Comparison of land inventory and using of Ikonos image in Google Earth database to estimate quantity characteristics of urban forest (Case study: Iran; Sari city)

Urban forests are an indicator for establishing cities and they have important aesthetic values due to environmental effects as well as providing green spaces. Trees have the most important effect on the weather of cities among green spaces and the larger the area of the forested land, the more positive outcomes would be obtained. The present study was done to compare ground survey method with Ikonos images in Google Earth Meta data for estimating various quantitative characteristics of urban forests in some parts of Sari, Iran. Using the ground survey method, we employed systematic random sampling design to estimate trees canopy cover on Jomhouri Eslami Street in Sari. The canopy of each tree was measured in two perpendicular directions and the diameter at breast height was also measured for each tree. The results of t-test showed that estimates resulting from the two methods were not significantly different (df = 118, t = 1.39). The results of regression analysis indicated that using Ikonos images (R2= 0.97) was suitable for estimating canopy area on the street. Based on our results, it can be concluded that considering the high accuracy and quick interpretation of satellite images, Ikonos images can be reliable alternatives for ground survey method in measuring tree canopies in cities with similar forest structure.