Abstract
High water deficits limit the new root growth of loblolly pine (
Pinus taeda L.), potentially reducing soil resource availability and stand growth. We evaluated new root growth and stand production in response to thinning and fertilization in loblolly pine over a 6-year period that consisted of 3 years of low water deficit followed by 3 years of high water deficit. We found that new root growth exhibited a distinct seasonal pattern, with the timing of maximum root growth affected by water deficit. The magnitude of root growth was affected by both water deficit and thinning. For the 3-year period of high water deficit, we observed an inverse relationship between stemwood production and root growth among the treatment combina-tions. We hypothesize that by the third year of high water deficit, absorbing roots had migrated deeper into the soil profile; as a result, deep soil water became available for the high rates of stand production observed.
Parent Publication
Citation
Sword-Sayer, M.A.; Tang, Z. 2004. Long-term Root Growth Response to Thinning, Fertilization, and Water Deficit in Plantation Loblolly Pine. Gen. Tech. Rep. SRS–71. Asheville, NC: U.S. Department of Agriculture, Forest Service, Southern Research Station. pp. 458-464