forest management Balancing Revenue and Nutrient Removals in Pinus elliottii Engelm. Stands Managed for Pinestraw and Wood Production Carlos A. Gonzalez-Benecke, Andres I. Susaeta, Timothy A. Martin, Eric J. Jokela, and Douglas R. Carter The forest floor is an important component for long-term forest productivity and sustainability because it plays a central role in carbon and nutrient cycling. Raking the recently senesced pine foliage off the forest floor (pinestraw raking) has become a profitable economic activity in the southeastern United States, despite its potential negative effects on long-term soil fertility. We analyzed the impact of different pinestraw raking scenarios on the profitability and carbon (C) and nitrogen (N) balance of slash pine (Pinus elliotti Engelm. var. elliottii) forests. To analyze the tradeoffs between economic returns and nutrient removals, we defined an index of ecological and economic efficiency: economic nutrient removal efficiency (ENRE), calculated as the amount of economic return (as defined by land expectation value) per unit of nutrient removed. Nutrient removals and economic returns were lower for forest stands that were managed less intensively for pinestraw raking (i.e., raking from age 8 until age 15) compared with stands managed intensively for pinestraw raking (i.e., raking from age 8 until rotation age). However, the former option was more efficient in terms of minimizing C and N removals per unit of economic return generated. Management practices that lead to increased site productivity can accelerate stand development and shorten the time to begin raking, increasing the ENRE of pinestraw raking. Stands managed exclusively for pinestraw production (with higher planting density and shorter rotations and wood harvest being a secondary objective) showed 5– 6 times lower ENRE than stands managed for traditional forestry, indicating much higher C and N removals for similar economic returns. Keywords: slash pine, forest floor, pinestraw raking, sustainability, economic nutrient removal F orest sustainability can be defined as the maintenance of the ecological integrity of forests, allowing them to provide envi- ronmental, social, and economic goods and services to meet the needs of people in perpetuity (Rempel et al. 2004). In slash pine (Pinus elliotti Engelm. var. elliottii) forests, without considering the mineral soil, the forest floor contains between 10 and 30% of total ecosystem carbon (C) (Gholz and Fisher 1982, Harding and Jokela 1994, Gonzalez-Benecke et al. 2010). Needlefall (NF) accounts for more than 75% of the total forest floor (Gonzalez-Benecke et al. 2010). The forest floor is an important component for maintaining long-term forest productivity and sustainability because it contrib- utes to C and nutrient cycling (Pritchett and Fisher 1987, Aaltonen et al. 2011), provides habitat for diverse plant and animal species (Knapp et al. 2005), regulates the effects of climate on soil temper- atures and moisture flow (Van Lear and Goebel 1976), and controls erosion (Gosz et al. 1976). The Oi soil horizon is typically defined as the upper layer of the forest floor composed of recently senesced, relatively nondecom- posed pine foliage. This “pinestraw” can be harvested and used for landscaping mulch in urban areas. Pinestraw mulch, typically from longleaf pine (Pinus palustris Mill.) and slash pine plantations, has become a lucrative initiative in the southeastern United States, gen- erating around $60 – 80 million annually to the economies of the states of Florida and Georgia (Casanova 2007). Factors such as increased population growth and improved economic conditions, particularly strong housing markets, favor the demand for pinestraw (Wolfe et al. 2005). Pinestraw raking may generate economic rents between $173 and 247 ha -1 year -1 for forest landowners (Minogue et al. 2007), although the current decline in the US demand for housing has led to lower demand and thus decreased prices for pinestraw. Pinestraw raking may also provide positive environmen- tal externalities such as reduction in fuel loads and lowering the risk Manuscript received November 16, 2012; accepted March 21, 2013; published online July 4, 2013. Affiliations: Carlos A. Gonzalez-Benecke (cgonzabe@ufl.edu), School of Forest Resources and Conservation, University of Florida, Gainesville, FL. Andres I. Susaeta (asusaeta@ufl.edu), School of Forest Resources and Conservation, University of Florida. Timothy A. Martin (tamartin@ufl.edu), University of Florida. Eric J. Jokela (ejokela@ufl.edu), University of Florida. Douglas R. Carter (drcart@ufl.edu), University of Florida. Acknowledgments: This research was supported by the University of Florida Carbon Resources Science Center, the Forest Biology Research Cooperative, and the National Institute of Food and Agriculture Coordinated Agricultural Projects (Grant 2011-68002-30185). FUNDAMENTAL RESEARCH For. Sci. 60(1):109 –118 http://dx.doi.org/10.5849/forsci.12-144 Copyright © 2014 Society of American Foresters Forest Science • February 2014 109 Downloaded from https://academic.oup.com/forestscience/article-abstract/60/1/109/4583733 by guest on 30 May 2020