[ 1 ] Bai LS, Feng ZK, Li YD, Nie ML, Sui HD. Inventory system of forest resources and its implementation based on PDA. J Beijing For Univ 2008;S1:138–42. Chinese. link1

[ 2 ] Wang GD, Guo GM, Cao BB, Jiao S. [On the application value of UAV remote sensing in forest resources investigation]. Technol Enterp 2014(15):383. Chinese. link1

[ 3 ] Feng ZK, You XB, Ren YQ. Discussion on monitoring system for forest resources and environment based on 3S technology. J Beijing For Univ 2001;23(4):90–2. Chinese. link1

[ 4 ] Fan YX, Feng ZK, Mannan A, Khan TU, Shen CY, Saeed S. Estimating tree position, diameter at breast height, and tree height in real-time using a mobile phone with RGB-D SLAM. Remote Sens 2018;10(11):1845. link1

[ 5 ] Gao X. [Research on informatization approaches for forest resources inventory and monitoring] [dissertation]. Beijing: Beijing Forestry University; 2015. Chinese. link1

[ 6 ] Liu J, Feng Z, Yang L, Mannan A, Khan TU, Zhao Z, et al. Extraction of sample plot parameters from 3D point cloud reconstruction based on combined RTK and CCD continuous photography. Remote Sens 2018;10(8):1299. link1

[ 7 ] Feng Z, Huang X, Forest Liu F. survey equipment and development of information technology. Trans Chin Soc Agric Mach 2015;46(9):257–65. Chinese. link1

[ 8 ] Gao FX. Characteristics and development suggestions of forest resources in Kaiyuan City. J Green Sci Technol 2014;5:116–7. Chinese. link1

[ 9 ] Zhou GH, Zeng WS, Chen XF. Problems and countermeasures of forest resource and ecological condition monitoring in China. Cent South For Inventory Plan 2006;25(4):1–5,9. Chinese. link1

[10] Qiu Z, Feng Z, Jiang J, Lin Y, Xue S. Application of a continuous terrestrial photogrammetric measurement system for plot monitoring in the Beijing Songshan National Nature Reserve. Remote Sens 2018;10(7):1080. link1

[11] Qiu ZX, Feng ZK, Wang MM, Li ZR, Lu C. Application of UVA photogrammetric system for monitoring ancient tree communities in Beijing. Forests 2018;9 (12):735. link1

[12] Chmura GL, Anisfeld SC, Cahoon DR, Lynch JC. Global carbon sequestration in tidal, saline wetland soils. Global Biogeochem Cycles 2003;17(4):1–22. link1

[13] Houghton RA. Aboveground forest biomass and the global carbon balance. Glob Change Biol 2005;11(6):945–58. link1

[14] Liu J, Feng Z, Mannan A, Yang L. Positioning of coordinates and precision analysis of sample trees using the intelligent forest survey calculator. Comput Electron Agric 2019;159:157–64. link1

[15] Chang C, Feng ZK, Lin YC, Qiu ZX. Development and application of new generation forest survey technology system and observation equipment. Beijing Surv Mapp 2018;32(12):1412–7. Chinese. link1

[16] Fang JY, Wang GG, Liu GH, Xu SL. Forest biomass of China: an estimate based on the biomass–volume relationship. Ecol Appl 1998;8(4):1084–91. link1

[17] Liu J, Feng Z, Mannan A, Khan TU, Cheng Z. Comparing non-destructive methods to estimate volume of three tree taxa in Beijing, China. Forests 2019;10(2):92. link1