DOI: 10.5061/dryad.d51c5b01q
title: Tropical rain forest canopy height measurements 1999 - 2018

description: The distribution of canopy heights in tropical rain forests directly
 affects carbon storage and the maintenance of biodiversity. We
 report here raw field data on annually-measured canopy height
 distributions over an old-growth tropical rain forest landscape in Costa
 Rica from 1999-2018. The data were taken at 231 points on a 5 x 5
 m grid in 18 0.50 ha plots that were initially sited with a stratified
 random design across local gradients of soil nutrients and
 topography. In temporal duration, resampling interval and spatial
 extent the data are currently the most detailed available for any forested
 landscape. A digitized version of the data has been published
 (Clark, Clark and Kellner 2021) based on this database. The
 version published here is the definitive raw data, and in case of
 discrepancies between the digitized and raw version the raw data are the
 primary data source. The raw data also contain numerous field
 notes that clarify rare or odd field events that provide context for the
 digitized data.
description: This data set contains the raw data for a study of tropical rain
 forest canopy heights carried annually from 1999 to 2018.  The study was
 carried out at the La Selva Biological Station in Costa Rica
 (10<sup>o</sup> 26’ N, 83<sup> o</sup> 59’ W) in
 old-growth Tropical Wet Forest.  All research was carried in a network of
 18 0.50 ha plots (50 x 100 m) that was sited using a strict
 stratified-random design based on local gradients of soil nutrients and
 topography (the CARBONO Project).  Plots were located in three contrasting
 edaphic conditions: flat areas on relatively more fertile old alluvial
 soils (A <i>alluvion</i> plots), flat ridgetops on less
 fertile residual soils (L <i>loma</i> plots), and steep
 residual soil slopes (P <i>pendiente</i> plots) (further
 explained in Clark et al. 2019).   Descriptions of forest structure and
 dynamics of these plots and the landscape, including analyses of the
 effects of the strong 1997-1998 El Niño event, have been reported in a
 series of publications (Clark et al. 2010, 2013, 2017, 2019). 
 Beginning in 1999 canopy height measurements were taken annually
 in the CARBONO plots on a 5x5 m grid.  Nine plots were censused in 1999,
 after which all 18 plots were censused annually from 2000-2018.  The
 detailed protocol for canopy heights measurements in given in S1
 Protocol.  At each of the 231 points per plot a 15-m extendable measuring
 pole was placed vertically at each point.  The pole was raised to the
 highest vegetation vertically above the point and vegetation height was
 measured to the nearest cm.  Verticality was measured with a Suunto
 clinometer.  If the highest vegetation was &gt;15 m tall, the point
 was classified as “high canopy”.  If there was no vegetation above the
 point in an area estimated to be at least 2 x 2 m canopy height was
 classified as &lt;2m.  Every
 year we assessed the precision of the canopy height estimates by
 remeasuring an average of 123 points after a one to several day interval. 
 Precision remeasurements were done in plot A1 in 1999, thereafter in plot
 L4.  Of the points that were classified as &gt;15 m height on the
 first census (N=1870), 99.4% were classified identically on the second
 assessment.  For the 571 points that measured &lt;15 m at both
 measurements the median absolute difference in height was 0.15
 m.   On 19 May 2018 a powerful storm hit the field site
 (Rader et al. 2020), causing extensive tree mortality and associated
 changes in canopy structure in several of the CARBONO plots.  All the data
 for 2018 were taken after than storm, beginning on 21 May 2018.
 Literature cited here: Clark, D.B., D.A. Clark and S.F. Oberbauer.  2010.  Annual wood production in a tropical rain forest in NE Costa Rica linked to climatic variation but not to increasing CO<sub>2</sub>.  Global Change Biology 16:747-759.  doi: 10.1111/j.1365-2486.2009.02004.x. Clark, D.A., D.B. Clark and S.F. Oberbauer.  2013.  Field-quantified responses of tropical rainforest aboveground productivity to increasing CO2 and climatic stress, 1997-2009.  Journal of Geophysical Research-Biogeosciences 118:1–12, doi:10.1002/jgrg.20067 Clark, D.B., D. A. Clark, S.F. Oberbauer and James R. Kellner.  2017.  Multidecadal stability in tropical rain forest structure and dynamics across an old-growth landscape.  PLOS One https://doi.org/10.1371/journal.pone.0183819. Clark, D.B., A. Ferraz, D. A. Clark, J. R. Kellner, S. G. Letcher and S. Saatchi.  2019.  ­Diversity, distribution and dynamics of large trees across an old-growth lowland tropical rain forest landscape.  PLOS One https://doi.org/10.1371/journal.pone.0224896 Rader AM, Cotrell A, Kudla A, Lum T, Henderson D, Krandikar H et al.  Tree functional traits as predictors of microburst-associated treefalls in tropical wet forests. Biotropica. 2020;00:1–5. https: //doi.org/10.1111/btp.12761
description: This data set contains the raw data for the canopy heights
 studies documented in the Related Works section. All digitized data on
 canopy heights were input from the field sheets archived here. In case of
 any discrepancy between the field sheets and the digitized data the field
 sheets are the original data source. In addition to being the original
 data, they also have a number of field notes that may clarify questions
 about the digitized data. To our knowledge there are no missing data, and
 all information necessary to interpret and use these data are given in the
 ReadMe.txt file. Each file also contains at the end copies of the
 protocols used by the field technicians each year (these vary very little
 from year to year). The original field data for the precision
 remeasurements (see Methods) are also included (plot A1 in 1999, plots L4
 thereafter). The data sheets all have the form shown
 below.  PLOT is the individual forest inventory plot (A1-A6, L1-L6, P1-P6
 see Clark et al. 2017), Y is the Y coordinate in the grid (0-50), X is the
 X coordinate in the grid (0 - 100), ALTURA CM is the canopy height at that
 point in cm (to 1500 cm, values exactly 1500 are coded as 1499, 1500 code
 = &gt;1500 cm), FECHA is the date, and COMENTARIOS are any additional
 field notes at that point. 
 PLOT Y X ALTURA  (CM) FECHA COMENTARIOS A1 0 0       A1 0 5