Productivity of loblolly pine as affected by decomposing root systems

Decomposing taproot systems of mature loblolly pine (Pinus taeda L.) trees harvested 16 years earlier were examined to assess their effects on product ivity of a naturally regenerated loblolly pine stand. Productivity by trees within a l-m radius of decomposing stumps was greater than that in zones f arther from the stump. Production of the 16-year-old naturally regenerated loblolly pine stand on this eroded Pacolet soil would have been at least 28 % less in the absence of decomposing root systems of previously harvested t rees. Live-root density of the natural stand within decomposing root system s was about twice that found in soil profiles centered 2 and 4 m distant fr om the stump. Below a soil depth of 20 cm, decomposing root systems contain ed significantly higher root densities than the soil matrix. Decomposing ro ot systems provide scattered microsites of enhanced fertility, aeration, an d moisture which benefit growth of nearby trees and may play an important r ole in sustaining and restoring productivity of marginal Piedmont sites. (C ) 2000 Elsevier Science B.V. All rights reserved.