Terpenes are emitted by countless number of plant species. They are the largest source of BVOCs in the atmosphere. Sampling techniques employed in terpene studies include solid sorbents, solvent extraction, distillation and sublimation, membrane devices among others, accompanied by gas chromatography-mass spectrometry (GC-MS). Most of these sampling methods are often strenuous and time consuming. The solid phase micro extraction (SPME) was recently developed to eliminate cumbersome sampling procedures. The temperature-programmed Kovats retention index is the widely known method of identifying organic compounds from GC retention times. In this study, the SPME and stainless steel Tenax-TA(R) sorbent tubes were used to sample the volatiles from the beech, oak, and Norway spruce trees. The samples were analyzed by thermo-desorption-GC-MS and GC-MS/MS on two stationary phases: DB-1 and DB-5 columns. The terpenes were identified using Kovats retention index from both columns for comparison. The content in this book is particularly useful to environmental chemist, ecologist, entomologist, plant pathologist, plant physiologist, etc.