# Title of Dataset: ---Enhanced Isohydric Behavior Decoupled the Whole-Tree Sap Flux Response to Leaf Transpiration under Nitrogen Addition in a Subtropical Forest This is the drawing data of each figure in the published article: Zhao Z, Zhao P, Zhang Z, et al. Enhanced Isohydric Behavior Decoupled the Whole-Tree Sap Flux Response to Leaf Transpiration under Nitrogen Addition in a Subtropical Forest[J]. Forests, 2022, 13(11): 1847. DOI: 10.3390/f13111847 Dates and Locations ------------------- * Dates of data collection: Field data collected between January and December in 2014 * Geographic locations of data collection: Shimentai National Nature Reserve in Northern Guangdong Province, China. (see publication for more details) Methodological Information ========================== * Methods of data collection/generation: In this study, two evergreen species (Schima superba Gardn. et Champ. and Castanopsis chinensis Hance) in our plots were selected to conduct fertilization experiments; these species have the highest importance value, implying their dominated role in the forest community. The N addition treatments were conducted from the canopy (CAN) of the forest with an iron tower (35 m). The following treatments were designed: the control (CK, without N addition); CAN25 (25 kg N ha−1 year−1); and CAN50 (50 kg N ha−1 year−1) to simulate a double (CAN25) and triple (CAN50) N deposition compared to a background wet deposition (CK). The shoot hydraulic conductance was measured using HPFM under a quasi-steady-state mode. The maximum shoot hydraulic conductance (Kshoot-max) was measured for both species. The sap flux density (JS) was measured on 38 (4–5 individuals in each plot) S. superba and 60 C. chinensis (5–6 individuals in each plot) individuals by self-made TDPs (thermal dissipation probes) sensors from January to December 2014. The stomatal conductance (GS) of the canopy can be estimated based on a equation. To characterize the water use strategy, the daily mean JS and GS (6:00–18:00) (JS-mean and GS-mean) were calculated, excluding the nocturnal data. In addition, the mid-day data (11:00–13:00) was also derived to depict the maximum water transport potential (JS-mid and GS-mid) for each tree individual. Considering the dry/wet oscillation throughout the year, those data were divided into dry and wet seasons. A boundary line analysis was adopted to depict the essential relation between the VPD and GS. To define the stomatal sensitivity to VPD, the boundary line data of the GS was log-transformed and linearly fitted to the VPD, and the slopes (GS-VPD) were used to characterize the stomatal controlling sensitivity to canopy the water loss, i.e., the isohydric behavior. The decreased GS-VPD under the fertilization treatments implied an enhanced stomatal control (a behavior more likely isohydric) and vice versa (a behavior more likely anisohydric). An analysis of variance (ANOVA) was conducted with SPSS Statistics (v18.0, IBM inc., Chicago, Illinois, USA) to evaluate the N fertilization treatment, seasonal change, and species difference effects (defined as Treatments, Seasons, and Species) on the JS, GS. GS-VPD was compared by an analysis of covariance (ANCOVA). All the data passed the normal distribution test. (see manuscript for details) Data and File Overview ====================== Summary Metrics --------------- * File count: 5 * Total file size: 63.9 KB * Range of individual file sizes: 15.6 KB - 20.3 KB * File formats: .xlsx Naming Conventions ------------------ * File naming scheme: data for each figure Table of Contents ----------------- * data for Figure 2.xlsx * data for Figure 3.xlsx * data for Figure 4.xlsx * data for Figure 5.xlsx * data for Figure 6.xlsx Details for: data for Figure 2.xlsx --------------------------------------- * Description: a file containing comparison of the maximum shoot hydraulic conductance (Kshoot-max) among different fertilization treatments. * Format(s): .xlsx * Size(s): 17.5 KB * Dimensions: 4 rows x 5 columns Details for: data for Figure 3.xlsx --------------------------------------- * Description: a file containing daily mean JS (JS-mean) and mid-day JS (JS-mid) under different seasons and species, JS-mean and JS-mid of S. superba and C. chinensis under nitrogen addition treatments. * Format(s): .xlsx * Size(s): 16.4 KB * Dimensions: 17 rows x 7 columns Details for: data for Figure 4.xlsx --------------------------------------- * Description: a file containing daily mean stomatal conductance (GS-mean) and mid-day stomatal conductance (GS-mid) under different N treatments for S. superba and C. chinensis, and in the dry and wet seasons. * Format(s): .xlsx * Size(s): 15.6 KB * Dimensions: 13 rows x 7 columns Details for: data for Figure 5.xlsx --------------------------------------- * Description: a file containing ANCOVA about the mid-day JS (JS-mid) fitted daily mean JS (JS-mean) and the mid-day GS (GS-mid) fitted daily mean GS (GS-mean) for S. superba and C. chinensis under different nitrogen addition treatments. ANCOVA indicated that the differences of slopes under nitrogen addition treatments were only significant for S. superba. * Format(s): .xlsx * Size(s): 20.3 KB * Dimensions: 22 rows x 7 columns Details for: data for Figure 6.xlsx --------------------------------------- * Description: a file containing the mean values(A-C) and ANCOVA about the linear fitting(D-E) of the slopes of VPD to GS (GS-VPD) under different nitrogen addition treatments, in the dry and wet seasons, S. superba and C. chinensis. ANCOVA indicated that the differences of slopes under nitrogen addition treatments were significant for both species. * Format(s): .xlsx * Size(s): 17.8 KB * Dimensions: 17 rows x 5 columns(A-C); 10 rows x 7 columns(D-E) - - - END OF README