CALIBRATION OF MODEL 3-PG FOR Eucalyptus saligna IN THE REGION OF GUA\ucdBA, RIO GRANDE DO SUL STATE

O trabalho teve como objetivo calibrar o modelo 3-PG para Eucalyptus saligna usando as var\ue1veis di\ue2metro a altura do peito (DAP), altura total, volume de madeira e biomassa de galho, casca e lenho. O estudo ocorreu na regi\ue3o de Gua\uedba - RS, sendo utilizados plantios clonais de Eucalyptus saligna, em diversos espa\ue7amentos. Foram selecionadas seis idades ao longo do ciclo de cultivo (2\uba ao 7\uba ano). Realizou-se o invent\ue1rio florestal para a coleta de biomassa (tr\ueas \ue1rvores, sendo fracionadas em: lenho, casca, galhos e folhas). Na \ue1rvore m\ue9dia de cada parcela, mensurou-se a biomassa de ra\uedzes at\ue9 a profundidade de 1 m. An\ue1lises f\uedsicas e qu\uedmicas em amostras de solo foram realizadas nas camadas de 0 a 20 cm, 20 a 40 cm e 40 a 100 cm. A deposi\ue7\ue3o de serapilheira foi estimada atrav\ue9s da aloca\ue7\ue3o de quatro coletores quadrados de 0,5 m\ub2. A \ue1rea foliar foi obtida por fotografias digitais e, a partir destas, estimou-se a \ue1rea foliar espec\uedfica. Os par\ue2metros fisiol\uf3gicos foram mensurados em seis parcelas, uma em cada idade. Os par\ue2metros clim\ue1ticos foram fornecidos pela EEA da UFRGS, localizada em Eldorado do Sul. A valida\ue7\ue3o do modelo n\ue3o foi estatisticamente aceita, mas os seus dados estimados podem ser utilizados para estimar as vari\ue1veis estudadas, evidenciando o potencial do seu uso, por\ue9m, com a necessidade de estudos adicionais.The study aimed to calibrate the model 3-PG for Eucalyptus saligna for the following the diameter variables at breast height (DBH), total height, wood volume and branch, bark and wood biomass. The study took place in the region of Gua\uedba, Rio Grande do Sul state, Brazil. Clonal plantations of Eucalyptus saligna in various spacings were used. Six different ages were selected along the crop cycle (2nd to 7th year). After the forest inventory was carried out, the biomass of three trees fractionated into wood, bark, branches and leaves was collected. The biomass of roots on the average tree of each plot was measured to a depth of 1 m. Physical and chemical analyses were performed in soil samples from the layers: 0 to 20 cm, 20 to 40 cm and 40 to 100 cm. Litter deposition was estimated by allocating 4 square collectors of 0.5 m\ub2. The leaf area was obtained through digital photographs and thus the specific leaf area was estimated. The physiological parameters were measured in six plots, one at each age. Climatic parameters were provided by EEA of UFRGS University, located in Eldorado do Sul, RS state. The model validation was not statistically accepted, but their estimated data can be used to estimate the studied variables, demonstrating the potential of its use although additional studies for the application of the model to this species are still needed