Effect of Nitrogen and Phosphorus Fertilization on Growth of a Sweetgum Plantation Damaged by an Ice Storm

Abstract

In 1994, an ice storm impacted a 19-year-old sweetgum plantation (Liquidambar styraciflua L.) fertilized with nitrogen (N) and phosphorus (P) at age 4. Thirty-nine percent of the stems were broken, 55 percent were not damaged, and 6 percent were leaning. After the ice storm, differences in height and dbh among the fertilization treatments disappeared. To test if fertilization can increase growth of both damaged and undamaged trees, we applied N and P fertilizers in early 1999. Two fertilizers, ammonia nitrate and superphosphate, were used in four combinations of treatments: N only (205 lb. N/ac), P only (123 lb. P/ac), N+P (205 lb. N/ac + 123 lb. P/ac), and a control. The treatments were on the same plots that were treated at age 4. After one growing season, N increased overall dbh growth, and P increased height growth. The effect of P was mostly on the damaged trees with height growths of 5.8 feet for P only, and 6.5 feet for the N+P treatment, compared to 4.8 and 5.1 feet for N only and the control, respectively. P had been shown to increase height growth with N at age 11.

Citation

Guo, Yanfei; Vanderschaaf, Curtis. 2002. Effect of Nitrogen and Phosphorus Fertilization on Growth of a Sweetgum Plantation Damaged by an Ice Storm. In: Gen. Tech. Rep. SRS–48. Asheville, NC: U.S. Department of Agriculture, Forest Service, Southern Research Station. pg. 223-226