My experience is the same--the minute you conjure up visions of mystical rare preciousness the average Joe Americans eyes turn into dollars signs. Swamp larch collecting is grueling unaesthetic work that, at best, produces rough stock and rarely anything substantive--its not like one is prying gems off of a mountain top.
Here is my advice--don't mention bonzo, it just confuses people, have mercy on them and instead have a selection of pre-conjured stories that seems innocuous--be creative. One has to come to terms with puritan morality at this point. Lets use the basis of intent, A) you are being righteous and square asking for permission to gather a few trees and in this it is your only obligation to be purely honest and now God and Mary have given you the nod and your mother sighs relief somewhere--accept this--so now comes the fun part, B): Bonzo is a artistic endeavor, kind of like writing a novel, so entering the land of fiction and exaggeration is totally OK, it is actually a poetic device that brings you closer and more benevolently toward the innocent observer and land owner. First, down play the whole thing: "just lookin fer some ratty old tamarack--best place to gettum this time of year is a swamp." Mention your local, "I live round here and gita few round these parts when I have a chance", mention your a plant guy but in a non-business way, "studied plants in school some", then , if pressed, say like, "plantin my own real swamp in my spare time--want to use local trees" or get technical and say, "studying or nitrogen deprived trees since I was in school, its a hobby of mine--the peat makes the PH high and makes um grow slow, looking for a few maimed ones to grow--some co-exist with bores you know, very interestin". I have used the, "I study local dwarfed swamp trees as a hobby" several times. If anybody ever mentions value I would laugh a large spittle ridden laugh in their face. These are runty,maimed and stunted trees of no timber value gently taken from swamps that make up endless tracks throughout the state.
And remind your self, without a doubt bonzo is not a profitable endeavor or business of any kind--slogging through swamps is hard work, potting up trees is expensive and for the 99.9% of us bonzo is a life and money sucking compulsion and we are just trying to find a few good trees or at worst help curb expenses by selling some stock.