cases the trees range through several of these communi- 
ties, whereas generally they are more restricted. T'awo- 
dium mucronatum Tenore forms Sabinales along river 
valleys in most of the vegetation types from hot to tem- 
perate regions. Sabinales are most common in the Sa- 
banas, Selva Alta Subcaducifola and Selva Baja Caduci- 
folia. The resin of T'awodium, which has a distinctive red 
color, is produced in moderate quantities in the bark. 
The color is of particular interest, as specimens of amber 
from a few Chiapas localities have this same red hue. 
Bursera simaruba (L.) Sarg., which produces large quan- 
tities of a gum-resin, also occupies a wide range of eco- 
logical conditions. It occurs commonly in the Selva Alta 
Perennifolia, Selva Alta Subcaducifolia and Selva Baja 
Caducifolia. It frequents upland sites but may occur 
along rivers. 
Calophyllum brasiliense Camb. and Myroxylon balsa- 
mum (L.) Harms. occur frequently within the Selva Alta 
Perennifolia and Selva Alta Subcaducifolia. Calophyllum 
produces a yellow resinous material in considerable abun- 
dance. The resin of Myroxylon is used commercially, 
particularly in Honduras, although artificial stimulation 
is necessary for abundant production. Verminalia ama- 
zonia (Gmel.) Exell and Protium copal (Schl. and 
Cham.) Engl. primarily occupy the Selva Alta Perenni- 
folia. Terminala does not appear to produce large quan- 
tities of resin, whereas Protiwm produces sufficient 
amounts for it to be used commonly for incense, espe- 
cially in Guatemala. 
Three important resin-producing trees occur principally 
along the rivers in the Selva Alta Subcaducifolia. These 
include Hymenaea courbaril L., Amyris attenuata 
Standl. and Styrax argenteus Presl. Hymenaea is espe- 
cially interesting, because it produces enormous quanti- 
ties of resin which are used commercially throughout 
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