Simple regressions of single band thematic mapper simulator (TMS) reflectance data against stand basal area and leaf biomass show that the spectral feature most strongly related to vegetation amount is visible reflectance (TM bands 1, 2 and 3), which decreases as conifer basal area increases. Principal components analysis of TMS spectral data for sample stands, and stepwise multiple regression of transformed axes, showed the first principal component, interpreted as scene brightness, to be the composite spectral feature most correlated to vegetation amount. TMS data showed some ability to discriminate spectrally between coniferous forest stands dominated by different species. Dense stands of large timber dominated by red fir (Abies magnified var. shastemis) had a different average spectral reflectance from white fir (Abies concolor) dominated stands, particularly in TM bands 4 (0.76-0.90μm) and 6 (10-4-12-5μm).