Mechanisms of nutrient limitation and nutrient acquisition in managed and unmanaged forest

212 Pages·2017·3.37 MB·English

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Doctoral Dissertations Student Scholarship
Spring 2013
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Matthew A. Vadeboncoeur
University of New Hampshire - Main Campus, [email protected]
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MECHANISMS OF NUTRIENT LIMITATION
AND NUTRIENT ACQUISITION
IN MANAGED AND UNMANAGED FOREST ECOSYSTEMS

BY

MATTHEW A. VADEBONCOEUR
Sc.B., Brown University, 2003

DISSERTATION

Submitted to the University of New Hampshire
in Partial Fulfillment of
the Requirements for the Degree of

Doctor of Philosophy
in
Earth and Environmental Sciences

May, 2013
____
This dissertation has been examined and approved.
Disserta ion Di ector, Dr. Erik A. Hobbie
Research Associate Professor ofEarth, Oceans, and Space
T4c&W
tr. Julia G. Bryce
Associate Professor ofEarth Sciences
s
\J \—.
Dr. Scott V. Ollinger
Professor ofEnvironmental Sciences and Forestry
and Earth, Oceans, and Space
/ Dr. $at’lJ. Ducey
Professor ofForestry
Dr. John D. Aber
Professor ofEnvironmental Sciences
Affiliate Professor ofEarth, Oceans, and Space
C13
Date
ACKNOWLEDGEMENTS

I am exceedingly grateful for the practical and intellectual guidance of my
committee members: Erik Hobbie, Julie Bryce, Scott Ollinger, Mark Ducey, Adrien
Finzi, and John Aber. Erik Hobbie was both a source of experimental advice and
intellectual insight, as well as a dedicated academic mentor. Julie Bryce even dedicated
her own time to running Pb isotope analyses for Chapter 3. In addition to my committee
members, Ruth Yanai, Steve Hamburg, Joel Blum, Mariann Johnston, Christy Goodale,
and others generously shared their thoughts on how to improve parts of this work.
Much of the work presented here would not have been possible without the
thoughtful input and dedicated help of Andy Ouimette. I am also indebted to a large
number of current and former Hobbie, Bryce, and Ollinger lab members who provided
assistance in the field or laboratory. These include Corey Neskey, Rachel Mixon, M.
Florencia Meana-Prado, Zach McAvoy, Nico Gagnon, Mary Santos, Nat Crompton,
Spencer Tate, John Clark, and Kevin Leahy, in addition to the students of the 2011
Isotope Geochemistry course. The soil data I present in Chapter 2 were collected by
crews of field assistants under the supervision of Elizabeth Hane, Marty Acker, and
myself (acknowledged previously by Park et al., 2007; Schaller et al., 2010;
Vadeboncoeur et al., 2012a).
Other data included in the rotation analysis were generated by Farrah Fatemi,
Carrie Rose Levine, and Andrea Klaue. Datasets generated with monumental effort by
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research groups led by Tom Siccama and Gene Likens were also used with permission.
Lead isotope ratios used in Chapter 3 were analyzed at the Laboratoire de Géologie de
Lyon in collaboration with Janne Blichert-Toft. XRF analyses were conducted by Mike
Rhodes. Genetic identification of sporocarp samples was done by Jeremy Hayward.
A variety of funding sources supported my graduate work, including a Graduate
Fellowship (2007-8), a Summer Teaching Assistant Fellowship (2011), and a Dissertation
Year Fellowship (2012-13) from the Graduate School, and a Switzer Environmental
Fellowship (2011-12) from the Robert and Patricia Switzer Foundation. Research was
also supported by the NRESS Program and NSF grants DEB9810221, DEB0235650,
DEB0614266, EAR0746248, NSF0930231, NSF0949324, and DEB1210560.
Ecosystem research depends on having appropriate research sites. Among these,
the Bartlett and Hubbard Brook Experimental Forests provide critical infrastructure and a
diverse and engaging research community with which to work. These sites are operated
by the USDA Forest Service Northern Research Station. HBEF is a Long Term
Ecological Research network site funded by NSF; site support is also provided by the
Hubbard Brook Research Foundation. My work builds on decades of research at both of
these sites; this dissertation is a contribution to the Hubbard Brook Ecosystem Study. My
collaborators and I are grateful to the Parker Family for over 30 years of stewardship of
the Bald Mountain research sites established by Hamburg (1984a) and Rhoads (2005),
and studied here in Chapter 2. Field work for Chapter 4 was conducted with permission
of the landowners: the UNH Office of Woodlands and Natural Areas, the Town of
Strafford Conservation Commission, and the NH DRED Division of Forests and Lands.
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TABLE OF CONTENTS
Dedication .................................................................................................................. iii
Acknowledgements .......................................................................................................... iv
List of Tables ................................................................................................................... x
List of Figures .................................................................................................................. xi
Abstract ................................................................................................................. xii

Introduction ................................................................................................................... 1
Global change in temperate forest ecosystems ............................................................... 1
Assessing nutrient limitation .......................................................................................... 3
Modeling potential nutrient depletion by forest harvesting ............................................ 4
Developing tools to constrain mycorrhizal weathering rates .......................................... 6
Quantifying the contribution of organic nitrogen uptake by mycorrhizal roots ............. 8

CHAPTER 1 Meta-analysis of fertilization experiments indicates multiple limiting
elements in northeastern deciduous forests .......................................................... 11
Abstract ......................................................................................................................... 11
1.1 Introduction ............................................................................................................. 12
1.2 Methods .................................................................................................................. 15
1.2.1 Study region ................................................................................................ 15
1.2.2 Dataset criteria ............................................................................................ 16
1.2.3 Meta-analysis methods................................................................................ 17
1.3 Regression analysis ................................................................................................. 19
1.4 Other statistical tests ............................................................................................... 19
1.5 Results ..................................................................................................................... 20
1.5.1 Meta-analysis results ................................................................................... 20
1.5.2 Multiple regression results .......................................................................... 21
1.5.3 Results of other statistical tests ................................................................... 28
1.6 Discussion ............................................................................................................... 28
1.6.1 Growth responses to nitrogen fertilization .................................................. 28
1.6.2 Growth responses to phosphorus fertilization............................................. 30
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1.6.3 Growth responses to calcium fertilization .................................................. 32
1.6.4 Fertilization responses by species ............................................................... 33
1.6.5 Effect of stand or cohort age ....................................................................... 34
1.6.6 Influence of mensuration methods .............................................................. 35
1.6.7 Multiple resource limitation ........................................................................ 36
1.6.8 Potential biases............................................................................................ 37
1.7 Conclusions and recommendations ........................................................................ 38

CHAPTER 2 Long-term sustainability of forest harvesting in central New
Hampshire ................................................................................................................. 41
Abstract ......................................................................................................................... 41
2.1 Introduction ............................................................................................................. 42
2.1.1 Nutrient cycles and sustainable forestry ..................................................... 42
2.1.2 Research approach and objectives .............................................................. 46
2.2 Methods .................................................................................................................. 47
2.2.1 Study sites ................................................................................................... 47
2.2.2 Sample collection ........................................................................................ 49
2.2.3 Laboratory analysis ..................................................................................... 49
2.2.4 Scenario description .................................................................................... 50
2.2.5 Soil stock depletion calculations ................................................................. 55
2.3 Results ..................................................................................................................... 55
2.4 Discussion ............................................................................................................... 59
2.4.1 Validity of assumptions .............................................................................. 59
2.4.2 Weathering .................................................................................................. 62
2.4.3 Implications for management and policy .................................................... 64

CHAPTER 3 Developing biogeochemical tracers of apatite weathering by
ectomycorrhizal fungi ............................................................................................... 70
Abstract ......................................................................................................................... 70
3.1 Introduction ............................................................................................................. 71
3.1.1 Soil weathering in the context of forest ecosystem nutrient budgets.......... 71
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3.1.2 Mycorrhizal fungi as soil weathering agents in forest ecosystems ............. 74
3.1.3 Geochemical tracers of apatite weathering ................................................. 75
3.1.4 Study design ................................................................................................ 78
3.2 Methods .................................................................................................................. 79
3.2.1 Greenhouse experiment methods ................................................................ 79
3.2.2 Field experiment methods ........................................................................... 83
3.2.3 Sample processing ...................................................................................... 85
3.2.4 Analysis of major and trace element concentrations .................................. 87
3.2.5 Analysis of Pb isotope ratios....................................................................... 88
3.2.6 Analysis of C and N stable isotope ratios ................................................... 88
3.2.7 Statistics ...................................................................................................... 88
3.3 Results and discussion ............................................................................................ 90
3.3.1 The apatite signature ................................................................................... 90
3.3.2 Greenhouse experiment results ................................................................... 93
3.3.3 Results of field-collected sample analyses ............................................... 104
3.4 Conclusions ........................................................................................................... 109

CHAPTER 4 Organic nitrogen uptake by mycorrhizal roots in a temperate forest
demonstrated by a novel experimental approach ................................................ 110
Abstract ....................................................................................................................... 110
4.1 Introduction ........................................................................................................... 111
4.1.1 Ecosystem consequences of organic nitrogen uptake ............................... 113
4.1.2 Methodological approaches assessing organic nitrogen uptake ............... 114
4.1.3 A revised field method assessing uptake of organic nitrogen................... 117
4.2 Methods ................................................................................................................ 118
4.2.1 Site description.......................................................................................... 118
4.2.2 Field methods ............................................................................................ 120
4.2.3 Laboratory methods .................................................................................. 121
4.2.4 Site characterization data .......................................................................... 122
4.2.5 Organic nitrogen uptake calculations........................................................ 123
4.3 Results ................................................................................................................... 125
viii
4.3.1 Site characteristics .................................................................................... 125
4.3.2 Uptake of organic nitrogen ....................................................................... 126
4.4 Discussion ............................................................................................................. 131
4.4.1 Organic nitrogen uptake across sites......................................................... 131
4.4.2 Methodological considerations ................................................................. 132
4.4.3 Comparison to other organic N uptake studies ......................................... 135
4.5 Conclusions ........................................................................................................... 136

CHAPTER 5 Summary of principal findings and recommendations ................... 138

References ............................................................................................................... 142

Appendices ............................................................................................................... 174
Appendix 1.1 Table of experimental data sets included in the meta-analysis. .......... 175
Appendix 2.1 Weathering rate calculations for phosphorus. ..................................... 177
Appendix 3.1 Greenhouse experiment photographs. ................................................. 180
Appendix 3.2 Sources of acid leachable Pb in Conway granite. ............................... 184
Appendix 3.3 Concentration and isotope data for birch roots and granite leachates . 185
Appendix 3.4 Birch biomass and C and N concentrations and isotope ratios. .......... 187
Appendix 3.5 Summary statistics for birch biomass and C and N data. .................... 188
Appendix 3.6 Stable C and N isotope ratios in birch roots and whole seedlings. ..... 189
Appendix 3.7 Isotope ratios and trace element concentrations in sporocarps. .......... 190
Appendix 4.1 Map of study sites used in the organic N uptake study. ...................... 191
Appendix 4.2 Floristic characterization of study sites. .............................................. 192
Appendix 4.3 Equations used to calculate the uptake of labeled organic N. ............. 194
Appendix 4.4 Attempted assessment of total organic N uptake ................................ 195

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LIST OF TABLES

Table 1.1 Sample sizes and effect directions in the meta-analysis dataset. ..................... 22
Table 1.2 Number of observations and mean response ratios by species. ...................... 24
Table 1.3 Multiple regression model summary. .............................................................. 27
Table 2.1 Long-term soil weathering rates and watershed-scale denudation rates. ........ 45
Table 2.2 Description of the 15 study stands used in the rotation analysis. .................... 48
Table 2.3 Net nutrient stock changes per rotation. .......................................................... 56
Table 2.4 Soil nutrient stocks measured at each site (kg ha-1). ....................................... 56
Table 2.5 Number of whole-tree rotations required to exhaust apatite P and Ca. .......... 59
Table 2.6 Total biomass (dry metric tons) harvestable before nutrient exhaustion. ....... 63
Table 3.1 The number of replicates in greenhouse experiment. ..................................... 82
Table 3.2 Concentrations (µM) of nutrient ions in the hydroponic solution. ................. 82
Table 3.3 Description of the study stands where soils and sporocarps were collected. .. 84
Table 3.4 Acid-leachable and whole rock Ba, REE, and Pb concentrations. .................. 91
Table 3.5 Pb isotope ratios for acid-leachable and exchangeable leaches of granite. ..... 91
Table 3.6 Multiple regression models for sporocarp trace element and isotope data. .. 108
Table 4.1 Characterization of study sites and ingrowth core soil. ................................ 119
Table 4.2 Mass and C and N isotope ratios from harvested ingrowth roots. ................ 124

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