Prepping Trees for Tornadoes and Hurricanes

The escalation in the frequency of hurricanes and tornadoes is alarming. This climate change has caused tree care services and owners of properties to alter their approach towards preparing for storms. For example, Ontarian and Prairie residents know fully how destructing these tornadoes can be after witnessing the Edmonton tornado (‘87) as well as the Barrie tornado (‘21). While the East Coast does not receive hurricanes as frequently, regions, such as Nova Scotia and Newfoundland faced severe destruction by Hurricane Fiona in 2022 which caused an excessive amount of tree damage in the Atlantic regions.

According to NOAA and the U.S. Forest Service, tree failures during hurricanes and tornadoes increase by 40–60% during summer months due to increased soil moisture and foliage mass that add to wind resistance. Tornadoes tend to happen in the summer and require warm, moist air alongside dry, cool air to form. Hurricanes are tropical cyclones that have a specific season, running from June to November, and don't tend to hit countries all that frequently. Running the risk of grounding trees, broken limbs, and landscaping damage that will not make any property safe for peace of mind are all extensive effects of these tornadoes.

Thus, tree storm preparation is not just a precautionary step, it is part of proactive land and asset management. The evaluation of a tree’s structure, its rooting conditions, and such conceived infrastructure enables one to manage the risks before any winds pick up.

Tropical cyclone season in Australia lasts from November to April, impacting the northern and coastal regions the most. New Zealand is less affected, but can occasionally see ex-tropical cyclones during January to March. Both countries do have tornadoes, but they are less frequent and less intense compared to North America.

The protective function of trees during wind storms is still the subject of urban forestry studies, even if their timing and severity differ. Some scientific work, including that of the U.S National Institute of Standards and Technology, has shown that trees placed in certain locations can reduce wind speed in a home’s vicinity by providing a barrier that directs wind flow upwards. That benefit occurs, however, only under specific circumstances. Mature, well-maintained, and balanced trees that have healthy, spaced roots do best at redirecting the wind’s pressure. Conversely, ill-maintained trees can lack the structure to support their claim to this benefit and instead turn into debris or worse still, projectile and structural hazards.

Extended Global Hurricane/Cyclone Activity Overview

From experience, trees have proven to cause damage during tornadoes as a result of secondary failures. This is when one tree gets dislodged and proceeds to wreak havoc on others. To cite an instance, during Hurricane Ida 2021, innumerable trees in Louisiana and Mississippi were said to have failed because of saturated soil coupled with canopy imbalance. Urban trees during the 2020 tornado surge in central Ontario suffered far more than rural trees due to being anchored in shallow compacted soils while rural trees enjoyed deep unconfined soil horizons that supported freer root access. 

Studies continue to conclusively demonstrate that storms are one of the critical weather phenomena that exacerbate wind-eroded flooding. Studies from the University of Florida IFAS Extension confirm that trees with root systems confined to shallow or compacted soils fail more often, even in winds as low as 60 mph. Arborists need to pay greater attention to vertical facades and use strong wood species dominantly, whose natural force-deflecting balance will push them away from their center of gravity. This empirical data advocates the need for multi-dimensional post-event assessments.

With digital platforms like ArboStar, arborists enhance GIS tree mapping and real-time condition reporting. These tools, as outlined in the Essential Tree Crew Checklist, help teams assess site risks, assign crews, and upload hazard documentation from the field, even when offline. These methods not only bolster resilience to storms but also improve recovery afterward. Statistically, trees that were correctly pruned and maintained post-tornado are more likely to survive and regrow. Hence, proper preparedness serves as both a protective measure and a restorative expenditure that mitigates prolonged ecological and monetary impacts.

Storm Season Tree Readiness Checklist

While studying the damage caused by tornadoes, researchers noticed structural damages concentrated toward trees with neglected crowns. This was particularly evident during the 2011 tornado outbreak in Alabama, where urban trees that were left unattended resulted in more field-cut power lines. Similarly, post-hurricane impact studies in Florida after Hurricane Michael in 2018 pointed out a lack of proper pruning as a major reason limbs were lost and caused secondary damage to structures.

That said, pruning needs to be done with caution. Poor pruning practices like over-thinning or topping trees leave them susceptible to decay and weaker structurally. Tailored to the tree’s form, modern arboriculture aims at natural target pruning which actively reduces stress points.

Like all professionals, tree care specialists must consider timing. Before a storm hits, all pruning work should be done well in advance of hurricane or tornado season to allow trees to heal. In most places, some local laws govern the ‘when’ and ‘how’ pruning takes place, particularly for protected or significant trees. Including pruning into an annual maintenance plan associated with storm predictions ensures that this preventive measure adds significantly to the urban tree's resiliency.

The integrity of the root systems is critical for the stability of a tree, especially when considering the lateral wind forces it would encounter during a tornado. Lone trees found in open zones are highly sensitive to toppling if the root anchorage is compromised. In a more historical context rather, in rural and agricultural regions, like the outskirts of towns, where trees were lost during tornadoes like the one observed in the 2013 Oklahoma tornado outbreak, tornadoes heavily relied on root system constraints compounded by shallow compacted soils and planting over softer earth. 

Soil conditions, along with the health and depth, define how well a tree will be able to endure extreme weather. Trees located in waterlogged or nutrient-poor soils have stunted growth in further root extension, which leads to weakened anchorage, making the tree less resilient. After Cyclone Drena, some studies done in New Zealand showed well-aerated urban trees outperformed the restrictive ones, in terms of survival, irrespective of a well-compressed soil.

In response, deep root fertilization, mulching, and soil decompaction have been added to “pre-storm” guidelines set by other arborists. These measures aid in conserving the structural resilience of a tree while simultaneously reducing soil erosion and flooding caused by prolonged rain. New trees require careful seesawing and bolstering to promote even root growth, where staking will limit competition to destabilize the tree during the wind.

Cabling is an important structural reinforcement strategy, and ArboStar enables professionals to log cabling installations, schedule inspections, and store condition photos directly within the client record. This turns manual work into auditable, timestamped service logs available to all team members. Cables control the movement of limbs or stems, distribute mechanical stress during wind loading, and reduce the chance of failure. It has been adopted widely for urban forestry management in public areas of high-risk zones, like Toronto, London, and Sydney.

Cabling has proven useful in tornado and hurricane events, especially in reducing failures for historically storm-damaged trees with multiple trunks. For instance, public parks across Florida brace heritage trees, which assists in preserving locally revered trees. Also, in New South Wales, cabled trees demonstrated superior survival rates during post-storm assessments compared to unreinforced trees.

It is very important that industry standards for cabling installation are followed and routine inspections are conducted. Cables are to be adjusted and changed over time due to the growth of the trees and exposure to environmental elements. All installations must be documented and local safety and liability regulations followed. In addition, cabling should be used in conjunction with root care, pruning, or species selection.

Integrating this form of positive reinforcement into a well-defined management plan enables arborist professionals to prolong the lifespan of critical-importance trees while maintaining public safety in high-wind hazard zones.

The specific selection of tree species is foundational storm preparedness. Certain species possess particular structural features which enhance their ability to withstand strong winds. For example, live oaks and bald cypress in the southeastern United States are famous for wind resistance because of their dense wood and low center of gravity. In Australia, Moreton Bay figs and some native eucalypts can also withstand cyclonic conditions.

Pōhutukawa and cabbage trees, New Zealand’s coastal species, display these features of above-average survival rates during cyclones owing to flexible limbs and deep root systems. Cyclone wind research in Sweden has pointed towards urban tree resilience focusing on lime trees and Norwegian maples as trees that withstand winter storms while losing very little structural integrity.  

While these species differ by region, they do share a common trait that was noted by arborists across the globe: resistance also comes down to the maturity, health, and maintenance of the tree. Well-maintained, appropriately spaced, and properly pruned trees consistently perform better during tornados and hurricanes.

Furthermore, response storm teams and municipalities are beginning to incorporate post-storm tree audits to inform future planting decisions. These audits help create tailored recommendations concerning which species to plant or avoid in areas that experience high winds.