Table 4. Change of importance percentage of the Quercus mongolica community in Mt. Cheongryang, Incheon
(Unit: 1,200m²)

Species name	1999				2013				Change value (%)
	C (%)	U (%)	S (%)	M (%)	C (%)	U (%)	S (%)	M (%)
Pinus rigida	11.2	9.5	-	8.8	6.9	-	-	3.5	-5.3
Pinus densiflora	0.6	-	-	0.3	-	-	-	-	-0.3
Juniperus rigida	-	-	-	-	-	-	1.1	0.2	+0.2
Betula davurica	6.0	1.4	-	3.5	4.1	1.2	-	2.4	-1.1
Corylus heterophyllavar. thunbergii	-	-	-	-	-	-	3.5	0.6	+0.6
Alnus hirsuta	5.3	-	-	2.7	2.3	-	0.4	1.2	-1.5
Castanea crenata	-	2.9	0.7	1.1	1.3	-	1.5	0.9	-0.2
Quercus acutissima	0.8	0.4	0.3	0.6	2.9	0.5	1.0	1.8	+1.2
Quercus dentata	1.0	-	-	0.5	1.3	-	-	0.6	+0.1
Quercus aliena	-	0.4	0.3	0.2	2.5	-	-	1.2	+1.0
Quercus mongolica	68.8	36.8	6.9	47.8	50.5	13.8	2.9	30.3	-17.5
Quercus serrata	-	0.5	-	0.2	16.1	-	0.8	8.2	+8.0
Magnolia obovata	-	-	-	-	-	1.1	1.3	0.6	+0.6
Lindera obtusiloba	-	0.5	0.3	0.2	-	4.3	5.0	2.3	+1.1
Sorbus alnifolia	2.8	27.7	8.9	12.1	1.4	52.5	8.8	19.6	+7.5
Prunus sargentii	2.0	1.9	0.7	1.7	5.5	-	1.2	3.0	+1.3
Lespedeza cyrtobotrya	-	-	0.3	0.1	-	-	-	-	-0.1
Lespedeza bicolor	-	-	0.3	0.1	-	-	-	-	-0.1
Robinia pseudoacacia	1.5	5.7	2.9	3.1	5.4	3.0	7.1	4.9	+1.8
Rhus trichocarpa	-	0.9	1.1	0.5	-	2.6	4.7	1.6	+1.1
Parthenocissus tricuspidata	-	-	1.5	0.3	-	-	-	-	-0.3
Rhododendron mucronulatum	-	1.7	64.9	11.4	-	3.8	42.2	8.3	-3.1
Symplocos chinensisfor. pilosa	-	-	2.2	0.4	-	0.5	0.4	0.2	-0.2
Styrax japonicus	-	9.4	7.4	4.4	-	16.8	12.8	7.7	+3.3
Fraxinus rhynchophylla	-	0.4	-	0.1	-	-	-	-	-0.1
Viburnum erosum	-	-	-	-	-	-	2.1	0.4	+0.4
Viburnum dilatatum	-	-	0.7	0.1	-	-	-	-	-0.1
Smilax china	-	-	0.3	0.1	-	-	1.8	0.3	+0.2
Smilax sieboldii	-	-	-	-	-	-	1.5	0.3	+0.3

C: importance percentage in canopy layer, U: importance percentage in understory layer, S: importance percentage in shrub layer, M: mean importance percentage.