Models For Attack Estimates Of Sirex Noctilio (Fabricius) In Pinus Taeda L.

One of the main pests of Pinus spp forest plantations is Sirex noctilio (Fabricius), popularly known as the woodwasp. This work aims to develop a mathematical model to estimate the number of trees attacked by Sirex noctilio in Pinus taeda L. stands based on the monitoring methods and the dendrometric characteristics of the reforestation itself. For the data collection, five areas were located in the city of Palmas, Parana state. Sequential sampling, number of plot individuals, trap trees, mean breast height diameter (DBH), mean height, individual mean volume, plot volume, age, spacing, site, plot basal area, mean transverse area, diameter quadratic mean and DBH stratified into three diameter classes were used as model independent variables to be selected by the Stepwise method. The greatest influence on the attack estimate (Y) was exerted by the variables number of attacked trees detected in the sequential sampling (AS) (p-value <0.001) and number of individuals in the plot (n) (p-value <0, 05). The most appropriate model for obtaining the response variable was delta = beta(0) + beta(1)AS + beta(2)n + epsilon, which presented an adjusted coefficient of determination (R-adj(2)) of 0.965, a standard error of estimation (S-yx%) of 18.65% and better performance in the graphical analysis of waste. It is also noteworthy that the model can be used by forest managers as a tool in decision-making regarding to the stand management.