filename: the name of the file currently being processed.
plot.file.path.pavd: path of plot file to be written, inherited from process_pcl or process_multi_pcl
hist: logical input to include histogram of VAI, if TRUE it is included, if FALSE, it is not.
save_output: if TRUE it saves the plot, if false it just runs
Returns
plant area volume density plots
Details
This function is a nested function inside of process_pcl. It could be run independently using the summary_matrix.csv output files created from running procesS_pcl as well.