Tree Planting in Somerville: Choosing Storm-Resistant Species

Understanding Somerville’s Storm Challenges

A tree is only as strong as the roots that hold it. In Somerville, urban trees face unique challenges such as limited root space, salt exposure from winter road treatments, and heat-island effects. However, these can be mitigated with proper tree planting, particularly if the correct tree species is chosen based upon both natural weather extremes and urban stressors.

Urban environments, such as those surrounding Tufts University and the busy areas around Porter Square, can further exacerbate urban tree stressors. When choosing a tree species for planting, it’s essential to consider a species’ ability to adapt to future climate projections, as well as its ability to immediately withstand extreme weather events, such as heavy snows, ice storms, and severe thunderstorms with high winds.

Climate Change Impacts on Tree Selection

Massachusetts climate projections suggest warmer temperatures, longer growing seasons, and more extreme precipitation events. Therefore, tree-planting strategies must take into consideration these changes and choose species that can grow in these projected climate conditions while still being able to withstand extreme weather events. Traditional New England species may have difficulty growing in a hotter and drier environment; however, many Southern species are now considered viable options. A professional arborist can assist you in determining which species will best meet your planting needs.

Somerville’s Native Plant Ordinance and Tree Planting

Somerville’s innovative Native Plant Ordinance is one of the first ordinances in the country that mandates specific types of plant material (trees) be used on City-owned properties. The Ordinance has two main objectives: to promote the use of native species in urban forestry projects and to encourage ecological health in urban environments. The Ordinance is based on the premise that native species are better adapted to the local environment and, therefore, will be more likely to grow and maintain themselves in the long term. Additionally, native species are typically less prone to tree diseases and insect infestations than non-native species.

Native Species Requirements by Location

On City-owned lands located along the Community Path, Green Line Extension Corridor, and riverfront areas, 100% native species are required in new tree-planting projects. These high-profile areas exemplify Somerville’s commitment to urban ecology and serve as models for other cities in implementing successful native species planting projects.

City parks are required to use a minimum of 75% native species in new tree-planting projects. Street trees and plantings in bioswales, plazas, and streetscapes are required to use a minimum of 50% native species. These minimum requirements acknowledge the challenges associated with tree planting in urban settings while recognizing the importance of using native species whenever possible.

Top Storm-Resistant Native Trees for Somerville

American sycamore provides excellent storm resistance because of its robust root system and the flexibility of its branches, which will bend instead of breaking in high winds. American sycamore is tolerant of urban conditions such as road salt, poor drainage, and air pollution, and grows rapidly to produce substantial leafy canopies.

Black gum, or tupelo, is another very storm-resistant native tree. Black gum has strong wood and a deep root system, making it highly resistant to wind damage and ice accumulation. It produces beautiful fall foliage and provides food and shelter to numerous local wildlife species.

Oak Species for Long-Term Resilience

White oak is the gold standard for storm-resistant tree planting in Massachusetts. White oaks have large taproots and strong branch structures, enabling mature trees to withstand extremely severe weather while providing centuries of service to communities. White oaks are food sources for many local wildlife species and help sustain healthy ecosystems.

Scarlet oak grows faster than white oak but maintains similar storm-resistance properties. Scarlet oak grows well in urban conditions and produces beautiful fall colors. Scarlet oak also becomes increasingly drought-tolerant as it matures.

Wind-Resistant Tree Architecture

Tree planting for storm-resistance focuses on tree species having architectural features that enable the tree to survive high winds. Trees with flexible branches, strong wood, and a well-developed canopy perform better in extreme weather events than trees with stiff branches or uneven canopies.

Additionally, trees with a larger root system have a greater anchor point to hold fast against severe wind forces, while trees that develop reaction wood will be better able to withstand prolonged winds.

Branch Angle and Storm Survival

Trees that have a wider angle of branch spread and a smooth transition of branch diameter from trunk to tip have better storm resistance. Species with two dominant leaders or a narrow branch angle tend to be more susceptible to wind damage and branch splitting during extreme weather events.

Trees that have a regular branching pattern, without included bark, will create stronger connections that will resist failure under wind loads. Selecting species that develop good branch architecture naturally will reduce maintenance costs over the life of the tree.

Storm-Prone Trees

Bradford pear trees have been a favorite of gardeners and landscapers for years because of their profuse spring flowering. However, Bradford pears are notorious for their weakness in storms. Due to their vertical branching and brittle wood, Bradford pear trees tend to split during ice storms and high winds. This results in hazardous situations and costly cleanup and repair efforts.

Silver maple is native to much of North America, but does poorly in terms of storm resistance due to its soft wood and excessive growth, causing structural weaknesses. Silver maple is generally avoided in favor of species with better storm resistance, such as red maple or sugar maple.

Invasive Species

Tree-of-heaven is not only an ecologically damaging invasive species but also has poor storm resistance and can become a hazard during severe weather. Arborists are trained to recognize and advise property owners of invasive species and how they can negatively impact their trees.

Although Norway maple is not as aggressively invasive as tree-of-heaven, it will compete with native species and has moderate storm susceptibility. Native alternatives, such as sugar maple or red maple, will offer superior ecological benefits and comparable-to-better storm resistance.

Urban-Adapted Storm-Resistant Options

London plane tree is an urban-tolerant and moderately storm-resistant tree that is suitable for challenging city conditions found in the vicinity of Davis Square or Assembly Row. London plane tree is a hybrid species that tolerates urban pollutants, compacted soils, and limited root space while providing a substantial amount of shade.

Ginkgo trees have remarkable urban adaptability and good wind resistance due to the flexibility of their branch structure. Ginkgo trees are among the oldest living things on earth and will tolerate almost any condition in urban environments except for messy female fruit.

Evergreen Options for Year-Round Screening

Eastern red cedar provides excellent storm resistance and year-round screening and adapts well to urban conditions. Eastern red cedar is drought-tolerant, can grow in poor soils, and will endure wind-force conditions.

White pine is susceptible to branch breakage in ice storms; however, it provides good wind resistance when properly pruned. Pruning of white pine to eliminate dead branches and thin out dense areas will greatly improve the tree’s performance in severe weather conditions.

Tree-Planting Techniques for Storm Resistance

Regardless of the tree species selected, proper tree-planting technique is key to establishing a long-term, storm-resistant tree. Deep planting of the tree, ideally 18 inches below grade, allows for adequate root establishment to provide strength and stability to the tree during extreme weather events.

Root girdling, which occurs when the roots of the tree are cut or severely restricted, is a major factor in poor root development and reduced storm resistance. Arborists who install trees are trained to avoid root girdling and to follow best practices in soil preparation, tree placement, and structural pruning to ensure optimal development of the tree.

Site Selection & Preparation

When selecting a site for a tree, the arborist evaluates wind exposure, drainage, and proximity to infrastructure that could be damaged by fallen trees. Arborists will provide guidance on species selection based on the selected site conditions to optimize long-term success.

Improving soil quality and providing proper drainage will enhance tree establishment and root development, thereby improving the tree’s ability to withstand extreme weather events. Urban soils are often in need of enhancements to support healthy tree growth and develop strong root systems.

Maintenance for Storm Resilience

Tree care is critical to maintaining a tree’s ability to withstand extreme weather. Proper pruning of the tree will eliminate dead branches, improve the tree’s structural integrity, and reduce the risk of wind damage by thinning out the tree’s canopy. Young tree training via pruning will also create a strong branch structure that will provide the tree with better storm resistance throughout its life.

Ongoing Health Monitoring

Healthy trees are more capable of surviving extreme weather conditions than stressed trees. Arborists will monitor the health of the tree on an ongoing basis and treat any health issues that may arise to prevent the structural integrity of the tree from failing during extreme weather.

Arborists will also recommend watering schedules during drought conditions, proper fertilizer applications, and pest management to ensure that the tree remains healthy and, thus, able to withstand extreme weather conditions.

Planning for Climate Resilience

Arborists will plan for future climates when selecting tree species. Arborists will look for tree species that will thrive in the expected future climate conditions, yet still possess storm resistance.

Selecting a variety of species will reduce the risk associated with species-specific pests and diseases while providing various storm-resistance characteristics. Arborists will provide guidance on how to achieve a diverse species mixture that will provide redundancy and resilience in the event of multiple extreme weather conditions.

Community Canopy Benefits

Storm-resistant tree planting provides for community canopy benefits, including cooling, stormwater management, and improved air quality, even after extreme weather events. These benefits are particularly important in densely populated urban areas like Somerville.

Strategic tree planting can create interconnected green infrastructure that supports both ecological health and community safety. Arborists will guide property owners to make planting decisions that support both local and regional urban forest goals and climate-change adaptation strategies.

Somerville Tree Masters is committed to assisting property owners in successfully planting trees in Somerville that balance storm resistance, ecological benefits, and urban adaptability in a changing climate.