Table 3. Relative importance of major plant species by groups (I–V) classified by TWINSPAN in plantation forests of Gwangneung Forest. Left: MIP based on the canopy, subcanopy, and shrub layers; right: importance in the herb layer only

Community*	Layer	C**	Su	S	MIP	Layer	H
	Species					Species
I	Pinus rigida	-	58.40	0.61	19.57	Acer pseudosieboldianum	8.90
	Quercus mongolica	21.84	8.25	3.63	14.27	Oplismenus undulatifolius	6.36
	Carpinus laxiflora	17.45	3.83	7.86	11.31	Lindera obtusiloba	6.32
	Quercus variabilis	13.72	5.86	1.41	9.05	Disporum smilacinum	5.84
	Prunus serrulata	10.51	-	3.23	5.79	Sorbus alnifolia	5.26
	Others (38 species)	36.48	23.66	83.25	40.00	Others (35 species)	67.32
	Total	100	100	100	100	Total	100
II	Quercus mongolica	21.84	-	-	10.92	Oplismenus undulatifolius	21.26
	Carpinus laxiflora	17.45	2.72	6.56	10.72	Parthenocissus tricuspidata	6.67
	Larix kaempferi	-	28.96	-	9.65	Acer pseudosieboldianum	6.25
	Pinus koraiensis	-	27.60	-	9.20	Clerodendrum trichotomum	2.97
	Quercus variabilis	13.72	2.72	0.22	7.80	Smilax sieboldii	2.85
	Others (61 species)	46.99	38.00	93.22	51.70	Others (95 species)	59.99
	Total	100	100	100	100	Total	100
III	Acer pseudosieboldianum	8.74	-	17.90	7.35	Oplismenus undulatifolius	15.70
	Prunus serrulata	7.16	0.99	0.98	4.07	Acer pseudosieboldianum	5.51
	Quercus aliena	6.38	0.98	2.90	4.00	Osmunda japonica	4.21
	Quercus mongolica	6.86	1.00	1.19	3.96	Parthenocissus tricuspidata	3.72
	Zelkova serrata	2.63	7.20	1.04	3.89	Polystichum tripteron	2.92
	Others (75 species)	68.24	89.83	75.99	76.73	Others (120 species)	67.94
	Total	100	100	100	100	Total	100
IV	Abies holophylla	8.94	21.20	3.65	12.14	Oplismenus undulatifolius	27.56
	Juglans mandshurica	12.39	5.24	2.13	8.30	Parthenocissus tricuspidata	3.28
	Pinus koraiensis	-	18.98	-	6.33	Carex siderosticta	2.95
	Quercus serrata	8.99	-	1.06	4.67	Akebia quinata	2.91
	Carpinus cordata	7.99	-	3.02	4.50	Clerodendrum trichotomum	2.67
	Others (83 species)	61.69	54.59	90.15	64.07	Others (163 species)	60.64
	Total	100	100	100	100	Total	100
V	Juglans mandshurica	33.33	5.36	11.32	20.34	Oplismenus undulatifolius	12.60
	Chionanthus retusus	22.22	-	8.26	12.49	Matteuccia struthiopteris	8.47
	Quercus aliena	15.56	5.36	3.41	10.13	Akebia quinata	7.07
	Abies koreana	-	17.77	3.49	6.50	Clematis terniflora	6.17
	Abies holophylla	-	15.00	8.35	6.39	Setaria viridis	6.13
	Others (25 species)	28.89	56.52	65.17	44.15	Others (68 species)	59.55
	Total	100	100	100	100	Total	100

I : P. rigida - Q. mongolica Community, II: Q. mongolica - C. laxiflora Community, III: A. pseudosieboldianum - P. serrulata Community, IV: A. holophylla - J. mandshurica Community, V: J. mandshurica - C. retusus Community
C, Su, S: Importance (%) in canopy, subcanopy, and shrub layers; MIP: mean importance percentage; H: Herb layer importance (%)