Clear-cutting during World War I and the 1920s was the largest logging campaign in the entire history of the Białowieża Forest. During the German occupation of 1915-1918 alone, more timber was removed than in the previous 500 years combined! Fortunately, the Polish authorities sought to mitigate the damage caused by industrial exploitation of the forest. Pine saplings were planted in the clear-cut areas. Some clear-cut areas regenerated naturally, producing a mixed forest. Today, large tracts of land near former narrow-gauge railways are teeming with young hornbeam, aspen, and birch trees—living reminders of past wounds.