Enriched Time-Series Dataset of Polish Forest Composition (2009-2019)

This dataset provides ready-to-use processed forest inventory data from Polish State Forests (Lasy Państwowe) covering 2009-2019, along with scientifically-derived metrics and publication-ready visualizations. This is the processed output dataset, whereas the related repository https://doi.org/10.34808/jks7-0274  provides the Python processing tool for users with custom data or analysis requirements.
DATASET CONTENTS
Data Format: CSV and Excel (XLSX)Temporal Coverage: 2009-2019 (11 years)Geographic Coverage: Polish State Forests (Lasy Państwowe)Species Covered: 10 major forest tree speciesTotal Records: 1,260 original records + 8 derived metric tables + 7 visualizations
FILE INVENTORY
Data Files (10):

forest_data_organized_main.csv - Enhanced original data with classifications (1,260 records)2. forest_data_organized_basic.csv - Annual summary statistics (11 years)3. forest_data_organized_diversity.csv - Biodiversity indices (11 years)4. forest_data_organized_age_structure.csv - Age distribution metrics (11 years)5. forest_data_organized_composition.csv - Species composition metrics (11 years)6. forest_data_organized_growth_productivity.csv - Growth and productivity (11 years)7. forest_data_organized_temporal_trends.csv - Year-over-year changes (10 transitions)8. forest_data_organized_species_specific.csv - Per-species annual metrics (110 records)9. forest_data_organized_METADATA_data_provenance.csv - Data source type definitions10. forest_data_organized_complete.xlsx - All tables combined with metadata sheet

Documentation Files (3):

 README.md - Complete dataset guide and usage examples
 DATA_DICTIONARY.md - Variable definitions and units
 METHODOLOGY.md - Scientific methods and formulas with citations

CALCULATED METRICS
All metrics calculated using scientifically-validated formulas:

Biodiversity Indices:  Shannon Index: H' = -Σ(pi × ln(pi)) [Shannon 1948],  Simpson Index: D = 1 - Σ(pi²),  Pielou's Evenness: J' = H'/ln(S), Species Richness: Count of distinct species
Age Structure Metrics:  Weighted Mean Age: Σ(Age_midpoint × Area) / Total_Area,  Age Class Distribution: % in Young/Middle/Mature/Old categories,  Age categories: Young (0-20 yr), Middle (21-60 yr), Mature (61-100 yr), Old (>100 yr)- Coefficient of Variation: std(age_class_areas) / mean(age_class_areas)
Composition Metrics: Coniferous/Deciduous ratios by area and volume,  Dominant species identification, Species proportion percentages
Growth & Productivity: Mean Annual Increment (MAI): Volume / (Area × Age) , Current Annual Increment (CAI): ΔVolume / Area,  Volume per hectare: Total_Volume / Total_Area, Year-over-year volume changes (absolute and percentage)
Temporal Trends:Annual area changes (ha and %),  Annual volume changes (m³ and %),  Volume per hectare changes
Species-Specific Metrics: Per-species area, volume, MAI, Species productivity (volume/ha), Area proportion by species

DATA PROVENANCE SYSTEM
Source Type Categories:- RAW: Original data from XLSX file (trustworthiness: HIGHEST)- RAW_SUMMED: Sum of raw values (trustworthiness: HIGH)- CALCULATED: Formula-derived from raw data (trustworthiness: MEDIUM-HIGH)- COUNTED: Direct count from raw data (trustworthiness: HIGH)- DETERMINED: Identified through analysis (trustworthiness: HIGH)- ESTIMATED: Model-based estimation (trustworthiness: MEDIUM) - not used in current version