Monitoring forest recovery with change metrics derived from Landsat time series stacks

Ecological restoration of degraded riparian Tugai forests in north-western China is a key driver to combat desertification in this region. The Chinese government launched its largest environmental restoration project in 2000 by transporting 27.98 × 10⁸ m³ (until 2011) of fresh water from an upstream dam through the dried up lower reaches of the Tarim until the end lake. The diverted water recharged the groundwater, which is considered to be the main driver for the apparent forest recovery. The presented study evaluates the long term trend in forest growth using a time series of 14 years from the Landsat satellites. Three different vegetation metrics were used as input for the pixel based trend analysis. The Theil-Sen estimator served as trend indicator. The results give restoration managers an important insight of the vegetation response and serve as decision support during the restoration project.