# Biomass Dynamics in a Fragment of Brazilian Tropical Forest (Caatinga) over Consecutive Dry Years
## 3 Results and Discussion
### Strub Layer  
For the diversity of woody cover in the area of DTF/CPD under regeneration for approximately 40 years, nine families, 14 genera and 15 species were identified in total which did not vary over the \begin{table}
\begin{tabular}{c c c c c c c c} \hline
**Group** & **Year** & **MCWD (mm yr\({}^{-1}\))** & **T (C\({}^{\circ}\)C)** & **R (mm yr\({}^{-1}\))** & **C1** & **C2** & **C3** \\ \hline \multirow{4}{*}{\(1\)} & & 2012 & \(-\)1478.8 & 28.4 & 925.0 & 2 & 0 & 1 \\  & & 2013 & \(-\)1376.0 & 28.5 & 957.7 & 5 & 1 & 1 \\  & & 2015 & \(-\)1458.2 & 28.6 & 785.0 & 5 & 2 & 0 \\  & & 2016 & \(-\)1481.3 & 28.6 & 929.0 & 3 & 1 & 3 \\  & & 2017 & \(-\)1440.4 & 28.2 & 753.5 & 5 & 3 & 0 \\  & \(\overline{\mathbf{x}}\) & & **\(\mathbf{-1446.9}\)** & **28.5** & **870.0** & **4** & **1** & **1** \\  & \(\sigma\) & & **\(\mathbf{\pm 43.0}\)** & **\(\mathbf{\pm 0.2}\)** & **\(\mathbf{\pm 93.5}\)** & **\(\mathbf{\pm 1}\)** & **\(\mathbf{\pm 1}\)** & **\(\mathbf{\pm 1}\)** \\ \hline \multirow{4}{*}{\(2\)} & & 2008 & \(-\)1239.1 & 27.4 & 1303.5 & 7 & 2 & 0 \\  & & 2009 & \(-\)970.9 & 27.3 & 1462.0 & 4 & 1 & 0 \\  & & 2011 & \(-\)1018.1 & 27.6 & 1651.5 & 6 & 2 & 0 \\  & \(\overline{\mathbf{x}}\) & & **\(\mathbf{-1076.1}\)** & **27.4** & **1472.3** & **6** & **2** & **0** \\  & \(\sigma\) & & **\(\mathbf{\pm 143.2}\)** & **\(\mathbf{\pm 0.2}\)** & **\(\mathbf{\pm 174.2}\)** & **\(\mathbf{\pm 2}\)** & **\(\mathbf{\pm 1}\)** & **\(\mathbf{\pm 0}\)** \\ \hline \multirow{4}{*}{\(3\)} & & 2010 & \(-\)1179.5 & 28.4 & 1054.0 & 9 & 1 & 1 \\  & & 2014 & \(-\)1203.3 & 27.8 & 960.0 & 7 & 2 & 2 \\ \cline{1-1}  & \(\overline{\mathbf{x}}\) & & **\(\mathbf{-1191.4}\)** & **28.1** & **1007.0** & **8** & **2** & **2** \\ \cline{1-1}  & \(\sigma\) & & **\(\mathbf{\pm 16.9}\)** & **\(\mathbf{\pm 0.4}\)** & **\(\mathbf{\pm 66.5}\)** & **\(\mathbf{\pm 1}\)** & **\(\mathbf{\pm 1}\)** & **\(\mathbf{\pm 1}\)** \\ \hline \end{tabular} MCWD—maximum cumulative water deficit; T: Temperature; R: Rainfall; C1: 5-10 consecutive dry days; C2: 11-20 consecutive dry days; C3: \(>\) 20 consecutive dry days.  
\end{table} 
Table 1: Mean values and standard deviations of the climate variables for each group formed, for the district of Iguatu, Ceariá, Brazil. Figure 3: Grouping dendrogram of homogeneous years for the district of Iguatu, Ceariá, Brazil. 11 years (Table 2), characterizing the area as a representative fragment of crystalline caatinga [15]. The number of families ranged from six to 26, while species from 12 to 64 [15]. The occurrence of families Anacardiaceae and Burseraceae, represented by the species _Myracrodruon urundeuva_ and _Comniophora leptrophloeos_ respectively, show that the area is in an advanced process of regeneration, since these are indicators of more-protected or well-preserved areas of the Caatinga [9; 29]. [PERSON] [7] found that after 25 years of fallow the density of the bushes begins to decrease to values below 5000 plants ha\({}^{-1}\), and after 45 years there is a dominance of tree species. Shrub species are in the majority (1762 ind. ha\({}^{-1}\)), while tree species account for 921 ind. ha\({}^{-1}\) (Table 2). It is therefore believed that the DTF fragment is in the process of transition between the third and fourth phase of secondary succession, due to the predominance of shrub species. The families with the highest number of identified species were represented by Fabaceae and Euphorbiaceae, with six and two species, respectively (Table 2). These two families are generally found in the floristic pattern of fragments of dry forest in the northeast of Brazil [15] and in other DTF across the world [2]; they are the most abundant woody families in terms of gender, species and plant abundance [22]. Among the identified species, _Croton_ spp. (885 ind. ), _Aspidosperma_ spp. (538 ind. ), _Combretum_ spp. (279 ind. ), _Mimosa caesalpinifolia_ Benth. (277 ind.) and _Bauulinia cheilantha_ ([PERSON].) Steud. (217 ind.) are noteworthy, and together accounted for around 80% of the total density (Table 2). _Croton_ spp.