Scielo RSS <![CDATA[Floresta e Ambiente]]> vol. 25 num. 2 lang. en <![CDATA[SciELO Logo]]> <![CDATA[Land use in Permanent Preservation Areas of Grande River (MG)]]> ABSTRACT The Brazilian Forestry Code established the Permanent Preservation Areas (PPAs) to preserve environmentally significant areas, such as the banks of waterways. Grande River is an important Brazilian river whose watercourse contains several hydroelectric plants, with few PPAs containing original features. Thus, this study analyzed land use in PPAs of a non-dammed stretch of the upper Rio Grande, in southern Minas Gerais. For this analysis, we used an image of the Rapideye sensor and the Maximum Likelihood classification method. The results showed the occurrence of pastures (49.63%), exposed soil (9.13%), others (0.77%), water (0.15%) and ornamental vegetation (0.13%) while the remaining native vegetation represented only 40.19% of PPAs. These numbers show that environmental laws have not been fulfilled in this area and there is strong human intervention in the PPAs studied. <![CDATA[Natural Wood Resistance of <em>Mimosa caesalpiniifolia</em> in Field Testing]]> ABSTRACT The natural wood resistance of sabiá (Mimosa caesalpiniifolia) was evaluated under field conditions for use in organic agriculture. A total of 97 one-meter length logs with bark and diameter classes (5.0-7.9 and 8.0-11 cm) were fixed (0.4 m) in the soil at a distance of 0.5 m from the edges of a forest fragment in Viana, Espírito Santo, Brazil and evaluated after 5 years and 5 months for their resistance to breaking through the application of manual force. The presence of xylophagous termites and fungi was verified. The percentages of unbroken pieces of wood were 81.82% and 79.24% respectively for the larger and smaller diameter classes. For the smaller diameter class, 52.83% showed moderate to superficial attacks, and the largest diameter class had 61.36%. In this case, 41% of the pieces presented superficial attacks (by termites and fungi) or were not attacked, confirming good performance of the tested wood. <![CDATA[Survival of Saplings in Recovery of Riparian Vegetation of Pandeiros River (MG)]]> ABSTRACT This study monitored the survival of saplings planted according to different recovery models in a riparian forest of the Pandeiros river (Januária, MG). The models consisted of planting the saplings in lines of 2 or 4 m with presence (T2S and T4S, respectively) or absence of direct seeding (T2 and T4, respectively). We planted 16,259 saplings of 17 botanical families, 32 genera and 33 species. The saplings, in general, presented a survival rate after one year of 34.4% (±1.8). The species with highest survival rates were Jacaranda brasiliana, with 85.0% (±13.5) of survival, Anadenanthera colubrina, with 70.1% (±7.0), and Triplaris gardneriana, with 69.3% (±9.1). Survival did not vary between the models tested, probably due to the short evaluation period (12 months). <![CDATA[Conversion Efficiency of Photosynthetically Active Radiation Into <em>Acacia mearnsii</em> Biomass]]> ABSTRACT The objective of this experiment was to determine the conversion efficiency of intercepted photosynthetically active radiation into biomass of Acacia mearnsii De Wild. seedlings. A forest species, plastic tubes (90 cm3), and 11 evaluation periods (up to 180 days after emergence) were used in this study. The leaf area index (LAI), total dry biomass (BIO), global solar radiation (GSR), cumulative intercepted photosynthetically active radiation (PARic), and conversion efficiency of radiation (εb) were determined using a pyranometer (LI200X, LICOR). The value of εb in BIO seedlings of Acacia mearnsii was 7.76 g MJ-1. LAI was directly related to the efficiency of PARic, and this influenced the development, production potential and accumulation of BIO. The value of GSR flow was 11.81 MJ m-2 day-1, while the value inside the greenhouse was 6.26 MJ m-2 day-1. <![CDATA[Comparing the Performance of Ground Filtering Algorithms for Terrain Modeling in a Forest Environment Using Airborne LiDAR Data]]> ABSTRACT The aim of this study was to evaluate the performance of four ground filtering algorithms to generate digital terrain models (DTMs) from airborne light detection and ranging (LiDAR) data. The study area is a forest environment located in Washington state, USA with distinct classes of land use and land cover (e.g., shrubland, grassland, bare soil, and three forest types according to tree density and silvicultural interventions: closed-canopy forest, intermediate-canopy forest, and open-canopy forest). The following four ground filtering algorithms were assessed: Weighted Linear Least Squares (WLS), Multi-scale Curvature Classification (MCC), Progressive Morphological Filter (PMF), and Progressive Triangulated Irregular Network (PTIN). The four algorithms performed well across the land cover, with the PMF yielding the least number of points classified as ground. Statistical differences between the pairs of DTMs were small, except for the PMF due to the highest errors. Because the forestry sector requires constant updating of topographical maps, open-source ground filtering algorithms, such as WLS and MCC, performed very well on planted forest environments. However, the performance of such filters should also be evaluated over complex native forest environments. <![CDATA[Relationship Between Spectral Data and Dendrometric Variables in <em>Eucalyptus</em> sp. Stands]]> ABSTRACT The present study aims (a) to assess the correlations between forest stand characteristics (viz., basal area, dominant height, and volume) and the reflectance values derived from Landsat 5 TM spectral bands as well as from vegetation indices and (b) to understand how Eucalyptus sp. stand age influences these correlations. Sampling data comprised a set of 35 permanent plots from a forest inventory conducted annually between 2006 and 2011. Spectral data were derived from Landsat 5 TM images. The results showed that TM4 and TM5 spectral bands, as well as vegetation indices ND54 and TM5/4, were better correlated with basal area and volume, while the TM2 spectral band was better correlated with dominant height. Eucalyptus sp. stand age directly influenced the correlations between spectral data and forest stand characteristics, and could not be disregarded in the spectral characterization of the forest variables. <![CDATA[Soil Compaction Due to Wood Harvesting Traffic at Different Extraction Distances]]> ABSTRACT This study evaluated the effect on Oxisol soil compaction of traffic by wood harvesting machines from different extraction distances carried out by a logging company located in Paraná State. The harvesting system was composed of a feller buncher, skidder and harvester, in which soil compaction was evaluated at four extraction distances and four depths by means of density, porosity and soil penetration resistance. Increased machine traffic resulted in the highest compaction in the soil surface layers on the extraction trail, with the highest intensity in the region near the edge of the stand and with values above the critical density limits. Soil penetration resistance was critical in the row of traffic over the stand with significant effects at a of 0.11 to 0.60 m, which is the recommended depth for soil preparation. <![CDATA[Growth Dynamics of Araucaria after Management Interventions in Natural Forest]]> ABSTRACT The objective of this study was to evaluate the effect of selective logging on the growth dynamics of Araucaria angustifolia in a natural forest of Rio Grande do Sul state, Brazil. Treatments were based on percentage reduction of the basal area per DBH class, namely, T0 (control) = 0%; T1 (light selective logging) = reduction of 20-30%; T2 (moderate selective logging) = reduction of 40-50%. Data were obtained prior to the management interventions and four, eight and 13 years after selective logging. Changes between treatments were assessed using the following parameters: absolute density, absolute dominance, importance value index, and growth rates. Results show that population reduction and canopy opening provided greater recruitment and higher growth rates for araucaria in the management treatments (T1 and T2) compared with those of the control treatment (T0). These results reinforce that management practices are necessary for the continuous development of araucaria in this forest formation. <![CDATA[Dissolved Air Flotation for Fiber Removal from Clear Water]]> ABSTRACT We investigated the use of dissolved air flotation (DAF) to treat clear water effluent from the paper industry in order to remove fibers. The dosage of polyaluminium chloride (PAC) was varied in the following concentrations: 0, 75, 100, 125, 150 and 175 mg/L; as well as bubble rise velocity of 18 and 9 cm/min for two types of paper wastewater: print and gloss. Data were statistically analyzed through factorial arrangement 6x2x2. The treatment of the print paper effluent showed better performance in removing the analyzed parameters with an optimal dosage of 100 mg/L PAC, whereas the gloss paper effluent treatment had satisfactory removal of analyzed parameters with an optimal dosage of 150 mg/L of PAC. This led to the observation that the high efficiency directly obtained with the DAF in conjunction with the use of PAC coagulant was an excellent primary treatment option for effluent resulting from the paper industry. <![CDATA[Anthropometry Applied in Dimensioning an Earth Auger]]> ABSTRACT The objective of this study was to show the application of anthropometric measurements in dimensioning an earth auger used in forest plantations, aiming to offer greater comfort, safety and health for workers. Based on anthropometric measures of a sample of 250 workers who worked on a forest implantation, seven measures in the 5, 50 and 95% percentiles obtained according to the German Standard DIN 33402/81 and related to the handling of the equipment were selected. Anthropometric standards of the workers were determined with minimum and maximum limits for the variables. Regression analyses were performed to verify the correlation between some anthropometric variables. The results show that the earth auger presented irregularities in terms of height and diameter of the handle; the measurements should range from 94 to 111 cm and 2.5 to 5.0 cm, respectively, enabling it to suit 90% of the worker population. The height showed a correlation of 68% with elbow height, and 67% with the hand center with arm hanging height. <![CDATA[Soil Stabilization with Lime for the Construction of Forest Roads]]> ABSTRACT The mechanical performance of soil stabilization using lime to improve forest roads was assessed. This study was conducted with lateritic soil (LVAd30) using lime content of 2% in the municipality of Niquelândia, Goiás state, Brazil. Geotechnical tests of soil characterization, compaction, and mechanical strength were performed applying different compaction efforts and curing periods. The results showed that lime content significantly changed the mechanical performance of natural soil, increasing its mechanical strength and load-carrying capacity. Compaction effort and curing time provided different responses in the unconfined compressive strength (UCS) and California Bearing Ratio (CBR) tests. The best UCS value (786.59 kPa) for the soil-lime mixture was achieved with modified compaction effort and curing time of 28 days. In the CBR test, soil-lime mixtures compacted at intermediate and modified efforts and cured for 28 days were considered for application as subbase material of flexible road pavements, being a promising alternative for use in layers of forest roads.