CERNE, Volume: 25, Issue: 4, Published: 2019
  • INFLUENCE OF SOIL FERTILITY ON THE ABILITY OF SCOTS PINE (Pinus sylvestris L.) TO ADAPT TO TECHNOGENIC POLLUTION Articles

    Zavyalov, Konstantin; Ivanova, Natalya; Potapenko, Anton; Ayan, Sezgin

    Abstract in English:

    ABSTRACT The purpose of the research is to identify the effect of soil factor on the ability of Scots pine to adapt to technogenic pollution based on comparative analysis of radial increment of the species which grows on soils of different fertility. The null hypothesis that soil fertility is a significant factor for adaptation was tested. The research area i.e. the plantation created in 1983 and exposed to pollution of aero-technogenic emissions of magnesium production Satka/Chelyabinsk Region/Russia, is located within the central part of the subzone of coniferous-broad-leaved and South-taiga coniferous forests of the Southern Urals. The analysis of annual growth rings (AGR) of Scots pine growing on soils of different fertility allowed us to estimate the effect of soil factor on the ability of Scots pine to adapt to magnesite pollution. As results of the research it was found that the differences in the AGR of Scots pine growing on soils of different fertility was statistically significant under the same level of technogenic pollution. During the investigation period (1994-2010), the AGR of Scots pine on fertile soils were significantly higher than those of on poor soils for 7 years. It was revealed that the positive effect of soil fertility on the Scots pine growth is leveled at the level of pollution exceeding 6-10 thousand tons per year of gaseous emissions and 25-30 thousand tons per year of total emissions. It was also found that soil fertility allows better adaptation of Scots pine to low temperatures, and more actively grow on sites with increasing precipitation.
  • THE LEGACY OF ELINOR OSTROM ON COMMON FORESTS RESEARCH ASSESSED THROUGH BIBLIOMETRIC ANALYSIS Articles

    Romanelli, João Paulo; Boschi, Raquel Stucchi

    Abstract in English:

    ABSTRACT A bibliometric analysis was performed to evaluate the research on common forest management that were influenced by the seminal work of Elinor Ostrom (Governing the Commons), from 1990 to 2018. This analysis was based on the online database of the Science Citation Index Expanded - Web of Science©. Six main aspects of the retrieved publications were evaluated: (1) publication years; (2) journals; (3) countries (or regions); (4) study approach type; (5) authors; and (6) keywords. This research topic has shown to be relevant all over the world. Authors from 34 different countries have been conducting studies based on Ostrom’s theory. Researchers have addressed this research topic primarily through case studies (approximately 83% of the publications). Among the retrieved literature body, the USA, Ecuador, Slovenia, Tanzania and Bangladesh have presented more than two case studies. All retrieved publications were published in 16 different journals. “Forest Policy and Economics” and “Ecology & Society” were the two most widely used journals to disseminate results. Around 115 different author’s expressions have been used as keywords to describe this subject. The main concepts addressed by the authors were: “Forest Governance”; “Institutional Analysis and Development Framework”; “Property Rights”; “Socio-ecological Systems”; “Community-based Forest Management”; “Co-management”; “Design Principles”; “Institutions”; “Common-pool Resource” and; “Sustainability”. Overall, this framework proved to be effective to evaluate the research trends, conflicting results and knowledge gaps surrounding the theme, and to contribute with researchers and governments on management and decision-making on this domain.
  • GENERALIZED LINEAR MODELS FOR TREE SURVIVAL IN LOBLOLLY PINE PLANTATIONS Articles

    Fiorentin, Luan Demarco; Bonat, Wagner Hugo; Pelissari, Allan Libanio; Machado, Sebastião do Amaral; Téo, Saulo Jorge; Orso, Gabriel

    Abstract in English:

    ABSTRACT To quantify the surviving trees in a forest stand and estimate the probability of an individual tree to survival are a fundamental task in forest management planning. Therefore, the main goal of this paper was to estimate the tree survival probability in loblolly pine (Pinus taeda L.) plantations based on generalized linear models (GLM). The data set was obtained from forest inventories carried out in the Midwest of Santa Catarina State, Brazil. The data analysis combined strategies for selecting covariates and different specifications of link functions in a Bernoulli GLM. We performed strategies for covariate selection at plot-level along with the standard stepwise procedure, where we considered the elastic net approach, as well as its special cases the lasso and ridge penalization. Our analyses showed that the stepwise procedure combined with the complementary log-log link function provide the best fit. The variables that most contributed to assess tree survival were basal area, number of individuals, maximum diameter, diameter of the average cross-sectional area and the diameter coefficient of variation per plots. This model presents 81.5% of accuracy given by ROC curve. Finally, we evaluated the fitted model by means of the half-Normal plots and randomized quantile residuals, whose results showed evidence of a suitable fit. We suggest the stepwise procedure for selecting covariates for a tree survival probability model, besides a complementary log-log link function.
  • INFLUENCE OF FERTILIZATION ON GROWTH OF YOUNG CHESTNUT TREES (Castanea sativa MILL.) MANAGED FOR WOOD PRODUCTION Articles

    Ribeiro, Stéphanie Lopes; Fonseca, Teresa Fidalgo; Pires, Ana Luísa

    Abstract in English:

    ABSTRACT In Portugal, chestnut wood demand has increased in the last decades. Since chestnut plantations are usually established in low fertility soils, addition of N, P and K as fertilizers usually have a benefic effect in increasing wood productivity. The study aims to evaluate the effects of fertilization on growth of chestnut tree (Castanea sativa Mill.) cultivated for wood purposes. An experimental essay was established in a 3-year old chestnut tree stand with a planting spacing of 3.5 × 3.0 m. Four treatments were applied to randomized blocks with three repetitions: control (C), addition of phosphorus (P), addition of phosphorus and potassium (PK) and addition of nitrogen, phosphorus, and potassium (NPK). The chemical properties of the soil and the concentration of nutrients in the leaves were evaluated after the treatment, and measurements of tree diameter and stem height were made for a monitoring period of 4 years. Treatments did not affect soil properties or leaf nutrient concentrations. On the counterpart, the effect of the fertilizers was noticed for tree dimensions and growth. Gains of NPK in relation to the control were observed for the height variable, over the years. Seven years after application of the treatments, differences were also noticed for the diameter and the volume index variables. The NPK treatment has presented a significant effect on tree growth compared to the control, with noticeable gains in the stem height.
  • PUBLIC SUPPORT FOR TIMBER HOUSING PRODUCTION IN BRAZIL Articles

    Araujo, Victor A. De; Morales, Elen A. M.; Cortez-Barbosa, Juliana; Gava, Maristela; Garcia, José N.

    Abstract in English:

    ABSTRACT Using face-to-face interviews and semi-structured questionnaires with timber housing developers, this study assed the perceptions of respective industries about government stimuli and public policies towards timber construction in Brazil. Four questions were developed under qualitative aspects, which were percentually measured to enable a response comparative. Thereby, 107 of 210 companies were evaluated here. Under statistical view, this sampling revealed a margin of error acceptable and next to the ideal condition. Results suggest that current policies have been apparently restrictive. Timber house producers still are dependant on strategies for whole national segments, whose scope does not promote both local cleaner industries and those focused on sustainable solutions such as from this studied sector. Tax cuts and exemptions for greener products could be an efficient alternative to incentive this production sector, and promote these sustainable timber houses. The creation of assertive public policies could attract more investors and developers to expand this industry and other forest-timber sectors and, consequently, contribute to reduce the housing shortage in Brazil.
  • IN VITRO GERMINATION OF MELANOXYLON BRAUNA SCHOTT. AND EVALUATION OF THE TOXICITY OF DISINFECTING AGENTS IN THE LACTUCA SATIVA L. MODEL PLANT Articles

    Silva, Elisa Regina da; Simões, Ingridh Medeiros; Baptista, Julcinara Oliveira; Bighi, Kelly Nery; Fontes, Milene Miranda Praça; Schmildt, Edilson Romais; Lopes, José Carlos; Caldeira, Marcos Vinícius Winckler; Alexandre, Rodrigo Sobreira

    Abstract in English:

    ABSTRACT The development of tissue cultured-based protocols applied to braúna, an endangeres species, would be though highly desirable. However, contamination-free explants are determinant for the success of this technique, which might be vulnerable to the toxicity of disinfectants. Here, we aimed at establishing an efficient protocol for in vitro production of axenic seedlings of braúna and to evaluate the toxicity of disinfectant agents in the Lactuca sativa model species. Experiments I and II: Seeds were treated with sodium hypochlorite (NaOCl) and fungicide captan, with and without residue, by different immersion times, respectively. The following were analyzed: contamination; germination and normal and abnormal seedlings. Experiment III: Lettuce seeds placed in Petri dishes were exposed to 2.5 mL captan at 0.5; 1; 2; 4 and 8%; 0.01% glyphosate and distilled water. The germination, length of seedlings, cell cycle, nuclear and chromosomal alterations of the cells of the root meristem were assesed. The isolated use of NaOCl was not efficient in the disinfestation of braúna seeds. However, the immersion of the seeds in captan, for 10 minutes with its residue, led to higher germination and vigor indexes; however, resulted in the formation of abnormal seedlings. This compound exhibited toxicity in the lettuce model seeds because affected the germination and the whole development of the seedlings, showing clastogenic and aneugenic action in the meristematic cell cycle.
  • ROOTING ENVIRONMENTS IN Sequoia sempervirens MINI-CUTTINGS OF CLONE A228 Articles

    Pereira, Mariane de Oliveira; Navroski, Marcio Carlos; Ângelo, Alessandro Camargo; Fonseca, Pedro Henrique Tavares da; Moraes, Carolina; Lovatel, Queli Cristina; Amaral, Milena

    Abstract in English:

    ABSTRACT Sequoia sempervirens is different from other species not only for its excellent vigor and longevity, but also for quality wood productivity. The objective of this work was to evaluate the rooting of Sequoia sempervirens mini-cuttings in different cultivation environments. In both experiments, rooting was evaluated in time to determine the root development in each environment. Mini-cuttings from clone A228 from clonal mini-garden were used. In the first experiment the material was placed to take root in three different environments: greenhouse (GH), shadehouse (SH) and mini-tunnel, with evaluation performed every 30 days (from 30 to 150 days). In the second experiment, we compared the development and rooting in mini-tunnel, greenhouse with intermittent mist (GWIM), with weekly evaluations (from 30 to 93 days). Both experiments were installed in a completely randomized design, with subsequent evaluation of the survival percentage, percentage of rooted cuttings and number of roots emitted by rooted cuttings. Humidity and temperature data were also collected in all environments observed. The mini-tunnel was the most efficient place for sequoia mini-cutting, presenting higher survival, rooting and number of roots when compared to the shadehouse and the greenhouse. In addition, it provided rooting similar to the greenhouse with intermittent mist (close to 90%). It is recommended to keep mini-cuttings in a mini-tunnel or greenhouse with intermittent mist for a period of 90 days for proper rooting to occur. Good temperature control was also observed in this structure, as well as excellent humidity control. The mini-tunnel can be used for sequoia propagation by mini-cuttings as it has shown good rooting results (> 80%).
  • MIXOTROPHISM EFFECT ON IN VITRO ELONGATION AND ADVENTITIOUS ROOTING OF Eucalyptus dunnii Articles

    Souza, Denys Matheus Santana Costa; Fernandes, Sérgio Bruno; Avelar, Maria Lopes Martins; Frade, Samira Rangel do Prado; Molinari, Letícia Vaz; Gonçalves, Douglas Santos; Brondani, Gilvano Ebling

    Abstract in English:

    ABSTRACT The relevance of Eucalyptus dunnii has been evidenced mainly for its wood quality and cold tolerance among cultivated subtropical eucalypts. However, rooting is a challenge for its propagation, particularly when adult material is involved. This study aimed to assess the mixotrophism on the in vitro elongation and adventitious rooting phases in Eucalyptus dunnii microcutting. The experimental material used was obtained from a ministumps of Eucalyptus dunnii clones. In order to evaluate gas exchange and sucrose supplementation on in vitro elongation and adventitious rooting, the experiment was prepared in a 3×4 factorial arrangements with three forms of sealing (rigid polypropylene caps with no membrane (0/M), with a membrane (1/M), with three membranes (3/M) and four sucrose concentrations (0, 10, 20 and 30 g.L-1). At 30 days in the elongation phase it was evaluated (length, number of shoots per explant, oxidation, bud vigor, pigment content, leaf area and anatomy) and rooting (length, root diameter and rooting). Results show that sucrose should be added in the culture medium for in vitro elongation and can be reduced to concentrations between 10 and 20 g.L-1. In vitro rooting requires the use of 30 g.L-1 of sucrose. The use of flasks with membranes that allow gas exchange is an effective alternative to promote the in vitro elongation and adventitious rooting of Eucalyptus dunnii microcutting.
  • ANALYZING CARBON STOCKS IN A MEDITERRANEAN FOREST ENTERPRISE: A CASE STUDY FROM KIZILDAG, TURKEY Articles

    Dinc, Musa; Vatandaslar, Can

    Abstract in English:

    ABSTRACT Carbon dioxide is one of the most important greenhouse gases responsible for global climate change. Terrestrial ecosystems are widely recognized as useful mechanisms, as they store large quantities of carbon in their bodies. In this context, the present study aims at analyzing carbon stocks in forest (both productive and degraded), grassland, and agricultural ecosystems of Kizildag Planning Unit. To this end, forest inventory data, published statistics, and GIS tools were used for modeling carbon densities of these three ecosystems in a spatially explicit manner. Moreover, carbon contents were estimated for different pools including above- and below-ground biomass, litter layer, deadwood, and soil components. Results showed that a total of nearly 3.5 million tons of carbon stored in the entire study area. When standardized to per unit area, productive and degraded forests stocked the most significant amounts followed by grassland and cropland land use/land cover (LULC) classes. The average density was 120.8 tons ha-1 for productive forests, while it was 32.3 tons ha-1 for croplands. The vast majority of these amounts stocked in soil pools for each LULC classes. Therefore, special attention should be paid for soil carbon studies which are very rare in the region. Regarding spatial distribution, Kizildag showed a rather non-homogeneous pattern in terms of carbon densities. Hotspots generally accumulated in the southwestern parts, as well as near the east border of the study area. Carbon densities could be as high as 200-245 tons ha-1 in these hotspots. Those areas were dominated by mixed stands of Taurus fir, cedar, and black pine at older ages and they were designated primarily for protective functions in the forest management plan. It is concluded that vast degraded forestlands in the region offer great opportunities to forest managers as an effective mechanism in combatting climate change. Therefore, rehabilitation, afforestation, and forest protection activities should be accelerated as possible.
  • INVESTIGATION AND EVALUATION OF STONE PINE ( Pinus pinea L.) CURRENT AND FUTURE POTENTIAL DISTRIBUTION UNDER CLIMATE CHANGE IN TURKEY Articles

    Akyol, Ayhan; Örücü, Ömer Kamil

    Abstract in English:

    ABSTRACT Climate change has negative effects on especially plant species that have a limited habitat. In this context, the stone pine (Pinus pinea L.), which has a limited distribution, is prominent with its economic, ecological and aesthetical characteristics, and it is frequently preferred in afforestation. In this study, the habitats in Turkey that are suitable for distribution of P. pinea L. were modelled by using Maxent based on high-resolution environmental data. In total, 13 field-based occurrence points and 19 bioclimatic variables were used to model the potential distribution area under current and two prediction model (RCP4.5 and RCP8.5) for the years 2050 and 2070. According to the results, the most important bioclimatic variables effective on the potential distribution of P. pinea L. were found as the minimum temperature of coldest month (Bio6), annual precipitation (Bio12) and precipitation of wettest quarter (Bio16). Prediction models under two future climate change scenarios displayed that P. pinea L. will lose habitat and it will shift geographical distribution towards north and higher elevation sites. Considering especially the economic contributions provided by P. pinea L., these results necessitate consideration of the areas where the rate of potential distribution of the species is the highest in afforestation work aiming rural development. In addition to habitat losses, climate change affects many variables of the ecosystem.
  • THE EFFECTIVENESS OF PROTECTED AREAS IN BIODIVERSITY CONSERVATION: THE CASE OF TURKEY Articles

    Birben, Üstüner

    Abstract in English:

    ABSTRACT The biodiversity on Earth, with the many species, ecosystems, and ecological processes that constitute the natural environment, is of incalculable value to humanity. Conservationists efforts are often inspired by Turkey’s unique biological system, which is highlighted by a broad biodiversity and a 34% rate of endemism. This fragile biotic wealth is sometimes threatened by pressures for economic development. Biodiversity-rich regions tend to have more urgent needs for conservation but frequently lack the financia resources and human capacity to achieve effective protections. Even so, there are many legislative leaders, institutional administrators, and other persons who are willing to work to save protected areas, or conservation areas (although this does not mean that their resource value would be properly protected); in fact, Turkey is one of the most enlightened nations in this regard. An institutional approach has been followed to bring new perspectives to the debate about the effectiveness of protected areas in Turkey. Protected areas have decreased steadily, from 5.647.568 ha in 2012 to 3.451.947 ha in 2018. This analysis confirms that protected areas face institutional restrictions, lapses in management, and capacity limitations. There is a need for a more adaptive approach to policy-making processes related to biodiversity conservation in Turkey.
  • CONICITY AND YIELD FOR LUMBER FROM COMMERCIAL SPECIES FROM THE AMAZON Articles

    Santos, Misael Freitas dos; Gama, João Ricardo Vasconcellos; Figueiredo, Afonso; Costa, Daniele Lima da; Retslaff, Fabiane Aparecida de Souza; Silva-Ribeiro, Renato Bezerra da; Rode, Rafael

    Abstract in English:

    ABSTRACT Stem conicity and the sawing pattern, besides the presence of hollows and sapwood, are among the principal factors that are responsible for the low yield of lumber from harvested wood in the Amazon. Therefore, the objective of this study was to analyze of logs and stem conicity, and its effect on yield of sawn wood from the species Handroanthus impetiginosus (Mart. ex DC.) Mattos, Lecythis lurida (Miers) S. A. Mori, Manilkara huberi (Ducke) Chevalier, Astronium lecointei Ducke and Couratari sp., which are currently the most important commercial species in the study area. The data used were obtained from six production units in the Tapajós National Forest, Pará. The variables analyzed were conicity (obtained as a function of the difference between diameters at the base and top) between logs, DBH classes (diameter at breast height) and species, as well as yield (estimated using the Software MaxiTora) between logs and species. The majority of the species showed differences in conicity between logs, with the first log being the most conic, which was directly reflected by the lower yield for this log. There was a tendency of increase in conicity in the larger DBH classes, and differences in conicity and yield between species. The estimated yields were superior to the percent yields observed for Amazonian species in studies done using samples with similar characteristics. Therefore, it was concluded that conicity can vary between species, logs, and DBH classes, and is a characteristic that directly effects the yield of lumber. Furthermore, the incorporation of cutting templates represents an alternative for maximizing lumber yield.
  • WOOD COLORIMETRY FOR THE CHARACTERIZATION OF AMAZONIAN TREE SPECIES: A SUBSIDY FOR A MORE EFFICIENT CLASSIFICATION Articles

    Sousa, Wilza Carla Santos e; Barbosa, Lucas de Jesus; Soares, Alvaro Augusto Vieira; Goulart, Selma Lopes; Protásio, Thiago de Paula

    Abstract in English:

    ABSTRACT The wood of different species may present macroscopic similarities, which hinders a reliable differentiation between the specie. This can be a problem, especially in the tropics, given the high species diversity in this region. To overcome this problem of wood identification, colorimetric criteria can be applied, aiming at a better and more objective classification, as opposed to the traditional anatomic criteria. Therefore, the aim of this research was to analyze the variability of the wood color considering the cutting planes (tangential and radial) and to determine its correlation with the wood basic density of ten Amazonian tree species. The following species were studied: Apuleia leiocarpa (amarelão), Hymenolobium modestum (angelim-pedra), Anadenanthera columbrina (angico), Dipteryx odorata (cumaru), Pouteria pachycarpa (goiabão), Mezilaurus itauba (itaubá), Hymenaea courbaril (jatobá), Simarouba amara (marupá), Astronium leicontei (muiracatiara) and, Bowdichia nitida (sucupira). The CIEL*a*b* system was used to determine the colorimetric parameters (L*, a*, b*, C*, and h*), which were obtained through a portable colorimeter. The species were classified in six color specific groups: light yellow, olive brown, yellowish olive, olive light, grayish white and reddish brown. We observed statistical effect of the cut planes only for luminosity, with higher mean for radial face. The correlation analyses between color and basic density showed that the denser woods are darker and have more red pigment (a*). There is negative correlation between luminosity (L*) and wood basic density (-0.78). The colorimetric parameter a* presented positive correlation with the basic density (r = 0.80).
  • STAND DENSITY MANAGEMENT DIAGRAMS OF Eucalyptus viminalis: PREDICTING STEM VOLUME, BIOMASS AND CANOPY COVER FOR DIFFERENT PRODUCTION PURPOSES Articles

    Gyenge, Javier; Lupi, Ana; Ferrere, Paula; Milione, Germán; Martínez-Meier, Alejandro; Caballé, Gonzalo; Daguer, Diego Dominguez; Fernández, María Elena

    Abstract in English:

    ABSTRACT Stand density management diagrams (SDMD) provide a guide for forest density management taking into account stands attributes such as trees´ diameter or volume. One of the most common species planted in Pampean plains of Argentina is Eucalyptus viminalis for multiple objectives: solid wood use or firewood in local markets, pulp for cellulose industry and to provide services for agriculture and cattle raising (windbreaks or cattle refuge). The objective of this study was to gather the available production information /inventory data and to develop a first SDMD for estimating standing volume, biomass and canopy cover of E. viminalis as a tool for forest managers aiming at different plantation purposes. Data to develop the SDMD were obtained from 161 plots, distributed along a climate and soil gradient. We also generated two predictive equations capable of estimating dominant height from the diameter of the trees as well as canopy cover from stand basal area. As an example of application, the SDMD was used to estimate the wood production of three alternative systems: a) an unmanaged plantation (simulating a common practice in the region), b) a mixed production system such as an agroforestry system, and c) a plantation that maximizes wood biomass or volume production.
  • CALIBRATING A TAPER MODEL FOR ORIENTAL SPRUCE IN TURKEY Articles

    ÖZÇELIK, RAMAZAN; CAO, QUANG V.; YAVUZ, HAKKI

    Abstract in English:

    ABSTRACT In this study, Max and Burkhart (1976)’s segmented taper model was used to describe stem profile and predict stem volume of oriental spruce in Turkey. Thirty procedures were evaluated, which include five fitting methods and six adjustment strategies. The fitting methods resulted in parameters that were optimized for (1) taper, (2) cumulative volume, (3) taper and cumulative volume, (4) taper and total volume, and (5) taper, cumulative volume, and total volume. The adjustment strategies are (1) unadjusted, and adjusted to match (2) DBH, (3) predicted total volume, (4) DBH and predicted total volume, (5) a combined estimator, and (6) DBH and a combined estimator. Results showed that, without adjustment, the model with parameters optimized for taper gave good prediction for both taper and cumulative volume. Mixed results were obtained when various adjustment strategies were used on different fitting techniques. The overall best-ranked procedure for predicting both taper and volume was the model optimized for taper and cumulative volume and then adjusted to fit the combined estimator.
  • FINANCIAL ANALYSIS OF INVESTMENTS IN FOREST CONCESSION FOR AMAZON BRAZILIAN BY DETERMINISTIC AND STOCHASTIC METHODS Articles

    Rodrigues, Maisa Isabela; Souza, Álvaro Nogueira de; Joaquim, Maisa Santos; Sanches, Keila Lima; Araújo, Juliana Baldan Costa Neves; Castanheira, Fernando; Coelho, Luiz Moreira

    Abstract in English:

    ABSTRACT Forest concessions were implemented in Brazil as a way to increase the areas of sustainable forest management. Little is known about the financial viability of forest management in Brazil, which is one of its main bottlenecks. In this context, the aim of the study was to evaluate the financial viability of an investment in forest concession. In order to do so, the Net Present Value (NPV), Periodic Equivalent Benefit (PEB), Internal Rate of Return (IRR) and Real Options Analysis (ROA) were adopted, and the option of abandonment was also analyzed. As a variable for ROA analysis, the productivity (m³.ha-1) at the first years of forest concession under study was adopted. The NPV of the investment corresponds to US$ 8.04.m-³, the PEB was US$ 0.52.m-³.year-1 and the IRR, 20.75%. In order to be considered feasible, the forest concession must have a minimum productivity of 17.75 m³.ha-1. Of the 861 managerial decisions, the option to proceed with the investment was adopted in 237 nodes (27.53%), and the decision to abandon was exercised in 624 nodes (72.47%). This is a worrying result for the concessionaire companies and also for the management entities of the forest concessions, mainly when comparing with the concessions reality, where abandonment is an option that has been performed. It can be concluded that the high probability of abandoning highlights a fragility of forest concessions. ROA proved to be a good methodology to complement traditional methods of financial analysis, presenting satisfactory results in aiding decision-making.
  • RATIONAL VOLUMETRIC MODELS: TESTED IN FOREST STANDS OF Acacia mearnsii DE WILD IN SOUTHERN BRAZIL Articles

    Péllico, Sylvio; Behling, Alexandre

    Abstract in English:

    ABSTRACT Tree volumes can alternatively be obtained by ratio estimates, instead of applying linear regression modeling. An interesting question was considered by the authors when comparing the precision of tree volumes obtained by these two statistical approaches, that allowed us to formulate a new hypothesis to conduct this study: “Is it possible to obtain better volume estimates if the form factor is associated only to the exponent of the independent variable that presents higher correlation with the stem volume?”. The research was conducted in commercial stands of black wattle (Acacia mearnsii De Wild) in the municipalities of Cristal, Encruzilhada do Sul and Piratini to answer this question. Forest stands were sampled in a sequence of ages after planting, varying from 1 to 14 years. In each forest stand, trees were felled, and the following characteristics were evaluated: diameter at breast height, total height, and stem scaling. The three age groups were specified according to the behavior of the form factor values. It was proposed three models to be solved by ratio estimates. A comparison of the proposed models with the Schumacher-Hall model, fitted by regression analysis, was done. The model in which the form factor was associated to the exponent of the diameter variable produced the best results, owing to a powerful correlation resulted of this confounding with volume as a dependent variable. Ratio estimates resulted in more accurate tree volumes predominantly, when compared with those obtained by the traditional Schumacher-Hall model fitted through regression analysis. Therefore, we recommend the application of model 2 fitted by ratio estimate.
UFLA - Universidade Federal de Lavras Universidade Federal de Lavras - Departamento de Ciências Florestais - Cx. P. 3037, 37200-000 Lavras - MG Brasil, Tel.: (55 35) 3829-1706, Fax: (55 35) 3829-1411 - Lavras - MG - Brazil
E-mail: cerne@dcf.ufla.br