Structural engineers, builders and inspectors in North America use grade stamps to regulate strength, quality and factors regarding different lumber used in construction or building projects. Lumber, timber and wood are naturally sourced so they can have defects, some of which are noticeable and some are not. Any defects can influence the strength of the lumber and can include knots or splits that ensue naturally. Why do loggers stamp their wood?
Unlike money, framing lumber does grow on trees. So, there is constantly the chance it will have some kind of natural defect like a long split or large knot. Either one of those defects can cause a reduction in strength. However, we always do not see every defect. That is why each piece of lumber that comes out of a sawmill is assessed by professional inspectors and then given a grade stamp. This obscure stamp will indicate that the piece of lumber meets reputable standards for stiffness and strength. It also provides useful information regarding the kind of wood and its moisture content.
What do the log stamp and timber marks mean?
We will interpret the stamp and explain how to get the most wood for your money.
1. Types
Represents the wood’s type or group with strengths that are alike. Although all types are classified at the same four appearance and strength levels, it does not make them equally strong. For example, joists made from a specific species such as Douglas fir, will have a greater span than another type like a hemlock of the exact grade and size. However, when you use joists that are bigger of an inexpensive type, that could save you money without losing strength.
Below are stamp abbreviations from strongest to weakest for framing-grade softwoods:
Hem, Hem-fir, H-F: Hemlock or fir
SYP: Southern pin
Doug Fir, D Fi-L: Douglas fir (L=western larch)
S-P-F: Spruce, pine, fir
2. Grade
Determines the quality of lumber based on visual inspection by a grader. It ranks from highest strength, best appearance (Select Structural) to lowest strength, not pretty (No.1, No.2 and No.3). The price and quality decrease as the numbers increase. Tom Silva, remember him? Contractor for This Old House. He purchases stacks of No. 2 lumber, which delivers good strength at a sensible price.
3. Moisture Content
Unseasoned lumber coming right from the mill is branded either surface green (S-GRN) or air dried (AD). This lumber is inexpensive due to its moisture content of 19 percent, however as it dries and shrinks, it can erratically move. You will have less movement with lumber that has a moisture content between 16 and 19 percent.
4. Certification Mark
The certification marks classify the association or bureau that oversee the grading accurateness, such as the National Lumber Grades Authority.
5. Mill
The mill provides the number or logo of the of the source.
How do loggers mark trees?
North American forests do not commonly accept marking codes using pain and other tree inscribing methods. There is no nationwide code that dictates using painted circles, slashes X’s and dots. No color that is used for a code is never more than a district preference and typically accepted only in the vicinity. Depending on the national forest region and/or the national forest, different colors and marks are used by the United States Forest Service.
Nevertheless, there are several reasons to mark forest lumber and trees. In accordance with the forest management, trees can be marked to specify a tree to be left or cut. Property ownership can be indicated by marking trees on forest boundary lines. As part of a forest account system, trees standing inside large forests may be marked permanently.
The Meaning of Forest Tree Markings
Even if many of the trees are alike, there are no national marking standards.
Forestry establishments have tries for years to put into place some rules for timber and tree markings. However, foresters are a self-governing breed and they view their marking system and strategies as their own kind or company stamp. Quick paint sprays, which include stump marks, circles and the number of slashes, typically indicates cutting position along with the grade or quality of the tree that is marked.
Using Marks to Select a Tree to Cut
Paint is often used as a mark when choosing a tree to cut. Trees that are left unmarked, typically have the best chance to create the most prolific second crop for the future. The trees that are going to be cut are usually marked with blue paint and the tree’s planned product is recognized by various paint symbols and slashes. So, you are choosing the best trees with the best possible value by not marking them.
Why Mark Trees for Removal
- Unless reserved as a wildlife tree, there is high risk of failure or impermanence
- Poor stem quality and form
- Letting go of crop trees for the future
- Less wanted species
- Expand spacing
- Low crown vigor
Boundary Line Marks
One important responsibility of the forest manager is maintaining forest boundary lines and marking trees is a part of that. Very few forest landowners have clearly marked lines on the ground even though they usually know their boundary lines having precisely charted photography and maps.
The best indication of knowing where your lines are is a clearly marked boundary. Boundaries that are clearly marked lessen the risk of problems like timber trespass, which can happen when others make incorrect assumptions about your actual boundaries. Mark boundaries also help you evade trespassing on nearby land when you build roads, trails and cut trees. Be sure to use the most up to date recorded survey.
Marking Forest Boundary
- Contact your boundary neighbor, it is courtesy after all, as new line claims may cause disagreements.
- Limit your cut to just enough bark and outer wood to make it noticeable. Evade blazing over old blazes, as they can become supportive indication of the original location of the line.
- Using a bright color, paint both the blazed surface and include 1-2 inches of bark.
- Blazing side trees on the line it faces are helpful, however, this would require an up-to-date survey accuracy.
- Marking trees close together is good practice so you can be sure to see the next mark from all directions.
