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Fertilization, weed control, and pine litter influence loblolly pine stem productivity and root development

Informally Refereed

Abstract

Development of forest plantations may be delayed or yield expectations curtailed by interference from competing vegetation. Competing vegetation can be controlled with herbicides after crop trees are planted, but herbicide use in public and private loblolly pine plantations may face greater restrictions in the future. Fortunately, there are ways to manage competition which can reduce the need for herbicides. These include litter accumulation as a mulch and fertilization. A combination of broadcasting 177 kg N/ha, 151 kg P/ha, and herbicides was the best treatment for increasing average5-year-oldloblolly pine volume and total stand productivity. However, this treatment combination suppressed all other plant communities. This may or may not be desirable depending on the objectives of the forest manager. For example, the maintenance of forest litter (allowing 37Mg/haof forest floor material to accumulate before harvest, careful harvesting practices, and post-harvest shredding of debris), followed by fertilization at planting, should be considered if rapid development of all woody vegetation is the manager's goal rather than loblolly pine productivity alone. Fertilization is an option if the manager wishes to initially increase herbaceous plant cover along with rapid development of all woody vegetation. However, each of the three alternatives will result in progressively less loblolly pine productivity in the following order,fertilizer-herbicide > fertilizer-litter > fertilizer only. Litter was clearly less satisfactory than herbicides for controlling weeds.

Citation

Haywood, James D.; Tiarks, Allan E.; Sword, Mark A. 1997. Fertilization, weed control, and pine litter influence loblolly pine stem productivity and root development. New Forests 14: 233-249, 1997.
https://www.fs.usda.gov/research/treesearch/538