Moisture retention for young trees

Do young trees grow better when Kaumera is mixed into the soil to retain moisture longer? Tests by the tree specialists at De Bilt-based Aannemingsbedrijf Hoefakker were promising. In spring 2022, a pilot started in the forest near Loenen Falls, an area where water board Vallei and Veluwe operates. Now, six months after planting, we are seeing the first positive results.

Young growth thrives

The Water Systems Management Department of the Vallei and Veluwe water authority plants about 500 trees every year to improve the ecology around the water system. These young plantings, on high sandy soils among others, require manual care such as extra watering in the first three years after planting. Often, this is also on difficult terrain. In dry seasons, such as in 2018-2020, this care was even more intensive. Initial trials have shown that Kaumera's properties include retaining soil moisture longer. In addition, it can potentially provide additional nutrition in the early stages of growth.

How did we go about it?

In March 2022, a total of 60 new trees were planted with Kaumera as a soil conditioner in two different concentrations and a control group (0%). The Kaumera used comes from the water authority Rijn and IJssel plant in Zutphen. Soil moisture sensors allow good monitoring of soil moisture levels. The starting point of the study is to determine whether there is a positive effect of Kaumera on the growth of the planted trees, so that additional care can be limited in the early stages.

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Measuring the effects of applying Kaumera

Landscaping and tree specialist company Hoefakker (de Bilt) and Flexyz B.V. from Harderwijk, an Internet-of-things (IoT) company, have developed the innovative concept SmartCityTrees©. Here, tree care takes place using soil moisture sensors and a web application. These are placed near the trees and provide a real-time measurement of soil moisture levels. In Loenen, these sensors are incorporated into tree poles so that they are optimally protected and can do their job for several years.

The first results

In the first six months of measurements, we see a clear difference in soil moisture contents. In particular, the growing sites where 10% Kaumera is mixed in show higher moisture contents on average compared to the 0% and 5% growing sites. This is a promising result that more than meets expectations. We watered the trees once at the beginning of the growing season and then a few months later. This is much less than you would normally expect.

Other factors such as location of the trees and weather conditions can also affect the results. Therefore, we monitor the trees daily using the moisture sensors and analyse the measurement results in combination with environmental factors.

The young trees are planted

Sensors register the real time moisture levels

Landscaper and tree specialist company Hoefakker is a family business that has now been in existence for 60 years. We are gardeners, tree specialists, outdoor space designers and green heritage managers. Outdoor space is getting more and more attention and with the current climatic developments, we desperately need the ecosystem services that trees provide. As a company, we aim to supply and plant healthy trees that can provide us with the desired ecosystem services. A sustainable product like Kaumera with soil-improving properties fits well with our goal. This is the motivation for us to contribute to this project.

Flexyz has been providing flexible custom IT solutions for businesses and governments for more than 20 years. These solutions are a mix of custom software, cloud and security components. Since 2016, under the name, the company has also been providing various Internet of Things applications. From the platform IoT Connect, Flexyz offers domain-specific sensor solutions for monitoring and controlling public space.
With the advent of small and affordable sensors, many of which work on rechargeable batteries, processes in outdoor spaces can be easily measured where previously this was not technically and/or financially possible. We offer these solutions together with partners such as Hoefakker. We focus on waste collection, air quality, water management and green space management, among others.
The information that becomes available provides a wealth of new insights. These insights are key to being able to carry out existing working methods and business processes smarter and with minimal use of (fossil) fuels. Sensor technology combined with developments such as Kaumera are essential to keep our planet livable.