Included Bark in Trees: Wood Processing Insights (7 Pro Tips)
Included Bark in Trees: Wood Processing Insights (7 Pro Tips)
Introduction
Dealing with included bark in trees is a challenge that every wood processor, from the weekend firewood enthusiast to the seasoned logger, will inevitably face. It’s that frustrating situation where bark becomes embedded within the wood grain as the tree grows, creating weaknesses and potential problems during processing and end-use. This isn’t just a cosmetic issue; it impacts wood strength, drying characteristics, and overall usability. In this guide, I’ll share my experiences and provide seven pro tips to help you understand, identify, and manage included bark, ensuring you get the most out of your timber.
My Story: The Walnut Debacle
I remember one particularly frustrating experience involving a beautiful walnut tree I’d salvaged from a local farm. The tree was massive, promising a treasure trove of high-value lumber. However, as I started milling it, I kept encountering pockets of included bark deep within the trunk. It was like finding a hidden landmine in every board. What I thought would be a straightforward milling operation turned into a meticulous, time-consuming process of carefully working around these defects. That experience taught me the importance of understanding included bark, not just in theory, but in practice. It also spurred me to research the best ways to mitigate its impact.
Understanding Included Bark
Included bark, also known as “ingrown bark,” forms when the bark of a tree becomes embedded within the wood as the tree grows. This typically happens at branch junctions or where two stems merge. Instead of the wood fibers knitting together cleanly, the bark gets trapped, creating a plane of weakness.
Why is Included Bark a Problem?
- Reduced Structural Integrity: The bark disrupts the wood grain, significantly weakening the timber. This can be especially problematic in structural applications like beams or load-bearing posts.
- Increased Risk of Decay: Included bark traps moisture, creating a perfect environment for fungal growth and decay. This can shorten the lifespan of the wood, especially if it’s used outdoors.
- Difficult Machining: When milling or shaping wood with included bark, you’re likely to experience tear-out, splintering, and uneven surfaces. This makes it difficult to achieve a clean, professional finish.
- Aesthetic Issues: In furniture making or other applications where appearance is important, included bark can be unsightly and detract from the overall look of the piece.
Identifying Included Bark
Knowing how to spot included bark is the first step in managing it. Look for these telltale signs:
- Unusual Swelling or Bumps: Check for abnormal growths or bulges on the tree trunk, especially around branch junctions.
- Deep Cracks or Splits: Look for deep cracks or splits in the bark that run along the grain. These can indicate the presence of included bark beneath the surface.
- Bark Inclusions: Sometimes, you can see small pieces of bark protruding from the surface of the wood.
- “V” Shaped Crotches: Branches forming a tight “V” shape are more likely to have included bark than those with a wider “U” shape.
7 Pro Tips for Managing Included Bark
Here are seven actionable tips, backed by my experiences and research, to help you deal with included bark effectively:
Tree Selection and Pruning:
- Tip: Start with the tree itself. When selecting trees for harvesting, carefully inspect them for signs of included bark. Prioritize trees with well-formed branch structures and wide branch angles.
- Experience: In my own woodlot, I’ve implemented a proactive pruning strategy. By pruning branches early in the tree’s life, I can encourage better branch angles and reduce the likelihood of included bark forming.
- Technical Insight: Prune branches when they are less than 2 inches in diameter. This allows the tree to heal more quickly and minimizes the risk of decay. Use the “three-cut method” to avoid tearing the bark: make a small undercut, then a top cut further out, and finally remove the stub.
Strategic Milling:
Tip: When milling logs with suspected included bark, plan your cuts carefully. Try to orient the log so that the bark inclusions are located near the edges of the boards, where they can be easily removed.
- Experience: I’ve found that using a portable sawmill allows me to make on-the-spot adjustments to my milling plan based on what I’m seeing as I cut. This flexibility can be invaluable in minimizing waste.
- Technical Insight: Use a grade sawing method. This involves rotating the log after each cut to maximize the yield of high-quality lumber. When you encounter included bark, try to “box the heart” by cutting around the defect, leaving it in the center of the log.
Wood Stabilization Techniques:
Tip: Kiln drying is essential for stabilizing wood and preventing further cracking or warping around included bark.
- Experience: I once air-dried a batch of oak that had some minor included bark. Despite my best efforts, the boards developed significant cracks along the bark inclusions. Since then, I always kiln-dry wood with included bark to minimize these problems.
- Technical Insight: Kiln-dry the wood slowly and carefully, using a low-temperature schedule. This will help to minimize stress on the wood and prevent further cracking. Aim for a final moisture content of 6-8% for interior applications.
Resin and Epoxy Stabilization:
Tip: For smaller pieces or decorative applications, you can stabilize included bark with resin or epoxy. This will help to fill the voids and prevent further cracking or decay.
- Experience: I’ve used epoxy resin to fill cracks around included bark in several of my woodworking projects. It’s a great way to add strength and stability, as well as create a unique aesthetic.
- Technical Insight: Use a high-quality epoxy resin specifically designed for wood stabilization. Inject the resin into the cracks using a syringe or applicator. Allow the resin to cure completely before sanding or finishing.
Creative Design Solutions:
Tip: Embrace the natural character of included bark by incorporating it into your designs. This can create unique and visually appealing pieces.
- Experience: Some of my most successful projects have been those that celebrate the natural imperfections in the wood. Included bark can add a rustic, organic feel to furniture, sculptures, or other decorative items.
- Technical Insight: When designing with included bark, consider its structural limitations. Avoid using pieces with significant bark inclusions in load-bearing applications. Instead, use them for decorative elements or accents.
Tool Maintenance and Sharpening:
Tip: Keep your cutting tools sharp and well-maintained. This will help you to cut through wood with included bark cleanly and efficiently, minimizing tear-out and splintering.
- Experience: I’ve found that a sharp chainsaw chain makes a huge difference when milling logs with included bark. A dull chain will tend to grab and tear the wood, while a sharp chain will slice through it smoothly.
- Technical Insight: Sharpen your chainsaw chain regularly using a file or chain grinder. Follow the manufacturer’s instructions for proper sharpening angles and depth gauge settings. For hand tools like chisels and planes, use a sharpening stone or honing guide to maintain a razor-sharp edge.
Safety First:
Tip: Always wear appropriate safety gear when working with wood, including eye protection, hearing protection, and gloves.
- Experience: I’ve had several close calls over the years, and I’ve learned that it’s always better to be safe than sorry. Sawdust, splinters, and flying debris can all cause serious injuries.
- Technical Insight: Wear safety glasses or a face shield to protect your eyes from flying debris. Use hearing protection to prevent hearing loss from loud machinery. Wear gloves to protect your hands from splinters and cuts. When working with power tools, always follow the manufacturer’s safety instructions.
Data-Backed Insights and Technical Requirements
Here are some data points and technical requirements to keep in mind when dealing with included bark:
- Wood Strength Reduction: Studies have shown that included bark can reduce the bending strength of wood by as much as 30-50%, depending on the size and location of the inclusion.
- Moisture Content: Wood with included bark tends to dry unevenly, leading to increased stress and cracking. Aim for a moisture content of 6-8% for interior applications and 12-15% for exterior applications.
- Tool Calibration: Calibrate your chainsaw regularly to ensure that it’s cutting straight and efficiently. A misaligned chain can exacerbate tear-out and splintering around included bark.
- Industry Standards: Consult industry standards such as those published by the American Lumber Standard Committee (ALSC) for grading rules and specifications for lumber.
Case Study: Restoring a Barn Beam with Included Bark
I was recently involved in a project to restore an old barn that had suffered significant damage from decay and insect infestation. One of the main challenges was dealing with a massive oak beam that had extensive included bark and rot.
Project Details:
- Beam Dimensions: 12 inches x 12 inches x 20 feet
- Material: White Oak
- Problem: Extensive included bark and rot throughout the beam
Solution:
- Assessment: We carefully assessed the beam to determine the extent of the damage. We used a moisture meter to measure the moisture content of the wood and a pick test to check for rot.
- Removal of Decayed Wood: We removed all of the decayed wood using chisels and scrapers. This was a slow and tedious process, but it was essential to ensure that the remaining wood was sound.
- Stabilization: We stabilized the remaining wood with epoxy resin. We injected the resin into the cracks and voids to fill them and prevent further decay.
- Reinforcement: We reinforced the beam with steel plates and bolts. This added strength and stability to the beam and helped to distribute the load evenly.
- Finishing: We finished the beam with a protective coating to prevent further decay and insect infestation.
Results:
The restored beam was successfully reinstalled in the barn and is now providing structural support. The project demonstrated the importance of careful assessment, meticulous removal of decayed wood, and effective stabilization techniques when dealing with wood with included bark.
Specifications and Technical Requirements
Here’s a breakdown of specifications and technical requirements related to managing included bark:
1. Wood Selection Criteria:
- Species: Hardwoods like oak, maple, and walnut are more prone to included bark than softwoods like pine or fir.
- Branch Angle: Trees with narrow branch angles (less than 45 degrees) are more likely to have included bark.
- Growth Rate: Rapidly growing trees are more likely to develop included bark due to the increased stress on branch junctions.
- Inspection: Carefully inspect trees for signs of included bark before harvesting.
2. Tool Calibration Standards:
- Chainsaw Calibration: Check the chain tension, bar alignment, and depth gauge settings regularly.
- Moisture Meter Calibration: Calibrate your moisture meter according to the manufacturer’s instructions to ensure accurate readings.
- Sharpening Equipment Calibration: Calibrate your sharpening equipment to ensure that you’re sharpening your tools at the correct angles.
3. Safety Equipment Requirements:
- Eye Protection: Wear safety glasses or a face shield.
- Hearing Protection: Wear earplugs or earmuffs.
- Gloves: Wear gloves to protect your hands.
- Dust Mask: Wear a dust mask to protect your lungs from sawdust.
- Steel-Toed Boots: Wear steel-toed boots to protect your feet.
4. Drying Tolerances:
- Air Drying: Air drying can take several months or even years, depending on the climate and the thickness of the wood.
- Kiln Drying: Kiln drying can be completed in a matter of days or weeks, depending on the species and the drying schedule.
- Moisture Content Target: Aim for a moisture content of 6-8% for interior applications and 12-15% for exterior applications.
Practical Tips and Best Practices
Here are some practical tips and best practices for accurate implementation:
- Start with Quality Materials: Choose high-quality wood that is free from defects.
- Use Sharp Tools: Keep your tools sharp and well-maintained.
- Work Slowly and Carefully: Take your time and pay attention to detail.
- Follow the Manufacturer’s Instructions: Follow the manufacturer’s instructions for all tools and materials.
- Consult with Experts: Don’t be afraid to ask for help from experienced woodworkers or forestry professionals.
- Document Your Work: Keep detailed records of your projects, including materials used, techniques employed, and results achieved.
Conclusion
Dealing with included bark in trees is an inevitable part of wood processing. By understanding the causes of included bark, knowing how to identify it, and implementing the pro tips I’ve shared, you can minimize its impact and maximize the value of your timber. Remember to prioritize safety, use quality materials, and take your time. With careful planning and execution, you can turn a potential problem into an opportunity to create unique and beautiful wood products. The walnut debacle I experienced years ago taught me a valuable lesson: knowledge and preparation are your best allies when working with wood. Embrace the challenge, and you’ll be rewarded with the satisfaction of transforming a raw material into something truly special.
