Table 4. Multiple linear regression results of occurrence of pine wilt disease.

Variable		Coefficient	S.D.	Variation Inflation Factor (VIF)	Standard partial regression coefficient	Significant level
Species of trees	White pine					0.0000
	Red pine	−79;.9200	2.1050	6.8291	−0.0749	0.0000
	Black pine	−89;.7500	2.2420	6.4078	−0.0765	0.0000
	Mixed forest	−85;.0400	2.3250	3.6427	−0.0527	0.0000
Altitude		0.0408	0.0087	2.7002	0.0058	0.0000
Slope		5.8900	0.0656	1.8454	0.0921	0.0000
Orientation		−9;.8780	0.6412	1.1516	−0.0125	0.0000
Mean Temp. from May to Aug.		35.4500	1.8160	1.5167	0.0181	0.0000
Wind direction from May to Aug.		2.8930	0.0255	3.1466	0.1520	0.0000
Duration of sunshine		626.8000	2.2390	1.9567	0.2955	0.0000
Distance to forest fire		0.0004	0.0001	1.1935	0.0046	0.0000
Distance to fumigation pile		0.0092	0.0001	1.2219	0.0634	0.0000
Distance to thinning forest		0.0005	0.0001	1.1676	0.0040	0.0000
Distance to road		0.3467	0.0056	1.6409	0.0598	0.0000
Distance to rail		−0.0003	0.0001	1.1941	−0.0031	0.0002
Distance to building		0.2887	0.0029	1.8509	0.1031	0.0000
Distance to harbor		−0.0018	0.0000	4.0080	−0.2284	0.0000
Distance to forest road		0.0012	0.0002	1.1432	0.0044	0.0000
Distance to pine tree handling facility		−0.0012	0.0001	1.2407	−0.0090	0.0000
Constant term		−5559;.0000	46.8400	-	-	0.0000
Coefficient of determination (R2)		0.4765		F=4648, df=18, 918751, p<0.001