Sampling procedure and method
In accordance with the proposal of the National Forest Inventory of Brazil, supported in studies by Netto (1979), Brena (1995) and Queiroz (1997), Santa Catarina’s inventory is structured using a) multiple choices with the possibility of total repetition of the sample sampling process, with systematic distribution of sample plots in population, from a network of systematic points (grid) of 10 x 10 km covering all state and consistent with the 20 x20 km grid of the national proposal; the sample plots selection is made from a preliminary stratification in forest and non-forest, based in orbital images interpretation;b) As a sampling method, the fixed area in conglomerates compost by four perpendicular subunits starting from a central point, and post-stratification by biome, phytoecological region, watersheds and city. The total fixed area sampling process requires a fixed sample structure and that the sample plot can be remeasured, having a definitive mark of galvanized iron rods buried for future localization with metal detector.
Location of sampling points
For the sampling points materialization and sample plot implantation it was defined by the IBGE a grid of points with 10 x 10 km of distance in UTM coordinates, with datum WGS 84. The sampling points of this grid that coincide with the 20 x 20 km grid, proposed by the National Forest Inventory and defined by IBGE for natural forests in Brazil, will be a part of the future database of NFI. For the Decidual Seasonal Forest, extremely reduced and fragmented, a 5 x 5 km grid was used to ensure a sufficient number of sample units that will enable: a) tree and shrub component documentation on the existing remnants, including the rare and endangered species, b) the quantitative analysis and statistical data.
Sources of spatial data
The topographic maps of the Brazilian Systematic Mapping were used as cartographic basis on a scale of 1:50.000 and 1:100.000. This material was used in digital form posted by EPAGRI in the form of Santa Catarina Digital Maps (http://www.epagri.sc.gov.br) in shape format to elaborate the planning maps and sample plot localization maps. The IFFSC uses as a Phytogeographical division of vegetation proposed by Klein (1978). According to this phytogeographical map, the Mixed Ombrophyllous Forest originally covered 43% of the state surface, the Grasslands 14%, the Dense Atlantic Rain Forest 30% and Decidual Seasonal Forest 8%. To support the inventory of Santa Catarina it was accomplished the forest remnants mapping through visual interpretation of multispectral satellite images of Landsat-5 TM and Landsat-7 ETM+ from 2003 and 2004. According to the results of this survey (SAR, 2005), Santa Catarina has one remaining natural forest cover of approximately 35.500 km² (37.2% of the territory). This mapping was used in the planning phase of IFFSC. Parallel to the activities of the inventory, the state government hired in 2007 new mapping of forest remains and soil use statewide, based on a unsupervised classification of satellite multispectral images SPOT-4 and SPOT-5 of 2005. The results of this mapping were used to refine the sample unit allocation from June 2008.
Sampling Intensity
The points for which the two maps of forest cover in the state indicate the existence of natural forests, are the points for the installation of the sample plots and collecting field data. Given the mapping scale (1:50000), it was adopted a tolerance of 250m of radius surrounding each grid point, considering it as sampling point if the map indicates forest presence inside that area. In this case, the sampling point is dislocated to the nearest forest fragment, so that the end of the subunit stays 20m far from the forest edge. Placing the grid of 20 x 20 km proposed for the National Forest Inventory on the area of 35.464.8 km² of forest remnants with an area larger than 10 ha, it is reached 86 sample plots for the entire state, three for the Decidual Seasonal Forest, 46 for Mixed Ombrophyllous Forest and 37 for the Dense Atlantic Rain Forest. This sampling intensity was considered insufficient to achieve the goal proposed for the IFFSC. Using the 10 x 10 km grid (for the MOF and DARF) and 5 x 5 km (for the DSF), both fractions of the IFN grid and, therefore coincide in part, resulted in 436 sample plots for the entire state, considering the Landsat images mapping. After the conclusion of the new forest cover mapping, were included in the IFFSC workplan 144 points for which the new mapping indicated the existence of forest, forming a set of 550 sample plots to e measured (Figure 1).
Figure 1: Location of the 550 sample units of IFFSC in Santa Catarina state, by phytocological region.
Sample unit
Each sample unit consists of a basic cluster with total area of 4000m², formed by four subunits, each with an area of 1000m², measuring 20m wide and 50m long, oriented towards the four cardinal points (North, South, East and West), keeping each, 30m of distance from the center of the cluster, ascribing the same area of inclusion of 2,56ha (Figure 2). Each cluster subunits of 20m x 50m, consisting of 10 basic units of 10 m x 10 m (100m²), is intended to survey all individuals with DBH≥10cm. In addition, each subunit contains a subplot of 5 x 5 m, intended to lift the plants stratum with DBH<10cm, called regeneration, despite including juvenil individuals of canopy species such as wood specialist. After survey the Mixed Ombrophyllous Forest and Decidual Seasonal Forest, still considering Calegaris work (1999), which resulted in a great sampling area of regeneration in 64m² for the Mixed Ombrophyllous Forest in Rio Grande do Sul, it was decided to intensify the sampling of this stratum in the Dense Atlantic Rain Forest and raise four plots of 5 x 5m per subunit, located at the ends of them (Figure 2), evaluating the plants with height ≥0.50m.
Figure 2: Structure of the IFFSC basic cluster (for the Dense Atlantic Rain Forest)
For all plants with DBH≥10cm, are registered its coordinates x and y in their basic units (10 x 10 m) so that the data processing considering different subunit sizes is possible. At the subplots of 5 x 5 m are identified and/or collected all the trees and shrubs with DBH<10cm and total height ≥1,50cm, generically called “regeneration”, although it’s also included specimens of unique wood, these are registered the DBH and the estimated total height. For the Dense Atlantic Rain Forest, the height of inclusion in this stratum was established at 0.50m, because many trees, due to its slow growth and by being present in the wood with small postage.
To survey the woody necromass are installed four linear units (transects) of 5m length, from the center of the cluster, one at each quadrant, total of 20m by cluster, using the necromass sampling method for transect (SHIVER & BORDERS, 1996) and measuring the circumference (≥ 3cm) of all dead woody material found on the transect line.
The principal measuring equipment used by the teams are: Bosch laser measuring tape, diameter tape, Haglöef hypsometer, binoculars, digital camera, tape measures, tags, sling, pruning shears with extended cable and radio communicator.
For each sample unit are registered on the field cards (in paper): date of the visitation, location and coordinates (accommodation) and access to the sample unit, time to get to the sample unit access, locality, city, land owner, physical aspects, topography, slope, and the general characteristics of the vegetation in the fragment and its surroundings, according to the NFI. In case of the sample units, whose points are visited, but without being able to install them (which are called “discarded sample unit”), is still noted the reason for the “dump”.
Physiognomic description
The field teams elaborated a detailed physiognomic description of the vegetation found inside the sample unit and its surround. Listed in this description the main aspects of vegetation (community height, closing the canopy, striking appearance species, the main disturbing anthropogenic factors), and the phytoecological classification, their states of succession and retention (as perceived in the field). This description, along with: the spread sheet of the forest main structural parameters, discriminated by species and total community, elaborated later, the vegetation definitive classification (based on the field description, floristic composition and phytosociological structure); the vegetation photos and the fragments localization maps, form a set of valuable information for each sample unit.
Dendrometrical variables raised
The main dendrometrical variables collected and registered in the field card for each tree individual and shrub component of the basic unit (10 x 10m) are: sequential number; scientific name; CBH in cm; commercial height (estimated); total height (estimated); trunk quality; tree health, sociological position; presence of lianas and epiphytes; it is registered if the plant was collected and which is the collector number (on the sequential list of the team biologist).
The measurement of DBH is performed with a diametric tape (the correct height of 1.3m in the uniform of the team). In each subunit of 20 x 50 m are measured, with Haglöef hypsometer, the commercial and total heights of two trees. These measures are accomplished to estimate the height of the remaining trees performed by the team engineer and to develop specific hypsometric equations. In the subplots of 5 x 5m, the individuals included are identified and have their height estimated
Tree Volume
To estimate the volume and biomass, the importance of specific volume equations for the species of the forest of South Brazil is evident. Views of the absence, the necessary information for the adjustment of volumetric models are collected through the scaling of two trees standing per subunit, a total of eight trees for sample unit. This work is performed by the team’s climber, sometimes in trees that are also climbed to collect botanical material, searching, however, to contemplate different groups of species and diameter classes. From the bottom to top, the diameter measurements in different heights are taken with a diameter tape at 0.3m (stump); 1.0m; 1.3m; 2.0m; 3.0; and so forth along the stem to the top crown. Were collected data of the stem form of the 728 trees in the Mixed Ombrophyllous Forest, 303 trees at the Decidual Seasonal Forest (until March 2010) and 550 at the Dense Atlantic Rain Forest.
Collection of botanical material
Of all plants unidentified in the field are collected samples, preferably fertile, but also sterile, for identification and herborization according to usual procedures and incorporation into the Roberto Michael Klein Herbarium, acronym FURB. To collect the botanical material are used, besides climbing equipment, binoculars (10x25), pruning shears with extended cable of 5m and catapult. All plants collected during the day are pressed in newspaper and wooden trellises, soaked in 70% alcohol and sealed in plastic bag. The plants need to be send weekly, especially on the summer, through a dispatch by bus companies or by a support vehicle. The fertile plants are separated in until five duplicates for exchange, the sterile plants are stored separately in the herbarium, of whom a copy is listed as a witness if is not collected a richer sample of the same species.
Terrestrial herbaceous plants and epiphytes
The vascular epiphytes survey on the pilot inventory (phase 1) was accomplished through the epiphytes survey in two drawn phorophytes in each sample unit. The herbaceous plants were collected in subunits. Both procedures proved to be inadequate, generating dissatisfaction and unrepresentative results, as the low number of fertile material collected and the small number of identified species.
On the 2nd and 3rd phase (Mixed Ombrophyllous Forest, Santa Catarina plateau, and Decidual Seasonal Forest 2007 and 2009), the floristic survey of the vascular epiphytes was accomplished in two phorophytes in different diameter classes per subunit, chosen by the team among those with the greatest diversity of that plant group. In addition, fertile epiphytes were collected at hand and the pruning shears with extended cable, and all the fertile terrestrial herbaceous plants in and around the sample unit, as well as along the access track.
At the Dense Atlantic Rain Forest the fertile terrestrial herbaceous plants collection was maintained in and around the sample unit. Due to the great epiphytes richness and density in the Dense Atlantic Rain Forest and the specificity of the methodology of their collection and identification, its survey is conducted by specialized teams that work in different rate of removal compared to the tree component teams. Were selected 30 sample units (from a total of 208 sample units) to evaluate the vascular epiphytes diversity of the Dense Atlantic Rain Forest in Santa Catarina, visited at least three times, once every three months between each visit, to find fertile individuals of the greatest number of species. The areas were chosen from the regular sample unit, located in conserved forest, with the most apparent epiphytes diversity, observing the most diverse vegetation formations, different altitudes, and the gradients north-south and east-west.
The sample unit area, defined by a circle, with 80m of radius around the central point of the sample unit is traversed by the pathway method (Figueiras et. Al., 1994) by two people on the team, while the climber and the assistant perform the record and collection of fertile epiphytic plants in the great individuals trees. The phorophytes suitable for climbing are selected by the team, using criteria of wealth and abundance of epiphytes and safety for the procedure. This is accomplished by using tree climbing techniques, allowing access to installed epiphytes in the trees. Besides the trees, are also analyzed saplings, lianas, tree ferns to locate the epiphytic species. Besides the fertile specimens, in each sample unit is recorded the presence of species with sterile individuals, since undoubtedly known, to analyze their spatial distribution in Santa Catarina.
