The Land Between The Lakes experienced a hard freeze event on 15 Apr. 2020 that damaged tree foliage. Damage was not homogeneous, as it varied by topography and by tree species. Tulip poplars were especially affected, as were the ravines where they preferentially occur. HiForm's true color Sentinel-2 maps show these browned areas well, but estimating the severity of frost damage is challenging at this time of year because spring canopy conditions are normally in flux, and April of 2020 was unusually cool after a warmer-than-average March. For a more qualified sense of change, these maps below show 2020's conditions compared to a similar time in both 2018 and 2019.  

We also contextualize spring progress with maps that convert the status of NDVI to percent completed, based on a starting value of late winter and the expected summer maximum based on 2019. As locations vary in their winter and summer NDVI values, this calculation standardizes spring progression in a way that provides rich insights into deciduous leaf vulnerability when spring disturbances occur.