Two new methods applied to crown width additive models: a case study for three tree species in Northeastern China

Table 6 Formulae of the final GAM systems for larch, birch, and poplar

Larch	Birch	Poplar
CRE_ij = α_E + S_1E(DBH_ij) + S_2E(HCB_ij) + S_3E(BA_i)	CRE_ij = α_E + S_1E(DBH_ij) + S_2E(HCB_ij)	CRE_ij = α_E + S_1E(DBH_ij) + S_2E(BA_i)
CRS_ij = α_S + S_1S(DBH_ij) + S_2S(HCB_ij) + S_3S(BA_i)	CRS_ij = α_S + S_1S(DBH_ij) + S_2S(HCB_ij)	CRS_ij = α_S + S_1S(DBH_ij)
CRW_ij = α_W + S_1W(DBH_ij) + S_2W(HCB_ij)	CRW_ij = α_W + S_1W(DBH_ij) + S_2W(HCB_ij)	CRW_ij = α_W + S_1W(DBH_ij) + S_1W(THT_i)
CRN_ij = α_N + S_1N(DBH_ij) + S_2N(HCB_ij) + S_3N(BA_i)	CRN_ij = α_N + S_1N(DBH_ij) + S_2N(HCB_ij)	CRN_ij = α_N + S_1N(DBH_ij) + S_2N(HCB_ij) + S_3N(BAL_ij)
CW_ij = (CRE_ij + CRS_ij + CRW_ij + CRN_ij)/2	CW_ij = (CRE_ij + CRS_ij + CRW_ij + CRN_ij)/2	CW_ij = (CRE_ij + CRS_ij + CRW_ij + CRN_ij)/2

Note: α_E, α_S, α_W, and α_N are intercepts of the four CR; S_1·(⋅), S_2·(⋅), and S_3·(⋅) are smooth functions of the four CR, and all other variables are as previously defined

ISSN: 1297-966X