Table 6. Relative density (RD), relative frequency (RF), relative coverage (RC), and importance percentage (IP) of tree species growing in the Q. mongolica forests.

Species	No. of trees (trees/ha)	Appearance rate (%)	Basal area (m2/ha)	RD (%)	RF (%)	RC (%)	IP (%)
Quercus mongolica	842	100.0	20.6	65.8	17.5	71.5	51.6
Pinus densiflora	51	42.5	2.1	4.0	7.4	7.3	6.3
Quercus variabilis	38	32.4	1.2	2.9	5.7	4.1	4.2
Acer pseudosieboldianum	52	33.8	0.3	4.1	5.9	1.1	3.7
Fraxinus rhynchophylla	28	29.7	0.4	2.2	5.2	1.4	2.9
Quercus serrata	23	27.4	0.5	1.8	4.8	1.9	2.8
Prunus serrulata var. pubescens	20	29.4	0.3	1.6	5.1	1.1	2.6
Betula schmidtii	22	18.9	0.5	1.7	3.3	1.7	2.2
Styrax obassis	24	20.1	0.2	1.9	3.5	0.5	2.0
Tilia amurensis	17	15.1	0.3	1.3	2.6	1.0	1.7
Acer pictum subsp. mono	10	14.9	0.2	0.8	2.6	0.6	1.3
Fraxinus sieboldiana	12	12.1	0.1	0.9	2.1	0.2	1.1
Sorbus alnifolia	9	12.2	0.1	0.7	2.1	0.3	1.0
Pinus koraiensis	12	7.4	0.2	1.0	1.3	0.7	1.0
Maackia amurensis	5	10.6	0.1	0.4	1.9	0.3	0.9
Cornus controversa	5	9.4	0.1	0.4	1.6	0.5	0.8
Betula davurica	4	9.8	0.1	0.3	1.7	0.5	0.8
Quercus dentata	5	8.1	0.1	0.4	1.4	0.3	0.7
Toxicodendron trichocarpum	4	9.4	0.0	0.3	1.6	0.1	0.7
Castanea crenata and so on (99 sp.)	98	‒	1.5	7.5	22.7	4.9	11.7
Total	1,281	‒	28.9	100.0	100.0	100.0	100.0