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.

ABSTRACT The aim of this study was to develop a mathematical model for the spatial forest planning of harvest activity scheduling. Thirty-eight (38) blocks were formed from stands aged 13 to 17 years considering a total area limit set to 350 hectares. The model was built in Excel ® spreadsheet and solved by CPLEX® optimization software using the Branch and bound method for the linear programming of problems with integer variables. The results of optimization are presented in the form of a map of spatial distribution of the selected blocks. The total harvested area was 5,989 hectares and the volume generated was 2,956,913 m3 in a planning horizon of five years. Higher results compared with those of traditional planning and efficiency to optimize forest harvesting proved to be a viable alternative to the inclusion of space and operational issues associated with forest harvesting.

ABSTRACT The aim of the present study was to propose a prediction system to estimate the diameter distribution and wood production in unthinned eucalyptus clone plantations. Data was obtained from permanent sample units, with ages from 28 to 78 months. The Weibull distribution was used to estimate the frequency of the number of trees per diameter class. Models were used to relate the Weibull distribution coefficients with forest stand attributes. The forest stand variables most correlated with the Weibull distribution parameters were the minimum, medium, maximum and quadratic diameters and the dominant height. The projected frequency of tree numbers and the production by diameter class obtained by the system of equations did not differ statistically from the observed values evaluated by the t-test at 95% probability.

RESUMO O objetivo deste trabalho foi avaliar diferentes critérios para amostragem de fustes para medição e identificar o critério mais adequado para a modelagem do volume de árvore individual. Os dados foram coletados em povoamentos de eucalipto com idade entre 58 e 65 meses. O modelo de Schumacher-Hall foi aplicado em cinco critérios de amostragem, com nove variações (45 no total): 1) número de árvores por classe diamétrica, sendo (a) número fixo, (b) proporcional à distribuição do diâmetro amostral, ou (c) proporcional ao desvio padrão da amostra; 2) tamanho da amplitude da classe diamétrica, que variou de 1,0 a 5,0 cm. As equações geradas em cada critério foram usadas para estimar o volume de fuste de árvores reservadas para validação. Isso permitiu calcular erros padrões da estimativa para esse conjunto de dados. Além disso, os resíduos das estimativas de volume foram examinados por meio de testes estatísticos para viés, autocorrelação e heteroscedasticidade. Os resultados mostraram melhores performances de equações de volume usando menores amplitudes. Não houve uma clara tendência em aumentar/reduzir a autocorrelação e/ou heteroscedasticidade dos resíduos. Aquelas amostragens com proporção à frequência da classe diamétrica apresentaram as melhores performances, inclusive usando apenas 36 árvores. Aquelas cuja escolha de árvores foi proporcional ao desvio padrão tiveram os piores resultados. Como conclusão, a seleção proporcional à frequência da classe diamétrica, sob condição de amostrar pelo menos duas árvores por classe, fornece modelos estatisticamente superiores aos demais quanto aos critérios sugeridos no estudo.

ABSTRACT The aim of this paper was to evaluate different criteria for stem measurement sampling and to identify the criterion with best performance for developing individual tree volume equations. Data were collected in eucalyptus stands 58 to 65 months old. Schumacher-Hall model was applied using five sampling criteria with nine variations (45 in total): 1) number of trees per diameter class, being (a) fixed number, (b) proportional to the diameter class of the sample, or (c) proportional to the standard deviation of the sample; and 2) the width of the diameter class, which ranged from 1.0 up to 5.0 cm. We used the equations generated from each of the five sampling criteria to estimate stem volume of trees reserved for validation. This allowed us to obtain standard errors of estimates from this data-set. In addition, residuals of volume estimates were examined by means of statistical tests of bias, autocorrelation and heteroscedasticity. Better performances of volume equations occurred when smaller diameter class widths were used, i.e., when the sample size increased. There was no clear trend in increasing/decreasing residual autocorrelation and/or heteroscedasticity. Both methods of sampling proportional to the frequency of diameter class had the best performances, inclusive using only 36 trees. The ones where choice of trees was proportional to the standard deviation had the worst. In conclusion, the selection proportional to the frequency of the diameter class, under the condition that at least two trees per class are sampled, provides models statistically better than all the other criteria.

RESUMO Nas plantações florestais industriais, a distribuição espacial das unidades de manejo agendadas para colheita influencia o custo de produção madeireira e o consumo de recursos não renováveis, devido às questões relacionadas com a logística de transporte. Neste contexto, o objetivo do estudo foi formular modelos de Programação Linear Inteira (PLI) por meio da aplicação do algoritmo de otimização em redes Floyd-Warshall na geração de rotas de produção madeireira, minimizando o custo de produção resultante das atividades de colheita e manutenção de estradas. Em seguida, foram simulados cenários considerando distintas idades mínimas de corte de talhões de Pinus spp. e Eucalyptus spp. O horizonte de tempo foi de 5 anos com periodicidade anual. A área de estudo foi 23.330 hectares de florestas, localizados no estado do Paraná (sul do Brasil). Nos comparamos os cenários simulados de acordo com os seguintes parâmetros indicadores: rendimento da colheita, rede de estradas utilizada e custo unitário de produção. A diminuição da idade mínima de corte reduz a produtividade média das unidades de manejo agendadas para colheita e, por outro lado, requer menos estradas edificadas, o que consequentemente diminui o custo unitário de produção. As soluções obtidas pelo uso dos modelos PLI estiveram menos de 0,1% distantes do ótimo global.

ABSTRACT In industrial forest plantations, the spatial distribution of management units for harvest scheduling influences the timber production cost and the non-renewable resources consumption, due to issues related to transport logistic. In this context, this research aimed to formulate Integer Linear Programming (ILP) by means of the application of Floyd-Warshall network optimization algorithm to generate timber production routes, minimizing the production costs resulting from harvest activities and forest road maintenance. Then, scenarios were simulated considering different minimal harvest ages for Pinus spp. and Eucalyptus spp. stands. The planning horizon was five years with annual periodicity. The study area was 23,330 hectares of forests, located in Paraná state (southern Brazil). We compared the simulated scenarios according to the following parameter indicators: harvest income, building road network and the production unit cost. The decreasing of the minimal harvest age reduces the mean production of management units scheduled to be harvested, in other hand, it requires fewer roads to be built, and consequently increases the production unit cost. The solutions obtained by using ILP models presented an optimality gap lower than 0.1%.

O objetivo desta pesquisa foi analisar o efeito da pecuária extensiva sobre a composição e a diversidade florística da regeneração natural em áreas de preservação permanente de Floresta Ombrófila Mista em Caçador, SC. Os dados são provenientes de 32 parcelas de área fixa temporária (4 × 17 m), distribuídas de maneira aleatória, em áreas de preservação permanente. Foi mensurado o diâmetro do colo (10 cm) e a altura total de todos os indivíduos que apresentaram altura superior a 30 cm e circunferência à altura do peito igual ou menor que 15,7 cm (diâmetro ≤ 5 cm). Na análise florística foram encontradas 61 espécies, 52 gêneros e 30 famílias botânicas. As áreas sem a presença de gado apresentaram uma diversidade ligeiramente superior às áreas com gado. De modo geral, a composição, diversidade e a equabilidade florística entre as áreas com e sem gado foram semelhantes.

The objective of this research was to analyze the effect of extensive cattle raising on floristic composition and diversity of natural regeneration in permanent preservation areas of Ombrophilous Mixed Forest in the municipality of Caçador, Santa Catarina state, Brazil. Data were collected in 32 temporary fixed area plots (4×17 m) distributed randomly in permanent preservation areas. We measured the collar diameter (10 cm) and total height of all individuals taller than 30 cm, with circumference at breast height smaller than or equal to 15.7 cm (diameter ≤ 5 cm). The floristic analysis showed 61 species, 52 genera and 30 botanical families. The areas without cattle presented diversity slightly higher than the areas with cattle. In general, the floristic composition, diversity and equability between areas with and without cattle were similar.