Cycle 2 (2014-2019)
Inventory of Forest Remnants
The first field measurements (Cycle 1) took place between 2007 and 2011; 480 sample plots distributed across the state were measured. The second cycle of measurements was conducted between 2014 and 2019, with the remeasurement of 361 sample plots distributed across the state, of which 314 were located in forests in intermediate or advanced succession stages and 47 in forests in initial succession stage.
The continuous inventory of Santa Catarina's forests provides relevant data to generate information regarding forest dynamics: growth, mortality, and recruitment rates. This information contributes to the study of ecological processes related to forests, and also supports the sustainable management of forest resources, the monitoring of carbon sink dynamics and the development of new forest policies.
Based on different measurements over time, one of the main interests of the IFFSC is to estimate the net change in variables such as number of trees, basal area and aboveground biomass per hectare.
The net change in number of individuals per hectare is defined as the number of trees that entered the forest minus the number of trees that died in a given time period.
The net change in basal area, on the other hand, consists of the increase in basal area of surviving trees plus the basal area of trees that entered the forest, minus the basal area of trees that died in the same period. The same applies to biomass.
Results
The net change in number of individuals per hectare in Santa Catarina's forests is positive over a 5-years period. This means that the number of trees that entered Santa Catarina's forests exceeds the number of trees that died.
The Evergreen Rainforest (ERF) presented, on average, an increase of 4.3% in the number of trees per hectare in five years;
The Araucaria Forest (AF) presented, on average, an increase of 4.8% in the number of trees per hectare in five years;
The Semi-deciduous Forest (SF) presented, on average, an increase of 7.7% in the number of trees per hectare in five years.
Mean net change in number of trees per hectare over 5 years
The net change in basal area in Santa Catarina's forests is positive over a period of 5 years. This means that Santa Catarina's forests are still growing.
The Evergreen Rainforest (ERF) presented, on average, an increase of 6.4% in basal area per hectare;
The Araucaria Forest (AF) presented, on average, an increase of 5.7% in basal area per hectare;
The Semi-deciduous Forest (SF) presented, on average, an increase of 5.7% in basal area per hectare.
Mean net change in basal area per hectare over 5 years
The net change in aboveground biomass in Santa Catarina's forests is positive over a period of 5 years. This means that Santa Catarina's forests are absorbing atmospheric carbon, as about 50% of forest biomass is carbon.
The Evergreen Rainforest (ERF) presented, on average, an increase of 7.7% in biomass/carbon stock per hectare;
The Araucaria Forest (AF) presented, on average, an increase of 5.9% in biomass/carbon stock per hectare;
The Semi-deciduous Forest (SF) presented, on average, an increase of 6.0% in biomass/carbon stock per hectare.
Mean net change in biomass per hectare over 5 years
The difference in number of species per sample plot from the first to the second measurement cycle is, on average, positive over a period of 5 years. This means that, on average, new species are entering Santa Catarina's forests.
The Evergreen Rainforest (ERF) presented, on average, 3 new species per sample plot;
The Araucaria Forest (AF) presented, on average, 2 new species per sample plot;
The Semi-deciduous Forest (SF) presented, on average, 3 new species per sample plot.
Difference in species richness between measurement cycles
Genetic diversity
In Cycle 2, the focus of the genetic analysis was changed to regenerating individuals of endangered species; species with economic and social relevance were also studied.
The results regarding regenerating individuals indicated that the processes of genetic diversity maintenance are different among species; therefore, distinct conservation actions may be needed for each species. For instance, young individuals of Apuleia leiocarpa ('grápia'), Euterpe edulis ('palmiteiro') and Araucaria angustifolia ('pinheiro-brasileiro') showed great potential to maintain their genetic diversity, unlike Ocotea catharinensis ('canela-preta'). It means that there is an imminent risk of decrease in genetic diversity in the next generations for this species.
When genetic diversity indices estimated for reproductive and regenerating populations were analyzed together, it was found that the most vulnerable species were Dicksonia sellowiana ('xaxim-bugio') and Podocarpus lambertii ('pinheiro-bravo').
Based on the results obtained since 2007, the following conservation measures are suggested: to increase the connectivity among forest fragments; to use native species in commercial plantations; to establish areas for seed collection; to preserve the fauna, which is responsible for flower pollination and/or seed dispersion of most of the studied species); to strengthen the fiscalization against illegal exploitation of forest resources.
For almost all species there are populations with substantial levels of genetic diversity to establish areas for seed collection. These areas would indeed add value to forest fragments and also would generate good quality seeds for ecosystem restoration activities, to increase the connectivity among forest fragments, as well as to create good quality commercial forest plantations.
The studied populations within Conservation Units proved to retain considerable amounts of genetic diversity. Therefore, Conservation Units may be regarded as effective areas to genetic diversity conservation, especially for the species Dicksonia sellowiana ('xaxim-bugio') and Ocotea catharinensis ('canela-preta').