10 Tree Myths and Misunderstandings
Introduction
Like many other facets of the natural world, trees are the subject of innumerable myths and misunderstandings. As professional arborists , our job is to help separate fact from fiction, thereby allowing our clients and readers to better care for their trees.
While some of the most common myths are only slightly off base and essentially harmless, others are wholly incorrect and may lead to tree damage should you follow the purported advice. For instance, misconceptions about watering practices or the belief that certain pruning techniques are beneficial can inadvertently harm your trees. By debunking these myths, we help our clients in the San Francisco Bay Area make informed decisions that promote the health and longevity of their trees.
Common Misconceptions about Tree Care
1. Wounded Trees Heal
When trees suffer damage, they undergo the process of compartmentalization to help wall off the injured tissues. The damage suffered always remains, although healthy wood often grows around it. This process is crucial for preventing the spread of decay and disease within the tree. By forming barriers around the damaged area, the tree effectively isolates the injury, allowing it to continue growing and thriving despite the wound. Understanding this natural defense mechanism is essential for proper tree care and management, especially in urban environments like the San Francisco Bay Area where trees face various stressors. Regular monitoring and professional care can help ensure that trees remain healthy and resilient even after sustaining damage.
2. Trees Use Deep Roots to Stay Upright
Tree Roots Growing Outward from a Tree's Base
While trees produce a few deep roots, most of the roots lie in the upper twelve inches or so of soil. Instead of relying on deep roots to anchor a tree, trees send their roots out radially to grip the ground and keep them standing.
This widespread root system allows trees to efficiently absorb water and nutrients from the soil surface. Additionally, understanding the shallow nature of tree roots is vital for proper mulching and landscaping practices. In urban areas like the San Francisco Bay Area, where soil compaction and space constraints are common, ensuring the health of these surface roots can significantly impact a tree's overall stability and growth.
3. Trees Must Be Pruned Following Transplantation
Historically, many believed that trees should be pruned when transplanted to balance the crown with the roots, which often sustain damage during the process. However, time and research has shown this to be a misguided practice, and trees should not be pruned during transplantation so that they can produce as much food as possible, which helps the process of establishment.
This approach ensures that the tree has sufficient leaf area to carry out photosynthesis, providing the necessary energy for root and overall growth. By avoiding unnecessary pruning, newly transplanted trees can better adapt to their new environment and develop a strong, healthy root system. This updated understanding highlights the importance of following current best practices in arboriculture to promote tree health and longevity.
4. Tree Wounds Must Be Painted
Although still practiced by some, most arborists have stopped painting tree wounds as a matter of course. Aside from special cases involving specific pathogens, the research demonstrates that trees heal more quickly when not painted.
The application of wound paint can interfere with the tree's natural healing process, trapping moisture and potentially promoting decay rather than preventing it. By allowing the tree to compartmentalize the wound naturally, the damaged area can dry out and begin to heal more effectively. This shift in practice underscores the importance of relying on updated scientific findings to inform tree care methods, ensuring the best outcomes for tree health and longevity in diverse environments.
5. Tree Hollows Should Be Filled with Concrete
Historically, people have often filled hollow trees with concrete for stability's sake. Aside from serving as a serious hazard to any tree workers who may cut down the tree in the future, cement does nothing to improve the integrity of a tree; in fact, the practice usually reduces the tree’s chances of survival.
The rigid nature of concrete can cause further injury to the tree, preventing it from flexing naturally in the wind and potentially leading to cracks and splits. Moreover, concrete can trap moisture inside the hollow, promoting decay and fungal growth. Modern arboricultural practices emphasize noninvasive techniques that support the tree's natural defenses, such as proper pruning and cabling, to maintain stability and health without causing additional harm.
6. “Topping" Is a Safe and Effective Pruning Technique
Flimsy Watersprouts Forming on Recently Topped Trees
The practice of topping is almost universally destructive to trees. Often carried out on trees that have outgrown their space, topping causes trees to produce numerous watersprouts, which are likely to fail in the future. Additionally, topping exposes a tree to a variety of pests, fungi, and bacteria, which may compromise its health and vigor.
This harmful technique creates large wounds that the tree struggles to seal, making it more susceptible to decay and infestations. Instead of topping, professional arborists recommend alternative solutions such as selective pruning or canopy reduction to manage tree size while preserving its health. Understanding these best practices is crucial for maintaining the beauty and safety of our urban forests.
7. Trees Should Not Be Pruned During the Spring
Some trees—particularly maples (Acer spp.) among others—will “bleed" copious amounts of sap if pruned during the spring. While this is unsightly, the trees suffer no harm from spring pruning. The sap helps to transport nutrients and water throughout the tree, and its flow during pruning simply reflects the tree's active growth period.
To minimize the visual impact of sap bleeding, consider pruning these trees during their dormant season in late fall or winter. Understanding the specific needs and behaviors of different tree species is essential for effective and safe tree care.
8. Trees Always Benefit from Fertilization
Trees growing in areas in which the soil is deficient in nutrients may benefit from the application of a slow-release fertilizer. However, fertilizing trees that do not require supplemental nutrition may cause damage to their roots. Fertilization should always be conducted in response to specific nutrient deficiencies identified through soil testing.
This targeted approach ensures that trees receive the nutrients they need without the risk of overfertilization, promoting healthier and more resilient growth. Professional assessment and tailored fertilization plans are crucial for maintaining the health and vitality of urban trees.
9. Trees Must Be Pruned Following Root Damage
As with transplantation, trees that are undergoing stress usually respond best when equipped with a full canopy of leaves. The full canopy allows the tree to maximize photosynthesis, which is essential for generating the energy needed to repair and grow new roots.
Pruning during this time can further stress the tree, reducing its ability to recover from root damage. By maintaining a healthy canopy, the tree can better support its overall recovery and resilience. In urban areas where trees often face various stressors, proper tree care practices, including avoiding unnecessary pruning, are vital for ensuring the long-term health and stability of the tree.
10. New Trees Must Always Be Staked
Our Certified Arborists Stake a Newly Planted Tree
While some saplings benefit from being staked to the ground, those that grow without such reinforcement usually develop more stable root systems and trunks. However, some municipalities require the use of tree stakes—in such cases, it is important to remove the stakes as soon as the tree and law allow.
Prolonged staking can hinder the tree's natural development, leading to weaker structure and an increased risk of failure in the future. When stakes are necessary, they should be installed correctly to allow some movement, encouraging the tree to strengthen its roots and trunk. Monitoring and timely removal of stakes ensure that the tree can continue to grow robustly and adapt to its environment effectively.
Conclusion
Understanding and debunking common tree myths is essential for ensuring the health and longevity of your trees. By relying on accurate information and professional advice, you can make informed decisions that promote the well-being of your urban forest. At Arborist Now, we are committed to providing expert tree care services and educating our community in the San Francisco Bay Area.
If you have any questions or need professional assistance with your trees, don't hesitate to contact us. Let's work together to keep our trees healthy and thriving. Visit our website or call us today to schedule a consultation with one of our ISA-certified arborists, who can help you with any tree-related need, from planting to pruning to removal .
Originally published on May 29, 2016.
