Regression models for estimating the volume of commercial trees in forests in Paragominas

In February 2009, the Ministryof the Environmentcreated theCONAMAResolution406,which provides thatfrom the secondAnnual Operating Plan(POA), thecalculation of volume ofstanding treeswill only beaccepted by thecompetent environmentalagencybythe volume equationdeveloped specifically for theSustainableForest Management Plan(PMFS). Thus, thestatistical modelto estimate the volumeofcommercialtrees needs to be specified. This study a djusted the statistical modelto the information collectedin a stand ofdenseOmbrophylousForestin Paragominas, Pará Stateto selectthe best fitand accuracy. The sample was composedof 234trees, distributed into sevendiameter class, with amplitudes of 12 cm in the range from 49to 127cm. The real volume was achieved by measuring the circumference in the sectionsat every 2m, determining the CBHandthe real tradeheight. The selectionfor choosing thebest model was based on the value of the F statistic, the highestcoefficient of determination(R²), the loweststandard errorof estimate inpercentage(Syx%) and the analysisof waste through thePercent Average Deviation (PAD). Based on the statisticsreferred to, it was concluded that the best traditional modelto beemployed inthe areawas the oneproposed bySchumacher-Hall. Finally, it is concluded that the alternative model with dummy variable is the best and should be adopted in the native forests of the Amazon.

equations ofvolume; forest management; Ombrophylous forest