Boomstudie by George Andries Roth (1809–1887). Original from the Rijksmuseum. Digitally enhanced by rawpixel. https://www.rawpixel.com/image/2098758/vintage-forest-park-artworkFree Image from public domain licenseBoomstudie (1801 - 1871) by Cornelis Gerardus t Hooft 1791 1871 https://www.rawpixel.com/image/13793042/boomstudie-1801-1871-cornelis-gerardus-hooft-1791-1871Free Image from public domain licenseBoomstudies (1838 - 1887) by Frederik Hendrik Weissenbruch https://www.rawpixel.com/image/13790301/boomstudies-1838-1887-frederik-hendrik-weissenbruchFree Image from public domain licenseBoomstudie (1864 - 1910) by Cornelia Christina Johanna van Trigt Hoevenaar https://www.rawpixel.com/image/13765506/boomstudie-1864-1910-cornelia-christina-johanna-van-trigt-hoevenaarFree Image from public domain license