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About On the way to PlanetProof


Certification scheme Plant Products


Tree Nursery Udenhout: sustainable from top to root

We would like to introduce you to Corné; employee at Boomkwekerij Udenhout. Corné Leenders, employed for over 25 years at Tree Nursery Udenhout, enthusiastically talks about the more sustainable cultivation of trees and his experiences with the label On the way to PlanetProof. The tree nursery has over 170 hectares of 600 different trees and solitary shrubs and sells them mainly to government agencies. The 130-year-old family business has been certified for Milieukeur – now On the way to PlanetProof – since 2010.

The logical course of action

Sustainable production has been a logical course of action for Tree Nursery Udenhout for a long time. Corné explains: “It all starts with the soil; it has to be optimal. We check it for minerals and see whether it contains everything the tree needs. This is then enriched with biological material, such as fungus-dominant humus compost. Before we start planting, there were peppermints. These are green manure crops that ensure that the soil is healthy and fertile. The loamy sandy soils in Brabant, where we are located, have a great advantage: in the summer months, we have a continuous release of moisture, which gives you a very gradual growth process and a fine root system. This makes it easy to transplant the trees to other soils.

Tree nursery Udenhout plants thin trees (spindles), with a stem girth of 8-10 cm. It then takes three years before the trees are saleable. Every other year a tree is sold, so that larger trees can be sold the following year. The trees remain standing for a maximum of 5 years. After that, the cycle begins again. “When the plot is empty, green manure is sown and then a plot lies fallow for 2 years. No trees are grown on it during that period. This is necessary to get the soil healthy again.”

Migration to green

Tree farming has not always been as sustainable as it is today. “25 years ago the nursery was ‘black’; everything was mechanical. Since 2010 we have started the transition to an Eco-label nursery. At the time, the government demanded a hallmark as proof of sustainable purchasing. The challenge then was the number and type of pesticides used. That was very difficult in the beginning because we were a traditional company. We had to do that slowly and research the balance of the right pesticide at the right time. There was always a lot of consultation with SMK – the developer and manager of the quality mark – about the practical elaboration of criteria for tree growers. This was always very transparent and worked very well. More than eleven years later we are a real green nursery”, says Corné.

Biodiversity along the lanes

Added value On the way to PlanetProof

According to Corné, the added value of On the way to PlanetProof is that the tree nursery can continue to participate in municipal tenders. This allows the company to sell the trees without any problems. In addition, the tree nursery experiences benefit from the quality label to make ISO certification easier and for its employees. The reduction of chemical substances makes it safer and everyone works in a pleasant environment. Biodiversity is an important theme within the scheme and that is paying off: “In the nursery, you see bees, butterflies and flower mixtures. It is a joy to walk in. It is accessible to everyone in the area and we regularly receive compliments.

When asked if Corné has any advice for other hallmark holders, he is very brief: “Just do it! It takes some searching, but it’s not that hard in the end. We still have a lot of benefit from it.