Year in which the forest was (re)afforested during past centuries – in classes of ten years. Reference: Forest Service Survey (MID 332: Jahr der Aufforstung)

Code	Text	NFI3	NFI4	NFI4b	NFI5
-1	no afforestation or unknown	x	x	x	x
1	before 1851	x	x	x	x
2	1851-1860	x	x	x	x
3	1861-1870	x	x	x	x
4	1871-1880	x	x	x	x
5	1881-1890	x	x	x	x
6	1891-1900	x	x	x	x
7	1901-1910	x	x	x	x
8	1911-1920	x	x	x	x
9	1921-1930	x	x	x	x
10	1931-1940	x	x	x	x
11	1941-1950	x	x	x	x
12	1951-1960	x	x	x	x
13	1961-1970	x	x	x	x
14	1971-1980	x	x	x	x
15	1981-1990	x	x	x	x
16	1991-2000	x	x	x	x
17	2001-2010	x	x	x	x
18	2011-2020		x	x	x
19	2021-2030				x