Dataset of plant species composition and community characteristics of the Changbai Mountain broadleaf Korean pine forest permanent plot from 2005 to 2010

1. Data Collection LocationThe Changbai Mountain deciduous Korean pine forest comprehensive observation site (central geographic coordinates: 128.0956E, 42.4030N, elevation 784 m) is located in Erdaobaihe Town, Antu County, Yanbian Korean Autonomous Prefecture, Jilin Province.2. Data Collection MethodsThe Changbai Mountain Forest Ecosystem Research Station, following the "Observation Indicators and Standards for Terrestrial Ecosystem Biology," further divides the long-term monitoring plot of 40 m × 40 m into secondary plots of 5 m × 5 m, totaling 64. For convenience and research needs, the monitoring plot is referred to as the Level I plot for tree layer observation, and the secondary plot is referred to as the Level II plot for shrub layer and herbaceous layer observation.  - Tree layer observation: Investigate the diameter at breast height, height, and cover of each tree in the Level I plot.    - Shrub layer observation: Mechanically sample and conduct long-term observation on 17 fixed Level II plots. Set up a 2 m × 2 m small plot in each selected Level II plot to investigate the height and cover of each shrub (clump).    - Herbaceous layer observation: Conducted within the Level II plots selected for shrub layer investigation. Set up a 1 m × 1 m small plot in each selected Level II plot for inter-annual observation of the herbaceous layer. If necessary, all herbaceous plants can be removed for observation to investigate the height and cover of each herbaceous plant (clump) within the small plot.- Epiphyte observation: Investigate the category of epiphytes on each tree in the Level I plot.  - Liana observation: Investigate the base diameter and length of lianas within the Level I plot.3. Data ProcessingData processing includes checking and completing original record information, data entry and verification, and data statistical analysis.The specific statistical analysis methods are as follows:  - Tree layer: Based on individual tree surveys, statistics are calculated by Level II plot and species: number of individuals, average diameter, average height, and biomass calculated using models (including stem dry weight, branch dry weight, leaf dry weight, fruit (flower) dry weight, bark dry weight, aerial root dry weight, aboveground total dry weight, and underground total dry weight). Based on the results of individual tree surveys by species, statistics are calculated by Level II plot: species number, dominant species, average height of dominant species, density, aboveground total dry weight, and underground total dry weight.  - Shrub layer: Based on species surveys by Level II plot, statistics are calculated by plot: number of individual plants (clumps), average height, biomass calculated using models (including branch dry weight, leaf dry weight, aboveground total dry weight, and underground total dry weight), species number, dominant species, average height of dominant species, density, aboveground total dry weight, and underground total dry weight.  - Herbaceous layer: Based on species surveys by Level II plot, statistics are calculated by plot: number of individual plants (clumps), average height, aboveground total dry weight, species number, dominant species, average height of dominant species, density, aboveground total dry weight, and underground total dry weight (underground sampling plot 1 m × 1 m × 0.25 m).  - Epiphytes: Based on the survey of epiphytes on each tree, statistics are calculated by Level II plot and species: number of individual plants (clumps).  - Liana: Based on the survey within the Level I plot, statistics are calculated by Level II plot and species: number of individual plants (clumps), average base diameter, and average height.4. Database CompositionThe data set is stored in Excel format, including eight sheets. Sheet1 is for the composition of tree species in the Changbai Mountain deciduous Korean pine forest, with a total of 269 records, including indicators as shown in Table 2; Sheet2 is for the composition of shrub species, with a total of 66 records, including indicators as shown in Table 3; Sheet3 is for the composition of herbaceous species, with a total of 193 records, including indicators as shown in Table 4; Sheet4 is for the community characteristics of the tree layer, with a total of 118 records, including indicators as shown in Table 5; Sheet5 is for the community characteristics of the shrub layer, with a total of 32 records, including indicators as shown in Table 6; Sheet6 is for the community characteristics of the herbaceous layer, with a total of 32 records, including indicators as shown in Table 7; Sheet7 is for the species composition of epiphytes, with a total of 130 records, including indicators as shown in Table 8; Sheet8 is for the composition of liana species, with a total of 65 records, including indicators as shown in Table 9.5. Data Quality Control and AssessmentThe quality control of this data set follows the relevant monitoring specifications of the "Observation Indicators and Standards for Terrestrial Ecosystem Biology," with field surveys conducted by technicians with rich experience and professional skills, and the survey data is reviewed and verified by scientific researchers to ensure the scientific and accurate nature of the data.Specific measures are as follows:  - During field surveys: The observation time for the species composition and community characteristics of the Changbai Mountain deciduous Korean pine forest is mid-August (the peak of plant growth). Standardized measurement tools and methods are used for data collection, such as using the same model of measuring instruments to measure tree diameter, plant height, and liana base diameter to reduce measurement errors. Plant species identification, common names, and scientific names are based on the Plant Smart database. For plant species that cannot be determined on-site, photos should be taken and specimens collected for indoor analysis and identification. Field survey data records are checked by both the investigator and the recorder to ensure the accuracy of the data.  - Data entry: Paper data is transformed into electronic data, with one person entering and another verifying to ensure the accuracy of the data entry.  - Quality control and assessment: Quality control methods include threshold checks (comparing monitoring data with historical data over the years, verifying data that exceeds the historical data threshold range, deleting outliers or marking explanations), consistency checks (such as different order of magnitude compared to other measurement values), etc. Quality assessment is carried out by plotting dynamic graphs based on annual or seasonal units and comparing data from the same period.