Litter Quality and Decompostion -- Effect of Elevated CO2 Description: The results of published and unpublished experiments investigating the impacts of elevated [CO2] on the chemistry (nitrogen and lignin concentration) of leaf litter are assembled in a format appropriate for statistical meta-analysis of the effect of [CO2]. The synthesis originated from a workshop, "Litter Quality and Decomposition under Elevated CO2" held in Capri, Italy, September 1998, under the auspices of Global Change and Terrestrial Ecosystems project (GCTE) and the European COST network. Data reference: Norby, R. J., M. F. Cotrufo, P. Ineson, E. G. O’Neill, and J. G. Canadell. 2001. GCTE synthesis of effect of elevated CO2 on litter quality and decomposition. Data package xxx. Oak Ridge National Laboratory, Oak Ridge, Tennessee, U.S.A. Also available on-line at http://www.daac.ornl.gov. Synthesis reference: Norby, R. J., M. F. Cotrufo, P. Ineson, E. G. O'Neill, and J. G. Canadell. 2001. Elevated CO2, litter quality, and decomposition: A synthesis. Oecologia 127: 153-165. http://www.esd.ornl.gov/facilities/ORNL-FACE/LitterSyn.pdf Methods: Data on litter chemistry and decomposition of plant tissue grown in elevated and ambient CO2 concentrations were gathered from participants of that workshop and from other published and pre-publication sources. The litter chemistry data base comprised observations of naturally senesced leaves of herbaceous and woody plants exposed to elevated CO2 (typically 600-700 ppm) in the field or in field chambers in the U.S., Europe, New Zealand, and Australia. Data from plants grown in growth chambers with artificial lighting were excluded because of the possible artifacts of unbalanced nutrition or abnormal senescence. Also excluded were data from non-sensecent green leaves. The measures of litter chemistry were N concentration (mg g-1) and lignin concentration (mg g-1), with the number of replications and standard deviations included when available. The decomposition data base was less restrictive and included a wide range of plant tissue from different types of CO2 enrichment regimes and different protocols for measuring decomposition. The measure of decomposition was percentage mass loss over time. Description of data files: The data are in two separate files -- one for leaf litter quality (nitrogen and lignin concentration) and the other for decompostion (mass loss rate) of plant tissue. Both are tab-deliminted ascii text files that are easily imported into a spreadsheet (e.g., Excel). The files are arranged so that they can provide input to statistical meta-analysis software. No data have been added since the publication of the 2001 synthesis paper. Missing data are coded as -999.99; missing values of categorical variables are entered as _NA_. Variable names are described below: LITTER_QUALITY Experiment identification SOURCE source of original data. Full citations are in associated reference list. SPECIES - the single species in the experiment or general description of the mixture of species. Categorical variables for meta-analysis VEGTYPE - whether the species or mixture is woody or herbaceous EXPTYPE - CO2 exposure system: OTC, open-top chamber; SD, Solardome; no-cham, chamberless system, either geologic CO2 spring, screen-aided CO2 control (SACC), or free-air CO2 enrichment (FACE) system. FIELD_POT - whether the plant was rooted directly in the ground or in a large pots or soil boxes. FERTILIZER - whether the plant was fertilized with inorganic nutrients. Response data N_CONC_CON - concentration of N (mg/g) in senesced leaves in ambient CO2 (control) N_OBS_CON - number of independent observations of N concentration in control N_STD_CON - standard deviation of N concentration in control N_CONC_TRT - concentration of N (mg/g) in senesced leaves in elevated CO2 (treatment), usually 600-700 N_OBS_TRT - number of independent observations of N concentration in treatment N_STD_TRT - standard deviation of N concentration in treatment LIG_CONC_CON - concentration of lignin (mg/g) in senesced leaves in ambient CO2 (control) LIG_OBS_CON - number of independent observations of lignin concentration in control LIG_STD_CON - standard deviation of lignin concentration in control LIG_CONC_TRT - concentration of lignin (mg/g) in senesced leaves in elevated CO2 (treatment), usually 600-700 LIG_OBS_TRT - number of independent observations of lignin concentration in treatment LIG_STD_TRT - standard deviation of lignin concentration in treatment DECOMPOSITION Experiment identification SOURCE source of original data. Full citations are in associated reference list. SPECIES - the single species in the experiment or general description of the mixture of species. Categorical variables for meta-analysis VEGTYPE - whether the species or mixture is woody or herbaceous EXPTYPE - CO2 exposure system: OTC, open-top chamber; SD, Solardome; geologic CO2 spring (CS), screen-aided CO2 control (SACC); free-air CO2 enrichment (FACE). INTERACT - treatnment interaction with CO2 treatment: N, none; F, fertilizer; W, water; T, temperature FIELD_POT - whether the plant was rooted directly in the ground or in a large pots or soil boxes. ORGAN - leaf, shoot, wood, root SENES - sensecence status of plant tissue: SD, standing dead; H, harvested green; S, naturally senseced; GROUND - how tissue was prepared for decomposition study: I, intact; cut, cut into pieces; g, ground DRIED - whether tissue was oven-dried or air-dried prior to decomposition experiment FIELD_LAB - whether decomposition experiment was carried out in the field or in the laboartory Response data ML refers to percentage of initial mass of plant tissuethat disappeared over the course of the dedcomposition trial; the tissue had been grown in ambient or elevated CO2. Decomposition trials were of different durations in different experiments, so only the response ratio (ambient vs. elevated) should be compared between studies. ML_PCT_CON - mass loss percentage of plant tissue grown in ambient CO2 (control) ML_OBS_CON - number of independent observations of mass loss in control ML_STD_CON - standard deviation of mass loss in control ML_PCT_TRT - mass loss percentage of plant tissue grown in elevated CO2 (treatment), usually 600-700 ppm ML_OBS_TRT - number of independent observations of mass loss in treatment ML_STD_TRT - standard deviation of mass loss in treatment _NA_ information not available (categorical variables) -999.99 - no data