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How do you do – forest?

“How do you do?” is a daily way for Lônders in my village of Overloon to greet each other or to start a chat. Usually the quick answer is: “Good.” If the emphasis on the question is slightly different, then there appears to be real interest in how the other person is doing. And usually there is, as they say, ‘some prior knowledge’.

I am regularly asked how the forests around Overloon or in the Netherlands or Europe are doing and the answer then, is not that simple. To answer this, a so-called forest inventory has been carried out in most European countries since the 1980s and in some countries since the 1920s. During a forest inventory, a sampling schedule is overlaid on the map of the entire forest in a country. This is a regular grid with one point every kilometer. A field team goes to each point every 5 years and measures, among other things, the diameter of all trees and the height of some. All kinds of other things are also measured, but for now it’s just about the trees. The Netherlands also has such a forest inventory of more than 3,000 points. It is an extremely small sample of Dutch forests of some 0.03% of all trees which are measured.

Photo: Fieldcrew making fun in the forest

Throughout Europe there are approximately 500,000 points where field teams go to measure the trees! There are also 6 points in the Lônse forests. By returning to exactly the same point every 5 years (with your GPS), you know exactly how much the same trees have grown, which ones have grown in, and which ones have died or been cut down for timber harvest. These 3000 sample points together say something about the state of the Dutch forest and the direction it is heading.

Does it have to be done in this time-consuming way? Yes!. Even though satellites fly overhead every hour and the satellites say something about the tree crowns, determining the subtle changes in a forest can only be measured on the ground. It’s not called ‘ground truth’ for nothing. These subtle changes are what matters, because they say something about the trends in the forest and the trends are important in a slow forest system because you can make adjustments in policy and forest management based on them.

Photo: The forests around Overloon have been used by my ancestors for millennia. You can still see this in the cultural historical richness in the forest; here overblown oak coppice.

But the question ‘how are the forests doing?’ remains difficult to answer. How difficult even depends on who asks it and where! When I am asked this question in Brussels, the question immediately takes on political connotations and data is often misused. When an environmental organization asks the question, they want an answer about birds, ants and fungi and they are often looking for a negative answer. If the forest is not doing well, more protection is needed. When the forestry industry asks the question, they want an answer about wood for construction or for toilet paper and they are often looking for a more positive answer. If the forest is doing well, more can be harvested. So it just depends on how you emphasize it.

The involvement of all these organizations is of course not surprising. It is a living system on which we all depend and despite Terabytes of data, it remains difficult to answer: ‘how are you doing?’. We scratch the surface a bit, but never know for sure…. 

If you want to know about the state of Dutch forests in 5 minutes, please check this out with Bas Lerink on youtube:

The Dutch national forest inventory is led by Bas Lerink from Wageningen Environmental Research, together with Probos, Borgman and Van Lierop.

This text was originally published in ‘Ons Eigen Erf’, the Overloon newsletter in 2022.

Improving the forest monitoring of European forests is core of EU funded Monifun project.

Feature photo: the author downloading data from an automated dendrometer

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