Do Wood Burners Produce Carbon Monoxide? (Safety Tips for Arborists)

The resurgence of wood-burning stoves and fireplaces as supplemental heating sources has brought with it a renewed focus on the safety aspects of wood combustion. While the cozy warmth and rustic charm are undeniable, the potential for carbon monoxide (CO) production is a serious concern, especially for arborists and anyone involved in handling, processing, and burning wood. I’ve witnessed firsthand the consequences of neglecting these safety measures, and I’m here to share my knowledge and experience to help you stay safe.

Understanding Carbon Monoxide and Wood Burning

Carbon monoxide is a colorless, odorless, and tasteless gas produced by the incomplete combustion of carbon-containing fuels, including wood. It’s a silent killer because you can’t detect it with your senses. When inhaled, CO replaces oxygen in your bloodstream, leading to oxygen deprivation in your brain and other vital organs. Even low levels of exposure can cause flu-like symptoms, while high concentrations can be fatal.

For arborists and those in the wood processing industry, understanding the factors that influence CO production during wood burning is crucial. We deal with wood from felling trees to seasoning and burning it, so we have a responsibility to be knowledgeable about the entire process.

Key Concepts: Green Wood vs. Seasoned Wood

Before diving deeper, let’s define two critical terms:

• Green Wood: This is freshly cut wood that has a high moisture content, typically ranging from 30% to over 50%. Burning green wood is inefficient and produces a lot of smoke and creosote.
• Seasoned Wood: This is wood that has been properly dried, reducing its moisture content to 20% or less. Seasoned wood burns cleaner, hotter, and more efficiently.

The moisture content of the wood significantly impacts carbon monoxide production. Green wood requires more energy to burn off the water, leading to lower combustion temperatures and incomplete burning, which in turn increases CO emissions.

Factors Influencing Carbon Monoxide Production in Wood Burners

Several factors contribute to the amount of carbon monoxide produced by a wood burner:

• Wood Moisture Content: As mentioned earlier, this is a primary factor. Drier wood burns cleaner and produces less CO.
• Air Supply: Proper air supply is essential for complete combustion. Insufficient air leads to incomplete burning and increased CO production.
• Burner Design and Maintenance: Older or poorly maintained wood stoves or fireplaces may not have adequate air circulation or combustion efficiency, leading to higher CO emissions. Cracks, leaks, and obstructions can all affect performance.
• Burning Technique: How you load and burn the wood can also affect CO production. Overloading the stove or using improper burning techniques can lead to incomplete combustion.
• Chimney Condition: A clean and properly functioning chimney is crucial for venting exhaust gases, including CO, safely outside. Blocked or damaged chimneys can cause backdrafts and CO buildup inside the home.

Step-by-Step Guide: Minimizing Carbon Monoxide Production

Here’s a detailed guide on how to minimize carbon monoxide production when burning wood, focusing on practices relevant to arborists and those in wood processing:

Step 1: Selecting the Right Wood

• Species Selection: Hardwoods like oak, maple, ash, and beech are generally preferred for burning because they are denser and produce more heat per volume than softwoods like pine, fir, and spruce. However, some softwoods can be burned safely if properly seasoned. I often recommend oak for its long burn time and high heat output, but maple is a great alternative if oak is unavailable.
• Avoid Treated Wood: Never burn treated wood, painted wood, or wood containing preservatives. These materials release toxic fumes when burned, including harmful chemicals in addition to CO. This is a non-negotiable safety rule. I once saw someone burning old fence posts that were heavily treated, and the fumes were so acrid they caused immediate eye and throat irritation.
• Size Matters: Cut wood into appropriate sizes for your wood burner. Smaller pieces ignite more easily and burn faster, while larger pieces provide a longer burn time. A good rule of thumb is to split wood into pieces that are about 4-6 inches in diameter.

Step 2: Seasoning Wood Properly

This is perhaps the most critical step in minimizing CO production. Seasoning wood involves drying it to reduce its moisture content.

• Splitting: Split the wood as soon as possible after felling. This increases the surface area exposed to air, speeding up the drying process. I use a hydraulic log splitter for larger logs, which significantly reduces the physical strain compared to using a manual axe. For smaller logs, a splitting axe or maul works well. A good hydraulic splitter can process several cords of wood in a day, making it a worthwhile investment for anyone who regularly burns wood.
• Stacking: Stack the split wood in a single row, off the ground, in a sunny and windy location. This allows for good air circulation, which is essential for drying. I prefer to use pallets as a base for my wood stacks to keep the wood off the ground and prevent moisture from wicking up from the soil. Leave about 2-4 inches between rows for optimal airflow.
• Covering: Cover the top of the wood stack to protect it from rain and snow. However, leave the sides open to allow for air circulation. I use tarps to cover my wood stacks, securing them with bungee cords to prevent them from blowing away in the wind.
• Drying Time: The drying time depends on the wood species, climate, and stacking method. Generally, hardwoods require at least 6-12 months of seasoning, while softwoods may dry faster. Use a moisture meter to check the moisture content of the wood before burning. Aim for a moisture content of 20% or less. I’ve found that oak takes at least a year to season properly in my region, while pine can be ready in as little as six months.
• Moisture Meter: Invest in a good quality moisture meter. Insert the probes into a freshly split piece of wood. Take readings from several pieces to get an average. Discard any wood that consistently reads above 20% moisture content.

Step 3: Wood Burner Maintenance and Operation

• Regular Inspections: Inspect your wood stove or fireplace regularly for cracks, leaks, and obstructions. Repair any damage promptly. Check the door seals to ensure they are airtight. Replace worn gaskets as needed.
• Chimney Cleaning: Clean your chimney at least once a year, or more frequently if you burn a lot of wood. Creosote buildup in the chimney is a fire hazard and can also obstruct the flow of exhaust gases, increasing the risk of CO poisoning. I recommend hiring a professional chimney sweep to inspect and clean your chimney.
• Proper Airflow: Ensure that your wood burner has adequate airflow. Adjust the air vents according to the manufacturer’s instructions. Avoid overloading the stove with wood, as this can restrict airflow and lead to incomplete combustion.
• Burning Technique: Use the “top-down” burning method, where you place the larger logs at the bottom and smaller kindling on top. This promotes a cleaner and more efficient burn. I’ve found that this method also reduces the amount of smoke produced, which is a good indicator of improved combustion.
• Ash Removal: Remove ashes regularly to maintain proper airflow and combustion efficiency. Allow the ashes to cool completely before disposing of them in a metal container.

Step 4: Carbon Monoxide Detection and Prevention

• Install CO Detectors: Install carbon monoxide detectors on every level of your home, especially near sleeping areas. Test the detectors regularly to ensure they are working properly. Replace the batteries at least once a year. I recommend using detectors with digital displays that show the CO level in parts per million (ppm).
• Ventilation: Ensure adequate ventilation in your home, especially when burning wood. Open a window slightly to allow for fresh air circulation.
• Know the Symptoms: Be aware of the symptoms of carbon monoxide poisoning, which include headache, dizziness, nausea, vomiting, confusion, and loss of consciousness. If you suspect CO poisoning, evacuate the premises immediately and call emergency services.
• Never Use Portable Generators Indoors: Portable generators produce high levels of carbon monoxide and should never be used indoors or in enclosed spaces. This is a common mistake that can have deadly consequences.
• Avoid Idling Vehicles in Garages: Never idle vehicles in garages, even with the door open. Carbon monoxide can quickly build up to dangerous levels.

Case Studies and Practical Examples

Let’s look at a few case studies to illustrate these principles:

Case Study 1: The Importance of Seasoning

I once worked with a homeowner who was experiencing persistent headaches and fatigue during the winter months. They were burning wood in their fireplace, but the wood was freshly cut and still very green. The homeowner was also overloading the fireplace, restricting airflow and causing incomplete combustion. I advised them to switch to seasoned wood, improve the airflow in the fireplace, and install a carbon monoxide detector. Within a few days, their symptoms disappeared. This case highlights the importance of using properly seasoned wood and ensuring adequate ventilation.

Case Study 2: Chimney Maintenance

A few years ago, I inspected a chimney that had not been cleaned in several years. The chimney was heavily coated with creosote, and there was a significant blockage near the top. This blockage was causing backdrafts, and carbon monoxide was leaking into the home. I recommended that the homeowner have the chimney professionally cleaned and repaired. After the repairs were completed, the backdrafts stopped, and the CO levels returned to normal. This case demonstrates the importance of regular chimney maintenance.

Case Study 3: Proper Wood Storage

I visited a client who had stacked their firewood directly on the ground, covered with a tarp that was sealed on all sides. The wood was damp and moldy, and it was taking a long time to dry. I advised them to raise the wood off the ground using pallets, stack it in a single row, and cover only the top of the stack to allow for air circulation. After implementing these changes, the wood dried much faster and burned more efficiently. This case illustrates the importance of proper wood storage techniques.

Tool Specifications and Measurements

Here are some specific tool recommendations and measurements to help you in your wood processing and firewood preparation:

• Chainsaw: For felling trees and bucking logs, I recommend a professional-grade chainsaw with a bar length of 18-20 inches. Stihl and Husqvarna are two reputable brands. Ensure that the chainsaw is properly maintained and sharpened. I personally use a Stihl MS 261 C-M for most of my work.
• Log Splitter: For splitting larger logs, a hydraulic log splitter with a splitting force of at least 20 tons is recommended. This will allow you to split even the toughest hardwoods.
• Splitting Axe/Maul: For splitting smaller logs, a splitting axe or maul with a weight of 6-8 pounds is sufficient.
• Moisture Meter: Invest in a digital moisture meter with a range of 6-40%. Look for a meter with a clear display and easy-to-use controls.
• Stacking Dimensions: Stack firewood in rows that are no more than 4 feet high and 4 feet wide. Leave at least 2-4 inches between rows for air circulation.
• Wood Size: Split wood into pieces that are about 4-6 inches in diameter and 16-18 inches long. This is a good size for most wood stoves and fireplaces.

Cost Considerations

The cost of wood processing and firewood preparation can vary depending on the tools and equipment you use, as well as the amount of wood you process. Here are some approximate costs:

• Chainsaw: \$500-\$1000
• Log Splitter: \$1000-\$3000
• Splitting Axe/Maul: \$50-\$100
• Moisture Meter: \$20-\$50
• Pallets: Free (often available from local businesses)
• Tarps: \$20-\$50

While the initial investment in tools and equipment can be significant, it can pay off in the long run by reducing your reliance on purchased firewood and allowing you to process your own wood safely and efficiently.

Drying Time Estimates

The drying time for firewood depends on several factors, including the wood species, climate, and stacking method. Here are some general estimates:

• Softwoods (Pine, Fir, Spruce): 6-12 months
• Hardwoods (Oak, Maple, Ash, Beech): 12-24 months

These are just estimates, and the actual drying time may vary. Use a moisture meter to check the moisture content of the wood before burning.

Safety Considerations

Safety should always be your top priority when processing and burning wood. Here are some important safety tips:

• Wear appropriate personal protective equipment (PPE), including safety glasses, gloves, hearing protection, and sturdy boots.
• Use caution when operating chainsaws and log splitters. Follow the manufacturer’s instructions carefully and never operate these tools when you are tired or distracted.
• Be aware of your surroundings. Watch out for falling branches and other hazards when felling trees.
• Never burn wood indoors without proper ventilation.
• Install carbon monoxide detectors in your home and test them regularly.
• Know the symptoms of carbon monoxide poisoning and seek medical attention immediately if you suspect exposure.

Strategic Insights

Beyond the tactical steps, here are some strategic insights to consider:

• Long-Term Planning: Plan your firewood needs well in advance. Start seasoning wood at least a year before you plan to burn it. This will ensure that you always have a supply of dry, seasoned wood on hand.
• Woodlot Management: If you have access to a woodlot, manage it sustainably. Remove dead, diseased, and overcrowded trees to improve the health and productivity of the forest.
• Community Resources: Connect with other arborists and wood processors in your community. Share knowledge, resources, and equipment.
• Energy Efficiency: Consider investing in a high-efficiency wood stove or fireplace. These challenges may include:
  • Limited Access to Equipment: In some regions, access to chainsaws, log splitters, and other essential tools may be limited or expensive.
  • Lack of Training: Many DIYers and small-scale loggers lack formal training in safe and efficient wood processing techniques.
  • Environmental Regulations: Environmental regulations regarding logging and wood burning may vary from region to region.
  • Climate Conditions: Climate conditions can significantly impact the drying time and quality of firewood.

  To address these challenges, it is important to:

  • Promote access to affordable tools and equipment.
  • Provide training and education on safe and sustainable wood processing techniques.
  • Support the development of appropriate environmental regulations.
  • Adapt wood processing and drying techniques to local climate conditions.

  Next Steps and Implementation Guidance

  If you’re ready to start your own wood processing or firewood preparation project, here are some practical next steps:

  1. Assess your needs: Determine how much firewood you need to heat your home or business.
  2. Identify your wood source: Determine where you will obtain your wood. Will you fell trees on your own property, purchase logs from a local supplier, or collect firewood from public lands?
  3. Gather your tools and equipment: Invest in the necessary tools and equipment, such as a chainsaw, log splitter, splitting axe, moisture meter, and PPE.
  4. Start seasoning your wood: Split and stack your wood in a sunny and windy location, off the ground, and covered on top.
  5. Maintain your wood burner: Inspect and clean your wood stove or fireplace regularly.
  6. Install carbon monoxide detectors: Install CO detectors in your home and test them regularly.
  7. Stay informed: Keep up-to-date on the latest safety recommendations and best practices for wood processing and burning.

  By following these steps, you can safely and efficiently process your own wood and enjoy the warmth and comfort of a wood-burning fire.

  Burning wood can be a sustainable and rewarding way to heat your home, but it’s crucial to do it safely. By understanding the factors that influence carbon monoxide production and following the steps outlined in this guide, you can minimize the risk of CO poisoning and enjoy the benefits of wood burning with peace of mind. Remember, safety is paramount. Take the time to learn and implement these practices, and you’ll be well on your way to enjoying a warm and safe winter.

Learn more