The effect of growing season and summer greenness on northern forests

Kaufmann, Robert K.; D’Arrigo, Rosanne; Laskowski, Cheryl; Myneni, Ranga B.; Zhou, Liming; Davi, Nicole

doi:10.1029/2004gl019608

Cited by 69 publications

(63 citation statements)

References 20 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Vedin (1990) noted when studying the GS in northernmost Sweden in two 10-year periods, one warm (1931)(1932)(1933)(1934)(1935)(1936)(1937)(1938)(1939)(1940) and one colder (1979)(1980)(1981)(1982)(1983)(1984)(1985)(1986)(1987)(1988), that GSL was shorter in the warm period than the cold one. Also, examining the relationship between NDVI and tree rings in North America and Eurasia, Kaufmann et al (2004) suggested that summer temperatures were more important to tree growth than the duration of the GS.…”

Section: General Trends In the Gbamentioning

confidence: 98%

Twentieth-century trends in the thermal growing season in the Greater Baltic Area

Walther²,

2007

View full text Add to dashboard Cite

Phenological data have shown an increase of ca. 10 days in European growing season length in the latter part of the twentieth century. In general, these changes have been associated with global warming. Here we present a study of thermal growing season (GS) trends in the Greater Baltic Area, northern Europe. Yearly dates for the start, end and length of the GS were computed for 49 stations in the studied area, using daily mean temperature measurements. Trends and tendencies of the GS parameters were analysed within the twentieth century. We also examined GS trends in long records (starting before 1850) from the region. The results show a general increase of the length of the GS of ca one week since 1951 in the area, where the most considerable change has occurred in spring (starting ∼6 days earlier). The largest increases were found at stations adjacent to the Baltic Sea and North Sea, where some Danish stations showed significant increasing trends in the length of the GS of more than 20 days. The only tendency for a shorter GS was found in Archangelsk, north western Russia. The three longest records displayed large inter-annual and decadal variability, with tendencies for increased frequencies of longer growing seasons since the 1950s.

show abstract

Section: General Trends In the Gbamentioning

confidence: 98%

Twentieth-century trends in the thermal growing season in the Greater Baltic Area

Walther²,

2007

View full text Add to dashboard Cite

show abstract

“…Both NDVI and EVI are direct optical measures of canopy greenness, are highly correlated with plant photosynthesis and chlorophyll content, and have been widely used to quantify vegetation dynamics and their responses to climate change [32][33][34][35][36][37][38][39][40]. The MODIS VI data from Terra (MOD13A1) and Aqua (MYD13A1) represent the best quality retrievals at a local solar time of~10:30 and~13:30, respectively.…”

Section: Satellite Datamentioning

confidence: 99%

Detecting Wind Farm Impacts on Local Vegetation Growth in Texas and Illinois Using MODIS Vegetation Greenness Measurements

Xia

Zhou

2017

Remote Sensing

View full text Add to dashboard Cite

This study examines the possible impacts of real-world wind farms (WFs) on vegetation growth using two vegetation indices (VIs), the Normalized Difference Vegetation Index (NDVI) and Enhanced Vegetation Index (EVI), at a~250 m resolution from the MODerate resolution Imaging Spectroradimeter (MODIS) for the period 2003-2014. We focus on two well-studied large WF regions, one in western Texas and the other in northern Illinois. These two regions differ distinctively in terms of land cover, topography, and background climate, allowing us to examine whether the WF impacts on vegetation, if any, vary due to the differences in atmospheric and boundary conditions. We use three methods (spatial coupling analysis, time series analysis, and seasonal cycle analysis) and consider two groups of pixels, wind farm pixels (WFPs) and non-wind-farm pixels (NWFPs), to quantify and attribute such impacts during the pre-and post-turbine periods. Our results indicate that the WFs have insignificant or no detectible impacts on local vegetation growth. At the pixel level, the VI changes demonstrate a random nature and have no spatial coupling with the WF layout. At the regional level, there is no systematic shift in vegetation greenness between the pre-and post-turbine periods. At interannual and seasonal time scales, there are no confident vegetation changes over WFPs relative to NWFPs. These results remain robust when the pre-and post-turbine periods and NWFPs are defined differently. Most importantly, the majority of the VI changes are within the MODIS data uncertainty, suggesting that the WF impacts on vegetation, if any, cannot be separated confidently from the data uncertainty and noise. Overall, there are some small decreases in vegetation greenness over WF regions, but no convincing observational evidence is found for the impacts of operating WFs on vegetation growth.

show abstract

Section: Relationship Between Rwi-ndvimentioning

confidence: 99%

“…Early work by Kaufmann et al [50] based on GIMMS data equally showed a positive correlation between tree-rings and NDVI over the entire growing season and monthly values for April-July and October. Nevertheless, the positive and robust relationship observed between radial growth and NDVI identified for 69 sites across the Northern Hemisphere at the local level cannot be considered a rule on the global scale [7].…”

Section: Relationship Between Rwi-ndvimentioning

confidence: 99%

Exploring Relationships among Tree-Ring Growth, Climate Variability, and Seasonal Leaf Activity on Varying Timescales and Spatial Resolutions

et al. 2017

View full text Add to dashboard Cite

Abstract:In the first section of this study, we explored the relationship between ring width index (RWI) and normalized difference vegetation index (NDVI) time series on varying timescales and spatial resolutions, hypothesizing positive associations between RWI and current and previous-year NDVI at 69 forest sites scattered in the Northern Hemisphere. We noted that the relationship between RWI and NDVI varies over space and between tree types (deciduous versus coniferous), bioclimatic zones, cumulative NDVI periods, and spatial resolutions. The high-spatial-resolution NDVI (MODIS) reflected stronger growth patterns than those with coarse-spatial-resolution NDVI (GIMMS3g). In the second section, we explore the link between RWI, climate and NDVI phenological metrics (in place of NDVI) for the same forest sites using random forest models to assess the complicated and nonlinear relationships among them. The results are as following (a) The model using high-spatial-resolution NDVI time series explained a higher proportion of the variance in RWI than that of the model using coarse-spatial-resolution NDVI time series. (b) Amongst all NDVI phenological metrics, summer NDVI sum could best explain RWI followed by the previous year's summer NDVI sum and the previous year's spring NDVI sum. (c) We demonstrated the potential of NDVI metrics derived from phenology to improve the existing RWI-climate relationships. However, further research is required to investigate the robustness of the relationship between NDVI and RWI, particularly when more tree-ring data and longer records of the high-spatial-resolution NDVI become available.

show abstract

The effect of growing season and summer greenness on northern forests

Cited by 69 publications

References 20 publications

Twentieth-century trends in the thermal growing season in the Greater Baltic Area

Twentieth-century trends in the thermal growing season in the Greater Baltic Area

Detecting Wind Farm Impacts on Local Vegetation Growth in Texas and Illinois Using MODIS Vegetation Greenness Measurements

Exploring Relationships among Tree-Ring Growth, Climate Variability, and Seasonal Leaf Activity on Varying Timescales and Spatial Resolutions

Contact Info

Product

Resources

About