The U.S. Forest Service last month released a technical report on “Urban Forests and Human Health Climate Change Measures.” A summary of current research on urban trees and climate change includes how trees benefit human health, how climate change affects urban trees, and how we can help our urban forests adapt.
Focuses on community-level trees, provides a menu for urban planners and community leaders to improve urban forest resilience options, some of which are highlighted in this week’s column.
One of the biggest threats to human health from climate change is the increase in frequency and duration of heat waves. The number of days with temperatures above 100 degrees Celsius across the United States is expected to triple by 2050. Extreme heat events include climate-related deaths in the United States each year and can intensify in urban areas due to island heat. Effects of high-density, heat-insulated floors such as concrete, flooring, and buildings.
Trees work through both shade and transition to dissipate heat around cities. They resist the effects of the tropics by freezing dense areas in the shade and influencing the microclimate around them. But urban environments are not ideal for them, and more plans are needed to make trees and tropical features more compatible and evenly distributed.
Extreme heat also affects the health of large and mature trees. Because their shelters provide great cooling benefits, communities should plan to provide protection and additional care, including watering, insect and disease control.
In most urban areas, the roots of mature trees are limited. As shields expand, it becomes more and more difficult to support the ground above for restricted root systems. In extreme heat and drought, additional tree care can be done to cope with these stresses.
Planting indigenous grass and forms helps to reduce the heat-island effect and can accommodate smaller areas with smaller zones. When there is very little space for large trees, growing local plants can be a great option.
Tree pollen contributes to seasonal air quality, affecting human health. Climate change is already increasing pollen:
It predicts the season for all plants, and this will continue. While houseplants from other plants and pollen (such as ragweed) contribute significantly to allergy symptoms, tree pollen certainly contributes.
However, since different forests with different urban structures work to better absorb pollen, trees can also be part of the solution. At the community level, in terms of roof size and shape, many different plants help reduce air pollution from both trees and other plants.
Planting options can also support trees with pollen, which is not easily dispersed by the wind and contributes very little to allergies. Trees such as dugwood, redwood, tulip poplar, katapapa, flowering, and magnolia all produce pollen. Some of the worst offenders are oak, maple, ash, sycamore, and other native trees that rely solely on wind. In some cases, these species live only on female, non-pollen trees. To reduce the effects of prolonged pollen seasons, urban planting can focus on using different canvas structures and a few male trees.
Climate change increases the incidence and intensity of hurricanes and hurricanes and increases the risk of tree damage. Mature urban trees provide great benefits in the early stages of frostbite and allergies, but they are more susceptible to branch failure by increasing wind stress.
Tree selection choices can be used to increase storm resistance, excluding vulnerable species such as Calerie Pear, Silver Map and Siberian Elm. Existing mature trees can be inspected and pruned before hurricanes to improve their resilience to harmful winds. Proper pruning at the age of a tree greatly reduces the risk of hurricanes and other impacts.
As climate change has a greater impact on the climate in the Middle East, pruning is more and more important to preserve mature trees in our area. In fact, as communities adapt to our changing climate, all aspects of tree care are becoming increasingly important to ensure healthy and diverse urban forests.
Ryan Pankaw is an interface gardener who has worked with the Chinese campaign, Ford, Iroquois and Vermilion provinces. This column is also available at go.illinois.edu/GardenScoopBlog on the “Garden Scoop” blog.