# Monitoring Changes in the Enhanced Vegetation Index to Inform the Management of Forests
## 2 Materials and Methods
### Statistical Methods
#### 2.3.2 Modeling EVI Magnitude of Change
\begin{table}
\begin{tabular}{p{113.8 pt} p{113.8 pt} p{113.8 pt}} \hline \hline
**Description** & **Short Form** & **Usage** \\ \hline Enhanced vegetation index & EVI & Input to BFAST functions (bfast \& bfast01). \\ \hline EVI abrupt change or break & break & Output of bfast function. Used in descriptive statistics. \\ \hline EVI magnitude of break & magnitude & Output of bfast function. Figure A2. Response variable in BRT models. BRT variable name: magnitude. \\ \hline EVI type of break & break type & Output of bfast function. Negative and positive breaks are produced. Used in descriptive statistics. Table 2, Figures 3 and A2. \\ \hline EVI time of break & time of break & Output of bfast function. This variable is associated with 95\% CIs. Used in descriptive statistics and for joining breaks with other data sources \\ \hline EVI gradual change or trend & trend & Output of bfastclassify function. Used in descriptive statistics. Trend classification proposed by [PERSON] et al. [57]. \\ \hline EVI monotonic increasing, greening trend (without breaks) & MIG & Output of bfastclassify function. Used in descriptive statistics. Table 3, Figures 4 and A4. \\ \hline EVI monotonic decreasing, browning trend (without breaks) & MDB & Output of bfastclassify function. Used in descriptive statistics. Table 3, Figures 4 and A4. \\ \hline EVI monotonic increasing, greening trend & MIGpb & Output of bfastclassify function. Used in descriptive statistics. Table 3. \\ \hline EVI monotonic increasing, browning trend with a negative break & MDBnb & Output of bfastclassify function. Used in descriptive statistics. Table 3. \\ \hline EVI interruption, increasing trend with a negative break & IInb & Output of bfastclassify function. Used in descriptive statistics. Table 3, Figures 4 and A4. \\ \hline EVI interruption, decreasing trend with a positive break & IDpb & Output of bfastclassify function. Used in descriptive statistics. Table 3, Figure A4. \\ \hline \hline \end{tabular}
\end{table} 
Table 1: List of key variables and terms used in this study. For the two climate-related predictors (winter DDC5 and summer CMI), 1-, 2- and 3-year lagged versions were created and used in boosted regression trees (BRTs). \begin{table}
\begin{tabular}{l l l} \hline \hline
**Description** & **Short Form** & **Usage** \\ \hline EVI reversal, greening to browning trend & RGB & Output of bfastclassify function. Used in descriptive statistics. Table 3. \\ \hline EVI reversal, browning to greening trend. & RBG & Output of bfastclassify function. Used in descriptive statistics. Table 3, Figures 4 and A4. \\ \hline Forest age & age & Forest-related predictor used in BRT models. BRT variable name: for\_age \\ \hline Percent coniferous composition & percentage of conifers & Forest-related predictor used in BRT models. BRT variable name: for\_con. \\ \hline Forest protection status & protection status & Forest-related predictor used in BRT models. BRT variable name: for\_pro\_0. \\ \hline Winter degree days above 5 \({}^{\circ}\)C & winter DD5 & Climate-related predictor used in BRT models. Temporal lagged versions were used. BRT variable names: dd5\_wt\_lag1, dd5\_wt\_lag3. \\ \hline Summer climate moisture index & summer CMI & Climate-related predictor used in BRT models. Temporal lagged versions were used. BRT variable names: cmi\_sm, cmi\_sm\_lag1, cmi\_sm\_lag2, cmi\_sm\_lag3. \\ \hline \hline \end{tabular}
\end{table} 
Table 1: _Cont._  
Figure 3: Spatial distribution of EVI negative and positive breaks in the AGPE from 2003 to 2022. Most of the breaks were found in the eastern half of the AGPE and more particularly in the northeast quadrant. There were 11,871 pixels with negative breaks (red pixels) and 3893 pixels with positive breaks (cyan pixels). These breaks were estimated with the bfast algorithm. The dashed black line shows the study area footprint. The solid black line shows Algonquin Provincial Park’s footprint.