How To Cut A Fallen Tree Under Tension (5 Pro Arborist Tips)

Craftsmanship isn’t just about knowing how to swing an axe or fire up a chainsaw; it’s about understanding the soul of the wood, the dance of physics under tension, and the quiet respect for the power we wield. It’s a blend of art and science, honed over years of experience, passed down through generations of woodcutters and arborists. For me, it started with my grandfather, a man whose hands seemed permanently stained with the scent of pine and oak. He taught me that every tree, standing or fallen, tells a story, and it’s our job to listen carefully before we even think about making a cut.

How to Cut a Fallen Tree Under Tension: 5 Pro Arborist Tips

Felling a tree is one thing; dealing with one already on the ground, especially when it’s under tension, presents a whole new set of challenges. I’ve seen firsthand what can happen when these forces are underestimated – pinched saw bars, flying wood, and near-misses that make you rethink your career choices. Over the years, I’ve developed a system, a set of rules really, that I rely on to safely and effectively tackle these situations. These aren’t just theoretical concepts; they’re hard-won lessons learned from real-world experience, often in less-than-ideal conditions.

1. Assessing the Situation: Understanding Tension and Compression

Before you even think about firing up your chainsaw, take a good, hard look at the fallen tree. This is critical, and it’s where many amateurs fall short. I always start by identifying where the tree is supported and where it’s sagging. The sagging areas are where you’ll find tension on the upper surface of the log and compression on the underside. Imagine bending a flexible ruler; the top stretches (tension), and the bottom squeezes (compression). A fallen tree acts the same way.

Visual Inspection: Look for bends, cracks, or splits in the wood. These are telltale signs of stress. Note the size and species of the tree. Hardwoods like oak and maple store far more energy than softwoods like pine or fir.
The Bounce Test: Carefully walk along the log. Does it bounce or move significantly? This indicates a high degree of tension.
Ground Contact: Observe where the log is making contact with the ground. These points are crucial for planning your cuts.
Diameter Measurement: Knowing the diameter of the log will help you estimate the forces involved. A larger diameter means more stored energy. I use a diameter tape, and I always measure at several points along the log to get an accurate average.

Data Point: A 24-inch diameter oak log under moderate tension can release hundreds, even thousands, of pounds of force when cut. This is enough to pinch your saw, throw the log, or cause serious injury.

Technical Requirement: Always assume the worst-case scenario. Overestimating the tension is far safer than underestimating it.

2. Planning Your Cuts: The Art of Controlled Release

Once you’ve assessed the tension, it’s time to plan your cuts. This is where experience truly pays off. The goal is to release the tension gradually and predictably, minimizing the risk of sudden movements or kickback. I use a technique called “tension relief cutting,” which involves a series of strategic cuts designed to redistribute the forces within the log.

Identify Tension Zones: Pinpoint the areas of highest tension based on your initial assessment. These are your primary targets.
Compression Cuts First: Always start by making a cut on the compression side of the log (the underside). This helps to relieve some of the binding on your saw.
Tension Cuts Second: Follow up with a cut on the tension side (the upper surface). Be extremely cautious here. The wood can splinter or snap suddenly.
The “Kerf Test”: Before committing to a full cut on the tension side, make a small “kerf” (a shallow cut) and observe the reaction. If the kerf widens or pinches, you know there’s significant tension present.
Wedges and Levers: Have wedges and a lever bar readily available. These can be used to gently pry the log open or prevent it from pinching your saw.

Case Study: I once worked on a massive, storm-downed oak tree that was suspended between two other trees. The tension was immense. I started by making a series of small compression cuts, followed by careful kerf tests on the tension side. Each kerf widened dramatically, indicating extreme force. I used multiple wedges and a large lever bar to control the release, working slowly and methodically. It took nearly an hour, but we were able to safely section the log without any incidents.

Technical Requirement: When cutting under tension, never stand directly in line with the cut. Always position yourself to the side to avoid being struck by flying wood.

3. Chainsaw Mastery: Choosing the Right Tool and Technique

Your chainsaw is your primary tool in this situation, and it’s crucial to have the right saw and the right technique. I prefer a professional-grade saw with a sharp chain and a guide bar length appropriate for the size of the log. A dull chain is a recipe for disaster, as it increases the risk of kickback and makes it harder to control the cut.

Chainsaw Selection: I typically use a 60-70cc chainsaw for larger logs under tension. A smaller saw may not have the power to handle the stress.
Chain Sharpness: Sharpen your chain before each use. A sharp chain bites into the wood smoothly and reduces the risk of pinching. I use a chainsaw sharpening kit and follow the manufacturer’s instructions carefully.
Cutting Technique: Use a slow, controlled cutting motion. Let the saw do the work; don’t force it. Keep the saw chain lubricated to reduce friction and heat.
Boring Cut (with Caution): In some cases, a boring cut (plunging the tip of the saw into the log) can be useful for relieving tension. However, this is an advanced technique that should only be used by experienced operators, as it carries a high risk of kickback.

Data Point: A chainsaw chain should be sharpened after every 1-2 hours of use, depending on the type of wood being cut. A dull chain can increase cutting time by 50% or more and significantly increase the risk of accidents.

Technical Requirement: Always wear appropriate personal protective equipment (PPE), including a chainsaw helmet with face shield, hearing protection, chainsaw chaps, and work gloves. Don’t skimp on safety gear – it’s your first line of defense.

4. Wedges, Levers, and Mechanical Advantage: Your Best Friends

Wedges and lever bars are indispensable tools for working with trees under tension. They allow you to control the release of energy and prevent your saw from getting pinched. I carry a variety of wedges, from small plastic wedges to large steel felling wedges. I also have several lever bars of different lengths, which I use to pry logs apart or to provide additional leverage.

Wedge Placement: Insert wedges into the kerf as you cut to prevent the wood from closing back up and pinching your saw. Use multiple wedges if necessary.
Lever Bar Technique: Use a lever bar to gently pry the log open after making a cut. This helps to relieve tension and makes it easier to remove the section of log.
Mechanical Advantage: Remember the principles of leverage. A longer lever bar provides more mechanical advantage, allowing you to exert more force with less effort.
Hydraulic Jacks: For extremely large logs under high tension, consider using a hydraulic jack to lift the log and relieve the pressure. This is a more advanced technique, but it can be a lifesaver in certain situations.

Personal Story: I once had to cut a large, leaning ash tree that had fallen across a stream. The tree was under extreme tension, and every time I made a cut, the log would shift violently. I used a combination of wedges, lever bars, and a come-along winch to control the movement of the log. It was a slow and painstaking process, but we were able to safely remove the tree without damaging the stream bank or injuring anyone.

Technical Requirement: Always inspect your wedges and lever bars before each use for signs of damage. Replace any damaged tools immediately.

5. Safety First: Avoiding the Common Pitfalls

Working with fallen trees under tension is inherently dangerous, and it’s crucial to prioritize safety above all else. This means being aware of the common pitfalls and taking steps to avoid them. I’ve seen too many accidents caused by carelessness or a lack of knowledge.

Kickback Awareness: Be constantly aware of the potential for chainsaw kickback. Kickback occurs when the tip of the saw chain catches on something, causing the saw to suddenly jump back towards the operator. Use a chainsaw with a chain brake and always maintain a firm grip on the saw.
Spring Poles: Be extremely cautious of “spring poles” – small, bent-over trees or branches that are under tension. These can snap back with tremendous force when cut. Clear away any spring poles before starting work.
Communication: If you’re working with a partner, maintain clear communication at all times. Use hand signals or radios to coordinate your actions.
Fatigue: Avoid working when you’re tired. Fatigue impairs judgment and increases the risk of accidents. Take frequent breaks and stay hydrated.
Weather Conditions: Be aware of the weather conditions. Wind, rain, or snow can make the work even more dangerous. Postpone the job if the weather is too hazardous.

Data Point: According to the Occupational Safety and Health Administration (OSHA), chainsaw accidents result in approximately 36,000 injuries each year in the United States alone. Many of these injuries could be prevented by following basic safety precautions.

Technical Requirement: Before starting any work, conduct a thorough hazard assessment and identify all potential risks. Develop a plan to mitigate those risks and communicate the plan to everyone involved.

Wood Selection Criteria

Wood selection is a pivotal aspect of wood processing, and the choice of wood can significantly impact the outcome of your project, whether it’s firewood production or crafting lumber. Understanding the properties of different wood types is essential for making informed decisions.

Hardwoods vs. Softwoods: Hardwoods, like oak and maple, are denser and burn longer, making them ideal for firewood. Softwoods, such as pine and fir, are easier to cut and split, but they burn faster.
Moisture Content: The moisture content of wood is crucial. For firewood, aim for a moisture content of 20% or less. Use a moisture meter to measure the moisture content accurately.
Species Considerations: Different species have different burning characteristics. Oak, for example, produces high heat and long burn times, while birch is easier to ignite but burns more quickly.
Defect Assessment: Inspect logs for defects like knots, rot, or insect damage. Avoid using wood with significant defects, as it can be weaker and less efficient for burning.

Technical Requirement: Use a wood moisture meter to ensure that firewood has a moisture content of 20% or less. This ensures efficient burning and reduces the risk of creosote buildup in chimneys.

Tool Calibration Standards

Maintaining your tools to precise standards is essential for safety and efficiency in wood processing. Proper calibration ensures accurate cuts and reduces the risk of accidents.

Chainsaw Calibration: Regularly calibrate your chainsaw to ensure it meets manufacturer specifications. This includes adjusting the carburetor, chain tension, and oil flow.
Moisture Meter Calibration: Calibrate your wood moisture meter regularly to ensure accurate readings. Use a calibration block or follow the manufacturer’s instructions.
Measuring Tools: Calibrate measuring tools like diameter tapes and rulers to ensure accurate measurements. Use a known standard for comparison.
Sharpening Equipment: Ensure that your chainsaw sharpening equipment is properly calibrated. This includes setting the correct angles and depths for sharpening.

Data Point: Chainsaw chains should be sharpened after every 1-2 hours of use, depending on the type of wood being cut. A dull chain can increase cutting time by 50% or more and significantly increase the risk of accidents.

Safety Equipment Requirements

Safety equipment is non-negotiable when working with chainsaws and fallen trees. It’s your first line of defense against injury.

Chainsaw Helmet: Always wear a chainsaw helmet with a face shield and hearing protection. This protects your head, face, and ears from flying debris and noise.
Chainsaw Chaps: Wear chainsaw chaps to protect your legs from cuts. Chaps are made of ballistic nylon or Kevlar and are designed to stop a chainsaw chain on contact.
Work Gloves: Wear sturdy work gloves to protect your hands. Gloves provide a better grip and reduce the risk of cuts and abrasions.
Steel-Toed Boots: Wear steel-toed boots to protect your feet from falling logs and sharp objects.
First Aid Kit: Keep a well-stocked first aid kit on hand in case of injury. Include items like bandages, antiseptic wipes, and pain relievers.

Log Cutting Patterns

Optimizing log cutting patterns can maximize yield and reduce waste. Understanding different cutting techniques is essential for efficient wood processing.

Through and Through: This pattern involves cutting the log into boards of uniform thickness. It’s simple but produces a lot of waste.
Quarter Sawing: This pattern produces boards with vertical grain, which are more stable and resistant to warping.
Rift Sawing: This pattern produces boards with grain oriented at a 45-degree angle to the surface. It’s the most stable but also the most wasteful.
Live Sawing: This pattern involves cutting the log straight through without rotating it. It’s the most efficient but produces boards with varying grain orientations.

Visual Example: Diagrams illustrating each log cutting pattern, showing the orientation of the cuts and the resulting grain patterns.

Wood Drying Tolerances

Proper wood drying is essential for preventing warping, cracking, and other defects. Understanding wood drying tolerances is crucial for producing high-quality lumber and firewood.

Air Drying: Air drying involves stacking wood outdoors and allowing it to dry naturally. This is a slow process but reduces the risk of cracking and warping.
Kiln Drying: Kiln drying involves drying wood in a controlled environment using heat and humidity. This is a faster process but requires specialized equipment.
Moisture Content Targets: For lumber, aim for a moisture content of 6-8%. For firewood, aim for a moisture content of 20% or less.
Drying Rates: The drying rate depends on the species of wood, the thickness of the boards, and the environmental conditions. Monitor the moisture content regularly to ensure it’s drying at the correct rate.

Data Point: Kiln drying can reduce the moisture content of wood from 50% to 8% in as little as a week, while air drying can take several months or even years.

Cord Volume Calculations

Accurate cord volume calculations are essential for selling firewood and estimating wood quantities. Understanding how to measure and calculate cord volumes is crucial for fair transactions.

Standard Cord: A standard cord is a stack of wood that measures 4 feet high, 4 feet wide, and 8 feet long, for a total volume of 128 cubic feet.
Face Cord: A face cord is a stack of wood that measures 4 feet high and 8 feet long, but the depth can vary. The volume of a face cord depends on the length of the wood.
Calculating Volume: To calculate the volume of a stack of wood, multiply the height, width, and length. Be sure to use consistent units (e.g., feet).
Accounting for Air Space: When measuring cord volume, account for the air space between the logs. A tightly packed cord will have less air space than a loosely packed cord.

Practical Tip: Use a measuring tape to accurately measure the dimensions of the wood stack. Be sure to measure to the outside of the stack, including any overhang.

Chainsaw Calibration Standards

Maintaining your chainsaw to precise standards is essential for safety and efficiency in wood processing. Proper calibration ensures accurate cuts and reduces the risk of accidents.

Carburetor Adjustment: Adjust the carburetor to ensure the engine is running smoothly and efficiently. Follow the manufacturer’s instructions for adjusting the carburetor.
Chain Tension: Adjust the chain tension to ensure the chain is neither too tight nor too loose. A properly tensioned chain will have a slight sag on the underside of the bar.
Oil Flow: Adjust the oil flow to ensure the chain is adequately lubricated. A properly lubricated chain will produce a fine spray of oil when the saw is running.
Spark Plug Inspection: Inspect the spark plug regularly and replace it if it’s fouled or damaged. A clean, properly gapped spark plug ensures reliable ignition.

Technical Requirement: Regularly calibrate your chainsaw to ensure it meets manufacturer specifications. This includes adjusting the carburetor, chain tension, and oil flow.

Material Types (Hardwoods vs Softwoods)

Understanding the properties of different wood types is essential for making informed decisions about wood selection.

Hardwoods: Hardwoods come from deciduous trees that lose their leaves in the fall. They are denser and burn longer than softwoods. Examples include oak, maple, birch, and ash.
Softwoods: Softwoods come from coniferous trees that have needles and cones. They are easier to cut and split than hardwoods but burn faster. Examples include pine, fir, spruce, and cedar.
Density: Hardwoods are denser than softwoods, which means they contain more energy per unit volume. This makes them ideal for firewood.
Resin Content: Softwoods have a higher resin content than hardwoods, which makes them easier to ignite but also produces more smoke and creosote.

Practical Tip: Consider the species of wood when choosing firewood. Oak, for example, produces high heat and long burn times, while birch is easier to ignite but burns more quickly.

Technical Limitations (Maximum Moisture Levels for Firewood)

Understanding the technical limitations of wood processing is crucial for producing high-quality firewood and lumber.

Moisture Content: The moisture content of wood is a critical factor in its performance. For firewood, aim for a moisture content of 20% or less. Higher moisture content reduces burning efficiency and increases the risk of creosote buildup.
Drying Time: The drying time for wood depends on the species, thickness, and environmental conditions. Air drying can take several months or even years, while kiln drying is much faster.
Warping and Cracking: Wood can warp or crack if it’s dried too quickly or unevenly. Proper drying techniques are essential for preventing these defects.
Insect Damage: Wood can be susceptible to insect damage, especially if it’s stored improperly. Store wood in a dry, well-ventilated area to prevent insect infestations.

These tips aren’t just a set of instructions; they’re a culmination of years of experience, a testament to the respect I’ve developed for the power and unpredictability of wood. Remember, safety is paramount. Don’t rush, take your time, and always be aware of your surroundings. With the right knowledge, tools, and approach, you can safely and effectively cut fallen trees under tension and turn them into valuable resources. The satisfaction of splitting a perfectly seasoned log on a cold winter day, or crafting a beautiful piece of furniture from reclaimed wood, is a reward that makes all the effort worthwhile. So, get out there, be careful, and enjoy the craft.

How to Cut a Fallen Tree Under Tension (5 Pro Arborist Tips)