Monitoring of phenology and irrigation responses of plantation forests based on vegetation remote sensing

Background and Aims The study of environmental factors affecting forest phenology has attracted attention, and we have proposed that moisture and precipitation in the rainy season have an influence on the growth of Populus tomentosa . Methods Near-earth remote sensing devices were applied to monitor the canopy phenology of planted Populus tomentosa B301 cultivated under full drip irrigation (DIFI), controlled drip irrigation (DICI), and non-irrigation (CK). The relative green vegetation index was calculated and the TIMESAT3.3 procedure was used to fit the time series curve of the phenological index of Populus tomentosa B301 and the key period of phenological growth was extracted. Results The data on the relative green vegetation index and the forest growth change rate are different. The tree species under controlled drip irrigation reached their growth peak on Day 111, 1 d after those with full drip irrigation and non-irrigation. 2) The tree species in the CK area withered and fell on Day 307, those in the DIFI region began to wither and decline on Day 315, and those in the DICI area began to wilt and decline on Day 291. The CK, DIFI, and DICI growing seasons were 222, 230, and 206 d, respectively. 3) Forests have different responses to different irrigation conditions. The use of different irrigation conditions changes the growth and development of the forests, resulting in significant phenological effects. Conclusion Appropriate irrigation techniques can improve water resource use efficiency, water environmental factors, and irrigation methods, all of which affect forest growth.