Botanical composition and forage production in an emulated silvopasture

Integrating trees into pasture may increase pasture production and improve nutritive value by altering both species composition and productivity. Our objective was to determine forage yield and botanical composition in response to tree species, tree density, and slope position in an emulated silvopasture (the site had no animals). In 1995, black walnut (Juglans nigra L.) and honey locust (Gleditisia triacanthos L.) trees were planted within plots (r = 3) of predominantly tall fescue (Festuca arundinacea Schreb.) pasture. Trees were planted down slopes in rows to create low, medium, and high tree densities at shoulder-, mid-, and toe-slope positions. Sampling sites (n = 54) under field treatment combinations were harvested May to October at 35-d intervals in 2002 and 2003. Before spring, summer, and fall harvests, plots were subsampled for botanical composition. Tree species did not affect botanical composition when compared over the two seasons. Plots under honey locust trees tended to have more fescue in a dry year (2002) and more legumes and less dead herbage in a wet year (2003). Greater percentages of warm-season grasses and fewer weeds were observed at low tree density sites in 2003. Forage mass (5280,6130, and 4970 kg ha(-1) at low, medium, and high tree densities) was 16% greater under medium-density trees. Plots under black walnut yielded 13% more forage than those under honey locust (5790 vs. 5130 kg ha(-1)). Appropriately spaced trees have potential to positively alter botanical composition and can support greater forage production in a southern Appalachian silvopasture.