Data Set Citation:
When using this data, please cite the data package:
NCEAS 6840: Harmon: Decomposition Synthesis , Harmon M , and National Center for Ecological Analysis and Synthesis.
Mass loss datafile and Nitrogen concentration data
bowdish.154.6 (
General Information:
Title:Mass loss datafile and Nitrogen concentration data
The primary objective of this study is to examine the control that substrate quality and climate have on patterns of long-term decomposition and nitrogen accumulation in above- and below-ground fine litter. Of particular interest will be to examine the degree these two factors control the formation of stable organic matter and nitrogen after extensive decay. These data sets are part of : (LIDET) Harmon, M. 2005. LTER Intersite Fine Litter Decomposition Experiment (LIDET): Long-Term Ecological Research.Corvallis, OR: Forest Science Data Bank: TD023. [Database]. (19 April 2006)
  • Nitrogen
  • Organic Matter
  • Soil Bulk Density
  • Carbon
  • Decay rates
  • Decomposition
  • Fine roots
  • Leaf litter
  • Litterfall
  • Phosphorous
  • Roots
  • Wood

Involved Parties

Data Set Creators:
Organization:NCEAS 6840: Harmon: Decomposition Synthesis
Individual: Mark E. Harmon
Organization:Oregon State University
Email Address:
Organization:National Center for Ecological Analysis and Synthesis
Data Set Contacts:
Individual: Mark E. Harmon
Organization:Oregon State University
Email Address:

Data Set Characteristics

Geographic Region:
Geographic Description:Andrews 44o14'N 122o11'W, Arctic Lakes 68o38'N 149o34'W, Barro Colorado 9o10'N 79o51'W, Bonanza Creek 64o45'N 148o00'W, Blodgett 38o52'N 105o38'W, Cedar Creek 45o24'N 93o12'W, Central Plains 40o49'N 104o46'W, Coweeta 35o00'N 83o30'W, Curley Valley Florida 29o30'N 82o15'W, Guanica 17o57'N 65o52'W, Hubbard Brook 43o56'N 71o45'W, Harvard Forest 42o40'N 72o15'W, Jornada 32o30'N 106o45'W, Juneau 58o00'N 134o00'W, Kellogg 42o24'N 85o24'W, Konza 39o05'N 96o35'W, LaSelva 10o00'N 83o00'W, Loch Vale 40o17'N 105o39'W, Luquillo 19o00'N 66o00'W, Monte Verde 10o18'N 84o48'W, Niwot Ridge 40o03'N 105o37'W, North Inlet 33o30'N 79o13'W, Northern Lakes 46o00'N 89o40'W, Olympics 47o50'N 123o53'W, Santa Margarita 33o30'N 106o40'W, Sevilleta 34o29'N 106o40'W, Virginia Coast 37o30'N 75o40'W
Bounding Coordinates:
West:  -146.375  degrees
East:  -63.75  degrees
North:  58.625  degrees
South:  9.625  degrees
Time Period:

Sampling, Processing and Quality Control Methods

Step by Step Procedures
Step 1:  


The major factors to be considered in this experiment will be site, species of and type of litter (leaves, vs. roots vs dowels) , and time. Twenty-one sites, representing a wide array of moisture and temperature conditions, will be used for litter incubations. Ten types of "standard" litters will be sent to each site. These include three types of fine roots (graminoid, hardwood, and conifer), six types of leaf litter (which range in lignin/nitrogen ratio from 5 to 75), and wooden dowels. Samples will be collected ten times; the time between samples will be one year for all sites except LaSelva and Luquillo which will collect samples every three months. There will be four replicates for each species, site and time.

In addition to the standard litters, each site will be represented by a "wildcard" litter which appears at one site for each sample collection. The purpose of the wildcard species is to verify the predictions from the standard species. There will be four replicates for each wildcard species, site and time.

Step 2:  

Litter Collection

Each site was responsible for collecting the litter used in the experiments. For most sites, the leaf litter was collected directly from senesecent plants or as freshly fallen litter. Green leaves were collected from the Jornada, San Diego, Luquillo, and LaSelva sites. All leaf litter except, Drypetes glauca which was oven dried at 40 C to prevent decay, was air dried prior to shipment to Oregon State University.

Fine roots (less than2 mm diameter) were collected by two methods: tropical hardwood (Drypetes glauca) and pine (Pinus elliotii) fine roots were collected by excavating surface roots and washing. Graminoid roots were collected from material exposed along stream banks. Graminoid and pine roots were air dried, whereas the tropical hardwood roots were oven dried at 40 C to prevent decomposition.

In the case of the LaSelva site, the litter was sterilized after the bags were filled to kill all invertebrates, fungi, and virus prior to shipment. Sterilization was conducted at the Battelle National Laboratory by exposing the litter to 20 hours of gamma rays with 60Co as the source. The total exposure was 2 Mrad.

Step 3:  

Bag Design

All bags were 20- by 20-cm and filled with 10 g leaves and 5-7 g of fine roots. Each bag was identified with a unique number embossed on an aluminum tag. The bag openings were sealed with six monel staples. The initial air dry weight, calculated oven dry weight, species, site, replicate number for each litterbag were recorded prior to placement in the field. Subsamples of litter material were taken to determine the air dry to oven dry conversion factor and the initial chemistry of the litter. Moisture content of the air dried litter ranged from 2-10% moisture content.

Three types of bags were used in this experiment. For the long-term leaf litter experiment the bags had a top mesh of 1 mm and a bottom of 55 micron mesh. The bags used for fine roots were entirely of 55 micron mesh. The bags used in the mesh size effects study had a top of 7 mm mesh and a bottom of 55 micron mesh.

Step 4:  


The wooden dowels used in the experiment are made of ramin (Gonystlylus bancannus). This species is a tropical hardwood from southeast Asia. It is not resistant to decay and rated as perishable. The dowels are 13 mm in diameter and 61 cm in length. One half of the dowel is to be embedded vertically into the soil and the other half is to be exposed to aerial conditions. The air dry weight of each dowel was recorded, and a subsample of dowels was measured for diameter, density, air dry moisture content, nitrogen content, and carbon chemistry.

Sampling Area And Frequency:
Sample Placement Samples were placed in the field during fall of 1990 by each of the participating sites. Locations were near climatic stations and in areas protected from disturbances that could destroy the litter bags. The locations were also selected to be typical of areas that other intersite decomposition experiments might be conducted. The exact method for placement varied from site to site, but the following standards were applied: 1) Four separate locations were selected to avoid pseudo- replication problems. 2) Each set of bags to be collected was connected by a cord; these sets of bags should be laid out in parallel lines in a random order. 3) Leaf litterbags should be placed so that contact with the underlying litter layer is made. Fine root litterbags will be inserted into the upper mineral soil (humus layer for histosols). A vertical cut with a shovel, the bag inserted the correct depth (0-20 cm), and another cut should be used to press the soil against the bag (Figure 3). 4. Dowels should be installed at the end of the string opposite the fine root bags. The dowels were placed so that 30 cm is exposed to the air and 30 cm is embedded in the soil.
Sampling Description:
Sample Processing Once the litter or dowels are collected they should be oven dried in a paper bags at 55oC until the mass is stable. In the case of fine roots and dowels, a rinse with distilled water to remove adhering soil prior to drying is recommended. Any mosses, lichens, fine roots, or other plant parts that have grown into the bags or dowels should also be removed prior to harvesting. Samples will be pooled by species, site, and time for grinding and archiving. A subset of unpooled samples will also be saved to determine the internal variability of pooled samples. Chemical analyses will be performed using two methods. Each pooled sample from each species, site, and time will be analyzed for total nitrogen, lignin, and cellulose using near infrared reflectance spectoscopy (Wessman et al. 1988). Internal variability of samples will be estimated by running replicates of high and low lignin species. Twenty five percent of the pooled samples will also be sampled for Kjeldahl nitrogen, lignin, cellulose, water extractive, non- polar extractive, and ash content using wet chemical methods. Wet chemical methods will then be used to calibrate the near infrared reflectance spectoscopy methods.

Data Set Usage Rights

Access Control:
Auth System:knb
Metadata download: Ecological Metadata Language (EML) File