No, the compound noun pecan tree is a word for any pecan tree anywhere. A proper noun is the name of a person, place, thing, or a title; for example: Pecan Tree Drive, Baton Rouge, LA or Pecan Tree Terrace, Colonial Heights, VA Pecan Tree Inn, Queen Street, Beaufort, NC Green Tree Pecan Company, Powell, TX "Lessons From a Pecan Tree" by Enid Sanford
Pecan shellers or pecan crackers are for extracting the nutmeats out of pecan shells by the harvesters. Pecan shellers are machine apparatuses with revolutionary designs in that they accumulate a translucent spin-per-minute ratio. A video on YouTube by user "855sheller" shows an electric pecan cracker demonstration with a spin-per-minute ratio of 26 revolutions per minute equivalent to 1,560 pecans being shelled in the span of 1 hour.