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DATA SET IDENTIFIER : Litterfall in tabonuco (subtropical wet) forest in the Luquillo Experimental Forest, Puerto Rico (MRCE Litterfall data)

PROJECT TITLE : MRCE Forest Plot Experiment

PROJECT DESCRIPTION : The Minority Research Centers of Excellence (MRCE) experiment was designed originally to determine whether forest productivity was limited by nutrient availability, genetic constraints or climatic variables along a steep environmental gradient in the Luquillo Mountains of Puerto Rico. Comparisons were made between dwarf forest at 500 m elev. and tabonuco forest from 300-400 m elev. There were two main experiments in the original design: 1) forest fertilization (complete versus none); 2) transplant experiments using common gardens at high and low elevation, with and without wind protection at high elevation. In addition, phenology of leaves was studied in the dwarf forest to determine the longevity of leaves in the canopy.

The occurrence of Hurricane Hugo in September 1989, just as the forest plot fertilization experiments were to begin, neccesitated the addition of a hurricane debris-removal treatment as a second type of control in the lower elevation tabonuco forest. The hurricane also changed the nature of the study into one of looking at changes in forest composition and the recovery of forest productivity in response to fertilization and hurricane debris-removal. Seedling, sapling, herbaceous plant, and fern responses, as well as measurements of light availability and canopy closure were added to the originally planned measurements of tree diameter growth, leaf litter production, and fine root production and turnover. Another hurricane in 1998 (Hurricane Georges) presented an opportunity to look at the effects of removing only the woody debris (in new plots) versus removing all hurricane debris.

Funding for continued studies of the MRCE plots ended in 1998, but they were of such great value as a long-term experiment that they were incorporated into the LTER program.
 
 

LTER CORE AREAS: Annotate all that apply
 

LTER ASST. (~primary productivity)

LEF LTER 1 RESEARCH TOPIC: (Annotate all that apply)
 

System Properties

We define a data file as a component of a data set. A data set can have only one data file or more. Basically, different data files have different data structures or format.

DATA SET FILES (SUBSETS):
 

No.	Data File Identifier	On-Line Filename
1	El Verde Research area	evlit.txt
2	Pico del Este	pelit.txt

RESEARCH LOCATION: El Verde Research area ( See attached maps) and Pico del Este
 Figure1.jpg

 

Figure 2

INVESTIGATORS:
PRINCIPAL INVESTIGATORS E-MAIL address
 

Xioming Zou

xzou@www.ites.upr.edu

Other Researchers E-MAIL address
 

Jess Zimmerman	jzimmer@www.ites.upr.edu
Ligia Lebron	llebron@lternet.edu
Matt Warren	mwarren@lternet.edu

CONTACT PERSONS E-MAIL address Phone Number
(Include area code)
 

Xioming Zou

xzou@www.ites.upr.edu

(787) 767-0371

SOURCE OF FUNDING (SPONSOR): LTER, NSF, MRCE ended 1998

DATA SET ABSTRACT: Data are litterfall in plots subject to 2 or 3 treatments at two sites contrasting in elevation. The sites are El Verde (ca. 400 m.a.s.l.) and Pico del Este (1000 m.a.s.l.).

Treatments common to both sites are quarterly fertilization (macro- and micronutrients) and unmanipulated. At El Verde, a third set of plots was subject to a one time removal of litter and woody debris generated by Hurricane Hugo (September 1989).

We have been recording litterfall in tabonuco forest near El Verde Field Station to investigate controls on primary productivity following hurricane damage. Plots in three treatments replicated in four blocks spread throughout the 70 ha El Verde Research Area have been monitored since March 1990, approximately six months after Hurricane Hugo removed the canopy from the forest. The three treatments are control plots, plots in which all hurricane debris (and standing stocks of litter) was removed from the forest floor within one month of the hurricane, and fertilized in which a complete mixture of supplemental nutrients are spread on the plots every three months (see Zimmerman et al. 1995, Walker et al. 1996 for details).

DATA SET METHODS: Plot layout at El Verde is a randomized block design (see map). Plots are 20x20 m square with 10x10 m inner measurement plots. Ten baskets 0.16 m ² in area were randomly placed in each measurement plot. At Pico del Este, 12 plots have been randomly assigned to control and fertilizer treatments.

Plot are 14x9 m with 10x4 m inner measurement plots. Six baskets were randomly placed in each measurment plot. Litter is collected fortnightly at each site, refrigerated until transfer the laboratory in San Juan. Each sample is dried at 60 C, sorted into leaves, wood, and miscellaneous components and weighed.

Originally, each basket sample was proccessed separately, but all samples within a plot are now combined for processing (in effect since September 1993).

Additional control plots ("new control") were added in Block 1 and 2 in late 1991. Plots measure 20 x 20 m with an inner 10 x 10 m measurement plot into which 10 baskets 40 x 40 were placed. Baskets are emptied every two weeks. Material in the baskets is then sorted into leaves, wood, and miscellaneous fractions, dried at 60 C, and weighed

Since August 15, 2000 El Verde litterfall are being sorted by leaves, wood, and miscelaneous, but leaves are further sorted by species on each of the twelve plots.

As a request from Dr. X. Zou. The sorted material is weighted, the weights of the leaves are reported by species, and the wood and miscelaneous weights are reported. As usual by plot.

DATA COLLECTION TIME PERIOD:

CROSS-REFERENCES (other data sets related to this one): LTERDBAS #93: Litter decomposition in tabonuco forest before Hugo; LTERDBAS #94: Litterfall of the tabonuco forest before Hurricane Hugo; LTERDBAS #95: Litterfall along topographic gradients at lower Bisley; LTERDBAS #111: Litterfall in tabonuco (subtropical wet) forest in the Luquillo Experimental Forest, Puerto Rico (MRCE Litterfall data); LTERDBAS #115: Short-term disappearance of foliar litter of three tree species native to rain forest of Puerto Rico

SAMPLE LOCATION : N/A

STORAGE SITES (of data files): DM 333-02 Drawer #1 (LEFDSET1#93)

KEYWORDS : Nutrient cycling, primary productivity litter fall.
 

PUBLICATIONS :

Fetcher, N., R.A. Cordero, and J. Voltzow. 1999. Lack of ecotypic differentiation: Plant response to elevation, population origin, and wind in the Luquillo Mountains, Puerto Rico. Biotropica (in press ).

Walker, L.R., J.K. Zimmerman, D. Jean Lodge, and S. Guzman-Grajales. 1996. An altitudinal comparison of growth and species composition in hurricane-damaged forests in Puerto Rico. Journal of Ecology 84:877-889.

Zimmerman, J.K., W.M. Pulliam, D.J. Lodge, V. Quinones-Orfila, N. Fetcher, S. Guzman-Grajales, J.A. Parrotta, C.E. Asbury, L.R. Walker, and R.B. Waide. 1995. Nitrogen immobilization by decomposing woody debris and the recovery of tropical wet forest from hurricane damage. Oikos 72:314-322.

DISSEMINATION : X UNRESTRICTED

SITES DESCRIPTIONS:
El Verde research area: This area is located at about 400 m.a.s.l. at 18ø20'N, 65ø49'W, in the Luquillo Experimental Forest, Puerto Rico. Annual rainfall is 350 cm distributed more or less evenly throughout the year. The site lies within Holdridge's subtropical wet forest. Forest in the region are relatively undistributed foress dominated by tabonuco (Dacryodes excelsa), Manilkara bidendata, Sloaena berteriana, and secondary forests dominated by Cesarea arborea.

Pico del Este research area: This area is located at about 1000 m.a.s.l. at 18ø16'N, 65ø46'W, in the Luquillo Experimental Forest, Puerto Rico. Annual rainfall is 420 cm, a large proportion of which is in the form of fog and mist. The site lies within Holdridge's low montane forest. The forest is cloud forest (also called elfin or dwarf forest) dominated by Tababuia rigida, Ocotea spathulata, and Eugenia borinquensis.

Geographical positional system (GPS) Coordinates for each location:
 

location	latitude	longitude
EL VERDE	180 19’N	650 49’W
PICO DEL ESTE	180 16’N	650 45’W

VARIABLES:
 

File Name or # above (all in which the variable appears)	1,2	1,2
Abbreviation (as it appears on the data file)	Date	Treatment
NAME OF VARIABLE	Date	Fertilization Treatment
DEFINITION OF VARIABLE	Date of collection	Quarterly fertilization (macro- and micronutrients) and unmanipulated
UNIT	Mm/dd/yy
PRECISION
RANGE OR LIST OF VALUES		{DR = Debris removal; FT = fertilized in which a complete mixture of supplemental nutrients are spread on the plots every three months; CN = control plots, plots in which all hurricane debris (and standing stocks of litter) was removed from the forest floor  within one month of the hurricane }
DATA TYPE	date	alphabetic
MISSING  DATA CODES	none	none

CONTINUE VARIABLES:
 

File Name or # above (all in which the variable appears)	1,2
Abbreviation (as it appears on the data file)	{ Leaves, Wood, Miscellaneous, Total}
NAME OF VARIABLE	Weight of { Leaves, Wood, Miscellaneous, Total}
DEFINITION OF VARIABLE	Weight of each sample’s leaves, wood, and miscellaneous after dried at 60 C and sorted into components.
UNIT	g
PRECISION	.01
RANGE OR LIST OF VALUES
DATA TYPE	decimal
MISSING  DATA CODES	none

COMPUTATIONAL METHODS:

DATE OF LAST REVIEW: Feb 2001
DATE OF LAST ENTRY : 2000
STAGE OF DATA SET MANAGEMENT (dates) :
DATE OF LAST REVIEW : January 29, 1997 (became funded by LTER in 1997)
DATE OF LAST ENTRY : 2000
STAGE OF DATA SET MANAGEMENT (dates) :
RECEIVED: March 19, 1993
CATALOGUED: 1993
ON-LINE: May 1, 1997
REVIEWED BY RESEARCHER: January 29, 1997
FILING MEDIA :
NAME OF DOCUMENTATION FILE : lterdset193.doc,htm
NAME OF ON - LINE CATALOG : LEFDSET1 RECORD # : 93
DOCUMENT TYPE : magnetic media
PRIORITY TO BE ENTERED : second
Rev. date of this form: 24 January 2001