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Long-term Root Growth Response to Thinning, Fertilization, and Water Deficit in Plantation Loblolly Pine

Informally Refereed

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
https://www.fs.usda.gov/research/treesearch/6737