The Effect of Physiographic Factors on Sudden Oak Trees Death (Case Study Area: Barz and Shvrs Watershed)

Persian oak (Quercus brantii) defoliation and dieback is becoming a widespread problem in Zagros forests. The people who are living in vicinity are receiving this landscape signal and its terrible consequences.In this situation, therefore,an up-to-date careful watch over tree attitudes has to be a routine practice. Airborne digital imagery and remote sensing methods are the favorite choices to avoid costly, time-consuming and tedious field methods. Moreover, it has already been shown that forest health can easily be detected with appropriate radiometric and high spatial resolution methods. In summer 2014, I used data from ETM+ sensors of LandSat-8 satellite on wilting oak forests in Barz-Showarz aria in Central Zagros. All tree and stand dimentions, from topographic records to defoliation differentiation in every crown direction. There were more defoliated trees on high altitudes, mostly south slope faces, colluvial soils and pure oak forests. Reverse correlation were also detected between tree height, dbh and crown diameter with dieback percentage.