the bit will penetrate. The core diameter capable of being extracted is set by the diameter of the opening of the thread at the end of the borer bit. For instance, a 0.169-inch opening will produce the same diameter of core sample. You can choose between a two-thread borer and a three-thread borer. A three-thread borer will enter the wood easier and faster, but a two-thread borer will penetrate deeper.
Straws are used to store the sample cores after they are extracted from the tree. Their job is to protect the cores from breaking during transport. The straws can be made of plastic or paper. Standard drinking straws are often used for storing tree core samples. A straw 6mm in diameter, for instance, is ideal for storing 4.3mm and 5.15mm cores. Paper straws are sometimes difficult to find, but can be ordered in bulk. A disadvantage of plastic straws is that they hold moisture, and the core sample must be removed promptly to prevent mold from growing.
After the sample cores have dried, they need to be mounted. A core mount consists of a piece of wood, usually made from yellow poplar that is 3/8 inch by 3/8 inch by 4 feet. It has a beveled top with a grove cut into it to hold the core samples. Core mounts can be purchased from woodworking supply centers, or you can make them yourself. Core samples are glued into the groove, then wrapped with masking tape or string until the glue dries.