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Investigation:

LC-14 (Nepstad / Moutinho)

LBA Dataset ID:

LC14_ABOVEGROUND_PROD

Originator(s):

1. NEPSTAD, D.C.
      2. MOUTINHO, P.R.

Point(s) of Contact:

ORNL DAAC User Services Office Oak Ridge National Laboratory Oak Ridge, Tennessee 37 (ornldaac@ornl.gov)

Dataset Abstract:

Measures of above ground productivity and canopy density were made in both control and dry down plots for a period of 5 years to estimate the effects of simulated drought on productivity and mortality in a seasonally dry tropical forest located in eastern Amazonia. Direct measurements of above ground productivity include fine and coarse litterfall, flower and fruit production, and wood increment. Indirect measurements of productivity include canopy density include leaf area index and canopy density.

Beginning Date:

1998-09-28

Ending Date:

2006-11-10

Metadata Last Updated on:

2013-10-22

Data Status:

Archived

Access Constraints:

PUBLIC

Data Center URL:

http://daac.ornl.gov/

Distribution Contact(s):

ORNL DAAC User Services Office Oak Ridge National Laboratory Oak Ridge, Tennessee 37 (ornldaac@ornl.gov)

Access Instructions:

PUBLIC

Data Access:

IMPORTANT: The LBA-ECO Project website is no longer being supported. Links to external websites may be inactive. Final data products from the LBA project can be found at the ORNL DAAC. Please follow the fair use guidelines found in the dataset documentation when using or citing LBA data.
Datafile(s):

LBA-ECO LC-14 Biophysical Measurements, Rainfall Exclusion, Tapajos National Forest:  http://daac.ornl.gov/cgi-bin/dsviewer.pl?ds_id=1196

Documentation/Other Supporting Documents:

LBA-ECO LC-14 Biophysical Measurements, Rainfall Exclusion, Tapajos National Forest:  http://daac.ornl.gov/LBA/guides/LC14_Aboveground_Prod.html

Citation Information - Other Details:

Nepstad, D.C. and P.R. Moutinho. 2013. LBA-ECO LC-14 Biophysical Measurements, Rainfall Exclusion, Tapajos National Forest. Data set. Available on-line [http://daac.ornl.gov] from Oak Ridge National Laboratory Distributed Active Archive Center, Oak Ridge, Tennessee, USA. http://dx.doi.org/10.3334/ORNLDAAC/1196

Keywords - Theme:

Parameter Topic Term Source Sensor
BIOMASS BIOSPHERE ECOLOGICAL DYNAMICS FIELD INVESTIGATION STEEL MEASURING TAPE
BIOMASS BIOSPHERE ECOLOGICAL DYNAMICS FIELD INVESTIGATION DENDROMETERS
COMMUNITY STRUCTURE BIOSPHERE ECOLOGICAL DYNAMICS FIELD INVESTIGATION PLANT CANOPY ANALYZER
COMMUNITY STRUCTURE BIOSPHERE ECOLOGICAL DYNAMICS FIELD INVESTIGATION DENSIOMETER
LITTER CHARACTERISTICS BIOSPHERE ECOLOGICAL DYNAMICS FIELD INVESTIGATION BALANCE

Uncontrolled Theme Keyword(s):  CANOPY COVER, CANOPY OPENNESS, DIAMETER AT BREAST HEIGHT, LEAF AREA INDEX, LITTER PRODUCTIVITY, RAINFALL EXCLUSION, TAPAJOS NATIONAL FOREST

Keywords - Place (with associated coordinates):

Region
(click to view profile)
Site
(click to view profile)
North South East West
Pará Western (Santarém) km 67 Primary Forest Tower Site -2.85700 -2.85700 -54.95900 -54.95900

Related Publication(s):

Brando PM, Nepstad DC, Davidson EA, Trumbore SE, Ray D, Carmargo P. (2008) Drought effects on litterfall, wood production and belowground carbn cycling in an Amazon forest: results of a throughfall reduction experiment. Philosophical Transactions of the Royal Society of London Series B-Biological Sciences

Nepstad DC, Tohver IM, Ray D, Moutinho P, Cardinot G. (2007) Mortality of large trees and lianas following experimental drought in an amazon forest. Ecology, 88, 2259-2269.

Nepstad, D.C., P. Moutinho, M.B. Dias, E. Davidson, G. Cardinot, D. Markewitz, R. Figueiredo, N. Vianna, J. Chambers, D. Ray, J.B. Guerreiros, P. Lefebvre, L. Sternberg, M. Moreira, L. Barros, F.Y. Ishida, I. Tohlver, E. Belk, K. Kalif, and K. Schwalbe. 2002. The effects of partial throughfall exclusion on canopy processes, aboveground production, and biogeochemistry of an Amazon forest. Journal of Geophysical Research-Atmospheres 107:53, 51-18.

Data Characteristics (Entity and Attribute Overview):

Data Characteristics:

Data Characteristics



Data are presented in six comma separated ASCII files:



File #1: Coarse_litter_REE_plots_1998_2006.csv

File #2: Fine_Litter_REE_plots_1998_2006.csv

File #3: LAI_REE_plots_1999_2006.csv

File #4: Canopy_density_REE_plots_1998_2004.csv

File #5: Stem_inventory_REE_plots_2000_2004.csv

File #6: Dendrometers_REE_plots_1999_2006.csv



Files are organized as follows:



File #1:

File name:,Coarse_litter_REE_plots_1998_2006.csv,,,

File date:,14-Jul-13,,,

Associated LME file:,LC14_Aboveground_Prod,,,

,,,,

Column,Column_heading,Units/format,Explanation,

1,Treatment,,Treatment is either control or exclusion,

2,Date,,Sampling date,

3,Production_coarse_litter,g m-2 d-1,Mean production of coarse litter (defined as stems and twigs greater than 1 cm diameter) reported in grams per meter squared per day (g m-2 d-1),

4,SE_Production,g m-2 d-1,Standard error of the mean mass of coarse litter collected reported in grams per meter squared per day (g m-2 d-1),

5,N,,Number of samples included in the calculation of the mean,

,,,,

Sample data for File #1:Coarse_litter_REE_plots_1998_2006.csv

Treatment,Date,Mass_coarse_litter,SE_Mass,N

Control,19981012,0.36,0.13,3

Control,19981027,0.49,0.09,3

Control,19981110,1.66,1.04,3

Control,19981217,0.37,0.11,3

Control,19990106,0.39,0.27,3

Control,19990218,0.26,0.14,3

...

Exclusion,20060308,0.77,0.18,3

Exclusion,20060324,0.52,0.19,3

Exclusion,20060410,0.37,0.15,3

Exclusion,20060425,1.25,0.64,3

Exclusion,20060508,0.65,0.23,3

Exclusion,20060522,0.77,0.39,3





File #2

File name:,Fine_Litter_REE_plots_1998_2006.csv,,,,,,

File date:,22-Jul-13,,,,,,

Associated LME file,LC14_Aboveground_Prod,,,,,,

,,,,,,,

Column,Column_heading,Units/format,Explanation,,,,

1,Treatment,,Plot identification: control or exclusion,,,,

2,Date,YYYYMMDD,Collection date,,,,

3,Point,,Location within the plot see accompanying documentation for grid map,,,,

4,Mass_fine_litter,g m-2 d-1,Mass of total fine litter collected in the previous 2 week sampling period reported in grams per meter squared per day,,,,

5,Mass_foliage,g m-2 d-1,Mass of the foliage contained in the total fine litter collected in the previous 2 week sampling period reported in grams per meter squared per day,,,,

6,Mass_reproduct,g m-2 d-1,Mass of the reproductive structures (fruits and flowers) contained in the total fine litter collected in the previous 2 week sampling period reported in grams per meter squared per day,,,,

7,Mass_fruits,g m-2 d-1,Mass of the fruits contained in the total fine litter collected in the previous 2 week sampling period reported in grams per meter squared per day,,,,

8,Mass_flowers,g m-2 d-1,Mass of the flowers contained in the total fine litter collected in the previous 2 week sampling period reported in grams per meter squared per day,,,,

,,,,,,,

,Missing data is represented by -9999,,,,,,

,,,,,,,

Sample data for File #2: Fine_Litter_REE_plots_1998_2006.csv

Treatment,Date,Point,Mass_fine_litter,Mass_foliage,Mass_reproduct,Mass_fruits,Mass_flowers

Control,19980928,B1,4.75,-9999,-9999,-9999,-9999

Control,19980928,B3,3.91,-9999,-9999,-9999,-9999

Control,19980928,B5,16.63,-9999,-9999,-9999,-9999

Control,19980928,B7,12.46,-9999,-9999,-9999,-9999

Control,19980928,B9,7.35,-9999,-9999,-9999,-9999

Control,19980928,B11,13.09,-9999,-9999,-9999,-9999

...

Exclusion,20060609,P4,6.05,6.05,0,0,0

Exclusion,20060609,P5,6.51,6.51,0,0,0

Exclusion,20060609,P6,8.98,8.98,0,0,0

Exclusion,20060609,P7,2.15,2.15,0,0,0

Exclusion,20060609,P8,4.21,4.21,0,0,0



File #3

File name:,LAI_REE_plots_1999_2006.csv,,,,

File date:,14-Jul-13,,,,

Associated LME file:,LC14_Aboveground_Prod,,,,,

,,,,,

Column,Column_heading,Units/format,Explanation,,

1,Treatment,,Treatments were either control or exclusoin,,

2,Grid,,Location within the plot see attached plot grid file,,

3,Date,YYYYMMDD,Sampling date,,

4,LAI,m2 per m2,Leaf area index reported in meters squared of leaf tissue per meter squared of ground,,

5,Gap_fraction,,Gap fraction reported in proportion,,

6,MTA,degrees,Mean tilt angle reported in degrees,,

,,,,,

,missing data are indicated by -9999,,,,



Sample data for File #3: LAI_REE_plots_1999_2006.csv

Treatment,Grid,Date,LAI,Gap_fraction,MTA

Control,B1,19990205,3.03,0.123,56

Control,B2,19990205,3.16,0.13,64

Control,B3,19990205,2.33,0.233,71

Control,B4,19990205,2.7,0.163,56

Control,B5,19990205,3.87,0.066,42

...

Exclusion,P5,20061110,6.93,0.007,50

Exclusion,P6,20061110,4.72,0.036,55

Exclusion,P7,20061110,5.9,0.014,52

Exclusion,P8,20061110,5.43,0.024,60





File #4:

File name:,Canopy_density_REE_plots_1998_2004.csv,,,,

File date:,22-Jul-13,,,,

Associated LME file:,LC14_Aboveground_Prod,,,,

,,,,,

,,,,,

Column,Column_heading,Units/format,Explanation,,

1,Treatment,,Plot identification: control or exclusion,,

2,Date,YYYYMMDD,Sampling date,,

3,Sampling_location,,Location within the plot see accompanying documentation for grid map,,

4,Open,%,Percent of open canopy above the sampling point,,

5,Cover,%,Percent of closed canopy above the sampling point,,

,,,,,

Sample data for File #4: Canopy_density_REE_plots_1998_2004.csv

Treatment,Date,Sampling_location,Open,Cover

Exclusion,19981217,A1,8.84,91.16

Exclusion,19981217,A2,5.2,94.8

Exclusion,19981217,A3,4.16,95.84

Exclusion,19981217,A4,3.64,96.36

...

Control,20010625,L8,4.94,95.06

Control,20010625,L9,4.16,95.84

Control,20010625,L10,3.64,96.36

Control,20010625,L11,3.9,96.1

Control,20010625,L12,3.64,96.36





File #5:

File name:,Stem_inventory_REE_plots_2000_2004.csv,,,,,

File date:,14-Jul-13,,,,,

Associated LME file:,LC14_Aboveground_Prod,,,,,

,,,,,,

Column,Column_heading,Units/format,Explanation,,,

1,Treatment,,Plot in which the stem was located: control or treatment,,,

2,Life_form,,Life form: trees palms and vines were measured,,,

3,Family,,Scientific family to which the stem belongs ,,,

4,Scientific_name,,Identification reported as Genus species,,,

5,DBH_2000,cm,Diameter at breast height measured in June 2000 when the experiment was established and reported in centimeters (cm),,,

6,DBH_2004,cm,Diameter at breast height measured in September 2004 when the experiment was terminated and reported in centimeters (cm),,,

7,OBS_final,,Field observations on the status of the tree made in September 2004 when the experiment was terminated ,,,

,,,,,,

,Missing data are represented by -9999,,,,,

,,,,,,

Sample data for File #5: Stem_inventory_REE_plots_2000_2004.csv

Treatment,Life_form,Family,Scientific_name,DBH_2000,DBH_2004,OBS_final

Exclusion,TREE,Moraceae,Brosimum guianense ( Aubl. ) Huber.,22.8,24.5,LIVE

Exclusion,PALM,Arecaceae,Astrocaryum gynacanthum Mart.,4.3,-9999,DEAD

Exclusion,VINE,Bignoniaceae,Anemopaegma parkerii Sprague.,8.8,-9999,DEAD

...

Control,TREE,Caesalpiniaceae,Tachigalia paniculata Aubl.,6.6,6.7,LIVE

Control,VINE,Combretaceae,Combretum laxum Jacq.,3.35,5,LIVE

Control,TREE,Apocynaceae,Tabernaemontana angulata Mart. ex Muell Arg.,5.12,-9999,DEAD

Control,TREE,Violaceae,Amphirrhox surinamensis Eichl.,2.31,2.5,LIVE



File #6



File name:,Dendrometers_REE_plots_1999_2006.csv,,,,,,,,,,,,,

File date:,29-Jul-13,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,

Associated LME file:,LC14_Aboveground_Prod,,,,,,,,,,,,,,,,,,,,

,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,

Column,Column_heading,Units/format,Explanation,,,,,,,,,,,,,,,,,

1,Treatment,,Plot in which the stem was located: control or treatment,,,,,,,,,

2,Tree_ID,,Tree identification,,,,,,,,,,,

3,Life_form,,Life form: trees palms and vines were measured,,,,,,,,,,,

4,Family,,Scientific family to which the stem belongs ,,,,,,,,,,

5,Genus_species,,Identification reported as Genus species,,,,,,,,,,

6,Common_name,,Local name for tree in Portuguese,,,,,,,,,,,,

7,Height_m,m,Tree height estimated reported in meters,,,,,,,,,,,,,,

8,DBH_init,cm,Initial diameter at breast height measured at 1.3 meters above ground level or above the butress where appropriate,,,,,,,,,,

9 through 83,DBH_MMMYY,cm,Estimated dbh at the midpoint reported in centimeters (cm) and calculated from the dbhs recorded at the previous and following sampling points. For actual midpoint date see the accompanying Midpoint dates file,,,,,,,,,,,,,,

84,Date_death,YYYMMDD,Date on which field observations included a report that the tree palm or vine was dead for those trees that died during the sampling period,,,,,,,,,,,,,

85,Field_notes,,Observations about the state of the tree vine or palm and the dendrometer with associated dates,,,,,,,,,,,,

,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,

Sample data for File #6:Dendrometers_REE_plots_1999_2006.csv

Treatment,Tree_ID,Life_form,Family,Genus_species,Common_name,Height_m,DBH_init,DBH_Jun99,DBH_Aug99,DBH_Oct99,DBH_Nov99,DBH_Dec99,DBH_Feb00,DBH_Mar00,DBH_Apr00,DBH_May00,DBH_Jun00,DBH_Jul00,DBH_Aug00,DBH_Sep00,DBH_Dec00,DBH_Jan01,DBH_Feb01,DBH_Apr01,DBH_May01,DBH_Jun01,DBH_Jul01,DBH_Aug01,DBH_Sep01,DBH_Oct01,DBH_Nov01,DBH_Dec01,DBH_Jan02,DBH_Feb02,DBH_Mar02,DBH_Apr02,DBH_May02,DBH_Jun02,DBH_Jul02,DBH_Aug02,DBH_Sep02,DBH_Oct02,DBH_Nov02,DBH_Dec02,DBH_Jan03,DBH_Feb03,DBH_Mar03,DBH_Apr03,DBH_May03,DBH_Jun03,DBH_Jul03,DBH_Aug03,DBH_Sep03,DBH_Oct03,DBH_Nov03,DBH_Dec03,DBH_Jan04,DBH_Feb04,DBH_Mar04,DBH_Apr04,DBH_May04,DBH_Jun04,DBH_Jul04,DBH_Aug04,DBH_LateAug04,DBH_Oct04,DBH_Nov04,DBH_lateNov04,DBH_Dec04,DBH_Jan05,DBH_Mar05,DBH_May05,DBH_Jun05,DBH_Jul05,DBH_Aug05,DBH_Sep05,DBH_Oct05,DBH_Nov05,DBH_Dec05,DBH_lateDec05,DBH_Jan06,DBH_Mar06,Date_death,Field_notes,,,,,,,,,,

Control,1,tree,Elacocarpaceae,Sloanea brevipes Benth,Urucurana,10,13.3,13.5,13.5,13.5,13.5,13.6,13.7,13.7,13.8,13.8,13.8,13.9,13.9,14,14.2,14.4,14.5,14.6,14.7,14.7,14.7,14.7,14.7,14.8,14.8,14.8,14.8,14.9,14.9,14.9,15,15.1,15.1,15.1,15.1,15.2,15.2,15.2,15.2,15.3,15.4,15.5,15.5,15.5,15.5,15.6,15.68,15.7,15.7,15.8,15.8,15.9,15.9,15.9,15.9,15.9,15.9,16,16,16.1,16.1,16.1,16.1,16.1,16.1,16.1,16.1,16.1,16.1,16.1,16.1,16.1,16.1,16.1,16.1,16.2,-9999,no notes,,,,,,,,,,

Control,10,tree,Sapotaceae,Ecclinusa ramiflora Mart.,Abiu balatarana,13,16.9,17.2,17.3,17.3,17.3,17.3,17.3,17.3,17.3,17.3,17.3,17.3,17.3,17.3,17.3,17.3,17.3,17.3,17.3,17.3,17.3,17.3,17.3,17.3,17.3,17.3,17.3,17.4,17.4,17.4,17.4,17.5,17.5,17.5,17.5,17.5,17.5,17.5,17.5,17.5,17.5,17.5,17.5,17.5,17.6,17.6,17.6,17.6,17.6,17.6,17.6,17.6,17.6,17.6,17.7,17.7,17.7,17.7,17.7,17.7,17.7,17.7,17.7,17.7,17.7,17.7,17.7,17.7,17.7,17.7,17.7,17.7,17.7,17.7,17.7,17.7,-9999,Field notes: December 2000 INT,,,,,,,,,,

Control,100,tree,Lauraceae,Ocotea tomentella Sandw,Louro leque,13,12.9,13.3,13.3,13.3,13.4,13.5,13.5,13.6,13.7,13.7,13.7,13.7,13.7,13.7,13.9,14,14,14,14,14,14.1,14.1,14.1,14.1,14.1,14.2,14.2,14.3,14.3,14.4,14.4,14.5,14.5,14.5,14.5,14.6,14.7,14.6,14.8,14.8,14.9,15,15.2,15.4,15.4,15.4,15.41,15.5,15.5,15.6,15.7,15.8,15.9,15.9,16,16.1,16.1,16.1,16.1,16.2,16.3,16.5,16.7,16.8,16.9,17,17,17,17,17,17.1,17.2,17.3,17.4,17.6,17.7,-9999,Field notes: November 2001 INT; January 2002 band; January 2005 band will be changed; March 2005 band will be changed; September 2005 just new,,,,,,,,,,

Control,101,tree,Rubiacea,Coussarea racemosa Ac. Rich ex DC,Caferana,10,13.2,13.1,13.1,13.1,13.1,13.1,13.1,13.1,13.1,13.2,13.2,13.2,13.2,13.2,13.2,13.2,13.2,13.2,13.2,13.2,13.2,13.2,13.2,13.2,13.1,13,13.2,13.2,13.2,13.2,13.2,13.2,13.2,13.2,13.2,13.2,13.2,13.2,13.1,13.2,13.2,13.2,13.2,13.2,13.2,13.2,13.21,13.2,13.2,13.2,13.2,13.2,13.2,13.2,13.2,13.2,13.2,13.2,13.2,13.2,13.2,13.2,13.2,13.2,13.2,13.2,13.2,13.2,13.2,13.2,13.2,13.2,13.2,13.2,13.2,13.2,-9999,no notes,,,,,,,,,,

Data Application and Derivation:

Data can be used to calculated biomass, productivity and rates of mortality for the control and rainfall exclusion treatments.

Quality Assessment (Data Quality Attribute Accuracy Report):

Quality Assessment:

Data have been reviewed for accuracy. To avoid confounding effects associated with trenching the experimental plots, trees located close to the trenches (< 5 m) were excluded from analyses of wood increment and tree mortality rates. In so doing, the areas of treatment and control plots were reduced from ~1 ha to 0.81 and 0.77 ha.

Process Description:

Data Acquisition Materials and Methods:

Site:

The experiment was located in the Tapajos National Forest, in east-central Amazonia. This forest receives 600 to 3000 mm of rain each year, with a mean of 2000 mm. The forest is situated on a flat terrace of Tertiary sediments capped by the Belterra Clay Formation (Clapperton, 1993), and is approximately 90 m above the water level of the Tapajos River, located 10 km to the west. The Oxisol soil (Haplustox) is dominated by kaolinite clay minerals and is free of hardpan or iron oxide concretions in the upper 12 m.



Drought effects on forest processes were studied by comparing a 1 ha forest plot from which a portion of throughfall was excluded with a nearby 1 ha control plot. Two floristically and structurally similar, 1 ha (100 by 100 m) plots were selected for the experiment from an initial survey of 20 ha of forest. The forest surrounding the plots had emergent trees up to 55 m in height, with continuous canopy varying in height from 18 to 40 m. The study plots were placed in areas where most of the canopy was less than 30 m high to facilitate access to the tree crowns.



A 1 to 1.7 m deep trench was excavated around the treatment plot to reduce the potential for lateral movement of soil water from the surrounding forest into the plot, and to provide a conduit for water excluded from the plot. A similar trench was excavated around the control plot to avoid the confounding of throughfall exclusion and trenching effects Following an intercalibration period of approximately one-year starting in November of 1998 throughfall was partially excluded during the rainy seasons of 2000 through 2006 using plastic panels and wooden gutters installed in the understory. Dates of panel installation and removal for each year of the study are included in the accompanying documentation.



Methods:



Sampling grids with 10 m distances between points were established with 100 points inside of each plot and a perimeter of sampling points outside of each plot, for a total of 144 points. These grids were used for measurements of leaf area index, canopy openness and litterfall. After the intercalibration period and the initiation of the throughfall exclusion treatment, measurements of leaf area index, canopy openness, and litterfall in the treatment plot were made above the plastic panels, at points along the wooden drainage gutters, described below. This elevated sampling grid had 102 sampling points inside of the plot, with a spacing of 6 m between each gutter, and 16 m between each point along each gutter (See accompanying grid sketch)





Inventory



An initial survey of stems greater than or equal to 1 cm dbh was completed in March 2000, including identification to species and measurement of diameter at breast height (dbh at 1.3 m). Diameters of highly irregular or buttressed stems were measured just above the irregularity. The survey was repeated in June 2004.



Stem Increment:

Dendrometer bands were installed on trees greater than or equal to 10 cm dbh (diameter at 1.3 m or above buttresses) and on vines greater than 5 cm dbh between January and March 1999, with measurements starting after a 3 to 5 month settling period. Trees that were 5 m or closer to the trenches in the exclusion plot were removed from the dataset. Bands were installed on 342 individuals in the exclusion plot and 409 individuals in the control plot. Diameter increment was monitored monthly between 2000 and 2006 using an electronic caliper from which relative stem diameter growth was calculated. From the calculated growth rates, an estimated diameter at the midpoint between sampling points was determined and is presented here.



Canopy Density:

Canopy light gaps were visually quantified using a spherical densitometer (a concave mirror etched with 24 quarter-inch squares and leveling bubble). Measurements are made in each of the four cardinal directions then averaged to provide a value for each sampling point. One technician made all of the measurements to reduce observer error. Data were collected from December 15, 1998 through June 24, 2005. These measurements were made from the ground prior to panel installation. Following panel installation and continuing after panel removal, treatment plot measurements were made from the water collection gutters, 1 to 3 meters above the ground.



LAI:

Leaf area index (LAI) was measured before and during the throughfall exclusion treatment at each of the grid sampling points using two Li-Cor 2000 Plant Canopy Analyzers in differential mode (Welles, 1990; LI-COR, 1992). One instrument was placed above the canopy on a wooden tower to measure incoming radiation with no canopy influence; the other instrument was used for the understory measurement, made with the same directional orientation as the above-canopy instrument. The instruments were intercalibrated above the canopy at the beginning of each set of measurements. The light field of each sensor was reduced to 90 degrees opaque, 270 degree sensor caps. Measurements were made under conditions of diffuse skylight, usually before 0800 in the morning or after 1700 in the afternoon local time. LAI calculations were made using the inner three quantum sensor rings to minimize the overlap among measurements made at adjacent grid points, and because this number of rings corresponded most closely with measurements calibrated in seasonally deciduous forests where LAI could be measured directly (Cutini et al., 1998).



Coarse Litter

Coarse litter defined as stems and twigs greater than 1 cm in diameter was collected at two-week intervals using three 1 by 100 m transects in each plot. All coarse litter which fell in the transect line was collected on each sampling date. Samples were dried at 65 degrees C, and weighed. When panels were installed, coarse litterfall in the treatment plot was measured by collecting twigs and branches that fell on three 50 by 6 m sections of panel. This sample area was reduced by the area of the gaps that occurred.



Fine litter:

Fine litter (leaves, reproductive parts, and twigs) was collected at 2-week intervals from 25 collectors (September 28 1999 through April 2000) and 100 collectors (remainder of study period). Collectors were 0.5 m2 in area (0.8 by 0.62 m) made of nylon mesh screen and located at each of the sampling grid points within the plots (see accompanying sketch). Twigs greater than 1 cm diameter were excluded from the fine litter collectors. Samples were dried at 65 degrees C, and weighed. Reproductive parts (buds, flowers, fruits, and seeds) were separated manually, dried and weighed. The collectors were suspended at 0.1 m height initially, and were elevated above the plastic throughfall exclusion panels (1.5 to 3.5 m height) and to 1.5 m height in the control plot following panel installation

References:

Clapperton, C. 1993. Quaternary Geology of South America, Elsevier Sci., New

York.



Cutini, A., G. Matteucci, and G. S. Mugnozza. 1998. Estimation of leaf area indexwith the Li-Cor LAI 2000 in deciduous forests, For. Ecol. Manage., 105,

55� 65.



LI-COR. 1992. LAI-2000 Plant Canopy Analyzer: Instruction Manual, LI-COR,

Inc., Lincoln, Nebr.



Welles, J. M. 1990. Some indirect methods of estimating canopy structure, Remote

Sens. Rev., 5, 31� 43.

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