Table 3.

Coefficient and fit statistics of different stem volume equations.

Model no	Equation	a	b	c	d	R2	RMSE	DBH range (cm)
1	V = a + bDBH2	− 0.06187	0.00087			0.9489	0.05274	3.6–47.5
2	V = a + bDBH + cDBH2	0.03957	− 0.01215	0.00118		0.9573	0.04822	3.6–47.5
3	V = aDBH + bDBH2	− 0.00783	0.001075			0.9562	0.04882	3.6–47.5
4	V = a + bDBH2H	0.02093	3.37e−05			0.9788	0.03399	3.6–47.5
5	V = aDBH2H	3.513e−05				0.9733	0.03808	3.6–47.5
6	V = a + bDBHcHd	79.22	− 79.4	− 0.00082	− 0.00106	0.3421	0.1892	3.6–47.5
7	V = DBH2/(a + b/H)	387.8	19,190			0.9833	0.03017	3.6–47.5