1961-1970 |
F. pennsylvanica1
|
Heilongjiang
and Liaoning |
2 |
2 |
Wei et al. 2004 |
1971-1980 |
F. pennsylvanica1
|
Heilongjiang
and Liaoning |
2 |
0 |
Wei et al. 2004 |
1981-1990 |
F. pennsylvanica, F. velutina
|
Heilongjiang,
Liaoning and Tianjin |
3 |
1 |
Liu et al. 1996 |
1991-2000 |
F. pennsylvanica, F. velutina
|
Heilongjiang,
Liaoning, Tianjin, and Beijing |
6 |
3 |
Pan & You 1994;
Field
surveys2
|
2001-2010 |
F. pennsylvanica, F. velutina, F. americana,
F. excelsior
|
Heilongjiang, Liaoning, Tianjin, Beijing, Jilin,
and Hebei |
13 |
7 |
Liu 2011; Field
surveys2
|
2011-2019 |
F. pennsylvanica, F. velutina, F. americana,
F. excelsior
|
Heilongjiang, Liaoning, Tianjin, Beijing, Jilin,
Hebei, Xinjiang, and Shandong |
22 |
9 |
Field
surveys2
|