Table 6. Changes in the number of trees in the Robinia pseudoacacia community of the World Cup Park slope district

Division	Individual(tree/100m2)
	Canopy layer							Understory laye							Shurb layer
	’99	’03	’05	’08	’12	’16	’21	’99	’03	’05	’08	’12	’16	’21	’99	’03	’05	’08	’12	’16	’21
Robinia pseudoacacia community	9.0	10.0	9.1	7.5	3.9	3.0	4.5	12.5	12.9	9.7	7.6	4.9	6.5	6.0	54.1	12.3	14.5	23.7	28.6	12.0	20.0