Collecting large diameter cores from living trees with commercial drill bits and increment borers

Foresters and scientists worldwide rely on the use of increment borers to collect wood cores from living trees for dendrochronology and a range of other applications. While there are many different types of increment borers, 4–5 mm diameter manual borers are most frequently used. Although these standard-size devices have a long history with well-established protocols, a range of newer analyses require the collection of larger diameter cores from living trees. To meet these needs, researchers worldwide have developed an array of techniques to collect these types of samples but little information is available comparing approaches and synthesizing options. Here, we summarize work testing several different commonly employed techniques for excising larger width (∼10 mm diameter) cores from living trees, comparing strengths and weaknesses of each approach. In addition to informing the selection of methods and equipment for researchers collecting larger diameter cores, this information may also provide new ideas for exploring core collection options beyond traditional increment borers.