StemAnalysis            package:treeglia            R Documentation

_P_e_r_f_o_r_m_s _s_t_e_m-_a_n_a_l_y_s_i_s

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

     Performs stem-analysis on ring-widths on stem cross-sections.

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

     StemAnalysis(RWdata, Tree.height=23.91, Tree.object)

_A_r_g_u_m_e_n_t_s:

  RWdata: a numeric value holding the multiplicative coefficients to
          get to [m] from ring-width measures. This is used in
          'StemAnalysis'.

Tree.height: a numeric value holding the height of the tree tip.

Tree.object: a 'data.frame' holding tree data. This object is easily
          created through 'BuildTreeObject'.

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

     The function first interpolates tree heights using the Carmean's
     algorithm, to yield past annual estimates of tree height. Yealry
     log volumes are computed using the Smalian's formula (trapezium
     formula): 

                       V=[(Gl+Gu)/2] * (Hu-Hl)

     where Gl if basal area of the lower section, Gu is the basal area
     of the upper section, Hu is the height of the upper section, Hl is
     the height of the lower section. The volume of the terminal cone
     is: 

                          V=Gl/3*(Htree-Hl)

     where Htree is the height of the tree. Dry-matter biomass is
     computed by converting volume to weight by means of basic density.
     Carbon biomass is given by dry-matter biomass multiplied by wood
     carbon ratio. The standard errors of volume coefficient, basic
     density and wood carbon ratio are combined using the standard
     formula of multiplicative error propagation for variables with
     uncorrelated variances:  

       se(Wc)=Wc[(se(Sv)/Sv)^2+(se(Dw)/Dw)^2+(se(Rc)/Rc)^2]^0.5

     where se() is standard error, Wc is wood carbon biomass, Sv is the
     volume coefficient from fresh matter to mean water-content matter,
     Dw is wood basic density, and Rc is wood carbon ratio. Yearly
     lateral surface area of the logs is: 

                       L=pi * (Ru+Rl) * (Hu-Hl)

     where Ru and Rl are the radia on the upper and lower
     cross-sections, Hu and Hl are the heights of the upper and lower
     cross-sections.for the lateral surface area of logs The lateral
     surface area of the terminal cone is: 

                 L=pi * Rl * (Rl^2 + (Htree-Hl))^0.5


     Volume and surface area increments are computed by difference of
     the consecutive stem volumes. Dry-matter biomass is computed by
     multiplying volume by basic density, carbon biomass is obtained by
     multiplyng dry-matter biomass by carbon content.

_A_u_t_h_o_r(_s):

     Marco Bascietto

_R_e_f_e_r_e_n_c_e_s:

     Carmean W.H., Site index curves for Upland Oaks in the Central
     States, Forest Science 18 (1972) 109-120.
      Fabbio G., Frattegiani M., Manetti M.C., Il metodo di analisi del
     fusto. Confronto tra cinque metodi di stima della relazione
     altezza-et, Annali dell'Istituto Sperimentale per la
     Selvicoltura, Arezzo 19 (1988) 117-154.
      Bascietto M., Scarascia-Mugnozza G., A collection of functions to
     determine annual tree Carbon increment via stem analysis, Annals
     of Forest Science (accepted).

_S_e_e _A_l_s_o:

     'BuildTreeObject''BuildAgeTable'

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

     # Recall and attach RW data
     data(Lei301)
     attach(Lei301)

     # Perform stem analysis
     SA.1.a <- StemAnalysis(RWdata = RW.1A, Tree.height=12.33, Tree.object=Tree.features.1)
     SA.1.b <- StemAnalysis(RWdata = RW.1B, Tree.height=5.5, Tree.object=Tree.features.1)

     detach(Lei301)

