Bearing Tree

A bearing tree is a tree near a survey corner that is marked and measured so the corner can be found if its monument is lost. BLM's Glossary of Surveying and Mapping Terms defines it as "a marked tree used as a corner accessory; its distance and direction from the corner being recorded." The glossary adds that bearing trees "are identified by prescribed marks cut into their trunks; the species and sizes of the trees are also recorded."

Bearing trees and witness trees

The older term witness tree is now obsolete. The glossary explains that under the General Instructions of 1846 and earlier instructions, "Witness trees are signalized and marked as (bearing trees), but the course and distance to them, as well as the small chop, are omitted." Later, all trees used as corner accessories were marked as bearing trees, with the bearing and distance recorded. Federal law keeps the older word: 18 U.S.C. 1858 makes it a crime to willfully cut down "any witness tree or any tree blazed to mark the line of a Government survey."

How they are chosen

BLM's Manual of Surveying Instructions (2009) lists bearing trees first among the corner accessories, whose purpose "is to evidence the position of the corner monument" (section 4-79). The Manual directs (sections 4-81 through 4-84):

• Bearing trees are selected "ordinarily within a distance of 3 chains of the corner" (198 feet), or farther if important
• Sound trees of the hardiest species, not yet mature, are preferred. Trees 5 inches or less in diameter are avoided if larger ones are available
• The field notes record the species, the diameter at breast height, the exact direction from the monument to the center of the tree, and the distance to the center of the tree at its root crown

How they are marked

The marks are scribed on the side facing the monument, reading downward and ending in "BT" about 6 inches above the root crown (section 4-82). A tree at a corner of four sections carries the township, range, and section it stands in, as in "T26N R17E S35 BT." A tree at a quarter corner carries "¼" and the section.

Why the record matters

The Manual states that "the species, size and exact position of the bearing trees are of vital importance," because this data can identify a bearing tree "without uncovering the marks, or even to identify two or more stumps after all evidence of the marks has disappeared" (section 4-83). An existent corner is one whose position can be identified "by substantial evidence of the monument or its accessories," among other evidence (section 6-11).

Why it matters for mining claims

Where an original monument is gone, a bearing tree or its stump, matched to the field notes, can prove where a section or quarter corner stands. That decides where the section lines fall, and so where a mining claim described by or tied to those corners actually lies.