Growth and survival of woody wetland vascular plants

Growth and survival of woody wetland vascular plants: a large scale mesocosm study HERMAN W. HUDSON III AND JIM E. PERRY VIRGINIA INSTITUTE OF MARINE SCIENCE ‘ Methods d Introduction • Successful forested wetland compensation in Virginia requires; f • 495 – 990 woody stems/ha (200 – 400 stems/acre)1 • Natural tree colonization 2 and/or planted trees • Wetland compensation sites are not meeting structural goals 3 -7 • Poor survival of planted woody vegetation 8 -15 • Improper species selection • Improper planting type selection • Poor nursery stock • Unfavorable site conditions • Improper planting techniques The purpose of this study is to determine the appropriate species and planting type combinations for use in wetland compensation sites and other afforestation or reforestation projects Ide al Sa tu ra te d Flo od e Seven Species • Betula nigra (River Birch) • Liquidambar styraciflua (Sweetgum) • Platanus occidentalis (Sycamore) • Quercus bicolor (Swamp white oak) • Quercus palustris (Pin oak) • Quercus phellos (Willow oak) • Salix nigra (Black willow) Three Planting Types • Bare root • Tubeling • 1 – Gallon Container Figure 1. Hydrologically distinct mesocosm cells Three Hydrologically Distinct Cells (Figure 1) • Increasing levels of water stress • Total = 2772 Trees (Planted Spring 2009) Survival • Measured April, August, October (2009 -2010) • Failure time analysis (PROC LIFETEST - SAS 9. 2) Saturated and Ideal Cell (2010) Growth • Basal diameter (mm) Height (cm) • Canopy Diameter (cm) (Three measurements) • Calculated absolute growth rate (ABG - cm/month) and relative growth rate (RGR – cm cm-1 month-1) • Combined RGRs using Principal component analysis (PCA) • Analyzed differences using ANOVA and Post Tests Saturated and Ideal Cell (2011) Growth Survival Overall • Saturated (79. 7%) - Ideal (71. 4%) - Flooded (65. 2%) (Figure 2) • Q. bicolor (78. 7%) (Figure 3) • Gallon (91. 9%) - Bare root (65. 1%) - Tubeling (59. 4%) (Figure 4) • Significant difference in the survival curves among cells (Figure 2, p<0. 001), species (Figure 3, p=0. 001), and planting types (Figure 4, p<0. 001) Overall • Significant difference in the growth rates (all three measurements) among cells (Figure 5, p<0. 001), species (Figure 6, p<0. 001), and planting types (Figure 7, p<0. 001) • Ideal > Saturated > Flooded • Gallon > Bare root > Tubeling • B. nigra had greatest RGR overall cells Within Cells • Significant difference in the survival curves among species (p<0. 001) and planting types (p<0. 001) within all cells • Ideal – Q. bicolor (82. 2%) – Gallon (96. 3%) • Saturated – Q. bicolor (91. 9%) – Gallon (98. 0%) • Flooded – S. nigra (90. 2%) – Gallon (81. 7%) Within Cells • Ideal and Saturated – B. nigra and P. occidentalis – Gallon • Flooded – S. nigra – Gallon • Tubeling = Bare root (Except Saturated) 2. 53 cm/month = 1 ft/year Tubeling Ideal Bare root Flooded Saturated Gallon (Months) Figure 2. Cell survival curves (Months) Figure 3. Species survival curves (Months) Figure 4. Planting type survival curves Figure 5. Height AGR for each cell. Error bars represent 95% CI. Figure 6. Height AGR for each species. Error bars represent 95% CI. Figure 7. Height AGR for each planting type. Error bars represent 95% CI. Discussion Survival • Transplant shock is an important process for planted trees • Soil saturation reduces transplant shock and increases tree survival • Gallon planting types have increased root mass allowing for increased uptake of water • Species have unique survival curves Growth • Growth rates are dependent upon size (exponential growth rates) • Growth rates change over time (sigmoid growth curve) • Growth rates differ for species, planting types, and environmental conditions Conclusion Forested wetland compensation efforts involving tree planting should focus on creating favorable hydrologic conditions for survival of early successional fast growing species using one gallon nursery stock when feasible. Future tree growth requirements need to take into account realistic growth rates based on water stress, species differences, initial planting size and changes over time. 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12. 13. 14. 15. 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Error bars represent 95% CI. Acknowledgements Peterson Family Foundation, Wetland Studies and Solutions, Inc. , Virginia Department of Forestry, New Kent Forestry Center, Sean Charles, Lori Sutter, Chris Hauser, Master Naturalists, CNU Center for Wetland Conservation, WM and VIMS Students, Friends and Family