Code associated with: Hansen, W.D., N.B Schwartz, A.P. Williams, K. Albrich, L.M. Kueppers, A. Rammig, C.P.O. Reyer, A.C. Staver, and R. Seidl. Global forests are influenced by legacies of past inter-annual temperature variability.

<p>These files are associated with,</p>
<p>Hansen, W.D., N.B Schwartz, A.P. Williams, K. Albrich, L.M. Kueppers, A. Rammig, C.P.O. Reyer, A.C. Staver, and R. Seidl.<em> </em>2022.<em> </em>Global forests are influenced by legacies of past inter-annual temperature variability. <em>Environmental Research:Ecology </em>1, 011001.</p>
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<strong>Abstract:</strong></p>
<p>Inter-annual climate variability (hereafter climate variability) is increasing in many forested regions with climate change. This variability could have larger near-term impacts on forests than decadal shifts in mean climate, but how forests will respond remains poorly resolved, particularly at broad scales. Individual trees and even forest communities often have traits and ecological strategies – the legacies of exposure to past variable conditions – that confer tolerance to subsequent climate variability. However, whether local legacies also shape global forest responses is unknown. Our objective was to assess how past and current climate variability influences global forest productivity. We hypothesized forests exposed to large climate variability in the past would better tolerate current climate variability than forests where past climate was relatively stable. We used historical (1950-1969) and contemporary (2000-2019) temperature, precipitation, and vapor pressure deficit and the remotely-sensed Enhanced Vegetation Index to quantify how historical and contemporary climate variability relate to patterns of contemporary forest productivity. Consistent with our hypothesis, forests exposed to large temperature variability in the past were more tolerant of contemporary temperature variability than forests where past temperatures were less variable. Forests were 19-fold less sensitive to contemporary temperature variability where historical inter-annual temperature variability was 0.66°C (2 standard deviations) greater than the global average historical temperature variability. We also found that larger increases in temperature variability between the two study periods often eroded the tolerance conferred by legacy effects of historical temperature variability. However, the hypothesis was not supported in the case of precipitation and vapor pressure deficit variability, potentially due to physiological tradeoffs inherent in how trees cope with dry conditions. We conclude that sensitivity of forest productivity to imminent increases in temperature variability may be partially predictable based on legacies of past conditions.</p>
<p><strong>File list:</strong></p>
<p>Processing_climate_data_final_1-21-2021.Rmd<br>
</p>
<p>Processing_EVI_NDVI_final_1-20-2021.Rmd</p>
<p>Processing_Modis_Landcover_final_1-20-2021.Rmd</p>
<p>Priming_analysis_sd_12-16-2021.Rmd</p>
<p>Spatial_runs_cluster_modern.1-30-2021.R</p>
<p>Spatial_runs_cluster_past.1-30-2021.R</p>
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