DOI: 10.6084/m9.figshare.21427230.v1
title: We have established a database of tropical rainforests in Hainan Island

description:  
Hainan Island in China is a special economic and pilot free-trade zone located on the northern edge of the Indo Malay Rainforest (18° 09’–20° 11’ N, 108° 36’–111° 04’ E). Hainan Island is composed of 18 cities and counties. The Hainan Island covers an area of 34,000 km2 and has a forest coverage of 57.36%. It is the largest contiguous tropical rainforest in China.
    Using ArcGIS 10.8 software, the database was established as follows:
    (1) Based on the daily observation data of 553 meteorological stations in Hainan Island from 2003 to 2018, a climate database (1 km resolution) consisting of annual average maximum temperature, annual average minimum temperature, and annual average rainfall was constructed by spatial interpolation. By providing a prototype of the dynamic climate data, a website can maintain local climate data in the local system, while another centralized website continuously updates the data through a public database and provides access to all website data.
    (2) The Chinese soil science database was utilized (the reference before 1 January 2021). In this study, spatial interpolation was used to generate the soil types: pH-H2O, pH-KCl, total nitrogen, potassium, and phosphorus contents, and other soil databases (2 km resolution).
    (3) Based on SRTM data and Hainan administrative boundary, a DEM terrain database (90 m resolution) was generated.
    (4) Combining the population statistics data of Hainan Island for 2003, 2008, 2013, and 2018 with land-use types, night light brightness, and residential density, the population data were distributed to 3.06 million grids according to the multiple-factor weight distribution method, and a human-disturbance database (1 km resolution) of population dynamic evolution was generated by spatial interpolation. In this way, the population of a specific area could be estimated by adding the population involved in each grid area.
    (5) Based on China’s National Forest Continuous Inventory data of Hainan for 2003, 2008, 2013, and 2018 and Landsat 7 and Landsat 8 remote sensing image interpretation data in Hainan Island, a woodland range database (1 km resolution) consisting of woodland, shrubbery, economic forest, bamboo forest, and other woodlands was generated.
    (6) Based on China’s National Forest Continuous Inventory data of Hainan for 2003, 2008, 2013, and 2018, 133 permanent sample plots were screened out, and the 133 permanent sample plots contained 16,280 sample trees. The forest biomass data of 70 main tropical rainforest tree species (280 trees) were collected using the standard tree full digging method. A tropical rainforest biomass database of permanent sample plots was generated using the <em>W</em>=<em>a×</em>(<em>D2H</em>)<em>b</em> model; where <em>W</em> denotes tropical rainforest biomass, <em>D</em> is DBH, <em>H</em> is tree height, and <em>a</em>, <em>b</em> are parameters. According to this model, we measured the forest biomass of 133 permanent plots in 2003, 2008, 2013 and 2018. Therefore, a forest biomass sample plot database for Hainan Island was established.
    (7) Based on the forest age from China’s National Forest Continuous Inventory data in Hainan (in 2018), the scope of the natural forest resource protection project in Hainan, manual visual interpretation data of Landsat historical remote sensing images, and a forest age database (1 km resolution) were generated by spatial interpolation.