Not really. Trees plant themselves. If it’s not being actively used for something/mowed it’ll turn back into forest.
I don't remember the details, but I believe it goes something like farm -> heath -> shrubland -> young forest -> mature forest, where each phase has a unique ecosystem of both plant species and animal life.
In an extremely heavily cultivated landscape like Denmark (seriously, look at a satellite photo), converting farmland back into forest is a multi-decade project requiring constant maintenance. Converting farmland into marshland (which is the "original" stone-age landscape in many areas) is a multi-century project.
Just like it was a multi-century project to convert it into farmland, by the way. Europe has been cultivated for millennia.
Source: I’ve planted thousands of trees.