Proposta de manejo de Araucaria angustifolia utilizando o quociente de Liocourt e análise de incremento, em propriedade rural no Município de Lages, SC

Equations express that height-diameter relationships are used to estimate tree heights that were not measured in the plots, as well as to calculate their volumes. In this study, we modelled height for Eucalyptus grandis Hill ex. Maiden stands using nonlinear mixed effect models in Mocuba District, Central Mozambique. Models were tested from 1414 trees measured, in 40 plots with dimensions of 20 x 20 m. Model one (M1) was the best in relation to the others according to the evaluated criteria (R2 = 0.9183; RMSE = 0.558; AIC = -1234.8; BIC = -1224.9). The inclusion of the variables dominant height (h100, m), basal area (G, m2.ha-1) and mean basal area diameter (dg, m) in model 1 (M1) within the scope of mixed effect model structures that involved both fixed and random effect parameters (Model 7) provides better fitting and more precise predictions. For calibration of random effects according to plot, height measurement of at least five trees is required (four dominant trees + one tree randomly selected in plot). Our model is site-specific and its application should therefore be limited to the stands with characteristics that were the basis of this study. Further works on recalibration, validation, and verification of our model using a larger dataset collected from a wider range of species distribution will be more interesting.

Artificial intelligence (AI) seeks to simulate the human ability to reason, make decisions, and solve problems. Several AI methodologies have been introduced in forestry to reduce costs and increase accuracy in estimates. We evaluate the performance of Artificial Neural Networks (ANN) in estimating the heights of Araucaria angustifolia (Bertol.) Kuntze (Brazilian pine) trees. The trees are growing in Uneven-aged Mixed Forests (UMF) in southern Brazil and are under different levels of competition. The dataset was divided into training and validation sets. Multi-layer Perceptron (MLP) networks were trained under different Data Normalization (DN) procedures, Neurons in the Hidden Layer (NHL), and Activation Functions (AF). The continuous input variables were diameter at breast height (DBH) and height at the base of the crown (HCB). As a categorical input variable, we consider the sociological position of the trees (dominant–SP1 = 1; codominant–SP2 = 2; and dominated–SP3 = 3), and the continuous output variable was the height (h). In the hidden layer, the number of neurons varied from 3 to 9. Results show that there is no influence of DN in the ANN accuracy. However, the increase in NHL above a certain level caused the model’s over-fitting. In this regard, around 6 neurons stood out, combined with logistic sigmoid AF in the intermediate layer and identity AF in the output layer. Considering the best selected network, the following values of statistical criteria were obtained for the training dataset (R² = 0.84; RMSE = 1.36 m, and MAPE = 6.29) and for the validation dataset (R² = 0.80; RMSE = 1.49 m, and MAPE = 6.53). The possibility of using categorical and numerical variables in the same modeling has been motivating the use of AI techniques in different forestry applications. The ANN presented generalization and consistency regarding biological realism. Therefore, we recommend caution when determining DN, amount of NHL, and using AF during modeling. We argue that such techniques show great potential for forest management procedures and are suggested in other similar environments.

Objetivou-se com o estudo verificar resgate vegetativo, enraizamento de estacas e adaptação das mudas enraizadas em sistema de minijardim clonal de Sequoia sempervirens. Realizou-se a decepa de cinco indivíduos com 20 anos de idade e após foi contabilizada a capacidade de emissão de brotações. Com as brotações, foram confeccionadas estacas, as quais foram submetidas a diferentes concentrações de ácido indolacético (AIA) (0, 2000, 4000 e 6000 mg.L-1). Foram avaliadas a porcentagem de enraizamento e o número e comprimento de raízes 160 dias após o estaqueamento. O experimento foi instalado em DIC, com 5 repetições de 10 estacas. Após a formação das mudas com as estacas enraizadas, elas foram transplantadas para vasos, para a formação do minijardim clonal. O resgate vegetativo através da decepa de árvores apresentou potencialidade para produção de estacas de sequoia e revigoramento do material. O uso entre 2000 e 4000 mg.L-1 de AIA aumentou a porcentagem de enraizamento e também o número e comprimento de raízes formadas. O minijardim clonal de sequoia mostrou ser uma boa opção para a multiplicação clonal da espécie. A clonagem da sequoia pode auxiliar tanto no melhoramento convencional como em plantios comerciais da espécie, principalmente no Sul do Brasil, local onde encontra condições adequadas para seu crescimento.Palavras-chave: Silvicultura clonal; coníferas; rejuvenescimento; minijardim clonal. AbstractRescue and vegetative propagation of Sequoia sempervirens. The objective of the study to verify the vegetative rescue, rooting cuttings and rooted plants adapt in mini-clonal hedge of Sequoia sempervirens system. Was held coppicing five individuals aged 20 years old and was recorded after the ability to shoot emission. Shoots with different concentrations of indole acetic acid were applied (IAA) (0, 2000, 4000 and 6000 mg.L-1) in cuttings made by evaluating the percentage of rooting, number and length of roots 160 days after striking. The experiment was a completely randomized with five replicates of 10 cuttings. After the formation of seedlings with rooted cuttings, these were transplanted to pots for the formation of mini-clonal hedge. The vegetative rescue through coppicing trees showed potential for the production of cuttings sequoia and reinvigoration of the material. The use from 2000 to 4000 mg.L-1 IAA increased rooting percentage and the number and length of roots formed. The mini-clonal hedge of sequoia proved to be a good option for clonal multiplication of the species. Cloning of sequoia can help both conventional breeding and for commercial plantations of the species, especially in southern Brazil, where finds suitable conditions for their growth.Keywords: Clonal forestry; conifers; rejuvenation; mini-clonal hedge.