Surveyors need a working knowledge of dendrology.

Preparing a black cherry veneer log for marketing.
Webster’s College Dictionary defines dendrology as the branch of botany dealing with trees and shrubs. Trees are usually considered to be woody plants that grow to be 20' at maturity, have a single trunk, are unbranched for at least several feet above the ground and have a definite crown. Shrubs are shorter than trees with several erect, spreading or prostrate stems, and have a general bushy appearance. There are two general classifications of trees: deciduous and coniferous. Deciduous trees lose their leaves or needles in the fall and winter. Coniferous trees retain their needles or leaves year-round. Surveyors first need to know how to identify the forest into these different classifications.

Trees are known by many different common names. For example, red maple is also known as soft maple; hard maple is also known as sugar maple. To eliminate confusion, trees are also identified with scientific names. The scientific names are useful because they are understoodinallareas, whereas several popular names may be applied to the same tree. For example, the scientific name for one particular tree is Platanaceae Platanus Occidentalis. However, in different parts of the country it is known as buttonwood, American sycamore, American planetree and army tree. Knowing scientific names can be very important to the surveyor working across a wide area. Once the tree has been identified, then some thought should be given to its quality and potential value.


In the northwestern section of Pennsylvania, some of the most valuable trees (on a value per board foot basis) in the country are grown such as black cherry and red oak. It is of paramount importance to the surveyor to be able to identify these trees when blazing and painting boundary lines. A black cherry of veneer quality can be ruined by a blaze. Individual black cherry trees worth more than $10,000 have been harvested. A blaze on a tree of this quality could reduce its value considerably. A valuable tree could equal the cost of doing a survey. If blazed on the adjoiner’s property, it could cause the surveyor liability problems.

In addition to the value of the tree, something else to keep in mind while blazing is the longevity of the particular tree species. Whenever possible, choose a long-lived tree. A beech can live for more than 100 years. An aspen will probably die within 30 years.

Measuring the diameter of a large red oak tree.

Identifying Called-For Trees

When surveying in forested areas, many deeds call for trees for corners. It is important to be able to identify the called-for tree. Something to keep in mind when identifying trees is their specific growing needs or the site requirements. Hemlock trees normally won’t be found on high dry ridges; they need a lot of moisture to grow and develop. Similarly, it is very unlikely that rock oak will be found in swamps; they prefer dry ridges. When identifying trees by site, you can eliminate many species.

A growing order of trees is based on the shade tolerance of the particular tree species. When the forest is reclaiming a parcel of land, the types of trees that will pioneer the site will be determined by the tolerance to sunlight among other factors. There are basically three stages of forest growth: intolerant, moderately tolerant and tolerant. The highly intolerant species of trees that require full sunlight will be the first to arrive on the scene. Some examples are the aspens, fire cherry and red maple. As these trees grow and mature, the ground will become partially shaded, allowing the moderately tolerant species to get a start. These might be black cherry, red oak and ash. Monetarily, this is the most valuable stage of the forest. As these mature and the forest floor becomes darker, the most tolerant species will arrive, represented by sugar maple, beech and hemlock. When this stage is reached, it is known as a climax forest.

A forester’s concern is to control the stage of the forest. In northwestern Pennsylvania, the moderately tolerant species is the most desired stage of a commercial forest. Timber harvesting is used to sustain this forest development. As the trees grow and mature, the less desirable trees are removed. As the majority of the desirable trees reach maturity, a two-stage harvest is made. First, the majority of the timber is removed to provide ample sunlight on the forest floor. All that is left is a cross representation of moderately and highly tolerant species. These are left to occupy the site for five to 10 years. During this time, studies are made to determine the amount and species of seedlings that occupy the forest floor. When an acceptable amount of seedlings are about knee-high, the final cut is made to remove the remaining overstory.

These final cuts can cause considerable problems for surveyors. Usually the final cut is just thatÑall trees are removed including corner trees, witness trees and trees blazed along the boundary lines. When this happens, the surveyor’s only recourse is to attempt to identify the stumps in the area. Knowing the characteristics of the bark of trees is useful if the stump is new enough that the bark hasn’t rotted off yet. If the stump is very old and is just a rotten pile of wood, not all is lost. Many forestry colleges have wood identification labs that are able to look at the cell structure of the wood and identify it. Also, the U.S. Forest Service has a wood product lab at Madison, Wis., that is able to do this type of identification.

I used the Forest Products lab once for a survey done for the Allegheny National Forest in Pennsylvania. At question in this particular survey were the ages of some blazes found along a disputed line. The deeds called for a bearing and distance between the two found corners and also for the line as blazed by the surveyor. We had the surveyor’s field notes and knew the date of the survey. We also knew the month the surveyor did the blazing. Unfortunately, the blazes didn’t follow a straight line between the two corners. We had three of the trees felled and the blazes blocked out. These were sent to the lab for aging and any other information we could gleam from the blocks. The lab was able to report the month and year of the blazes, the chemical makeup of the paint and the type of instrument used to blaze the trees. All of this was in keeping with the records of the surveyor, and these blazes were determined to be the original ones. This changed the line from a straight one to one with three angle points in it.

Dendrology plays a major role in surveying throughout the country. When looking for tree corners and preparing deeds, it is essential to have knowledge of tree identification. Sometimes deeds incorrectly identify the tree. Reading a deed that calls for a rock oak and is in a swamp can be frustrating. Recognizing that some tree species are more valuable than others is important when blazing a tree for boundary lines or witness corners so that care can be taken not to decrease their value. Also, knowing which species are long-lived can be helpful when deciding which trees to use for witnesses.


From the surveyor’s point of view, three basic questions need to be answered:
  • Is it a tree or a shrub?

  • Is it deciduous or coniferous?

  • What is its name?


  • The Shrub Identification Book by George W. Symonds
  • The Tree Identification Book by George W. Symonds

  • A Field Guide To Trees And Shrubs by George A. Petrides

  • Common Trees Of Pennsylvania by the Pennsylvania Department of Conservation & Natural Resources, Bureau of Forestry