Wind farms (WFs) can affect the local climate, and local climate change may influence underlying vegetation. Some studies have shown that WFs affect certain aspects of the regional climate, such as temperature and rainfall. However, there is still no evidence to demonstrate whether WFs can affect local vegetation growth, a significant part of the overall assessment of WF effects. In this research, based on the moderate-resolution imaging spectroradiometer (MODIS) vegetation index, productivity and other remote-sensing data from 2003 to 2014, the effects of WFs in the Bashang area of Northern China on vegetation growth and productivity in the summer (June–August) were analyzed. The results showed that: (1) WFs had a significant inhibiting effect on vegetation growth, as demonstrated by decreases in the leaf area index (LAI), the enhanced vegetation index (EVI), and the normalized difference vegetation index (NDVI) of approximately 14.5%, 14.8%, and 8.9%, respectively, in the 2003–2014 summers. There was also an inhibiting effect of 8.9% on summer gross primary production (GPP) and 4.0% on annual net primary production (NPP) coupled with WFs; and (2) the major impact factors might be the changes in temperature and soil moisture: WFs suppressed soil moisture and enhanced water stress in the study area. This research provides significant observational evidence that WFs can inhibit the growth and productivity of the underlying vegetation.

An extreme drought event is usually a long-term process with different stages. Although it is well known that extreme droughts that have occurred frequently in recent years can substantially affect vegetation growth, few studies have revealed the characteristics of vegetation responses for different stages of an extreme drought event. Especially, studies should address when the vegetation growth was disturbed and how it recovered through an extreme drought event. In this study, we used the Normalized Difference Vegetation Index (NDVI) and Palmer Drought Severity Index (PDSI) to evaluate the response of vegetation to different stages of a severe drought event during 2009–2010 throughout Southwestern China. The PDSI time series indicated that the drought can be divided into three stages, including an initial stage represented by moderate drought (S1), a middle stage represented by continual severe drought (S2), and a final recovery stage (S3). The results revealed that the drought during the initial stage inhibited the growth of grassland and woody savanna, however, forest growth did not decrease during the first stage of droughts, and there was even a trend towards higher NDVI values. The continual severe drought in the middle stage inhibited growth for all vegetation types, and the woody savanna was affected most severely. In the final stage, all vegetation types underwent recovery, including the grassland that had endured the most severe drought. This study provides observational evidence and reveals that the responses of forest to the extreme drought are different from grassland and woody savanna in the different drought stages.

There have been hiatuses in global warming since the 1990s, and their potential impacts have attracted extensive attention and discussion. Changes in temperature not only directly affect the greening of vegetation but can also indirectly alter both the growth state and the growth tendency of vegetation by altering other climatic elements. The middle-high latitudes of the Northern Hemisphere (NH) constitute the region that has experienced the most warming in recent decades; therefore, identifying the effects of warming hiatuses on the vegetation greening in that region is of great importance. Using satellite-derived Normalized Difference Vegetation Index (NDVI) data and climatological observation data from 1982–2013, we investigated hiatuses in warming trends and their impact on vegetation greenness in the NH. Our results show that the regions with warming hiatuses in the NH accounted for 50.1% of the total area and were concentrated in Mongolia, central China, and other areas. Among these regions, 18.8% of the vegetation greenness was inhibited in the warming hiatus areas, but 31.3% of the vegetation grew faster. Because temperature was the main positive climatic factor in central China, the warming hiatuses caused the slow vegetation greening rate. However, precipitation was the main positive climatic factor affecting vegetation greenness in Mongolia; an increase in precipitation accelerated vegetation greening. The regions without a warming hiatus, which were mainly distributed in northern Russia, northern central Asia, and other areas, accounted for 49.9% of the total area. Among these regions, 21.4% of the vegetation grew faster over time, but 28.5% of the vegetation was inhibited. Temperature was the main positive factor affecting vegetation greenness in northern Russia; an increase in temperature promoted vegetation greening. However, radiation was the main positive climatic factor in northern central Asia; reductions in radiation inhibited the greenness of vegetation. Our findings suggest that warming hiatuses differentially affect vegetation greening and depend on meteorological factors, especially the main meteorological factors.