DURABILITY OF BEARING TREES

INTRODUCTION

This document is prepared as a guide, to aid in the search for old bearing trees as well as in marking new trees.

TREE SPECIES AND GENERAL DURABILITY

The durability of a tree when marked for a bearing tree is of great importance to the Cadastral Surveyor. The original bearing trees are one of the primary methods used to determine the position of the original corner point. The surveyor must be able to identify the many tree species for which he is searching, not only by the proper common name but also by the common name used by the original surveyor, he should know what to expect in his search because of  the widely divergent growth habits, growth rate, life span and resistance to decay of the many tree types. The methods of blazing and marking the trees by the original surveyor will play a large part in the search also. When marking new bearing trees judgment must be made in selecting the most durable species available and proper method of  marking to prevent excessive injury, or even destruction of the tree. 

When marking a bearing tree be sure of the identification and enter the correct common name in the field notes. Distinguish between the various species in the tree family. There is a world of difference between a Ponderosa pine and a Knob cone pine; or a California live oak and a California black oak.

EFFECTS OF MATURITY

The normal life span of a tree is of primary importance. The black locust is highly resistant to decay but has a normal life span of only about 100 years, though some may attain a greater age. On the other hand the wood of Douglas-fir Is considered only moderately resistant to decay but the tree may live over a thousand years (left unmolested) and is known to be an excellent bearing tree. Another contradictory example is the California black oak; this tree may live to over 300 years of age, yet is so susceptible to decay when injured that it is a poor choice for a bearing tree. Thus the life span is only an Indication of what may be a good tree for witnessing a corner.

When searching for original bearing trees the size at maturity, expected life span, and growth rate are very important. If a tree which has an expected life span of 200 years and 24 inches diameter at maturity was marked when 20 inches diameter the tree was already near maturity. The blaze would be slow to heal, decay sets in and the tree soon dies, falls and disappears. If the field notes call for a mature tree the chance of recovery after 100 years or more are then greatly reduced.

In some cases the season of the year when marked is important. with deciduous hardwoods the dormant season is the most desirable time for blazing. The wound has a chance to heal and harden before insects and fungus are active and attack. in the nortern states this will play a part in recovery possibilities. A tree marked in the fall or winter would be more likely to survive than one marked in spring or summer. This will be especially true of trees with a high sugar content in the sap, such as maple and birch.

METHOD OF BLAZING

The methods of blazing and marking by the original surveyor are also very important. If the original surveyor made large blazes, cutting deeply into the tree, loss is much greater from decay. If the blazes were made high on the tree, logging will remove the entire blaze. Fortunately many of the original surveyors used a "double blaze"; the township, range and section on a blaze at breast height and a smaller "BT" blaze nearer the root crown. When logged the lower blaze frequently remains on the stump. The smooth barked trees and those with very thick bark were often bark scribed. The bark scribing expanded on the smooth barked trees as they grew and may be hard to detect though readily apparent to the experienced eye. On thick barked trees the bark was smoothed enough to scribe but no penetration made into the sapwood. This scribing may appear as disjointed lines or even be mistaken for worm or beetle "tracks". Sometimes the bark scribing is all but lost in the roughened and maturing bark. 

The surveyor must keep an open mind at all times when searching for the original trees. He must consider not only the species of tree, time of year, size of tree, type of scribing, growth rate, life span and site location but also the characteristics of the original surveyor and the instructions which he had been given to govern his work. 

When selecting new trees to mark for bearing trees at a corner several things must be considered. Is the tree young or near maturity, resistant to decay, long lived, well formed, suppressed by other (though inferior) trees, in a good location not subject to undercutting by a stream, large enough to receive all the marks and in good location in reference to the corner? Often there is very little choice, but when there is, all aspects should be considered. It is a well established fact that a large Douglas- fir stump, with the bark removed, is superior to poor trees such as dog- wood or cascara, and in most cases young alder. 

The blazes should also be kept as small and narrow as possible, consistent with the amount of scribing required. The blaze should be smooth at the edges and carefully done to avoid breaking the bark loose from the cambium layer. This is especially important when blazing trees such as birch, aspen and spruce. The bottom of the blaze should be smooth and well drained to avoid accumulation of sap, water, and dirt. This can frequently be done with a stroke of the axe at the bottom of the blaze. On many species of smooth barked young trees bark scribing is preferred. If the only suitable trees available are too small to accept all the marks making a small "BT" blaze at the root crown and marking the tree only "BT" is better than taking no tree at all. Manual requirements should always be fulfilled when possible but should never be used as an excuse to avoid marking bearing trees. 

Much of the work performed by the Cadastral Surveyors today is dependent resurvey of intermingled ownership. An original bearing tree marked before the land was patented remains Federal property. But trees now standing on private lands are private property. Permission should always be acquired before marking privately owned trees, particularly highly prized trees such as walnut or hickory. Never use an ornamental tree in someone's yard!! Painting is recommended. When injured by blazing and scribing the tree is opened to attack by insects, bacteria and fungus. If the wound is painted with a special tree wound paint, manufactured for this purpose and available in aerosol spray cans, the tree is protected until it can heal the injury. Painting is essential on many trees to prevent swift loss to decay.

Many trees, such as lodgepole pine, aspen and alder, grow in dense stands when young. They carry on a continuous battle of "survival of the fittest". When injured by blazing, the tree must attempt to heal the wound and is then less able to survive the battle. When marking such a tree it is recommended that the tree be freed from its close competition. This is done by cutting down, or "ringing" the close neighbors in a thinning process, called releasing. Releasing gives the bearing tree the advantage in the battle for sunlight, water, air and nutrients. Releasing is not always possible or prudent; on private lands the land- owner may willingly give permission for cutting of survey lines or marking bearing trees, but would object to releasing. Dense thickets of hawthorn or vine maple make releasing nearly, if not totally, impossible at times. It should be done however, whenever ground conditions dictate or permit.
                                                  

  ARRANGEMENT OF LIST

This list is prepared by the common name of the tree. The common names are listed in capital letters. Many trees are very similar in appearance or durability and are listed together in the interest of simplicity and brevity. This should not be construed that the names are interchangeable. Following the common name is the scientific name, always the genus and in most cases the species. Next is given a list of other common names which may have been used by the original surveyor in his field notes. The original surveyor may have called for a redwood where none exist, the tree was actually an incense-cedar. Or he may have called for a hackmatack, the tamarack in Minnesota, when the tree was really a western larch., These other names are cross-referenced in the index. Following the other names is a grading ranging from unsuitable or very poor up to excellent. A tree graded very poor should be used only as a last resort and probably be supplemented with a mound of stone or other accessory. These grades are given as an aid in making the decision about which tree(s) should be used to witness a corner. The scale is generally based on young, vigorous trees and not mature or old growth trees. Following the grading is a written narrative of what is known of the particular species, both as an original bearing tree and recommendation for use as a new bearing tree.

BEARING TREE INDEX

The following persons and offices of the Bureau of Land Management contributed to this document which are gratefully acknowledged:

               Wayne C. Fields Alaska
               Boyd C. Owens Arizona
               Beverly Capell California
               Joseph S. Gawro~ Idaho
               William Smart Portland Service Center
               Jerry Pittman Montana
               Joe N. LaRue Montana
               Lane Bouman Eastern States Land Office
               Fred L. Waskowiak New Mexico
               Wayne M. Gardner Wyoming
               Robert Buckman and
               Ken Witt Colorado
               Richard Larimer Montana
               Don Lappala Ottawa National Forest. U.S.F.S.

Compiled and prepared by C. Albert White, Portland Service Center

Revised by Daryl K. Moistner (2008)

               References used in this document:

               C. Frank Brockman, Golden Press
               "A Guide to Field Identification"
               Trees of North America

               U. S. Printing Office
               "Silvics of Forest Trees of the United States"
               Agriculture Handbook No. 271
               Dover Publications, Inc.

               "Forest Trees of the Pacific Slope"
               George B. Sudworth
               U. S. Printing Office

               "Trees"
               The Yearbook of Agriculture, 1949
               Telegraph Press

               "The Book of Trees"
               William Gary Grimm
               U. S. Printing Office

               "Diseases of Forest and Shade Trees of the United States" Dept. of Agriculture, Handbook No. 386
               U. S. Printing Office

               "Alaska Trees and Shrubs"
               Agriculture Handbook, No. 410

               Photographs by Daryl K. Moistner
               Hereby released to the public domain