Why municipalities struggle to keep their urban forests alive

January 24, 2020
I’ve always believed that cities have the power to change the world.

Yes, they are these monsters of consumption and the world’s biggest polluters and emitters of CO2, but for centuries, they’ve also been the centers of commerce and culture and innovation. I like to call them the greatest social experiments that we’ve ever been able to witness.

They’re really the birthplace of some of humankind’s greatest ideas. In the near future, the majority of future humans will live in cities, it just makes sense that our solution to climate change will reside there too.

Trees play such a vital role in making cities livable. They clean the air which we breathe, they cool the streets our children play in, and actively combat climate change. Yet due to urbanization, deforestation, and stress from a warming climate, city councils are struggling to manage their green urban spaces.

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When I found out that urban trees live only a fraction of the lives of their forest counterparts, it’s safe to say I was shocked.

The average tree in an urban environment lives only 7–20 years-most never reaching adulthood. Outside the cityscape, that number is easily over 100.

When these teenagers are cut down, they may be replaced with new seedlings. There’s also a chance that they may not. What’s more, trees really begin to benefit the community and the city at large, when they enter double digits. That’s when they begin to sequester carbon and create large-scale shade canopies. However, the vast majority of the time that trees finally start to give back to the community, they’re removed.

As a result, they’re simply not having the maximum impact they could and contributing to flourishing cities. In fact, each year over 36 million trees are fallen in US cities alone. And even though we know that green cities are smart cities, municipalities are struggling to combat this phenomenon. Whilst cities continue to grapple with the root causes of this situation, they must also arm those with the knowledge to prevent its aggravation.

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This map from Nowak & Greenfield’s study shows the percentage of tree coverage loss or gain for all 50 states.

And like all things in life, it all starts with a starting place. Understanding where a city is and where it’s going is important in fighting urban deforestation. Having the data and the knowledge on hand gives the custodians of green spaces the ability to make decisions in real-time.

However, the greatest challenge that cities face in this endeavour is time. Today, it takes far too long to get all the information in one place.

Put yourself into an urban forester’s, or a city arborist’s shoes. These professionals are on the front line of creating sustainable cities and are responsible for upwards of 50,000 trees. In large cities like New York, that can be over 600,000 street trees alone. You’re not only responsible for the day-to-day operations of those trees, the maintenance, the pruning, the irrigation, but also just the overall strategy and the master plan when it comes to protecting them, and oftentimes, increasing their numbers.

A tree inventory is, quite simply put, a database or a map of all of the (typically, public) trees in a city. It will include information on the species, the location, maybe the condition, the size and this type of thing. The tree inventory has been around since the late 1800s, when one of the first ones was created in Brookline, Massachusetts. And they really are a prerequisite in planning for and making sound urban forestry and green space management decisions.

Particularly in longer-term monitoring, it is essential to track longitudinal data about the same individual trees and planting sites. The only problem is that on the ground tree inventory surveys are filled out with manual surveying. They are also notoriously expensive and can be difficult to maintain. They can have errors because they’re based on field observations in terms of actual metrics and measurements.

Furthermore, I think one of the most compelling points is that they fail to visualize the up to 70% of privately owned urban trees, which are still offering significant community benefits. Just because a tree is on private land doesn’t mean that the city shouldn’t protect it, doesn’t mean that they don’t maintain it even sometimes, and it definitely doesn’t mean that the city doesn’t have to invest interest in trying to understand the benefits that are coming out of those trees.

Empowering tree stewards with the information they need creates a huge opportunity to increase their capabilities for protecting and increasing numbers in cities.

With such a large responsibility on their shoulders, small — and oftentimes diminishing — budgets, they have a mammoth of a job to do. But the fact is that when cities approach urban forestry management, it just takes so long.

Collecting tree inventories — the baseline of any urban forestry management strategy — takes on average between 3 and 7 years to complete. That’s half the life of an urban tree. What’s more, when they are completed, it’s likely that many individual trees present in the inventory will have already been removed, due to the factors we discussed earlier.

With data quickly becoming outdated, the traditional methods still used today to inventory, map, and monitor urban trees are, in my opinion, in desperate need of an upgrade. The urban foresters and arborists that we’ve been fortunate enough to speak with have all expressed a desire for the same thing; up-to-the-minute, real-time information on the status of their urban forests.

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Classic root-sidewalk conflict. The photo was taken by me in Boston.

Arborists really are tree doctors, and if you could imagine that if you were an actual doctor and you had a bunch of patients in your waiting room, it would be incredibly helpful to you if you had a way to get that clipboard of information on each individual patient. That’ll give you the quick lowdown on how that patient is doing. That is exactly what arborists need to do their job properly and it’s data that they simply don’t have.

The reason they don’t have this data is that it’s simply too expensive and takes too long to gather that information on the ground. So that’s precisely where Industry 4.0 technology steps in; to offer the same information, and perhaps even more, in terms of data in near real-time. By combining artificial intelligence, satellite and drones, and geospatial technology, it’s possible to analyze the city’s forestry in bird’s-eye view, down to each individual tree.

Smart cities are using cutting edge Industry 4.0 technology for everything today, from the Internet of Things sensors to health and transport connectivity. So why shouldn’t they be using it for protecting and enhancing nature as well? The answer is as obvious as the benefits of doing so.

Listen to the whole podcast here.

Nadina is the CEO and Co-Founder of Green City Watch, a geospatial AI firm specializing in urban ecological engineering. Green City Watch’s new technology TreeTect™ provides municipalities with a better overview of their tree inventory and empowers urban foresters to take nature online. The company is part of a new field of study which she dubs the “Internet of Nature”. This article was originally published at https://www.linkedin.com.