Tree Fungus Identification Pictures (5 Decay Signs Every Logger Knows)

Tree Fungus Identification: A Logger’s Guide to Decay Signs

As someone who’s spent countless hours in the woods, I can tell you that identifying tree fungus and understanding its implications is absolutely essential. It’s not just about knowing which trees to avoid; it’s about safety, sustainability, and maximizing the value of the timber we harvest. This guide will walk you through the five key signs of decay that every logger (and anyone working with trees) should be able to recognize. Ignoring these signs can lead to dangerous situations, wasted resources, and the spread of tree diseases.

Why Tree Fungus Identification Matters

Imagine you’re about to fell a seemingly healthy tree. You make your cuts, and as it falls, it shatters, revealing a rotted core. Not only is that timber worthless, but the sudden and unexpected failure of the tree could have caused serious injury. This is why understanding tree fungus is paramount.

• Safety: Decayed wood is structurally weaker and can lead to unpredictable tree falls.
• Timber Value: Decay significantly reduces the quality and quantity of usable timber.
• Disease Control: Identifying infected trees helps prevent the spread of fungal diseases to healthy trees.
• Forest Health: Knowing the types of fungi present can provide insights into the overall health of the forest ecosystem.

Key Terms and Concepts

Before we dive into the specifics, let’s define some key terms:

• Decay: The decomposition of wood caused by fungi.
• Fungi: Microscopic organisms that feed on organic matter, including wood.
• Fruiting Body: The reproductive structure of a fungus, often visible on the tree’s surface (e.g., mushrooms, conks).
• Heart Rot: Decay that occurs in the heartwood (the non-living center of the tree).
• Sap Rot: Decay that occurs in the sapwood (the outer, living layer of the tree).
• Cankers: Localized areas of dead or diseased bark, often caused by fungal infection.

Now, let’s get to the identification process.

The 5 Decay Signs Every Logger Knows

These five signs are the most common indicators of internal decay. Remember that not all fungi are visible, and some trees can be severely decayed internally without showing obvious external symptoms.

1. Visible Fruiting Bodies (Mushrooms, Conks)

This is often the most obvious sign. The presence of mushrooms or conks (shelf-like fungal growths) on a tree trunk, branches, or at the base is a strong indication of internal decay.

• What to Look For: Pay close attention to the shape, color, texture, and location of the fruiting body. Different fungi cause different types of decay.
• Examples:
  • Artist’s Conk (Ganoderma applanatum): A common bracket fungus found on hardwoods. Its presence usually indicates significant heart rot. I’ve seen trees completely hollowed out by this fungus, even though they appeared healthy from the outside.
  • Turkey Tail (Trametes versicolor): A colorful, fan-shaped fungus often found on dead or decaying wood. While it can indicate decay, it’s also a common saprophyte (feeding on dead wood) and may not always indicate significant structural weakening in a living tree.
  • Honey Mushroom (Armillaria spp.): This fungus can cause root rot, leading to instability and eventual tree death. Look for clusters of honey-colored mushrooms at the base of the tree.
• Important Considerations: Not all fruiting bodies are created equal. Some are relatively harmless, while others are a clear sign of imminent danger. It’s important to identify the specific fungus to assess the severity of the decay. I always carry a good field guide with me to help with identification.

2. Cankers and Wounds

Cankers are dead or diseased areas on the bark, often sunken or swollen. Wounds, such as broken branches or injuries from logging equipment, can also provide entry points for fungi.

• What to Look For: Inspect the tree trunk and branches for any unusual growths, cracks, or discoloration. Pay attention to areas where the bark is missing or damaged.
• Examples:
  • Nectria Canker: This canker is characterized by target-like rings on the bark. It weakens the tree and makes it susceptible to breakage. I once had to remove a large oak tree that was riddled with Nectria cankers. It was a tricky job because the wood was so brittle.
  • Hypoxylon Canker: This canker often appears as a black, crusty patch on the bark. It’s particularly common on stressed or weakened trees.
• Important Considerations: The size and location of the canker are important factors. A large canker that encircles the trunk is a serious threat. Wounds should be properly treated to prevent fungal infection. I always recommend cleaning wounds with a pruning sealant to protect the exposed wood.

3. Swollen or Distorted Trunks

Unusual swelling, bulges, or distortions in the tree trunk can indicate internal decay or the presence of a burl (a growth caused by stress or injury).

• What to Look For: Compare the shape of the trunk to other trees of the same species in the area. Look for any areas that appear abnormally swollen or misshapen.
• Examples:
  • Burls: While not always a sign of decay, burls can sometimes indicate underlying fungal infection. They are often prized for their unique grain patterns and used in woodworking.
  • Swollen Base: A swollen base can be a sign of root rot, which weakens the tree’s foundation and makes it prone to falling.
• Important Considerations: Swelling can also be caused by other factors, such as insect infestations or genetic mutations. It’s important to carefully examine the tree for other signs of decay before making a determination. I’ve seen trees with massive burls that were perfectly healthy, while others with subtle swelling turned out to be completely rotten inside.

4. Open Cavities and Hollows

This is a very obvious sign of advanced decay. Open cavities or hollows in the trunk or branches are a clear indication that the wood has been extensively broken down by fungi.

• What to Look For: Inspect the tree for any holes or openings in the bark. Look for loose or crumbling wood around the edges of the cavity.
• Examples:
  • Squirrel Holes: While not always caused by decay, squirrel holes can sometimes expose underlying rot.
  • Large Cavities: Large cavities are a serious safety hazard. The tree is likely to be structurally unsound and prone to falling.
• Important Considerations: The size and location of the cavity are critical. A large cavity near the base of the tree is particularly dangerous. I once had to remove a huge oak tree that had a cavity so large, I could stand inside it! It was amazing (and a bit scary) to see how much decay was hidden within the tree.

5. Changes in Bark Texture and Color

Subtle changes in the bark’s texture and color can be early indicators of fungal infection. Look for peeling bark, unusual discoloration, or the presence of fungal mats on the bark surface.

• What to Look For: Compare the bark of the tree in question to other trees of the same species in the area. Look for any areas that appear different or unusual.
• Examples:
  • Peeling Bark: Peeling bark can be a sign of stress or fungal infection.
  • Discoloration: Discoloration of the bark can indicate the presence of fungal spores or mycelium.
  • Fungal Mats: Fungal mats are thin, sheet-like growths of mycelium that can appear on the bark surface.
• Important Considerations: Bark changes can also be caused by other factors, such as insect infestations or environmental stress. It’s important to carefully examine the tree for other signs of decay before making a determination.

Tools and Techniques for Assessing Decay

While visual inspection is a good starting point, sometimes you need to dig a little deeper (literally) to assess the extent of the decay. Here are some tools and techniques I use:

• Increment Borer: This tool allows you to extract a core sample of wood from the tree without causing significant damage. By examining the core, you can assess the presence and extent of internal decay. I’ve used increment borers on countless trees to get a clear picture of what’s going on inside.
• Resistograph: This is a more advanced tool that measures the resistance of the wood to a fine drill bit. It provides a detailed profile of the wood’s density and can detect even small areas of decay. Resistographs are expensive, but they can be invaluable for assessing the structural integrity of valuable trees.
• Sounding: Tapping the tree trunk with a hammer or axe can help you detect hollow areas. A solid tree will produce a clear, ringing sound, while a decayed tree will sound dull or hollow. I use a small hand axe for sounding, and I’ve learned to recognize the subtle differences in sound that indicate decay.
• Visual Inspection (Close Up): Use a magnifying glass to examine the bark, wood, and fruiting bodies for subtle signs of decay. Look for changes in color, texture, or the presence of fungal spores.

Safety Considerations

Working with trees that may be decayed is inherently dangerous. Here are some safety precautions to keep in mind:

• Assess the Risk: Before felling any tree, carefully assess the risk of decay. Look for all the signs mentioned above.
• Plan Your Escape Route: Always have a clear escape route planned in case the tree falls unexpectedly.
• Use Proper Safety Gear: Wear a hard hat, safety glasses, hearing protection, and appropriate clothing.
• Work with a Partner: Never work alone when felling trees.
• Be Aware of Wind Conditions: Wind can significantly increase the risk of tree failure.
• Consider Hiring a Professional: If you’re not comfortable assessing the risk or felling the tree, hire a qualified arborist or logger.

Case Studies

Here are a couple of real-world examples of how I’ve used these techniques to assess tree decay:

Case Study 1: The “Healthy” Oak

I was asked to remove an oak tree that appeared perfectly healthy from the outside. However, I noticed a small conk growing near the base of the tree. Using an increment borer, I extracted a core sample and discovered extensive heart rot. The tree was structurally unsound and posed a significant hazard. We carefully felled the tree, taking extra precautions to avoid any unexpected breakage.

Case Study 2: The Windblown Pine

After a strong storm, I was called to assess a pine tree that had been partially uprooted. The tree showed no obvious signs of decay, but the roots were heavily damaged. I used a resistograph to assess the density of the wood near the base of the tree. The results showed significant decay, likely caused by root rot. The tree was deemed unsafe and was removed.

Wood Processing and Firewood Preparation Considerations

The presence of decay significantly impacts the suitability of wood for various uses.

• Timber: Decayed timber is generally unsuitable for structural applications. It can be used for non-structural purposes, such as mulch or compost, but it should be properly composted to kill any fungal spores.
• Firewood: Decayed firewood burns poorly and produces less heat. It can also be more difficult to split. I generally avoid using decayed wood for firewood, but if I have to, I mix it with seasoned wood to improve its burning characteristics.
• Chainsaw Maintenance: Cutting decayed wood can dull your chainsaw blade more quickly. Be sure to sharpen your chain frequently and clean your saw thoroughly after use to prevent the spread of fungal spores. I use a Stihl MS 261 C-M for most of my felling and firewood processing. It’s a reliable saw that can handle a variety of wood types. I typically use a 20-inch bar with a full chisel chain.

Drying Methods and Moisture Content Targets

Whether you’re using the wood for timber or firewood, proper drying is essential.

• Air Drying: This is the most common method for drying wood. Stack the wood in a well-ventilated area, away from direct sunlight and rain. Allow the wood to dry for several months or even years, depending on the species and climate. For firewood, I aim for a moisture content of 20% or less. I use a moisture meter to check the moisture content of the wood before burning it.
• Kiln Drying: This is a faster method for drying wood. The wood is placed in a kiln and heated to a specific temperature. Kiln drying can significantly reduce the drying time, but it can also be more expensive. Kiln drying is typically used for timber that requires a specific moisture content for manufacturing purposes.

Strategic Insights and Benefits

Understanding tree fungus isn’t just about identifying decay; it’s about making informed decisions about forest management and timber harvesting.

• Selective Harvesting: By identifying and removing infected trees, you can improve the overall health of the forest and prevent the spread of disease.
• Optimizing Timber Value: By knowing the extent of decay, you can make informed decisions about how to utilize the timber. Even if the wood isn’t suitable for structural applications, it may still be valuable for other purposes.
• Reducing Risk: By identifying and removing hazardous trees, you can reduce the risk of injury and property damage.

Practical Next Steps

Now that you’ve learned about the five key signs of tree decay, here are some practical steps you can take:

1. Get a Field Guide: Purchase a good field guide to help you identify different types of tree fungi.
2. Practice Your Identification Skills: Spend time in the woods, observing trees and identifying potential signs of decay.
3. Invest in the Right Tools: Purchase an increment borer, moisture meter, and other tools to help you assess tree decay.
4. Take a Course: Consider taking a course on tree identification and forest management.
5. Consult with an Expert: If you’re unsure about the extent of decay in a tree, consult with a qualified arborist or logger.

Challenges Faced by Global DIYers and Small-Scale Logging Businesses

I understand that accessing advanced tools like resistographs can be a challenge for DIYers and small-scale logging businesses. Here are some tips for overcoming these challenges:

• Focus on Visual Inspection: Develop your skills in visual inspection. The more you practice, the better you’ll become at identifying subtle signs of decay.
• Use Simple Tools: Use simple tools like a hammer or axe to sound the tree and assess its structural integrity.
• Network with Other Professionals: Connect with other loggers, arborists, and foresters in your area. Share your knowledge and learn from their experiences.
• Rent or Borrow Tools: Consider renting or borrowing specialized tools from local equipment rental companies or cooperatives.
• Prioritize Safety: Always prioritize safety when working with trees. If you’re unsure about the extent of decay, err on the side of caution and hire a professional.

Conclusion

Identifying tree fungus is a critical skill for anyone involved in wood processing, logging, or firewood preparation. By learning to recognize the five key signs of decay, you can improve safety, maximize timber value, and promote forest health. While it takes time and experience to become proficient, the rewards are well worth the effort. So, get out there, start observing, and become a more knowledgeable and responsible steward of the forest. Remember to always prioritize safety and consult with experts when needed. Happy logging!

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