The dwarf trees of China are the great curiosities of the forestry[sic].  Every child knows how the Chinese cramp their women's feet by bandaging them while they are infants, and thus render it impossible for them to walk.  It is, however, wonderful to see minature oaks, chestnuts, pines and cedars growing in flower pots, 50 years old and yet not a foot high.  A friend of mine, who is an invalid and confined to his room, has been, during several years past, amusing himself, among other matters, with the cultivation of dwarf trees, and he has succeeded admirably.  He takes a young plant, cuts the tap root, and places it in a basin in which there is good soil kept well watered.  If it grows too rapidly he digs down and shortens in several roots.  Every year the leaves grows smaller, and the little dwarf trees make interesting pets, just as some people raise canary birds, and others, squirrels. 1 

1      The Agassiz Association Journal (Lynn, MA), Volume 1, No. 2, July, 1885,  in the "Botany" section, pg. 23. 

Per White, Harold B., III  "Philip Powell Calvert: Student, Teacher, and Odonatologist," ENTOMOLOGICAL NEWS 95(4): 155-162.  September & October, 1984, "When [paleontologist, glaciologist, and geologist] Louis Agassiz died in 1873, America lost its most popular and influential scientist.  In the spirit of the Swiss-born naturalist who had advocated, 'study nature, not books,' Harland H. Ballard founded the Agassiz Association in 1875.  This organization grew rapidly and boasted hundreds of chapters and over 20,000 members by the early 1890's.  Although the organization attracted many adults, its original intent was to promote natural history interests among young people.  The first general convention of the Agassiz Association was held in Philadelphia in September 1884 in conjunction with the meeting of the American Association for the Advancement of Science.