lterdb119-Census of species, diameter and location at the Luquillo Forest Dynamics Plot (LFDP), Puerto Rico

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PERSON(S) COMPLETING THIS FORM: E-MAIL ADDRESS:

Jill Thompson

Jill@coqui.net

DATA SET IDENTIFIER: Census of species, diameter and location at the Luquillo Forest Dynamics Plot (LFDP), Puerto Rico

PROJECT TITLE: Luquillo Forest Dynamics Plot - Community Structure and Disturbance in a Tropical Forest.

PROJECT DESCRIPTION: The processes that determSine the plant species diversity and structure of tropical forest are still uncertain despite many years of investigation. A tropical forest characteristically has few common species and many rare species, with conspecifics often widely distributed throughout the forest. The potential for inter and intra-specific interactions are numerous, and it is difficult to determine which factors maintain species diversity or how rare species survive in the population. Factors that we believe contribute to tropical forest structure and composition include the physical environment and past history of the forest, species-specific physiological requirements for light, nutrients and water necessary for growth, survival and reproduction, and pathogens and herbivores. Despite the substantial amount of information available about these factors, we are still unable to accurately model the current composition of tropical forest or to predict its future response to human and natural disturbances.

The Luquillo Forest Dynamics Plot (LFDP), previously known as the Hurricane Recovery Plot (Zimmerman et. al. 1994) and the Luquillo long-term ecological research grid (Soil Survey 1995), is a 16-ha forest plot (SW corner 18° 20’ N, 65° 49’ W) located near El Verde Field Station. The plot is 500 m N-S and 320 m E-W and is divided into 400 20 x 20 m quadrats, with each quadrat sub divided into 16 5 x 5 m sub-quadrats. The field station and LFDP are in the Luquillo Mountains of northeastern Puerto Rico, approximately 35 km southeast of San Juan. Information from the LFDP contributes to the efforts of the Center for Tropical Forest Science (CTFS, Smithsonian) network of large tropical forest plots in order to improve our understanding of tropical forest and to predict its future. Large plots (typically 50 ha) are required to cover local environmental variation, include sufficient numbers of individuals of both the common and rare species, and to determine plant spatial relationships. Population monitoring is required over many years to elucidate tree life histories, species interactions and population changes in order to determine the forest response to environmental changes and disturbance.

The LFDP is unique among the CTFS sites as it has a history of land use disturbance and also hurricane damage. These two disturbance types interact and influence the community dynamics and species composition in the LFDP. The Northern area (approximately two thirds of the plot) was disturbed by tree felling and farming until 1934 when the land was purchased by United States Department of Agriculture, Forest Service. The Southern third was not farmed and only suffered relatively light disturbance from selective logging. Aerial photographs taken in 1936 show differences in canopy cover caused by the patterns of land use history. Clear patterns in the distribution of some species reflect this land use history (Thompson et. al. in press). The distribution of species as a result of the land use history interacts with hurricane disturbance, as those species colonizing the northern part of the LFDP are more susceptible to hurricane damage (Zimmerman et. al. 1994). Major hurricanes struck the forest area of the LFDP in 1928 and 1932 and after a 66 year period with relatively little hurricane damage, the forest was struck by Hurricane Hugo in 1989 and Hurricane Georges in 1998, both hurricanes causing significant damage.

LFDP CENSUS HISTORY.

The LFDP was established in 1990 and the censuses are carried out in accordance with CTFS protocol (Condit 1998) with only minor variations. The first assessment of stems >= 10 cm D₁₃₀ (diameter at breast height [DBH] of 130 cm from the ground) consisting of stems damaged by Hurricane Hugo (September 1989) was carried out from August 1990 to September 1991 (Everham 1996). The first complete census of all stems >=1 cm D₁₃₀ lasted from August 1990 to September 1993. This first census was divided into three surveys with the first survey (August 1990 to February 1992) comprising all free standing (excluding lianas) woody stems >= 10 cm D₁₃₀. The second survey (overlapping the third survey) consisted of checks on a small number of quadrats in which a few large stems >= 10 cm D₁₃₀ were found that had been "missed" during the first survey. The third survey of woody stems >= 1 cm <10 cm D₁₃₀was carried out between April 1992 and September 1993. During Census 1 surveys 2 and 3 stems were found that were >=10 cm D₁₃₀ and, therefore, were most likely to have been present in the forest at the time of Census 1 survey 1. In addition in Census 2 (November 1994 to October 1996), stems were found >=3 cm D₁₃₀ (>=5 cm D₁₃₀for Cecropia schreberiana and Schefflera morototoni) which may have been missed in Census 1. In order to include these "missed" stems in the appropriate census and survey we calculated what diameter the stem would have been at the time the quadrat in which it was located was initially assessed. These "missed" stems were allocated to earlier censuses and census surveys based either upon the actual growth rate of that stem, if more than one measurement was available, or the median growthrate for that species. The median growthrate was calculated for two size classes of stems >=1, <10 cm, or >=10 to 30 cm D₁₃₀. Using the most appropriate growthrate the diameter of the "missed" stem was extrapolated back in time to estimate the stem diameter at the correct survey time in Census 1. If the calculated diameter matched the size class for an earlier survey the stem was allocated to it with its estimated diameter. Information for stems >=10 cm D₁₃₀ damaged during Hurricane Hugo was combined with data for stems >=10 cm D₁₃₀, in census 1 survey 1 together with "missed" stems recorded in later surveys to reconstruct the forest as it was at the time of Hurricane Hugo. The reconstruction to represent the forest at the time of Hurricane Hugo did not include diameter extrapolations back to September 1989, but to the time at which the appropriate size class of stems were measured between August 1990 and September 1993. The palm Prestoea acuminata was allocated to earlier census surveys based upon the height of the point of measurement and additional observations. Further details on the procedures for allocating these "missed" stems to the appropriate census surveys can be found in the descriptions in the relevant data files. The last corrections to the Census 1 this data were made in May 2001.

In all censuses individual stems of the specified size were tagged, identified and measured for D₁₃₀. On multiple stemmed plants, all stems were individually tagged and the group of stems representing an individual plant was recorded. In the first and second census stems >=10 cm D₁₃₀ were mapped. Following CTFS protocol we are conducting the censuses at 5 year intervals. The second census (November 1994 to October 1996) consisted of only one survey with all stems >=1 cm D₁₃₀ censused at the same time, although only stems >=10 cm D₁₃₀were mapped. The third census (funded by the Andrew Mellon Foundation) started in July 2000 and is expected to finish in April 2002. In this third census, in addition to mapping stems >=10 cm D₁₃₀, we are also mapping the location of stems >=1 cm D₁₃₀.

ACKNOWLEDGMENTS:

We are grateful for the work of many people who helped inventory the LFDP. In particular, technicians: R. DeLeon, J. Bithorn, M. Aponte, A.-L. Méndez, M. Estades, A. Estrada, S. Matta, plant taxonomist B. Boom, and data manager Eda Melendez. Many volunteers, too numerous to mention, were also a tremendous help with the census. We thank the United States Department of Agriculture and Natural Resources Conservation Service, Lincoln, Nebraska, USA for the soil survey. The International Institute of Tropical Forestry (IITF) gave us access to their historical records and timber cruise surveys, and we thank Dr. Frank Wadsworth and Octavio Jodan who helped interpret them. John Thomlinson helped prepare the digital maps of stem locations and the soil map. The aerial photographs were analyzed at The Harvard Forest, Harvard University.

LTER CORE AREAS: (Annotate all that apply)

Population Dynamics

Disturbance Patterns

Primary Productivity

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

Recovery After Disturbance

Disturbance Regime

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):

Note: If for some reason you have problems accessing and downloading the data through the forms, send us a message to emelendez@lternet.edu in which you give us a brief statement of the purpose to use the data.

DATA SET ABSTRACT: File LFDP_CENSUS1 contains data for the Census 1 (Survey 1,2,and 3) of the LFDP including the Tag number Species code, quadrat location and date and stem diameter D130 (diameter measured at 130 cm from the ground (DBH). It also contains the diameter as recorded for all stems in survey 1, 2 and 3. LFDP_CENSUS1a has the same structure as LFDP_census1. In LFDP_census1a file, however, the stem diameters have been calculated to allocate "missed" stems that were found in survey 2, 3 or Census 2 to either Census 1 survey 1 (stems >=10 cm D130) or Census 1 survey 3 (stems >=1, <10 cm D130).

We calculated the diameter the stem would have had, if it had been recorded at the same time the quadrat it was located in was assessed, in the appropriate survey for that stem size. To extrapolate the stem size back in time, we used the actual growth rate of that individual stem if more than one measurement was available. If only one diameter measurement was available we used the median growth rate for that species in the appropriate size class (median growthrate of stems <10 cm, or median for stems >=10, <30 cm D130). In our publications we will combine data sets LFDP_census1 and LFDP_census1a to make Census 1 and to reconstruct the forest for stems >= 10 cm D130 at the time of Hurricane Hugo.

We have divided the data into two separate files to ensure that when stem diameters are compared to future censuses the diameter data in LFDP_census1a is not used to calculate growth rates. The dates in LFDP_census1a show the date at which the real diameter was measured in survey 2 or 3 and not the time that the calculated diameter (Fdiam sur1/s2/s3) represents for the quadrat in which the stem was located. Blank in the date field in LFDP_census1a means that the tree was first measured in Census 2 and the diameter given (Fdiam sur1/s2/s3) was extrapolated back in time to Census 1. The last corrections to the Census 1 data were made in May 2001.

The National Science Foundation requires that data from projects it funds are posted on the web two years after any data set has been organized and “cleaned”. The data from each census of the LFDP will be updated at intervals, as each survey of the LFDP shows errors in the previous data collection. After posting on the web, researchers who are not part of the project are then welcome to use the data. Given the enormous amount of time, effort and resources required to manage the LFDP, obtain these data, and ensure data accuracy, LFDP Principal Investigators request that researchers intending to use this data comply with the requests below. Through complying with these requests we can ensure that the data are interpreted correctly, analyses are not repeated unnecessarily, beneficial collaboration between users is promoted and the Principal Investigators’ investment in this project is protected.

· Submit to the LFDP PIs a short (1 page) description of how you intend to use the data;

· Invite LFDP PIs to be co-authors on any publication that uses the data in a substantial way (some PIs may decline and other LFDP scientists may need to be included);

· If the LFDP PIs are not co-authors, send the PIs a draft of any paper using LFDP data, so that the PIs may comment upon it;

· In the methods section of any publication using LFDP data, describe that data as coming from the “Luquillo Forest Dynamics Plot, part of the Luquillo Experimental Forest Long-Term Ecological Research Program”;

· Acknowledge in any publication using LFDP data the “The Luquillo Experimental Forest Long-Term Ecological Research Program, supported by the U.S. National Science Foundation, the University of Puerto Rico, and the International Institute of Tropical Forestry”;

· Accept that the LFDP PIs can not guarantee that the LFDP data you intend to use has not already been submitted for publication or published.

DATA SET METHODS: The LFDP censuses are carried out according to CTFS protocol (Condit 1998) with minor exceptions. All stems >= 1 cm D₁₃₀ (diameter at 130 cm above the ground [DBH]) are measured for diameter, tagged, identified and mapped. Stems <5 cm diameter were measured with calipers and stems >= 5 cm were measured with diameter tape. There are three notable differences between this data set and the CTFS protocol. In addition we also recorded Heliconia carribea culms and tree fern Cyathea arborea and fern Nephelea portoricensis. A full protocol is available on request.

· The Census 1 data contained in these files is comprised of three surveys as noted in the dataset abstract and project description above.

· Recording multiple stemmed plants and trees with sprouts. As this forest suffers hurricanes many trees do not die standing, before falling over, but are pushed over by wind and other trees during hurricanes. These trees then sprout and contribute significantly to the structure of the forest. In the LFDP one stem (usually the largest diameter) on a multiple stemmed plant is designated as the "main stem". This tag number always represents that individual plant even if the actual stem so numbered eventually dies. The stem with a main stem tag number is always recorded as alive if there are any sprouts or other stems living on the plant. All sprouts that arise along the whole length of a prone stem are individually tagged and measured and the corresponding number of the "main stem" that they are grow from, is put in the "main stem" field in the data set. The "main stem" system is also used for branches and sprouts that arise below 130 cm from the ground and attain a diameter of >= 1 cm D₁₃₀. Counts of individuals must be distinguished from counts of stems in most analyses.

· The third difference is that palms Prestoea acuminata are not always measured only at 130 cm from the ground see below on discussion for "palm height".

· Heliconia sp. culms were included in Census 1 survey 3. Culms were counted in easily countable groups (it is not possible to distinguish individuals). Culms were counted it they reached 10 cm in height in a clump. The number of culms is recorded in "no culms sur3" field. Musaseae sp. ie plantains and bananas were not identified to species and were also counted as culms.

· Tree ferns were included in the census as soon as it was possible to measure the diameter of the stem at 130 cm from the ground, without interference from the frond bases.

· Tag number is a unique number to identify each individual stem (not individual tree). A negative tag number means there was an error in the census data and two stems were given the same number. These duplicates could not be given new tag numbers for a variety of reasons, so remain in the data as negative tag numbers to preserve the unique tag number requirement.

Quadrat describes the position of each 20 x 20 m quadrat within the grid structure of the 16 ha plot (see details of variables). Each 20 m x 20 m quadrat is subdivided into 16 5 m x 5 m subquadrats and each stem is located at the subquadrat scale by the subquadrat number.

NEWSPP is the species code after the stem was re-identified during the second census. This code represents the first three letters of the genus and first three for the species in most cases. Exceptions occur when species have changed their names, or when confusion between species may arise using this 6 letter code. Full species names are listed in another file (see other data sets below)

Palm height sur1/s2/s3, is the height at which the diameter on the Prestoea acuminata previously called Prestoea montana (PREMON). Palms do not usually increase in diameter with time and in order to incorporate this important component of this forest the palms are measured in a slightly different manner than tree stems. When the newest frond of a palm arises at a height of 130 cm from the ground the palm is entered into the census and the diameter is measured between the leaf scars on the "bole" of the last two fronds that have fallen off. Measuring above this would involve measuring around fronds that would fall off at a later date. The height at which this diameter measurement was taken was recorded as "palm height". Older palms that have a bole that extends above 130 cm from the ground always have their diameter measured at this height. Errors in the data recording meant that for many palms in Census 1 survey 1 no palm heights were recorded. Where this is the case I have inserted -130 to indicate that the diameter measurement was most likely recorded at 130 cm from the ground. For some palms I used supplementary data to allocate palms to the appropriate survey when the palm height information was not recorded. These codes -100, and -101 do not indicate any palm height measurement.

Everham, E. M. III 1996. Hurricane disturbance and recovery: An empirical and simulation study of vegetation dynamics in the Luquillo Experimental Forest. PhD. State University of New York.

Soil Survey Staff. 1995. Order 1 Soil Survey of the Luquillo Long-Term Ecological Research Grid, Puerto Rico. United States Department of Agriculture, Natural Resources Conservation Service, Lincoln, Nebraska, USA.

Zimmerman, J. K., E. M. Everham, III, R. B. Waide, D. J. Lodge, C. M. Taylor, and N. V. L. Brokaw. 1994. Responses of tree species to hurricane winds in subtropical wet forest in Puerto Rico: implications for tropical tree life histories. Journal of Ecology 82:911-922.

CROSS-REFERENCES (other data sets related to this one): LTERDBAS46: Elevation at grid points on the Luquillo Forest Dynamics Plot (LFDP), Puerto Rico; LTERDB47: Physical environment of the Luquillo Forest Dynamics Plot (LFDP), Puerto Rico, LTERDB57: Tree damage by Hurricane Hugo at the Luquillo Forest Dynamics Plot (LFDP), Puerto Rico, LTERDB60: Tree Map for Census at the Luquillo Forest Dynamics Plot (LFDP), Puerto Rico; LTERDB62: Canopy height profile starting 1992, 1994 and 1996 of the Luquillo Forest Dynamics Plot (LFDP), Puerto Rico; LTERDB118: Species names and codes of the Luquillo Forest Dynamics Plot (LFDP), Puerto Rico; LTERDB119: Census of species, diameter and location at the Luquillo Forest Dynamics Plot (LFDP), Puerto Rico; LTERDB129: Temperature and humidity in the LFDP (40 points)

STORAGE SITES (of data files): Paper and computer files at ITES; Computer files at El Verde Field Station

INVESTIGATOR'S ASSIGNED KEYWORDS: Luquillo Forest Dynamics Plot, LFDP, Hurricane Recovery Plot, plant community composition, plant diversity, Luquillo Experimental Forest, El Verde Field Station, Puerto Rico

LEF LTER OFFICIAL KEYWORDS (See table): EL VERDE, LFDP (EV Big Grid), MOIST, TABONUCO, COMMUNITY COMPOSITION, DISTURBANCE, HUMAN, HURRICANE, ENVIRONMENTAL VARIABLES, POPULATION DYNAMICS , PRIMARY PRODUCTION, TREE GROWTH, HIGHER PLANTS, FERNS, HERBS, PALMS, SHRUBS, TREES , PEER REVIEWED JOURNAL

PUBLICATIONS:
Brokaw, N., Fraver, S., Grear, J.S., Thompson, J., Zimmerman, J.K., Waide, R. B., Everham, E.M., Hubbell, S.P., Condit, R. and Foster, R.B., (2000). Disturbance and Canopy structure in two tropical forests. In press. R. Condit, and J. Lafrakie (eds) Tropical forest diversity and dynamism: results from a network of large plots. Smithsonian Institution.

Brokaw, N. and Thompson. J. (2000). The H for DBH. Forest Ecology and Management 129, 89-91.

García-Montiel, D. C. (In press). La presencia humana en los bosques neotropicales húmedos. In M. Guariguata and G. Kattan, editors. Ecología de Bosque Lluvioso Neotropical. Editorial Agroamérica, San José, Costa Rica.

Thompson, J., N. Brokaw, J. K. Zimmerman, R. B. Waide, E. M. Everham, III, D. J. Lodge, C. M. Taylor, D. García-Montiel, and M. Fluet. (In press). Land use history, environment, and tree composition in a tropical forest. Ecological Applications.

Thompson, J., Brokaw, N., Zimmerman, J.K., Waide, R.B., Everham, E.M.. and Schaefer, D.A. (2000). The Luquillo forest dynamics plot. (In press). R. Condit, and J. Lafrakie (eds) Tropical forest diversity and dynamism: results from a network of large plots. Smithsonian Institution.

FILING:
_X_ "File" copy only : Data Management will only file an electronic copy of the data file and its documentation
___ "Enter" data on-line : Data Management will be in charge of entering the data on computer files (Contact Eda C. Meléndez)

SITES DESCRIPTION: The LFDP is within the Luquillo Experimental Forest (LEF, established in 1956) which is coterminous with the Caribbean National Forest and covers 11,330-ha of the Luquillo mountains (Brown et al. 1983). There are four different forest types within the LEF including tabonuco, colorado, palm-brake, and dwarf forest. These forest types are associated with different soil types and are roughly stratified by elevation (Brown et al. 1983). The LFDP lies within the tabonuco forest that is named after a dominant tree, Dacryodes excelsa Vahl (Burseraceae). Tabonuco forest develops best on low, protected, well-drained ridges below 600 m a.s.l. Mean canopy height in tabonuco forest is about 20 m, with tallest trees to c. 35m. Few trees in the LFDP exceed 1 m D₁₃₀. The forest in Puerto Rico is subject to hurricane damage and canopy height is lower, and canopy structure is broken, in the years after hurricanes.

The climate is classified as tropical montane in Walsh’s (1996) tropical climate system, and as subtropical wet in the Holdridge life zone system (Ewel and Whitmore 1973). Annual rainfall at El Verde averages just over 3500 mm yr^-1 (1975-1999). On average there is no month with <200 mm of rain, although a drier season occurs from January through April. The highest rainfall recorded at El Verde between 1975 and 2001 (370 mm in less than 12 hours) fell on 17 April 1997. There are also severe droughts, such as in 1994, when less than 70% of the average annual rain fell, and many small streams in the forest stopped flowing entirely for two months. Daily average maximum air temperature is 25.2 ^°C, minimum is 20.5 ^°C, and average is 22.8 ^°C (Brown et al. 1983, and also see weather data on this web site). Severe hurricanes struck the LFDP forest area in 1928, 1932, 1989 and 1998.

Geographical positional system (GPS) Coordinates for each location:

location	latitude	longitude
South West Corner of plot	18° 19' 26" North	65° 49' 3" West

VARIABLES (ATTRIBUTES):

FILE NAME OR #ABOVE (all in which the variable appears)	1, 2
ABBREVIATION (as it appears on the data file)	No. culms sur 3
NAME OF VARIABLE	Number of culms recorded in survey 3
DEFINITION OF VARIABLE	No of culms of Heliconia sp or Musaseae sp. recorded in Census 1 survey 3
UNIT	none
PRECISION	N/A
RANGE OR LIST OF VALUES	1-43
DATA TYPE	Integer
MISSING DATA CODES	Blank probably means the species was a woody stem so no count was recorded. Blank for HELCAR or MUSSPP means not recorded.

Data File No.	Data File Identifier	On-Line Filename	Starting Date	Periodicity of sample	Period
1	LFDP census 1 species, diameter and location.	LFDP_census1.txt	August 1990	once	February 1992 ( May 2001, including data corrections)
2	LFDP census 1 species, diameter and location.	LFDP_census1a.txt	August 1990	once	February 1992 ( May 2001, including data corrections)
3	LFDP census 2species, diameter and location.	LFDP_CENSUS2.txt	November 1994	once	October 1996 (May 2001, including data corrections)
4	LFDP census 2species, diameter and location.	LFDP_CENSUS2a.txt	November 1994	once	October 1996 (May 2001, including data corrections)

Jill Thompson	Jill@coqui.net
Jess Zimmerman	jzimmerman@lternet.edu
Nicholas Brokaw	nbrokaw@lternet.edu

Robert B. Waide	rwaide@lternet.edu
Wyn M. Everham III	eeverham@fgcu.edu
D. Jean Lodge	DJLodge@coqui.net
Charlotte M. Taylor
Diana Garcia-Monteil
Marcheterre Fluet

Jill Thompson	Jill@coqui.net	787-380-3220
Nicholas Brokaw	nbrokaw@lternet.edu	1-787-764-0000 x 4940

File Name or # above (all in which the variable appears)	LFDP_CENSUS2 and LFDP_CENSUS2a	LFDP_CENSUS2 and LFDP_CENSUS2a
Abbreviation (as it appears on the data file)	Tag	Date Census 2
NAME OF VARIABLE	Tag	Date stem diameter recorded in census 2.
DEFINITION OF VARIABLE	Unique number for each stem.	Date in form month/day/year
UNIT	None	month/day/year
PRECISION	N/A	+ or - 2 weeks
RANGE OR LIST OF VALUES	From -127736 to 139316 with many numbers not used	From 10/26/94 to 6/12/97 with many dates not used. For combined files LFDP_CENSUS2 and LFDP_CENSUS2a
DATA TYPE	Integer	Date
MISSING DATA CODES	None	Blank, should not be any