Slash pine: still growing and growing! Proceedings of the slash pine symposium

Abstract

Slash pine is the premier tree species on many sites throughout the South. Its ease of establishment and early growth, however, has extended its range to many sites where its performance has been less than ideal. For that reason, the acreage and volume of slash pine are declining. Nonetheless, it will continue to be the favored species on many sites where it is the most appropriate and productive species. This paper reviews slash pine's important silvical characteristics, its history of use and management, and the status and trends of this important resource. PhenologySeeds mature in a 3-year period from when the strobili are initiated. The primordia of new strobili are detectable in late spring. These cone initials overwinter as buds the first year. When pollen is shed in late January or February of the second year, the male strobili are purple and 2 inches long. The female strobili appear on stalks in the upper crown and are about 1 inch long and red to purple at the time of pollination. Soon after pollination, the pollen tube stops growing and appears to remain in a quiescent state for the summer and winter. During the third growing season fertilization occurs-some 12 to 14 months after pollination. Cones enlarge and seeds mature during the third summer. Needles develop on new growth in spring and persist until the end of the second growing season. DistributionThe natural range of slash pine is the most restricted of all major southern pines, extending from southern South Carolina to central Florida and westward to southeastern Louisiana (fig. 2). Although its natural range is relatively small, slash pine has been planted widely and its range extended into eastern Texas, southern North Carolina, and the sandhills between the Coastal Plain and the Piedmont through much of the Southeast (Fisher 1983). Slash pine has been introduced into many countries for timber production. Large-scale introductions have occurred in Brazil,

Slash pine growth and nitrogen leaching potential following fertilization and pinestraw removal

“…In an earlier research, diammonium phosphate fertilization also did not have a positive effect on wood production at Ultisol and Entisol sites in Florida and increased slash pine mortality at medium and high rates (Minogue et al, 2013). Our results differ from several literature reports of accelerated tree growth, stand development, and increased wood production following mid-rotation southern pine fertilizations Jokela, 2004;Jokela et al, 2010;S. Martin et al, 1999), but are consistent with other accounts of lack of response, especially for slash pine.…”

“…Lack of response to N or P additions may also be caused by deficiencies of other nutrients (Carlson et al, 2014). This was not the case in our study, as baseline foliar nutrient concentrations of K, Ca, and Mg were 0.42, 0.17, and 0.07%, respectively, exceeding critical values for slash pine (Jokela, 2004), and no micronutrient deficiencies were observed (Minogue et al, 2020).…”

“…Rising concentrations of NO 3 in ground waters and surface waters around the world is often attributed to NO 3 leaching from agricultural production systems (Di & Cameron, 2002). Questions about forest fertilization effects on water quality were raised decades ago (Allen, 1987;Jokela, 2004), and are still important because forests occupy almost 60% of the total land area in the southeastern United States (Wear, 2002); 80% of freshwater resources in the United States originate in the forests (West, 2002). Forests can protect water quality or be a nonpoint pollution source, depending on the local stand-scale management combined with broader environmental drivers, including climate and soil.…”

“…Intensive management can significantly increase productivity of the southern pine plantations, which are among the most intensively managed forests in the world (Fox, Jokela, et al, 2007;Jokela & Long, 2018). Fertilization, one of the most cost-effective silvicultural treatments, can accelerate stand growth and improve financial returns Jokela, 2004). Forest managers base fertilization decisions on pine species grown, site and stand characteristics, target product goals, fertilizer costs, and stumpage values for anticipated products (Dickens et al, 2003).…”

“…Harvesting pinestraw in slash pine plantations may result in large nutrient removals (Morris et al, 1992;Osiecka et al, 2020), which can potentially affect stand productivity. To enhance pinestraw production and maintain stand vigor, fertilization is usually recommended every 5 yr on most soils (Dickens et al, 2003;Morris et al, 1992;Wallace & Ward, 2011), except excessively drained sandhill sites, group G in Cooperative Research in Forest Fertilization (CRIFF) classification (Jokela, 2004;Jokela & Long, 2018). A survey of North Florida slash pinestraw producers found that half of the responders were fertilizing their stands, almost all on sandy soils, often without any diagnostic tests or consultation with fertilization experts (Chevasco & Minogue, 2012).…”