Plant Litter: Decomposition, Humus Formation, Carbon Sequestration

by Björn Berg, Charles McClaugherty

Overview

This book gives basic facts about litter decomposition studies, which are of guidance for scientists who start studies. Since the publication of the third edition, there has been quite a development not only in the field of litter decomposition but also in supporting branches of science, which are important for fruitful work on and understanding of decomposition of plant litter and sequestration of carbon. A consequence is that ‘old established truths’ are becoming outdated.

New knowledge in the fields of phyhemistry and microbial ecology has given a new baseline for discussing the concepts ‘litter decomposition’ and ‘carbon sequestration’. We can also see a rich literature on litter decomposition studies using roots and wood as substrates. These have given new insights in factors that regulate the decomposition rate and as regards roots their contribution to sequestered carbon in humus. Additional facts on the role of temperature vs the litters’ chemical compositionmay in part change our view on effects of climate change.

Further information on applications of the new analytical technique (¹³C-NMR) for determining organic-chemical compounds has allowed us to develop these parts.

Focus is laid on needle litter of Scots pine as a model substrate as this species has been considerably more studied than other litter species. Also the boreal/northern temperate coniferous forest has in part been given this role. Still, new information may allow us to develop information about litter from further tree species.

Product Details

ISBN-13:	9783030596330
Publisher:	Springer International Publishing
Publication date:	12/03/2020
Edition description:	4th ed. 2020
Pages:	332
Product dimensions:	6.10(w) x 9.25(h) x (d)

Table of Contents

Introduction     1
Overview of Plant Litter Decomposition     1
A Short Retrospective     2
The Ecological Significance of Litter Decomposition and the Formation of Humus     3
Factors Influencing Decay and Humus Formation     4
Accumulation of Humus and Nutrients     5
The Contents and Organization of the Book     6
Motives for the Present Synthesis     9
New Developments Included in the Second Edition     10
Decomposition as a Process     11
Litter Decomposition - a Set of Different Processes     11
Definition of Litter Decomposition     15
Degradation of the Main Groups of Compounds in Litter     15
Degradation and Leaching of Soluble Organic Substances     15
Patterns of Degradation of the Main Organic Compounds in Litter     16
A Model for Decomposition from Newly Shed Litter to Humus-Near Stages     19
Degradation of Solubles and Non-Lignified Carbohydrates     21
Degradation of Lignin, Modified Lignin, and Lignified Holocellulose Tissue     23
Effect of N on Lignin Degradation     26
Effects of Litter Mn Concentration on Lignin Degradation and Litter Mass Loss     29
Humus-Near Stage in Litter Decomposition - Limit Values     30
Decomposer Organisms     35
Introduction     35
General Properties of a Given Microbial Population     36
The Degradation of the Main Polymers in Litter     38
Degradation of Cellulose     38
Degradation of Hemicelluloses     41
Degradation of Lignin     41
Degradation of Fibers     48
Bacteria     48
Soft-Rot     48
Brown-Rot     49
White-Rot     49
Mycorrhizae     50
Ecological Aspects     50
Initial Litter Chemical Composition     53
Introduction     53
Organic-Chemical Components of Plant Litter and Fiber Structure     54
Organic-Chemical Components     54
Fiber Structure     56
Nutrient Concentrations in Newly Shed Litter     58
General Features     58
Nutrient Resorption and Withdrawal Efficiency     60
Nutrient Concentration Change, Green vs. Brown Foliage     60
Nutrients in Needle Litter of Pine spp. - a Case Study     63
Several Deciduous and Coniferous Leaf Litters     70
Variation in N and Lignin Concentrations     77
Wood and Fine Root Litter      78
Anthropogenic Influences on Initial Litter Composition     78
N-fertilized Scots Pine and Norway Spruce Monocultures     79
Heavy Metal Pollution and Initial Litter Chemical Composition     82
Changes in Substrate Composition During Decomposition     85
Introductory Comments     85
Organic-Chemical Changes During Litter Decomposition     86
A Case Study on Scots Pine Needle Litter     86
Other Species     90
Relationships Between Holocellulose and Lignin     91
Nutrient and Heavy Metal Concentrations During Decay     93
Changes in Concentrations of Elements in Decomposing Litter     93
Ash Dynamics     96
Special Studies on K, N, Mn, and Lignin Dynamics     97
K Concentration Dynamics     97
Mn Concentration Dynamics     100
N Concentration Dynamics Along a Climatic Transect     101
Lignin Dynamics Along a Climatic Transect     108
Chemical Constituents as Rate-Regulating: Initial Variation and Changes During Decomposition     115
Introduction     115
A Three-phase Model Applied to Litters of Different Chemical Composition     116
Initial Decomposition Rates for Newly Shed Litter - Early Decomposition Stage in Plant Litter     119
Decomposition in the Late Stage - Lignin-Regulated Phase     127
Litter at a Humus-Near or Limit-Value Stage     142
Does Chemical Composition Influence Leaching of Compounds from Humus?     147
Climatic Environment     149
Introduction     149
Microbial Response to Temperature and Moisture     150
Early-Stage Decomposition of Scots Pine Needle Litter     150
Decomposition at one Site     150
Decomposition Along Transects     152
Soil-Warming Experiments     159
Local Topography     160
Effect of Substrate Quality on Mass-Loss Rates along Scots Pine Transects     161
Early Stage     161
Late Stage     162
Climate and Decomposition of Norway Spruce Needle Litter     167
Climate Versus First-Year Mass Loss     167
Late Stage     168
Climate and Decomposition of Root Litter     170
A Series of Limiting Factors     171
Climate, and the Decomposition of Humus and Litter in Humus-Near Stages     172
Influence of Soil and Plant Community Factors     175
Introduction     175
Soil Factors     176
Soil Texture      176
Site's Natural Nutrient Availability     181
Artificially Added Nitrogen     183
Forest Floor Type     186
Plant Community Composition and Structure     189
Effect of Litter Species Composition     190
Community Structure and Development     190
Carbon Dioxide Levels     191
Decomposition of Fine Root and Woody Litter     193
Introduction     193
Woody Litter Decomposition     194
Methods     194
Decomposition Rates Versus Climate     198
Carbon Dioxide Release     200
Organic-Chemical Changes     200
Changes in Nutrient Concentrations     202
Fine Root Decomposition     204
Fine Root Litter     204
Mass-Loss Rates     205
Changes in Chemical Composition     207
Models that Describe Litter Decomposition     211
Introduction     211
Two Main Kinds of Empirical Models     213
Models Used to Describe Decomposition of Whole Litter as a Single or "Unified" Substrate     214
Single Exponential     214
Asymptotic Model     214
Dominant Factors that Influence the Unified-substrate Models      215
Extent and Quality of the Dataset     216
Substrate Quality     216
Models Based on Two or Three Substrate-quality Fractions     222
The Double Exponential     222
The Triple Exponential     223
Decomposition and Ecosystem Function     225
Introductory Comments     225
Humus is Accumulating in Undisturbed Forest Ecosystems     226
Accumulation of Humus in Single and Paired Stands     226
How Far can Humus Accumulate?     228
A Mechanism For Humus Accumulation Under Undisturbed Conditions     230
An Accumulation Mechanism can be Validated     237
How Stable is Humus?     244
Do Limit Values Indicate a Complete Stop in Litter Decomposition?     244
Four Classes of Humus Turnover     244
Possible Effects of Increased Temperature on Humus Decomposition - an Artifact?     249
Can Different Tree Species Form and Accumulate Humus at Different Rates?     250
Storage of Nutrients in Humus     253
What Amounts of Nutrients can be Stored in Accumulating Humus?     253
Human Activities that Influence Decomposition     259
Introduction     259
Global Warming     260
Regional Pollution     261
Atmospheric N and S Deposition     261
Heavy Metals     263
Nuclear Radiation, Ozone, and Proximity to Urban Centers     264
Effects of Selected Forest Management Practices     265
Long-term Perspective     266
Estimating Carbon Sequestration Rates on a Regional Scale     269
Introductory Comments     269
Long-Term Accumulation of Carbon in Organic Layers (O-Horizon)-General Comments     271
Direct Observations of Long-Term Humus Accumulation and Accumulation Rates     271
Factors that may Influence Carbon Sequestration Rates Over Larger Forested Areas     273
General Factors Both at Undisturbed Sites, and at Sites with Anthropogenic Influence     273
Spatially Explicit Database for Regional Modeling     275
Three Case Studies: an Overview     276
Case Study 1 - Limit-Value Approach     276
Geographical Database     276
Expanding Data to a Regional Scale     278
Calculation of the Buildup of Humus and Carbon     279
Potential Carbon Sequestration Rates     279
The Effect of Tree Species on Carbon Sequestration Rates     280
Sources of Error in the Limit-Value Approach     281
Case Study 2 - N-Balance Method     283
Background and Comments     283
Carbon Sequestration on a Regional Level     286
Assumptions and Uncertainties     287
Comparisons with Other Studies     288
Case Study 3 - Direct Measurements of Humus Depth     289
Introductory Comments     289
General Design of the Humus Inventory     289
Scaling up from Field Measurements on Humus Depth in Plots, to C Sequestered on a Country Level     290
Changes in Organic-Layer Thickness Over Time     290
Calculations of Bulk Density of Carbon in the Humus Layer     295
Calculated Carbon Sequestration Rates, and Some Patterns     295
Possible Sources of Error in Estimates of C Sequestration Rates     297
Carbon Sequestration Rates in the Three Case Studies, Compared to Quantitative Measurements in Single Stands and Chronosequences, as well as among these     297
References     299
Appendix I     319
Glossary     319
Appendix II     323
Scientific Names of Vascular Plants     323
Appendix III     327
Site descriptions     327
Appendix IV     329
A Data Base for Litter Chemical Composition, and Limit Values for Decomposition - DELILA      329
Index     331

Editorial Reviews

A major component of ecosystems and plays a major role in determining their structure and function by virtue of being the source of energy for a large diversity of heterotrophic organisms. … provides a comprehensive account of the subject based on the extensive studies in boreal forest ecosystems. … The fundamentals are applicable to a great extent also to the process in other climatic regions where the researchers would surely find the book useful in many ways.” (Brij Gopal, International Journal of Ecology and Environmental Sciences, Vol. 41 (3-4), 2015)

“The book … presents a clear, thorough introduction to plant litter decomposition processes, providing detailed coverage of specific topics and ending with a summary chapter on regional carbon sequestration rates. It contains numerous diagrams, tables, and figures, a valuable glossary, 24 pages of references, and appendixes specific to field experiments and analytical methods that will be useful to researchers for many years to come. Summing Up: Highly recommended. Upper-division undergraduates and above.” (D. L. Richter, Choice, Vol. 51 (11), July, 2014)

"The authors of the volume ‘Plant Litter’ present an up-to-date and interesting contribution … . The book is well arranged, relatively easy to read, contains fantastic graphics … . this fundamental and rather detailed book is an absolutely necessary resource about transformation and decomposition of plant litter ... . In summary, we strongly recommend this book for all scientists concerned with … plant litter … . The authors can be congratulated for their impressive efforts in publishing this highly professional volume." (Oliver Bens, Reinhard F. Hüttl, Journal of Plant Physiology, Vol. 161, 2004)

"The work of Berg and Mc Claugherty resumes the state of the art concerning litter decomposition mainly in boreal forests but also in a few temperate situations. … this book is a remarkable synthesis of the current knowledge about the decomposition of plant residues in forest ecosystems. … This book is well structured and gives a comprehensive overview about the process of litter decompositions and itis a well written synthesis of the enormous work done by B.Berg during the last two decades." (Bernd Zeller, Annals of Forest Science, Issue 2, 2004)

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