https://doi.org/10.5061/dryad.8931zcs19

The dataset contains detailed information on 1801 large old trees (LOTs) collected from a variety of sources, including the local forestry authority, academic databases, and other public records. Over the course of field survey, researchers collected data on each tree’s growth status, biological traits, biomass structure, geographic location, and environmental context. The fieldwork adhered to official technical guidelines for surveying old trees and involved measuring tree age using wood cores extracted with an increment borer at a height of 1.3 meters. Tree height, trunk circumference, and crown spread were also recorded with high precision.

Description of the data and file structure

This study combined field surveys with government data to analyze LOTs in Hainan. We consulted the "Announcement on the List of Old and Valuable Trees in Hainan Province" issued by The People's Government of Hainan Province. Hereinafter referred to as "the LOT-list", the document provides essential tree data of trees over 300 years old, such as serial number, geographical location, elevation, age, height, diameter at breast height (DBH), and crown size.

1. No. (Number):
   This serves as an identifier for each tree in the dataset. It is a simple numbering system that helps keep track of individual trees for reference during analysis.
2. Location:
   This column specifies the geographic coordinates or administrative region where the tree is located. Location data is crucial for spatial analysis and understanding the environmental factors affecting tree growth and distribution. In this study, coordinates were cross-verified using GPS and Google Earth to ensure accuracy.
3. Family:
   The biological family to which the tree species belongs. The family classification helps group trees with similar genetic and biological traits. This is important for comparing trees within the same family or across different families in terms of growth patterns, environmental adaptability, and biodiversity significance.
4. Species Name:
   The scientific name of each tree species, typically in Latin. Knowing the species is essential for determining ecological characteristics, growth rates, and responses to environmental factors. Species identification also enables comparisons between different species and their conservation status.
5. Tree Age (Year):
   The estimated or measured age of the tree in years. Tree age is a key criterion for identifying large old trees (LOTs). In this study, the tree age was measured using growth rings from wood cores or obtained from local forestry records. This data is critical for studying the age structure of LOTs and their ecological importance over time.
6. Height (m):
   The total height of the tree, measured in meters. Tree height provides an indication of the tree's growth stage and overall health. It also contributes to understanding the tree's biomass and its role in carbon storage and ecosystem dynamics.
7. DBH (cm) (Diameter at Breast Height):
   The diameter of the tree trunk at 1.3 meters above ground level, measured in centimeters. DBH is one of the primary indicators of tree size and age. It helps in estimating biomass, wood volume, and other structural attributes of the tree. DBH is often used as a benchmark for tree classification in ecological studies.
8. Average Crown (m):
   The average width of the tree's crown (the spread of branches), measured in meters. The crown size reflects the tree’s growth environment, light availability, and competition with neighboring trees. Crown size also influences the tree's contribution to the ecosystem, such as shading, habitat provision, and interactions with other species.

Each of these data attributes contributes to understanding the ecological, biological, and spatial characteristics of large old trees in the study area. Together, they help reveal patterns in tree growth, environmental interactions, and conservation needs.

Sharing/Access information

Other publicly accessible locations of the data:

https://www.hainan.gov.cn/hainan/szfwj/202006/078af845e5e0484c8967e9bcc6b9fa74.shtml