Running examples in 'forestmangr-Ex.R' failed
The error most likely occurred in:

> ### Name: average_tree_curve
> ### Title: Generate the curve of a forest's average tree using the Kozak
> ###   taper model
> ### Aliases: average_tree_curve
> 
> ### ** Examples
> 
> library(forestmangr)
> data("exfm7")
> head(exfm7)
      MAP PROJECT SPACING STRATA GENCODE TREE      DBH   TH  hi    di_wb bark_t
1 FOREST1   PEQUI     3x3      4  FLO014    1 12.41409 22.1 0.1 13.05071      6
2 FOREST1   PEQUI     3x3      4  FLO014    1 12.41409 22.1 0.5 12.57324      6
3 FOREST1   PEQUI     3x3      4  FLO014    1 12.41409 22.1 1.0 12.41409      5
4 FOREST1   PEQUI     3x3      4  FLO014    1 12.41409 22.1 1.5 12.25493      5
5 FOREST1   PEQUI     3x3      4  FLO014    1 12.41409 22.1 2.0 11.77747      4
6 FOREST1   PEQUI     3x3      4  FLO014    1 12.41409 22.1 4.0 11.30000      4
>    
> average_tree_curve(df = exfm7, d = "di_wb", dbh = "DBH", h = "hi", th = "TH")
Error in namespaceExport(ns, exports) : 
  undefined exports: %s!=%, %s!==%, %s+%, %s<%, %s<=%, %s==%, %s===%, %s>%, %s>=%, %stri!=%, %stri!==%, %stri+%, %stri<%, %stri<=%, %stri==%, %stri===%, %stri>%, %stri>=%, stri_datetime_add<-, stri_sub<-, stri_subset<-, stri_subset_charclass<-, stri_subset_coll<-, stri_subset_fixed<-, stri_subset_regex<-, stri_c, stri_c_list, stri_cmp, stri_cmp_eq, stri_cmp_equiv, stri_cmp_ge, stri_cmp_gt, stri_cmp_le, stri_cmp_lt, stri_cmp_neq, stri_cmp_nequiv, stri_compare, stri_conv, stri_count, stri_count_boundaries, stri_count_charclass, stri_count_coll, stri_count_fixed, stri_count_regex, stri_count_words, stri_datetime_add, stri_datetime_create, stri_datetime_fields, stri_datetime_format, stri_datetime_fstr, stri_datetime_now, stri_datetime_parse, stri_datetime_symbols, stri_detect, stri_detect_charclass, stri_detect_coll, stri_detect_fixed, stri_detect_regex, stri_dup, stri_duplicated, stri_duplicated_any, stri_enc_detect, stri_enc_detect2, stri_enc_fromutf32, stri_enc_get, stri_enc_inf
Calls: average_tree_curve ... tryCatch -> tryCatchList -> tryCatchOne -> <Anonymous>
Execution halted