Understory Biomass Response to Microsite and Age of Bedded Slash Pine Plantations

Abstract

Understory standing crop biomass was studied on three culturally imposed microsites (bed, furrow, and flat) bedded slash pine (Pinus elliottii) plantations in north Florida. Biomass was clipped in the late spring of 1977 on plantations 2,5, and 10 years old and separated into five classes: grass, forb, sedge, shrub, and litter (including standing dead). After an initial abundance following site preparation, sedges and forbs dropped to relatively low levels within the first 5 years of plantations development. Grasses were the dominant live vegetation in two-year-old plantations. Shrubs became dominant by the fifth year and remained so through the 10th year. Litter, as a result of the lack of cultural treatments designed to remove accumulated dead vegetation, was the major biomass class (more than 8,000 kg/ha by the fifth year following pine establishment). Total live understory biomass increased from the second to the fifth year after which it decreased. Grass standing crop biomass was highest on the flats, lowest in furrows. Hence, forage inventories should be stratified by microsite. Prescribed burning on a properly managed cattle operation may prevent high accumulations of litter while effectively improving the availability of palatable forage. Forage may also be increased by decreasing the proportion of land occupied by the less productive microsites, namely the furrows and beds.