Pitch
Growing vines can allow us to quickly access the ecosystem services that come from urban greenery.
Description
Summary
Urban trees provide ecosystem services with value that far exceeds the cost of their planting and maintenance. Basic self-interest says we as citizens should call for planting many more trees in our cities. The problem is that politics says otherwise. The benefits of trees can require decades to come to fruition, and that timeline is too long for elected decision makers to reap much benefit from a decision to plant more trees.
The benefits of trees come mostly from 1% or so of a tree's mass. Most of a tree's mass is structural non-living wood. The living mass of a tree is only a tiny fraction. Clearly it is that tiny living fraction that matters: compare the value of a healthy tree to one that has died. Most of the mass is still there in the dead tree, but without living green leaves, a tree has little value. Furthermore, it's the structure that makes trees slow. Building up the structural non-living wood is why a tree takes decades to reach maturity. In contrast, a tree can create its full canopy of leaves in just a few weeks in the spring.
What we need is a way to separate these two functions: get the the leaves (and roots and fluid transporting stems) while figuring out a way around the slow build up of structure.
Structure is something that humans are really good at. We can erect a skyscraper in weeks. Quickly building structures on the scale of a tree is child's play.
Getting the living leaves, stems, and roots is also easy, because nature has already done the work. Climbing vines have evolved to basically be just leaves, stems, and roots. They rely on available structures instead of slowly building their own.
We should plant climbing vines and construct structures to support them throughout our cities. This will enable us to get the benefits of trees and reap the rewards in just a handful of years. That fast payoff will make bringing greenery to our cities much more feasible politically.
Is this proposal for a practice or a project?
Practice
What actions do you propose?
Pseudo tree trunks: telephone poles
Pseudo tree boughs: steel cables strung between the telephone poles
Pseudo tree branches: strings that run between the steel cables
The "trunks" and "boughs" are designed to be robust. The "branches" are designed to be light enough to fall onto a pedestrian without causing injury and weak enough that a vehicle can easily break through if a string comes down onto the roadway.
Ideally, trees would be planted at the same time. As the trees get bigger, the vines and their supporting structures can be trimmed back to make way for the trees to take over.
Who will take these actions?
City governments will build the structures, plant the vines, and care for and maintain everything. Utility companies can be utilized as subcontractors with expertise in installing poles and hanging lines.
Where will these actions be taken?
In cities around the globe.
In addition, specify the country or countries where these actions will be taken.
No country selected
Country 2
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Country 3
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Country 4
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Country 5
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Impact/Benefits
What impact will these actions have on greenhouse gas emissions and/or adapting to climate change?
Main impact is to combat the urban heat island effect and increase resilience against heat waves.
Will also help with stormwater management.
Impact on greenhouse gas emissions comes from reducing the need for air conditioning and encouraging walking and biking instead of motor vehicle use on hot days.
May also contribute to success with establishing urban trees and rain gardens.
What are other key benefits?
Vines are likely to be more robust than trees.
Another benefit is to combat nitrogen oxide and particulate air pollution.
It should also be noted that we would be mimicking nature's progression. To cover over an expanse of asphalt, nature would likely start with vines.
When rain falls on hot asphalt, the water heats up. Gases do not stay dissolved in hot liquids, so the rainwater loses its dissolved oxygen. The resulting low oxygen water can suffocate the roots of plants trying to grow close to the asphalt.
To cover over an expanse of asphalt you need plants that sprawl along the ground. Their roots can be away from the low oxygen water while their stems can carry their leaves into the middle of the asphalt. Once the asphalt is covered by vine foliage, the asphalt is kept shaded and cool. Trees and raingarden plants can then establish themselves at the edges of the asphalt and take advantage of the extra runoff water.
We would be following the same progression by starting with vines. The difference is that we would be using a structure to raise the vines into the air to allow vehicles and pedestrians to move across the asphalt without interfering with the vines. Once the vines are established, that will create the conditions to allow trees and raingarden plants to thrive.
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