The Projeto Caatinga has a team responsible for the phenological monitoring of 15 native species from the Caatinga biome. Phenology studies biological events that repeat throughout the year and summarize the cycle of a plan life. These events are called phenophases: flowering, fructification, defoliation, and budding. The phenological monitoring of species of trees, which may be observed for at least a one-year period, makes possible the identification (occurrence) and quantification (intensity) of phenophases, allowing to better understand the processes that occur in a forest community.
The product of a phenological monitoring is the phenological calendar, which allows, for example, to program seed harvests for seedling production.
The data collection in the field follows this protocol:
- Going out to the field for the identification of trees that will be monitored. Using the trees’ vigor as a criterion;
- Select 10 trees per species
- A minimum distance of 20 m (65.6ft) between trees from the same species
- Collect primary data from each tree:
- Location (using a GPS)
- Trunk diameter at the base (30 cm above soil surface)
- Height
- Crown height
- Mark selected trees with a sign (usually an easy-to-see-through-the-vegetation tape)
- Phenological data collection
- Choose two branches (using a compass), in each cardinal direction (North, South, East and West), in which one branch will be in the lower portion of the crown, and the other in the upper level; random selection
- Biweekly observations (organize a schedule)
- Phenophases: flowering, fructification, defoliation, and budding
- Criteria for Flowering and Fructification phenophases: will be accounted for the real quantity, for each selected branch (use field glasses for small flowers in the upper level)
- Criteria for Defoliation and Budding phenophases: based on the intensity of the mentioned biological event; expressed in percentage (subjective)
- Use specific forms
Studied areas
The phenological monitoring of tree species performed by the Projeto Caatinga team is held in two different areas: at the Fazenda Experimental Rafael Fernandez (Rafael Fernandez Experimental Farm), located in the city of Mossoró-RN; and at the Fazenda Baixa da Oiticica (Baixa da Oiticica Farm), located in the city of Upanema-RN.
Distribution of selected trees for phenological monitoring in the Fazenda Experimental Rafael Fernandez, Mossoró-RN.
Distribution of selected trees for phenological monitoring in the Fazenda Baixa da Oiticica, Upanema-RN.