Tree thinning and prescribed burning effects on ground flora in Arizona ponderosa pine forests: A review

Ground flora is an important response variable to monitor after tree thinning and prescribed burning treatments de signed to restore Arizona ponderosa pine {Pinusponderosa P.& C. Lawson) forests. This paper reviews published liter ature on the effects of thinning and burning on ground flora in Arizona ponderosa pine forests in five main categories of research: ground flora biomass, species diversity, plant community composition, population processes, and individual species ecology. Research published to date suggests that thinning and burning generally increase ground flora biomass, whereas other categories of research such as community composition and population processes have been little studied in Arizona ponderosa pine forests. Additional research needs include determining the relative importance of soil seed banks, seed dispersal, and site conditions in post-treatment ground flora compositional dynamics using a demographic approach; developing predictive models for exotic species distribution and containment; monitoring long-term (>5 years) treatment effects; and geographically replicating experiments at dispersed sites differing in ecological conditions to deter mine the spatial and contextual applicability of research findings. To meet desired outcomes of ecological restoration including criteria for high native and low exotic species diversity, treatments supplementary to thinning and burning such as seeding of native species and life-history specific control methods of exotic species might be needed on some restora