Table 4. Parameter estimates of Kozak’s stem taper model for Ver.2 (2021 stem volume table) (NIFoS, 2021).

Parameter	Pinus densiflora in Gangwon region	Pinus densiflora in central region	Pinus thunbergii	Pinus rigida	Pinus koraiensis	Larix kaempferi	Cryptomeria japonica	Chamaecyparis obtusa	Quercus acutissima	Quercus variabilis	Quercus mongolica	Quercus serrata	Betula playphylla	Liriodendron tulipifera
a1	1.0742	1.0046	0.9834	1.0693	1.0332	0.9817	1.1858	1.0991	1.4721	1.3095	1.1996	1.0838	1.1202	1.0925
a2	0.8968	0.9217	0.9722	0.9470	0.9370	0.9690	0.9117	0.9526	0.8104	0.8613	0.9141	1.0095	0.9070	0.9099
a3	1.0013	1.0009	0.9972	1.0003	0.9998	0.9988	0.9997	0.9983	1.0046	1.0016	0.9985	0.9911	0.9991	0.9984
b1	−0.0123	−0.1732	−0.0809	0.2309	0.6748	0.5749	1.3045	1.3792	0.8144	0.7293	1.3611	2.0063	0.7334	−0.1338
b2	−0.1073	−0.0876	−0.0997	−0.1019	−0.1551	−0.0857	−0.3416	−0.3023	−0.2510	−0.1883	−0.3368	−0.4896	−0.1566	−0.0181
b3	0.4714	0.4003	0.5580	0.7172	1.0178	0.3104	1.9306	1.5786	1.8770	0.6833	2.2856	3.6518	1.1076	−0.2964
b4	0.1232	0.2271	0.0653	−0.0978	−0.3670	−0.0934	−0.9738	−0.8785	−0.7478	−0.2647	−1.1219	−1.8286	−0.3902	0.4614
b5	−0.0220	−0.0408	0.0315	0.0162	0.0628	0.1238	0.0795	0.1159	0.0422	0.0817	0.1378	0.0797	0.1726	0.1212
p	0.3	0.3	0.25	0.2	0.3	0.25	0.2	0.2	0.2	0.2	0.2	0.18	0.25	0.25