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<br> 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}

本数据集引用格式为：Ramos P, Villareal P, Condit R, Cushman KC, Muller-Landau HC. 2022. 巴拿马巴罗科罗拉多岛50公顷森林动态样地2015-2020年树木径向生长仪（dendrometer）年度观测数据. 史密森尼学会Figshare. DOI: 10.25573/data.19985066. 通讯作者：Helene C. Muller-Landau，邮箱：[e-mail]。
本数据集源自巴罗科罗拉多岛50公顷森林动态样地（隶属于史密森尼学会ForestGEO大型森林动态样地网络）内选定树木的径向生长仪绑带复测数据，其格式与Jessica F. Needham用于以下论文分析的数据一致：Needham JF, Arellano G, Davies SJ, Fisher RA, Hammer V, Knox R, Mitre D, Muller-Landau HC, Zuleta D, Koven CD. 热带森林树冠损伤及其对碳循环的影响. 2022. Global Change Biology。
本存档数据集包含2015年（第16次调查）、2016年（第18次调查）、2017年（第20次调查）、2018年（第22次调查）、2019年（第23次调查）及2020年（第24次调查）湿季末期的6次树木径向生长仪调查数据。
贡献说明：研究设计与监督：Helene C. Muller-Landau；数据收集：Pablo Ramos、Paulino Villareal；数据库设计与管理流程：Richard Condit、Helene C. Muller-Landau、Anudeep Singh；曲率校正直径计算：Matteo Detto、Helene C. Muller-Landau；质量保证与质量控制（QAQC）：Helene C. Muller-Landau、Pablo Ramos、Richard Condit、KC Cushman、Adam Collins、Pete Kerby-Miller、Suzanne Lao。
资助说明：巴罗科罗拉多岛50公顷样地树木径向生长仪数据收集工作始于汇丰银行气候合作伙伴项目（2007-2011年），后续由史密森尼学会ForestGEO项目资助。本研究依托巴罗科罗拉多岛50公顷样地开展并完成。该样地截至2015年的主要调查数据可通过以下文献获取：Condit R, Perez R, Aguilar S, Lao S, Foster R, Hubbell SP. 2019. 巴罗科罗拉多岛50公顷样地完整数据集：423617株树木，35年观测，2019版. DOI: 10.15146/5xcp-0d46。
树木选取采用尺寸分层与空间分层结合的设计，具体如下：在样地内随机布设100个40×40米的副样地，要求副样地互不重叠且其边界与20×20米样方的边界对齐。本数据集附带的`bci40x40sxy.txt`文件给出了这些副样地的中心坐标（采用50公顷样地的米级坐标系）。
所有胸径（DBH，即1.3米处树干直径，存在板根的样木取板根上方1.3米处直径）≥80厘米的树木均纳入全样地调查。胸径40-80厘米的树木，若位于40×40米副样地内则被纳入；胸径20-40厘米的树木，若位于40×40米副样地内的20×20米中心样方内则被纳入；胸径10-20厘米的树木，若位于40×40米副样地内的10×10米中心样方内则被纳入；胸径5-10厘米的树木，若位于40×40米副样地内的5×5米中心样方内则被纳入（注：此处5-10厘米胸径指胸径≥5厘米且<10厘米，其余胸径区间以此类推）。
初始样本于2007年基于2005年样地调查数据选取，且在每次主要样地调查（2010年、2015年）后，向空间-尺寸分层样本中补充新招募的个体。在基于2005年调查数据纳入初始样本的树木时，筛选阈值低于纳入阈值，以确保2005年后生长至目标胸径级的树木均被纳入。
部分选定树木因以下一种或多种原因不适宜安装树木径向生长仪绑带：棕榈科植物（因通常无直径生长而排除）、绞榕类植物（树干形态极不规则，绑带式径向生长仪无法有效获取木质部生长数据）、板根过大导致绑带需安装于7.6米以上高度（现有梯子和人员无法安全安装并复测该高度的绑带）、或大型藤本或绞榕类植物紧密附着于树干，导致绑带无法置于其下方，且置于上方的绑带无法有效反映树木生长情况。
对于多茎个体，若主茎符合纳入标准，则在所有直径≥5厘米的茎干上安装绑带，直径更小的茎干将采用游标卡尺测量。
树木径向生长仪调查最初每年开展两次，分别在湿季初期（5-6月）与湿季末期（11-12月）。但湿季初期的调查常显示树木较上一次湿季末期的测量值出现干缩现象。对附近AVA样地内另一小样本树木的两周一次复测结果显示，多数树木的干季干缩现象普遍存在，且多数树木需至湿季中期才能恢复至干季前的胸径水平。因此，为开展年度生长量监测，自2019年起取消湿季初期的调查。
树木测量与观测遵循以下协议：_{https://figshare.com/s/00d6ba1e9f113bcf3ac3}；基于绑带式径向生长仪数据计算胸径的流程遵循以下文档：_{https://figshare.com/s/43e3375f6614253a8bdd}