Summary: This supporting material contains multi-year image and measurement data used to document tree species identity and structural attributes in a Miyawaki forest across three consecutive years (2023-2025). The dataset includes tree-level image records organized by year, comprising photographs used to document tree height (H) and circumference at breast height (CBH), with file-naming conventions linking each image to a unique Tree ID (a number between 1 to 1200). For multi-stemmed trees, CBH measurements are provided separately for individual branches and explicitly labeled. Species identity corresponding to each Tree ID is supplied in a dedicated spreadsheet, enabling linkage between structural measurements and species information. Measured values of CBH were divided by pi (3.14) to calculate the corresponding value of DBH. Tree height and diameter at breast height (DBH) were measured directly in the field using a levelling staff and measuring tape, while DBH and height estimates were independently derived from images using WebPlotDigitizer (https://automeris.io/WebPlotDigitizer; Rohatgi, 2024). In addition, a consolidated spreadsheet provides measured and estimated values of tree height and DBH for all sampled trees across the three study years, supporting reproducible analyses and method validation. For a subset of trees, image records are absent due to field-based constraints such as mortality, occlusion, or limitations in capturing complete tree profiles. Together, these data support methodological development and evaluation of image-based tree measurement approaches and facilitate transparent assessment of temporal changes in tree structural attributes. Data Organization: This data is provided in a zip file (Miyawaki_Tree_Data), Upon extraction you will find two excel files and three subfolders. Name of the excel files are Tree_id_and_Species_name.xlsx and Measured_Estimated_Data(2023-2025).xlsx and name of subfolders are Tree_image_2023, Tree_image_2024, Tree_image_2025. Description of each item is provided below: Tree_id_and_Species_name.xlsx : This excel file contains columns for Tree ID (a number between 1 to 1200) and corresponding species name. Measured_Estimated_Data(2023-2025).xlsx : This excel file contains six sheets. Each sheet provides the Tree ID, Species name, Measured Data (cm) and Estimated Data (cm) for Tree H and DBH for the years 2023, 2024 and 2025. Tree_image_2023 : Contains images of tree measurement in the year 2023 and names of the image files based on Tree ID. Tree_image_2024 : Contains images of tree measurement in the year 2024 and names of the image files based on Tree ID. Tree_image_2025 : Contains images of tree measurement in the year 2025 and names of the image files based on Tree ID. Note: Image files named with only the Tree ID (without c/c1/c2/c3,etc.) represent tree height (H) measurement. In the image file names, the labels c, c1, c2, or c3 along with Tree ID indicate that the file contains images showing the measurement of CBH. For trees with multiple branches, CBH was measured separately and labeled as c1, c2, c3,etc. For certain Tree IDs, image records may be unavailable due to field constraints such as tree mortality, limited visibility, or difficulty in capturing the entire tree within the frame.