Effects of Mechanical Site Preparation, Planting Stock, and Planting Aids on the Survival and Growth of American Sycamore in a Marginal Old Field Riparian Restoration

Jason K Steele,John R Seiler,Wallace Michael Aust

doi:10.3390/f12101295

Abstract

Survival and growth of planted tree species are common indices used to evaluate success of wetland restoration efforts used to compensate for wetland losses. Restoration efforts on marginal agricultural lands have typically resulted in less than satisfactory survival and growth of desired tree species. In an attempt to determine the effects of bottomland hardwood silvicultural methods on the survival and growth of pioneer tree species, this study evaluated combinations of five mechanical site-preparation techniques (mound, bed, rip, disk, pit), four levels of planting stock (gallon, tubeling, bare root, and direct seed), and three planting aids (mat, tube, none) on the four-year survival and growth of American sycamore planted in an old field riparian area in the Piedmont of Virginia. After four growing seasons, results indicated that mounding mechanical site preparation combined with gallon (3.8 L) planting stock provided the most positive influences on mean survival (100%), height (4.72 m), and groundline diameter (9.52 cm), and resulted in the greatest aboveground dry biomass accumulation (5.44 Mg/ha/year). These treatments may be economically viable for restoration and mitigations efforts, and could offer other economic alternatives such as short-rotation woody crops, which might make restoration efforts in marginal old field areas more attractive to private landowners.

Highlights

Wetlands are a valued resource for water quality, wildlife use, and food/fiber production, yet an estimated 50% of wetlands in the United States have been converted to nonwetlands [1]
The observed survival and biomass results of this study indicated that the appropriate species selection, application of site-preparation techniques, and use of appropriate planting stock type can increase survival and growth within old field and marginal agricultural sites in the Piedmont of Virginia
The survival rates observed in this study for both site preparation and planting stock were much higher than in previous studies of sycamore survival in compensatory mitigation sites, which ranged from 59% to 45% after 4 years [4,33]

Summary

Introduction

Wetlands are a valued resource for water quality, wildlife use, and food/fiber production, yet an estimated 50% of wetlands in the United States have been converted to nonwetlands [1]. The actual implementation of compensatory wetland and mitigation site design are oftentimes not successful in replacing the functions and values of the permanently impacted wetland. Establishing pioneer tree species on mitigation sites may accelerate the restoration of these wetland functions and values, and increase compliance with wetland mitigation regulations. Commercial forestry operations have been successful in harvesting and planting in wetland areas, such as wet mineral flats and bottomland hardwood areas of the southeastern United States [5]. These techniques are not widely used by wetland design and construction groups within the current compensatory mitigation market [6,7]

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