ppine               package:systemfit               R Documentation

_T_r_e_e _G_r_o_w_t_h _D_a_t_a _f_o_r _P_o_n_d_e_r_o_s_a _P_i_n_e

_D_e_s_c_r_i_p_t_i_o_n:

     A subset of tree growth observations from a Ponderosa pine growth
     database.

     The 'ppine' data frame has 166 rows and 8 columns.

_U_s_a_g_e:

     data(ppine)

_F_o_r_m_a_t:

     This data frame contains the following columns:

     _e_l_e_v Altitude of the plot, in feet above mean sea level.

     _s_m_i Summer moisture index is the ratio of growing season heating
          degree days to growing season precipitation.

     _d_b_h Diameter of the tree at breast height (4.5 feet).

     _t_h_t Total stem height for the tree.

     _c_r Crown ratio code. The scale is from 1 to 9 where a crown class
          of one represents a crown ratio between 0 and 15 percent. A
          crown ratio code of 2 represents a crown ratio value between
          16 and 25%,...,8=76-85%, 9 >=85%.

     _b_a Plot basal area at the beginning of the growth period.

     _d_g Five-year diameter increment.

     _h_g Five-year height increment.

_D_e_t_a_i_l_s:

     The exogenous variables are 'elev', 'smi', 'dbh', 'tht', 'cr', and
     'ba'; the endogenous variables 'dg' and 'hg'. There are no lagged 
     variables in the dataset and the observations are for a single
     remeasurement.

     The data was provided by the USDA Forest Service Intermountain
     Research Station.

_S_o_u_r_c_e:

     William R. Wykoff wwykoff@fs.fed.us _Rocky Mountain Research
     Station, 1221 South Main Street, Moscow, ID 83843_

_E_x_a_m_p_l_e_s:

     data(ppine)

