Sample Collection Methods For each individual location collection, three replicate bags are placed in zip-lock bags and are identified by species, field location, collector initials, and date of collection. A general maintenance survey of each location is done at this time by the collector(s). At the time of placement, three bags of each species were collected and placed into a gallon-sized zip-loc bag for transport to the lab. This method insured that each replicate was handled the same way with bouncing during transport and sample handling consistent for all samples. These three samples taken at the time of placement determine the starting (incubation in the field time 0) replicate litters. For each collection date, 28 gallon-size zip-lock bags were be needed. Sample Analysis Methods Overview: Handling of the field samples involves three phases: (1) initial cleaning and oven-dry weight; (2) grinding and ash correction; and (3) chemical analyses. Once in the laboratory, field samples will come in with 3 replications/plant type in a bag labelled with the site, plant material, and collection date. In Phase 1, the samples are cleaned, oven dried at 60° C for a minimum of 24 hours, and oven-dry weight recorded. The samples are then transferred to coin envelopes, ground on the Tecator grinder, and stored back in the coin envelope. In Phase 2, ground plant material is then used for ash-free weight determinations. In Phase 3, the remaining ground plant litter is used for chemical analyses. Phase 1. WEIGHING Overview Specifics The following equipment is needed for weighing out the samples: Balance Large and small weigh boats Oven: 60° C Cafeteria tray Permanent marker Staple remover Scissors Decomp Record Book Desiccators Make sure to reserve all equipment as needed ahead of time. 1. Select a zip-loc bag with field samples to begin weighing out. Select one mesh bag, you have now arbitrarily assigned this sample a replicate number and Sample ID number. Label a weigh boat (large for the grasses and cottonwood, small for salt bush, creosote, pinyon, yucca, and juniper) with the site number, plant type and Sample ID number. Tare the balance and weigh the empty weigh boat, recording the weight in the record book. Carefully remove any foreign material from the outside of the bag, such as: differen plant material, mud, ROCKS, etc, making sure to lift up the side folds to release any trapped rocks. MAKE SURE YOU REMOVE ALL ROCKS, OR ELSE YOU MAY DESTROY THE GRINDER ROTOR LATER ON (not to mention throwing off the weight). Carefully remove the staples from the top fold ONLY. MAKE SURE that should any staples break you retrieve ALL parts of it, so that your weight is accurate, and so that you don't attempt to grind it later on (ouch!). Place the weighed and labelled weigh boat on a sheet of paper in front of you, and empty the contents of the bag into the weigh boat. NOTE: for cottonwoods and the grasses, first reach the scissors into the mesh bag and cut up the material into SMALL pieces, keeping in mind that the smaller they are now, the easier it will be to stuff into the coin envelopes and the faster it will be to grind. For yucca, remove the numbered tag, and record that number in the record book to the left of the replication number, and cut it up into small pieces. Repeat this for all samples, weighing out a mix of big and small weigh boats (they fit better in the oven that way), and place in the oven. BE CAREFUL not to weigh out more samples than you have oven space! Make several trips to the oven instead of one big load to gauge oven capacity. 2. Dry for a minimum of 24 hours at 60° C, although longer times will not hurt the sample, it has not been found to be beneficial. Remove the weigh boats filled with dried samples, and place in a desiccator to cool for about 20 minutes. Reweigh the filled weigh boat, record the weight in the record book. Working over a piece of paper, stuff the plant material into a coin envelope labelled with the collection date, site number, plant type, and Sample ID number. GRINDING NOTE: MAKE SURE YOU READ THE FULL SET OF INSTRUCTIONS FOUND IN THE DRAWER UNDER THE Tecator GRINDER. Overview Plant material is ground in order to perform ash-free weight corrections and chemical analyses. The only plant material needed to be ground using liquid N are: pinyon, juniper and creosote. All others are ground warm. SUGGESTED ITEMS USEFUL FOR GRINDING Mortar & pestle Small kimwipes Flat-edged spatula Paint brush Q-tips Ethanol Toothbrush Small beaker (Et2OH) Liquid N Brown gloves Plastic beaker on a string for liquid N EVERY DAY BEFORE GRINDING Before grinding, take apart the machine to make sure it is clean: 1.Remove the rotor, using the wrench and the L shaped piece of metal. Scrape out any residue on the underside of the rotor and clean it with an ethanol-soaked Q-tip. 2.Clean the flat piece under the rotor (with concentric circles) with a wet Q-tip. Lift out this piece and make sure any dust is cleaned out of the area. 3.Replace the rotor, finger tightening the nut. Then only SLIGHTLY tighten it back with the wrench. IF you don't tighten it with the wrench, the grinder will make an awful noise when you turn it on. 4.Reassemble the grinder, inspecting the rotor blades, sample pan, screen (arrow up), lid and funnel for residue. Clean as necessary. Replace the black screw knobs and you're ready to go. TURNING ON THE GRINDER SO AS NOT TO BLOW A FUSE ALWAYS start the machine in this order: 1.Plug into the wall circuit 2.Have the speed button on I (15000 rpm) 3.Turn on the ON switch. 4.Turn on the timer to 5 or so. 5.Wait for the orange light to come on before adding the sample. 6.Add the sample SLOWLY or you will overload the motor and blow a fuse. Phase 2. ASH-FREE WEIGHT CORRECTION METHOD Methods 1989 through 1991: 1. ASH THE EMPTY CRUCIBLES. Line up a sufficient quantity (about 40) of the tall, narrow, numbered porcelain crucibles. Wipe them out with a Kimwipe. Load them into the muffle furnace making sure not to touch the oven sides or each other. Use the shelf to fit them all in. Close the muffle furnace. Turn on the exhaust fan. Turn the controller to 5.0, and turn the timer to 2 hours. After about 1.5 - 1.75 hours, check to verify that the temperature has or will reached 500 °C. If it hasn't, add additional time to the controller. When it does hit 500 °C, it is hot enough and ready to shut off. Let cool, closed, overnight. The next day the crucibles can be removed, USING TONGS (DO NOT TOUCH WITH YOUR HANDS) and stored in a desiccator. 2. DRY THE GROUND MATERIAL. The ground material in their envelopes should be placed in the 60 °C oven for 24 hours prior to weighing out for ashing. When the crucibles are thoroughly cooled, weigh the empty crucible and then place out approximately 1 gram using the analytical balance (BE SURE TO MIX THE SAMPLE WELL BECAUSE PARTICLES TEND TO SEPARATE DURING STORAGE AND HANDLING) of ground material into the crucible, and then record the filled crucible weight on the data charts in the front of this book. Remember to weigh and include a blank (empty) crucible with each run. 4. ASH THE WEIGHED SAMPLE. Using tongs, load the crucibles into the muffle furnace, making sure not to touch the oven sides or each other. Use the shelf to fit them all in. Close the muffle furnace. Turn on the exhaust fan. Turn the controller to 5.0, and turn the timer to 2 hours. After about 1.5 - 1.75 hours, check to verify that the temperature has reached 500 °C. If it hasn't, add an extra 15 minutes to the timing. When it does hit 500°C, and the timer has turned off the furnace, turn the controller to 2.0, and the timer to 2 hours. Let cool, closed, overnight. 5. WEIGH THE ASHED SAMPLES. Using tongs, remove the crucibles to a desiccator. When they are thoroughly cooled, use the same analytical balance and record the filled crucible weight on the data charts in the front of this book. Remember to weigh and include the blank (empty) crucible from each run. Dump out the ashed sample into the garbage, wiping the crucible with a Kimwipe if necessary. The crucibles are now ready to be filled again and fired. No need to ash the empty crucibles between runs AS LONG AS YOU KEEP THEM CLEAN! Methods after 1991: Ashing methods were changed in 1991 when the use of porcelain crucibles was replaced by use of disposable aluminum boats. All methods stayed the same EXCEPT: The disposable aluminum boats did not need to be 'tared' or fired before use. The clean boats were taken directly from the package and placed into use. To identify the boat, the SAMPLE ID # was 'written' (etched indented with a pencil-pen) on the bottom of the boat. The boat weight was recorded and the sample (WITH MIXING!) was added (about 1 gram). The rest of the procedures remained the same. If the muffle furnace was allowed to exceed 550 °C, the aluminum boats would melt and significant changes in their weight could occur. Blank boats are run with each operation to insure no significant loss-gain during firing. Analytical Methods Used: Kjeldahl Nitrogen and Phosphorus by Technicon Industrial Method No. 369-75A (Revised 8/21/75) Digestion and sample preparation for the analysis of total kjeldahl nitrogen and/or phosphorus in food and agricultural products using the technicon BD-20 Block digestor. and Technicon Industrial Method 334-74A (revised 8/21/75) Individual/simultaneous determination on nitrogen and phosphorus in BD acid digests Percent Nitrogen and Percent Carbon were determined by High Temperature combustion, the resulting gases were eluted on a gas chromatography column and detected by thermal conductivity and integrated to yield carbon and nitrogen content. Analyses were performed on a ThermoQuest CE Instruments NC2100 Elemental Analyzer, ThermoQuest Italia S.p.A., Rodano, Italy. Study Instrumentation:ThermoQuest CE Instruments, NC2100, Elemental Analyzer (Nitrogen and Carbon) CHAIN OF CUSTODY 1. Field personnel. The number of personnel involved in the field collection of Sevilleta LTER Decomposition study samples is usually limited to 1 or 2 individuals. The collection procedure is relative simple and is dominated by time taken driving from location to location. It is important that the field personnel responsible for sample collections be familiar with the collection protocol, sample identifications,and location locations. It is the responsibility of the field personnel to deliver the samples to the laboratory personnel, as quickly and carefully as possible. 2. Laboratory personnel. Once delivered by the field personnel, the inventory, storage and management of the samples becomes the responsibility of the laboratory personnel. The laboratory personnel are responsible for conducting all analytical laboratory procedures, in addition to attaining, entering, verifying and archiving any relevant data. These tasks usually were performed by student technicians, but the samples are the direct responsibility of the staffed Sevilleta LTER laboratory technician, under supervision of the Laboratory Director.

Sample Collection Methods For each individual location collection, three replicate bags are placed in zip-lock bags and are identified by species, field location, collector initials, and date of collection. A general maintenance survey of each location is done at this time by the collector(s). At the time of placement, three bags of each species were collected and placed into a gallon-sized zip-loc bag for transport to the lab. This method insured that each replicate was handled the same way with bouncing during transport and sample handling consistent for all samples. These three samples taken at the time of placement determine the starting (incubation in the field time 0) replicate litters. For each collection date, 28 gallon-size zip-lock bags were be needed. Sample Analysis Methods Overview: Handling of the field samples involves three phases: (1) initial cleaning and oven-dry weight; (2) grinding and ash correction; and (3) chemical analyses. Once in the laboratory, field samples will come in with 3 replications/plant type in a bag labelled with the site, plant material, and collection date. In Phase 1, the samples are cleaned, oven dried at 60° C for a minimum of 24 hours, and oven-dry weight recorded. The samples are then transferred to coin envelopes, ground on the Tecator grinder, and stored back in the coin envelope. In Phase 2, ground plant material is then used for ash-free weight determinations. In Phase 3, the remaining ground plant litter is used for chemical analyses. Phase 1. WEIGHING Overview Specifics The following equipment is needed for weighing out the samples: Balance Large and small weigh boats Oven: 60° C Cafeteria tray Permanent marker Staple remover Scissors Decomp Record Book Desiccators Make sure to reserve all equipment as needed ahead of time. 1. Select a zip-loc bag with field samples to begin weighing out. Select one mesh bag, you have now arbitrarily assigned this sample a replicate number and Sample ID number. Label a weigh boat (large for the grasses and cottonwood, small for salt bush, creosote, pinyon, yucca, and juniper) with the site number, plant type and Sample ID number. Tare the balance and weigh the empty weigh boat, recording the weight in the record book. Carefully remove any foreign material from the outside of the bag, such as: differen plant material, mud, ROCKS, etc, making sure to lift up the side folds to release any trapped rocks. MAKE SURE YOU REMOVE ALL ROCKS, OR ELSE YOU MAY DESTROY THE GRINDER ROTOR LATER ON (not to mention throwing off the weight). Carefully remove the staples from the top fold ONLY. MAKE SURE that should any staples break you retrieve ALL parts of it, so that your weight is accurate, and so that you don't attempt to grind it later on (ouch!). Place the weighed and labelled weigh boat on a sheet of paper in front of you, and empty the contents of the bag into the weigh boat. NOTE: for cottonwoods and the grasses, first reach the scissors into the mesh bag and cut up the material into SMALL pieces, keeping in mind that the smaller they are now, the easier it will be to stuff into the coin envelopes and the faster it will be to grind. For yucca, remove the numbered tag, and record that number in the record book to the left of the replication number, and cut it up into small pieces. Repeat this for all samples, weighing out a mix of big and small weigh boats (they fit better in the oven that way), and place in the oven. BE CAREFUL not to weigh out more samples than you have oven space! Make several trips to the oven instead of one big load to gauge oven capacity. 2. Dry for a minimum of 24 hours at 60° C, although longer times will not hurt the sample, it has not been found to be beneficial. Remove the weigh boats filled with dried samples, and place in a desiccator to cool for about 20 minutes. Reweigh the filled weigh boat, record the weight in the record book. Working over a piece of paper, stuff the plant material into a coin envelope labelled with the collection date, site number, plant type, and Sample ID number. GRINDING NOTE: MAKE SURE YOU READ THE FULL SET OF INSTRUCTIONS FOUND IN THE DRAWER UNDER THE Tecator GRINDER. Overview Plant material is ground in order to perform ash-free weight corrections and chemical analyses. The only plant material needed to be ground using liquid N are: pinyon, juniper and creosote. All others are ground warm. SUGGESTED ITEMS USEFUL FOR GRINDING Mortar & pestle Small kimwipes Flat-edged spatula Paint brush Q-tips Ethanol Toothbrush Small beaker (Et2OH) Liquid N Brown gloves Plastic beaker on a string for liquid N EVERY DAY BEFORE GRINDING Before grinding, take apart the machine to make sure it is clean: 1.Remove the rotor, using the wrench and the L shaped piece of metal. Scrape out any residue on the underside of the rotor and clean it with an ethanol-soaked Q-tip. 2.Clean the flat piece under the rotor (with concentric circles) with a wet Q-tip. Lift out this piece and make sure any dust is cleaned out of the area. 3.Replace the rotor, finger tightening the nut. Then only SLIGHTLY tighten it back with the wrench. IF you don't tighten it with the wrench, the grinder will make an awful noise when you turn it on. 4.Reassemble the grinder, inspecting the rotor blades, sample pan, screen (arrow up), lid and funnel for residue. Clean as necessary. Replace the black screw knobs and you're ready to go. TURNING ON THE GRINDER SO AS NOT TO BLOW A FUSE ALWAYS start the machine in this order: 1.Plug into the wall circuit 2.Have the speed button on I (15000 rpm) 3.Turn on the ON switch. 4.Turn on the timer to 5 or so. 5.Wait for the orange light to come on before adding the sample. 6.Add the sample SLOWLY or you will overload the motor and blow a fuse. Phase 2. ASH-FREE WEIGHT CORRECTION METHOD Methods 1989 through 1991: 1. ASH THE EMPTY CRUCIBLES. Line up a sufficient quantity (about 40) of the tall, narrow, numbered porcelain crucibles. Wipe them out with a Kimwipe. Load them into the muffle furnace making sure not to touch the oven sides or each other. Use the shelf to fit them all in. Close the muffle furnace. Turn on the exhaust fan. Turn the controller to 5.0, and turn the timer to 2 hours. After about 1.5 - 1.75 hours, check to verify that the temperature has or will reached 500 °C. If it hasn't, add additional time to the controller. When it does hit 500 °C, it is hot enough and ready to shut off. Let cool, closed, overnight. The next day the crucibles can be removed, USING TONGS (DO NOT TOUCH WITH YOUR HANDS) and stored in a desiccator. 2. DRY THE GROUND MATERIAL. The ground material in their envelopes should be placed in the 60 °C oven for 24 hours prior to weighing out for ashing. When the crucibles are thoroughly cooled, weigh the empty crucible and then place out approximately 1 gram using the analytical balance (BE SURE TO MIX THE SAMPLE WELL BECAUSE PARTICLES TEND TO SEPARATE DURING STORAGE AND HANDLING) of ground material into the crucible, and then record the filled crucible weight on the data charts in the front of this book. Remember to weigh and include a blank (empty) crucible with each run. 4. ASH THE WEIGHED SAMPLE. Using tongs, load the crucibles into the muffle furnace, making sure not to touch the oven sides or each other. Use the shelf to fit them all in. Close the muffle furnace. Turn on the exhaust fan. Turn the controller to 5.0, and turn the timer to 2 hours. After about 1.5 - 1.75 hours, check to verify that the temperature has reached 500 °C. If it hasn't, add an extra 15 minutes to the timing. When it does hit 500°C, and the timer has turned off the furnace, turn the controller to 2.0, and the timer to 2 hours. Let cool, closed, overnight. 5. WEIGH THE ASHED SAMPLES. Using tongs, remove the crucibles to a desiccator. When they are thoroughly cooled, use the same analytical balance and record the filled crucible weight on the data charts in the front of this book. Remember to weigh and include the blank (empty) crucible from each run. Dump out the ashed sample into the garbage, wiping the crucible with a Kimwipe if necessary. The crucibles are now ready to be filled again and fired. No need to ash the empty crucibles between runs AS LONG AS YOU KEEP THEM CLEAN! Methods after 1991: Ashing methods were changed in 1991 when the use of porcelain crucibles was replaced by use of disposable aluminum boats. All methods stayed the same EXCEPT: The disposable aluminum boats did not need to be 'tared' or fired before use. The clean boats were taken directly from the package and placed into use. To identify the boat, the SAMPLE ID # was 'written' (etched indented with a pencil-pen) on the bottom of the boat. The boat weight was recorded and the sample (WITH MIXING!) was added (about 1 gram). The rest of the procedures remained the same. If the muffle furnace was allowed to exceed 550 °C, the aluminum boats would melt and significant changes in their weight could occur. Blank boats are run with each operation to insure no significant loss-gain during firing. Analytical Methods Used: Kjeldahl Nitrogen and Phosphorus by Technicon Industrial Method No. 369-75A (Revised 8/21/75) Digestion and sample preparation for the analysis of total kjeldahl nitrogen and/or phosphorus in food and agricultural products using the technicon BD-20 Block digestor. and Technicon Industrial Method 334-74A (revised 8/21/75) Individual/simultaneous determination on nitrogen and phosphorus in BD acid digests Percent Nitrogen and Percent Carbon were determined by High Temperature combustion, the resulting gases were eluted on a gas chromatography column and detected by thermal conductivity and integrated to yield carbon and nitrogen content. Analyses were performed on a ThermoQuest CE Instruments NC2100 Elemental Analyzer, ThermoQuest Italia S.p.A., Rodano, Italy. Study Instrumentation:ThermoQuest CE Instruments, NC2100, Elemental Analyzer (Nitrogen and Carbon) CHAIN OF CUSTODY 1. Field personnel. The number of personnel involved in the field collection of Sevilleta LTER Decomposition study samples is usually limited to 1 or 2 individuals. The collection procedure is relative simple and is dominated by time taken driving from location to location. It is important that the field personnel responsible for sample collections be familiar with the collection protocol, sample identifications,and location locations. It is the responsibility of the field personnel to deliver the samples to the laboratory personnel, as quickly and carefully as possible. 2. Laboratory personnel. Once delivered by the field personnel, the inventory, storage and management of the samples becomes the responsibility of the laboratory personnel. The laboratory personnel are responsible for conducting all analytical laboratory procedures, in addition to attaining, entering, verifying and archiving any relevant data. These tasks usually were performed by student technicians, but the samples are the direct responsibility of the staffed Sevilleta LTER laboratory technician, under supervision of the Laboratory Director.

Description of Initial Study: The decomposition study began with litter grown during 1989, which was harvested in the fall of1989, prepared during the winter and placed in the field the following spring. The initial study was designed by Dr. J. Gosz and Dr. R. Parmenter with C.S. White the project manager. The basic design included placement of three (3) primary litter-types (black grama (Bouteloua gracilis), juniper (Juniperus monosperma), and Indian rice grass (Oryzopsis hymenoides)) at seven (7) locations. The seven locations included: along an approximate north-south transect from grass habitat to creosote habitat, Location 1 = Black Butte; Location 2 = Deep Well; Location 3 = 1 mi. east of 5 points (central point along the transect representing a grass-juniper-creosote junction); Location 4 = between Location 3 and south boundary within a creosote stand (Larea); and Location 5 = south boundary at a stand of Ocotillo (Ocotillo); and along an approximate east transect from location 3; Location 6 = Sepultura Canyon; and Location 7 = Cerro Montoso (increasing favorable juniper habitat and into pinyon). There were two other locations off the Sevilleta NWR in the first year: Location 8 at the Bosque del Apache (which later was lost during a fire at that location); Location 9 in the Magdelena Mountains west of Socorro. At all locations (except Bosque del Apache), litter of the three common species were included. Litter of different species were placed at locations where that litter may be dominant. The other litter types included: creosote (locations 2 and 4), blue grama (location 2), 4-wing saltbush (location 2), yucca (location 2), pinyon (location 7), cottonwood (location 8); and Arizona fescue, Douglas fir, Ponderosa pine, and aspen (location 9). At each location and for each species, the experimental design included placement of enough bags for three replicate bags per collection date; one collection at the time of placement and eight additional collections over a two year period, and 7 additional bags to allow for some mortality of bags (34 bags total). Each bag initially contained 5.00 g +/- 0.05 g (4.95-5.05 g) air-dried material. Bags were placed at each location in late February, 1990. Collections are projected to be made in: (1), May 1990 (2), July 1990 (3), Sept. 1990 (4), January 1991 (5, one-year), May 1991 (6), Sept 1991 (7), and January 1992 (8, two-year). Changes in 1990: In 1990, litter was only placed at the Deep Well location (#2) and only litters of black grama, juniper, rice grass, creosote, blue grama and saltbush were used. It was decided that all the sites were not worth continuing because there were no other data associated with the site that could be used to explain why decomposition may or may not vary at that site versus and other site. Thus, the location with the most complete meteorological data was maintained (Deep Well, location 2). Changes 1991 through 1998: Starting with litter collected in the fall of 1991 and continuing through litter collected in 1997, litter bags were placed at four (4) locations that represented the range of climates present on the Sevilleta and that were all near meteorological stations. Deep Well (location 2) and Cerro Montoso (location 7) were retained from the previous work because they were near meteorological stations. Cerro Montoso (location 7) represented a pinyon-juniper forest, upper elevation climate (wettest of all locations), Deep Well (location 2) represented a short-grass prairie climate, a location near the Rio Salado (new, location 10) represented a Chihuahuan desert climate (driest of all locations), and Red Tank (new, location 11) represented a Great Basin grass-shrub climate. Deep Well and Cerro Montoso (location 1 and 7, respectively) are on the east side of the Sevilleta while Rio Salado and Red Tank (locations 10 and 11, respectively) are on the west. At these four locations, black grama, creosote, Indian rice grass, and juniper litter were placed every spring. Blue grama litter also was placed at Deep Well to maintain a long-term blue and black grama comparison. Changes in 1998: Beginning with placement of litter collected in the fall of 1998, efforts to conserve resources and to address changes across vegetation transition zones lead to addition of 2 new locations: Blue Springs (location 12), a juniper-short grass prairie mixture; and 5 points (location 13), a creosote area near the Deep Well short grass-desert grass area. No new litter was placed at Rio Salado and Red Tank (locations 10 and 11), but remaining litter were collected for the 1 year decomposition measurement in Feb. of 1999 and will be collected again in Feb. of 2000 for the two year decomposition measurement. The four common litter types were placed at Cerro Montoso, Blue Springs, Deep Well, and 5 points (locations 7, 12, 2, and 13, respectively) with blue grama also at Deep Well. Study Methods:Experimental Design: Setting up each location: 1989 through 1991: The design of this decomposition study includes placement of three (3) primary litter-types (black grama, juniper, and indian rice grass) at seven (7) locations. Litter of each species was collected after senescence in the fall. The grasses were clipped from standing plants before the litter was on the ground. All material that was not produced during the previous growing season was discarded. All reproductive parts were discarded. If there was any doubt about whether or not the material was produced that growing season, it was discarded. Juniper was collected from trees with senescent material or that had recently died and were still on the branch. Juniper litter consisted of only that material that still had bracts (woody stems without bracts were discarded). Pinyon was collected from trees that still retained senescent needles by shaking and capturing on a cloth or plastic sheet. Branches of 4-wing saltbush were trimmed from bushes in October when material looked senescent and leaves were picked from the branches and air-dried. Creosote leaves were attempted to be collected by spreading sheets on the ground; however, litterfall is very episodic and not enough material could be collected. Thus, creosote was collected by cutting live plants and drying in a forced-air oven at 60 °C; then the freshly dried leaves were removed from the branch and any reproductive parts (seeds) were discarded. Yucca was collected by cutting leaves from a recently dead yucca plant. Cottonwood leaves were collected in plastic trays as they fell and before the fresh litter was rained on. Arizona fescue, douglas fir, ponderosa pine and aspen were collected by others and we do not know what methods were used. All litters were sorted and damaged material or reproductive parts were discarded. Unless previously dried, litter was air-dried in the laboratory. Litter bags consisted of coated fiberglass window screen material cut into 12 by 7.5 sheets, which were folded in half and two of the edges folded over and stapled. Litter was inserted through the unstapled edge, which then was folded over and stapled. Each bag initially contained 5.00 g (4.95-5.05 g) of air-dried material. For each litter type, a total of 34 bags were prepared for placement at each location. All the litter bags of one species for an individual location were placed in a separate bag and the bag was sealed for transport the field. At each location and for each species, the experimental design included placement of enough litter bags for three replicate bags per collection date; one collection at the time of placement, eight collections over a two year period, and 7 additional bags to allow for some mortality of bags (34 bags total per location). When the litter bags were placed at each location, the location was marked with fence posts as a warning. Each location was identified by a color-coded marker. The color-coded markers for each location are as follows: location (1)=plain, (2)=tan, (3)=green, (4)=orange, (5)=orange/green, (6)=tan/green, (7)=green/tan, (8)=green/orange, and (9)=tan/orange. Litter bags were placed on bare soil between plants at all times. Each litter bag was anchored by inserting a 16 penny nail through diagonal corners of the bag and into the ground. Decomposition bags with creosote, blue grama, yucca (tethered, not bagged), and four-wing saltbush all were placed at the deep well location (location 2); and cottonwood at the Bosque del Apache (location 8). In the fall of 1990, only 5 litter types (black grama, blue grama, juniper, creosote, and Indian ricegrass) were collected for placement in Feb. of 1991. Blue grama litter was only placed at Deep Well, while the four other litter types were place at 4 locations (#2, 7, 10, 11). Litter was collected as described in the previous year and bags were placed on bare soil at each location. In February of 1999, the Rio Salado and Red Tank sites did not get new litter bag placements; instead the new locations at Blue Springs and 5 points were established and the 4 common litter types were placed at these locations along with Deep Well and Cerro Montoso.