Let’s make the city green again

Growing urbanization forces us to think of constant changes for a better life. Local governments chase each other to be the most modern place in Europe. They are providing smart city solutions to refine basics needs for every citizen. And it is not the first thing which came up with our minds, but for citizens, one of the most important things is how they are feeling in the city. 

For several years most cities in the whole of Europe are changing their look. How is it going? Of course with plants. Revitalization is slowly becoming a number one for local governments. More and more greenery is appearing on the streets, even on the most crowded ones. After many years we understood we are missing green color in urban areas. But it turns out that planting even the smallest tree is a long process that requires extraordinary knowledge. We do not have to look far away from examples of urbanization and revitalization. Our hometown Lublin. The renovation of one of the main streets in the city has just started. The road was old, devastated but still very important for most of the citizens. Before the renovation the city council was talking with people about changes. It was very important to confront the view with citizens, finally, changes are for them. Reconstruction of Racławickie street includes planting 170 trees and over 5.5 thousand shrubs. The contractor will protect the area of bedding and bowl at the trees from excessive evaporation by using special mats and covering them with a layer of composted ground conifer bark. The ground part of tree trunks will be covered with special plastic covers to protect the trees from damage to the bark during e.g. mowing. These are standard treatments for new plantings in the city. 


But what if we don’t have enough space for plants, especially trees which in the future are going to grow big and tall? 


Here come challenges


Everything seems to be simple but you cannot even imagine how many solutions have to be found before the investment. There are a lot of challenges when it comes to planning the revitalization in the city. For a tree to grow tall and healthy, it is not enough just to dig a hole, plant a tree and cover it with soil. The most apparent problems are a limited area between buildings and hard landscaping. It is quite challenging to create conditions in which the tree will be able to grow under the surface without any problems and without the influence of external factors. So to plant the tree we have to prepare special supports that hold the hard surface above the tree roots. This ensures that the plant is free of pressure and can grow normally. According to TreeBuilders, a company that has experience with urban change, there are some useful methods to avoid the problem. The company is using the TreeParker system which connects green, blue and grey. What does it mean? The underground structural soil cell system provides unlimited expansion for roots and uses space beneath the ground for the maximum. Everything thanks to special cantilevers. The system uses the experience gained by extensive trials, projects, and discussions with landscape architects, clients, contractors and nurseries to provide the most cost-effective, fit-for-purpose solution to the problems associated with growing large trees in urban environments. But here comes another question - how to guess what is going on with the soil? 


The solution

Next to the construction, another thing is to explore the soil. In this case, the soil is the most important part of all projects. The tree will be growing healthy and tall only if the soil will be doing well and be humidified. There are methods that will not only improve the planting process of trees but will also take care of the plants for many years. The solution assumes how to collect pieces of information hidden beneath the ground. The goal is to measure soil and plants for the entire life of the tree without a need for replacing sensors every few years. Thanks to the dedicated sensors we know when to water the tree and when the soil is well saturated - taking care of humidity is very important, too much water in the soil means no oxygen, and trees will not grow. To collect data for long years PICO Soil Moisture Probes could be used, which are dedicated to monitoring volumetric moisture in the soil and some other porous materials. The solution assumes to use two sensors and thanks to his solution we can read information about moisture and temperature even for 20 years. During this time there will be no need to change or charge the sensor. 

Wireless approach

One of the ideas includes a connection between sensor and server. The concept assumes placement of autonomous, powered by long-life sensors in the ground. And how the readouts are going to be collected from a hidden sensor? The answer is simple - through wireless transmission via LoRaWAN - readouts go to the LoRaWAN getaway over a distance of several hundred meters. The server architecture consists of 2 servers. One of them is an aggregator which will store all the data and will be responsible for communication between server and sensor. The second one, the application server, will be responsible for the management, configuration, or monitoring data from readouts that will bring to us alerts and statistics. 

Advantages: easy installation (no need to use cables, only install the sensor), self-contained (the solution is maintenance-free during the battery life-time), resistance to external damage. 

Disadvantages: cost of batteries (these with a long-life battery are quite expensive). 

Wired approach

That is not all. Another idea is using PoE. The concept is a little different from the first method, it assumes creating a network of sensors located in the ground, connected and powered by Power Over Ethernet(POE). The network is connected to a Gateway in which the switch would power the sensor and trigger data readings on sensors at any time. The Gateway has additional readout processing mechanisms that prepare the data packets to be sent to the Cloud Server using the WAN on GSM module. 

Advantages: sustainability (there is no radio interference), relatively low price of the device (there is no battery, data is connected directly to the Internet), less power consumption (it can be disconnected when not used). 

Disadvantages: the installation procedure is more complex, during usage there is a risk of wire cut.


Samples of use sensors


This only an example of how to improve revitalization in the city with benefits for all of us and the solution to how to improve it. In Chile, they are using special sensors placed on the trees. The device is continuously monitoring the air, sending data back into a system that is detecting the start of a wildfire. Thanks to this solution firefighters are getting respond more quickly about the danger in the forest. 

Source: Fastcompany.com

Source: Entel


There is also a company from Bergen that is working on a project of tree-shaped urban farming. Glasir is a project evolving since 2018. It assumed that on Brooklyn’s street there will be special trees hidden in the glass. The projects assumed that Glasir will be fitted with artificial intelligence sensors that would be used to monitor plant growth and environmental conditions.

Source: FramLab


A good example straight from our hometown is the city program Smart Mobility. Intelligent Transportation System is a solution that improves the flow of cars on the streets. It helps to prevent traffics and cares about the safety of every citizen. The system is responsible for traffic management, mobility management, charging and information and may cooperate with similar systems used in other modes of transport. 

Source: lublin.eu

So it seems that technology based on sensors could be not only a modern solution but very helpful in everyday use and will be more economical for city’s budget. 


Better tomorrow for all of us

The solution has many positive results, you can use it for many years. The purpose is to collect data about the trees, their health, and humidity of the soil, for long years. This solution can be good not only for trees which are now planted in the city but also for future planting when the old trees will be replaced. So far the most popular moisture sensors were working only for a few years or less what generated problems and additional costs. Creating such an innovative system is caring about the future on the streets. Solutions described in the article are long-term and flexible. Depending on needs and budget both of the projects can be modified. Finally, the idea of every project from the smart city area is to improve the quality of life of residents. Technology is becoming a basic engine for every decision-maker and has a big influence on the world as we see it.