Annual dendrometer data from the Barro Colorado Island 50-ha forest dynamics plot for 2015-2020

Please cite these data as

Ramos, Pablo, Paulino Villareal, Richard Condit, KC Cushman, and Helene C.
Muller-Landau. 2022. Annual dendrometer data from the Barro Colorado Island
50-ha forest dynamics plot for 2015-2020. Smithsonian Figshare. DOI
10.25573/data.19985066

Corresponding author: Helene C. Muller-Landau, [e-mail]

These are data from recensuses of dendrometer bands on selected trees on the
Barro Colorado Island 50 ha forest dynamics plot, part of the Smithsonian
ForestGEO network of large forest dynamics plots.

They appear in the form in which they were used by Jessica F. Needham in
analyses for the following publication:

Needham, J.F., Arellano, G., Davies, S.J., Fisher, R.A., Hammer, V., Knox, R.,
Mitre, D., Muller-Landau, H.C., Zuleta, D., and Koven, C.D. Tree crown damage
and its effects on forest carbon cycling in a tropical forest. 2022. Global
Change Biology.

The data archived here are for six dendrometer censuses that took place in the
late wet seasons of 2015 (census 16), 2016 (census 18), 2017 (census 20), 2018
(census 22), 2019 (census 23), and 2020 (census 24).

Contributions:

Research design and supervision: Helene C. Muller-Landau
Data collection: Pablo Ramos, Paulino Villareal

Database design and curation procedure: Richard Condit, Helene C. Muller-
Landau, Anudeep Singh

Calculation of diameter with correction for curvature: Matteo Detto, Helene C.
Muller-Landau

Data QAQC (quality assurance and quality control): Helene C. Muller-Landau,
Pablo Ramos, Richard Condit, KC Cushman, Adam Collins, Pete Kerby-Miller,
Suzanne Lao.

Funding: The BCI 50 ha plot dendrometer data collection was initiated with
funding from the HSBC Climate Partnership (2007-2011) and was continued with
funding from the Smithsonian Institution ForestGEO program.

This study was located within and enabled by the Barro Colorado 50-ha plot.

The data for the main censuses of this plot through 2015 are available in the
following data publication:

Condit R., Perez, R., Aguilar, S., Lao, S., Foster, R., Hubbell, S.P. 2019.
Complete data from the Barro Colorado 50-ha plot: 423617 trees, 35 years, 2019
version. https://doi.org/10.15146/5xcp-0d46.

Trees were selected in a size-stratified and spatially stratified design, as
detailed below.

100 40x40 m subplots were placed randomly across the plot, with the constraint
that these plots were nonoverlapping and that their edges aligned with the
edges of 20x20 m quadrats. The centers of these plots, in 50 ha plot
coordinates (units of meters), are given in the file “bci40x40sxy.txt”,
included as part of this repository. All trees with a dbh (diameter at 1.3 m
or above buttresses) of 80 cm or larger were included throughout the plot.
Trees with a dbh of 40-80 cm were included if they were located within the
40x40 m subplots. Trees with a dbh of 20-40 cm were included if they were
located within 20x20 m subplots centered within the 40x40 m subplots. Trees
with a dbh of 10-20 cm were included if they were located within 10x10 m
subplots centered within the 40x40 m subplots. Trees with a dbh of 5-10 cm
were included if they were located within 5x5 m subplots centered within the
40x40 m subplots. (Here, dbh of 5-10 cm means dbh greater than or equal to 5
cm, and less than 10 cm, and so forth.)

The initial sample was selected in 2007 (based on the 2005 census data), and
new recruits into the spatially and size-stratified sample were added after
each main plot census (main plot censuses in 2010, 2015). In adding trees to
the initial census based on the 2005 census data, the size threshold for
checking trees was lower than the size threshold for inclusion, to try to
insure that trees that had grown into the size class since the 2005 census
were included. Some selected trees were not appropriate for installation of
dendrometers for one or more of the following reasons: palms (excluded because
they do not generally grow in diameter), strangler figs (form too irregular
for band dendrometers to provide useful information about woody growth), very
large buttresses which would require a band being placed above 7.6 m (not
possible to safely place and remeasure bands at this height with the available
ladder and personnel), or large lianas or strangler figs affixed so closely to
the trunk that a band could not be placed underneath them and that a band
above them would not provide useful information on tree growth. In the case of
multi-stemmed individuals, bands were placed on all stems above 5 cm if the
biggest stem qualified for inclusion, and smaller stems were measured with
calipers.

Dendrometer censuses were initially conducted twice per year, at the beginning
of the wet season (May-June) and end of the wet season (November-December).
However, the early wet season censuses often showed shrinkage of trees from
the previous late wet season measurements. Biweekly remeasurements of another
smaller sample of trees on the nearby AVA plot showed that dry season
shrinkage was common in many trees, and that many did not recover to their
previous dbh until well into the wet season. Thus for the purposes of annual
growth measurements, it was decided to abandon the early wet season
measurements starting in 2019.

Tree measurements and observations followed the protocol at
<https://figshare.com/s/00d6ba1e9f113bcf3ac3>

The calculation of dbh from the band dendrometer data follows the procedure
described at

<https://figshare.com/s/43e3375f6614253a8bdd>