*Biodiversity of Fabaceae in the Brazilian Amazon and Its Timber Potential for the Future DOI: http://dx.doi.org/10.5772/intechopen.110374*

14 different morphological types [23]. An illustration of the morphological aspect of the fruits and seeds of Fabaceae from the Brazilian Amazon is shown in **Figure 4**. For the advance in basic forestry research of Fabaceae of the Amazon, there is a need to ensure the correct identification of taxa in existing herbaria. The following is the application of drying techniques, cleaning and fruit processing, germination studies, seedling production and sequential forest plantations contributes to the generation of

**Figure 4.**

*Morphology of fruits and seeds of Fabaceae species from the Amazon region of wood interest. Photos: Souza LAG.*

basic information to identify the species with the greatest potential, followed by their silvicultural use.

In the tropical forest, tree populations with higher potential for regeneration or management should present the following ecological parameters: (1) Seed dispersal facility; (2) Abundance of rods in regenerating forests; (3) Good growth rate; (4) Good regrowth capacity after cutting/burning; (5) Fire resistance; (6) Good breadth of geographical distribution; and, (7) Plenty of adults [21].

In Brazil, at the National Institute of Amazonian Research - Inpa, in Manaus, Amazonas, the research actions follow sequential steps to identify the species with higher potential for management and planting. In bioprospecting in natural or altered areas throughout the region, after fruit collection, the studies follow the following flow: → correct botanical identification of the taxon and its ecological group; → evaluation of fruit and seed production; → seed resistance to desiccation germination of seeds quickly and homogeneity → evaluation of seedling production in nurseries → identification of N2 fixing ability → phytosanitary aspects and survival after planting → planting definitive to identify rapid growth, rusticity, high biomass production and adaptation to dystrophic soils→ progeny assays, genetic improvement and more advanced stages of research.

Basic forestry studies prioritize the generation of information that can help the planting of species contributing to their conservation and value of biodiversity resources. To contribute to the planting on a larger scale of little-known native species, the basic determinations in the fruit processing phase provide information for seed acquisition or marketing of propagules. Among the relevant information scans are the average weight of the fruits and in the processing phase the fruit purity test provides data on the investment of the fruit in seed formation, and can be an important indicator to evaluate the quality of a batch of intraspecific fruits.

The number of seeds per kilo and the weight of 1000 seeds are auxiliary information for seed acquisition, and, considering their size, provide indicators for the later forestry stages such as seedling production, defining the size of the container and total amount of substrate to be used for each species, managed in the nursery phase. Some of these basic determinations for 45 species of Fabaceae of wood importance are presented in **Table 4**. There is great variety in the fruit size of Fabaceae trees, some developing very large and heavy fruits such as *Inga edulis* whose fruits reach almost 400 g or *Swartzia polyphylla* with just over 200 g. The heavy fruits are commonly dispersed by weight, and are deposited under the canopy of the mother tree, and can then be distributed by water or wildlife.

In the flooded forests of Igapó, vegetation that occurs in black water rivers in areas with nutrient scarcity, large and heavy fruits may have structures that allow floating, and some species with large and voluminous fruits such as *Cassia grandis*, *Mora paraensis* and *Vatairea guianense* form their own comparatively mass group. In the Igapó, the fruits containing seeds with high biomass compensate for the loss of nutrients in the initial phase of seedling establishment and in the floodplains, in sedimentary basins with high nutrient availability, the seeds may be small, but produce elongated seedlings, suitable for survival in regular flood cycles [24].

There are also species with small fruits with weight < 1 g as observed for *Acosmium nitens*, *D. guianense*, *Ormosia excelsa* and others and also a large group of intermediate weight defined in the range of the median fruits. The size of the fruit, therefore, can sometimes be associated with vigor and growth capacity of seedlings and, therefore, development in juvenile stages. For this, each self-ecological species the investment in the fruit in the formation of seeds, also defined as fruit purity index, which is very varied and is not related to its size (**Table 4**).


#### *Biodiversity of Fabaceae in the Brazilian Amazon and Its Timber Potential for the Future DOI: http://dx.doi.org/10.5772/intechopen.110374*


*1 – Determinations made at Inpa, in Manaus, AM, Brazil.*

#### **Table 4.**

*Fruit weight, percentage of purity, number of seeds per kilo and weight of 1000 seeds of Amazonian legumes of wood interest.\*1*

Among the species the greatest investment in seed formation in relation to the fruit was verified in *Cynometra bauhiniifolia*, where the purity indexes (%) of the fruits reach 87.78%, but also *Campsiandra laurifolia* and *Macrolobium acaciifolium* all of the flooded forests, which possibly relate to their dispersal syndrome, which in this environment is by hydrocoral process. There is a group of species with low purity in fruits, with little investment in seed formation, which in *Hymenolobium pulcherrimum* is <5%, and there are others with <20% such as *Cassia fastuosa*, *D. odorata*, *Enterolobium maximum*, etc. Many species have intermediate values, reflecting their variety and diversity.

Basic forestry determinations of the number of seeds per kilo and/or the weight of 1000 seeds are important for the acquisition and/or marketing of germplasm for planting or reforestation. A kilo of *Cassia fastuosa* seeds can contain >20,000 seeds, because they are small and light seeds. For other species, in 1 kg of seeds there are >10,000 seeds such as for *Cassia leiandra*, *Dinizia excelsa*, *Enterolobium schomburgkii*, *Stryphnodendron guianense*, etc.

On the other hand, in 1 kg of *Mora paraensis* seeds is the weight of only 12 seeds and the high individual weight is a hindrance to its acquisition, regardless of its timber value. Thus also, in 1 kg of *Swartzia polyphylla* seeds there are only 15 seeds, 23 in *Vatairea guianense*, and 58 of *Swartzia laevicarpa*. They are large fruits and seeds, characteristic of the flooded areas of Igapó.

The acquisition of 1000 seeds for planting trees of various species of trees in the Amazon exceeds 10 kg. In this group, for the species that has heavier seeds, *Mora paraensis*, to gather 1000 seeds is necessary more than 90 kg of seeds. In contrast, to dispose of 1000 seeds of *Cassia fastuosa* are <50 g of seeds.

There is a sequence of research steps generating applied silvicultural technology, which will not be explored at this time. In seed germination there are large differences

#### *Biodiversity of Fabaceae in the Brazilian Amazon and Its Timber Potential for the Future DOI: http://dx.doi.org/10.5772/intechopen.110374*

between species regarding the classification for desiccation tolerance and also a predominant characteristic among Fabaceae: the existence of dormancy mechanisms in seeds, associated with the impermeability of the integument, which can be overcome by the application of scarification methods.

They follow the experimental research on seedling formation in forest nurseries followed by definitive planting for selection of the best-developing species. The oldest experimental plantations with native species are more than 60 years old and over time new groups of species have been evaluated to identify their potential for cultivation and favor reforestation actions and forest production. In more advanced phases of forest research, progeny tests are performed for selection of superior germplasm in forest breeding programs.
