Components of Growth for Tropical Dry Deciduous Forest, Brazil.

Continuous forest inventory is essential to understand the dynamics of tree population growth. Unfortunately, the majority of tropical forests in developing countries have few inventory data, particularly, the tropical deciduous dry forests. In Brazil, the most typical dry deciduous forest is the Caatinga, a vegetation type that has been maintained by man through a long history of cutting and cultivation. The majority of the Caatinga trees have multiple stems. Traditionally, the components of forest growth have been expressed as: V₂ – V₁= S + I – M – C, where V_i = the total value at time i (i = 1,2); S = survivor growth (the growth value that occurs on trees that are above some minimum merchantability limit of DBH at both measures times); I = ingrowth (value of trees not measured in t₁ and mensurable in t₂); M = mortality (t₁ value of trees that die during the interval t₁,t₂) and C = cut (t₁ value of trees that are harvested during interval t₁,t₂). However, this methodology is applied for individual trees. It is proposed a modification to the case of multi-stem trees considering M = mortality of individuals (MI) + mortality of stems (MS); I = ingrowth of individuals (VI) + ingrowth of stems (VS); and C = cut of individuals (CI) + cut of stems (CS). Thus, with the definitions, the stand growth can be defined by the following equations: 1. Gross growth including ingrowth - Ggi = V₂ + MI + MS + CI + CS - V1, 2. Gross growth of initial volume - Gg = Ggi - VI – VS; 3. Net growth including ingrowth: Gni = V₂ + CI + CS - V₁; 4. Net growth of initial volume - Gn = Gni - VI – VS; and 5. Net increase – Gd = V₂ - V₁.