Database of Allometric Equations for Tree DBH–Sapwood Area Relationships in China

We present a comprehensive dataset comprising 139 allometric equations that describe the relationship between tree diameter at breast height (DBH) and sapwood area, compiled from 81 monitoring sites across China . The dataset encompasses 59 tree species from 37 genera and 23 families. Data are provided in both CSV and RData formats.All allometric relationships are expressed in power-law form, with 69% of the entries including the original data used to derive the equations. Overall, the equations exhibit strong goodness of fit, as evidenced by 83% of the models having an R² value of 0.9 or higher.The monitoring sites are widely distributed across China, spanning longitudes from 85.02°E to 122.37°E and latitudes from 18.6°N to 53.46°N. Site elevations range from 3 to 3,100 m, with mean annual temperatures varying from −6.7 to 24.5 °C and mean annual precipitation ranging from 90 to 1,956 mm, reflecting broad climatic and geographic representativeness.This dataset serves as a reference database for DBH–sapwood area allometric relationships and can be applied to sapwood area estimation, tree-level transpiration modeling, upscaling transpiration from individual trees to stand and regional levels, and the parameterization of forest hydrological models.