The Effect of Multinutrient Fertilization on Understory Vegetation Annual Production

This study quantified the effects of operational multinutrient fertilization on understory shrub, forb, and grass production in inland Northwest forests. Understory vegetation annual production increased at some sites while other sites showed no change or decreases following fertilizer treatments. The greatest understory response to fertilization occurred in low density, shade-intolerant, overstory-dominated stands. Understory vegetation response was lower under overstories dominated by more shade-tolerant conifers. Multinutrient fertilization produced increases in annual understory production of up to 2,400 lb/ac for combined understory growth forms over the entire growing season. West. J. Appl. For. 17(3):147–153.