In 1997, four 1-ha plots were established in secondary forests (12-25 yr since establishment on former pasture) in northeastern Costa Rica, in and around La Selva Research Station. In 2005, four additional plots were established, two in 10-yr old sites and two in old growth sites. The dataset contains information for 155,378 trees. Each year, from 1997-2017 all stems with a diameter of breast height ≥ 5 cm were censused in each site within 100 subplots of 10m x 10m. All but a few individuals were identified to species with confirmed identifications by local experts and vouchers. Life form for each species was also recorded as tree (reaching canopy), midtree (midstory tree), treelet (understory tree), shrub, liana, palm, or understory palm. The specimen-based data set contains data for all trees that were alive (not completely dead) and standing in each annual census, including notes on new recruits or damaged trees. Each tree individual is identified by a unique stem identifiation code and each entry has a unique specimen code. Each tree had a unique numbered tag, nailed into the stem. Locations of diameter measurements were painted on each tree to minimize annual variation and field technians had data from the prior year to confirm information for each tree. These were generally taken at 1.3 m height. In cases where a buttress or stilt root caused a stem irregularity, the measurement point was moved upwards beyond any stem irregularity. The diameter measurement for each specimen reflects each year's measurement point.

Data were collected by a team of local trained field technians (paraforesters) each year on a regular cycle. First, in each plot, tagged trees were relocated and measured for DBH and new recruits (5cm or greater) were tagged, identified, and measured for DBH. Tree condition was noted and dead trees were recorded as dead (fallen, rotted, standing dead). Vouchers were collected for species that needed identification and were compared with specimens in the La Selva herbarium.

Data were first processed in excel files and then transferred to a relational database (Biota) and checked carefully each year. Any mistakes were corrected in the field and reentered in the database. Species names were updated in the database following information provided by the La Selva scientific staff. 

Any missing values are indicated with NA. Some specimens are identified to genus only. A species list and plot information is also uploaded. 

Data columns are: 

1. Specimen code (unique for each tree censused)

2. Date of measurement

3. DBH in cm

4. Census year

5. Plot code

6. Species code

7. Genus

8. Species name

9. Lifeform

10. Family

11. X coordinate in meters

12. Y coordinate in meters

13. Stem ID (unique to each individual)

14. Quadrat (1-100 in each plot)

15. Stem Status (recruit, damaged, resprout, etc.)