Modified Ecosystem Demography (ED2) model with sagebrush (shrub) parameters

# Original Ecosystem Demography (ED2) model was developed by Moorcroft et al., 2001 and Medvigy et al., 2009, and team, which is available at github (https://github.com/EDmodel/ED2). # This repository contains modified Ecosystem Demography (ED2) model for sagebrush (shrub) PFT. In order to do so we primarily updated ed_params.F90 with additional PFT, which is represented by number '18'. For the initial works, we selected allometrics equations for temperate PFTs in ED2 to develop coefficients (parameters) related to allometric relationships (such as dbh to height , dbh to leaf biomass etc). We used cube root of volume to represent diameter to calculate allometric equations for shrubs, since they do not have clear main trunk like trees. Another source code ed_max_dims.F90 was also changed to update PFT dimensions. # This repository also includes namelist (ED2IN) file used to run sensitivity and optimization of sagebrush parameters. References Medvigy, D., Wofsy, S. C., Munger, J. W., Hollinger, D. Y., and Moorcroft, P. R.: Mechanistic scaling of ecosystemfunction and dynamics in space and time: Ecosystem Demography model version 2, J. Geophys. Res., 114, G01002, doi:10.1029/2008JG000812, 2009. Moorcroft, P. R., Hurtt, G. C., Pacala, S. W.: A method for scaling vegetation dynamics: the Ecosystem Demography model (ED), Ecol. Monogr., 71, 557–586, https://doi.org/10.1890/0012-9615(2001)071[0557:AMFSVD]2.0.CO;2, 2001.# 原始生态系统人口模型（Ecosystem Demography Model, ED2）由Moorcroft等人于2001年以及Medvigy等人与团队于2009年开发，其源代码可从GitHub获取（https://github.com/EDmodel/ED2）。 # 本仓库针对山艾树（灌丛）植物功能型群（Plant Functional Type, PFT）对原始ED2模型进行了改进。为此，我们主要对`ed_params.F90`文件进行了更新，新增了编号为“18”的PFT。在初步研究中，我们选取ED2中原温带PFT的异速生长方程，以推导与异速生长关系相关的系数（参数），例如胸径（dbh）与树高、胸径与叶生物量之间的对应关系。由于灌丛不具备类似树木的明显主干，我们采用体积的立方根来表征直径，以此构建灌丛的异速生长方程。此外，我们还修改了另一源代码文件`ed_max_dims.F90`，以更新PFT的尺寸参数。 # 本仓库同时包含用于开展山艾树参数敏感性分析与优化的namelist配置文件（ED2IN）。 ## 参考文献 Medvigy, D., Wofsy, S. C., Munger, J. W., Hollinger, D. Y., and Moorcroft, P. R.: 生态系统功能与动态的时空机制性尺度转换：生态系统人口模型第2版，《地球物理研究杂志》，114卷，G01002，doi:10.1029/2008JG000812，2009年。 Moorcroft, P. R., Hurtt, G. C., Pacala, S. W.: 植被动态尺度转换方法：生态系统人口模型（ED），《生态学专论》，71卷，557–586，https://doi.org/10.1890/0012-9615(2001)071[0557:AMFSVD]2.0.CO;2，2001年。