Cow tree (Couma macrocarpa)
Family: Apocynaceae
Common names: Ama apa, Ama-apa, Avichuri, Caw tree, Cow tree, Cuma assu, Cuma-assu, Cumsskaballi, Guaimaro macho, Hosca, Leche caspi, Leche-caspi, Melk boom, Milktree, Palo de vaca, Pendare, Perillo, Perillo negro, Popa, Purva, Sorva, Vaca, Vacahosca
Distributed in: Brazil, Colombia, Columbia, Guyana, Peru, Suriname, Venezuela (Central America, Latin America)
Distribution overview: An Amazonian species but also found in the Carare-Opon and Serrania de San Lucas regions of the Rio Magdalena in Colombia. Found mostly in low areas. Venezuela, Guyana, Surinam, Peru, and Brazil.
Common uses: Beams, Bent Parts, Boxes and crates, Building construction, Building materials, Cabin construction, Cabinetmaking, Casks, Chairs, Chests, Concrete formwork, Construction, Core Stock, Decks, Decorative veneer, Desks, Dining-room furniture, Drawer sides, Factory construction, Fiberboard, Figured veneer, Fine furniture, Form work, Foundation posts, Framing, Furniture , Furniture components, Furniture squares or stock, Furniture, Hatracks, Heavy construction, Interior construction, Interior trim, Joists, Kitchen cabinets, Light construction, Living-room suites, Millwork, Office furniture, Packing cases, Particleboard, Plain veneer, Veneer
Environment profile: Status unknown in many of its growth areas
Tree size: Trunk diameter is 100-150 cm
Colors: the heart isWhite to cream, Yellowand the sapwoodWhite, Yellow.The grain isWavy, the textureMediumand the lusterMedium
Natural durability: Susceptible to blue and sap-stain, Susceptible to insect attack
Odor: No specific smell or taste
Kiln Schedules: Drying (speed) is fast
Kiln Drying Rate: Naturally dries quickly
Drying Defects: Distortion, Splitting
Ease of Drying: Rapidly
Tree Identification: Bole/stem form is straight
Comments: General finishing qualities are rated as good
Boring: Good results
Carving: Easy to carve
Cutting Resistance: Easy to saw
Gluing: Fairly Easy to Very Easy
Mortising: Worked surfaces tend to be woolly
Nailing: Fairly Easy to Very Easy, Good nailing properties
Planing: Very Good to Excellent
Resistance to Impregnation: Resistant sapwood
Response to hand tools: Easy to machine
Routing recessing: Routing yields good results
Sanding: Good sanding finish
Screwing: Easy to screw, Good screwing properties; Turning: Easy to turn
- Numerical data Metric
- Numerical data English
- Strength properties
- References
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| Item |
Green |
Dry |
Metric |
| Specific Gravity |
0,46 |
|
|
| Density |
|
608 |
kg/m3 |
| Bending Strength |
729 |
1138 |
kg/cm2 |
| Crushing Strength |
345 |
502 |
kg/cm2 |
| Hardness |
|
435 |
kg |
| Impact Strength |
|
|
cm |
| Shearing Strength |
|
|
kg/cm2 |
| Stiffness |
|
|
1000 kg/cm2 |
| Tangential Shrinkage |
6 |
|
% |
| Radial Shrinkage |
3 |
|
% |
| Weight |
576 |
464 |
kg/m3 |
| Maximum Load |
|
|
cm-kg/cm3 |
| Toughness |
|
|
cm-kg |
| Static Bending |
|
|
kg/cm2 |
|
 |  |  |  | | Item | Green | Dry | English | | Bending Strength | 10376 | 16187 | psi | | Density | | 38 | lbs/ft3 | | Hardness | | 960 | lbs | | Maximum Crushing Strength | 4911 | 7149 | psi | | Specific Gravity | 0.46 | | | | Weight | 36 | 29 | lbs/ft3 | | Radial Shrinkage | 3 | | % | | Tangential Shrinkage | 6 | | % | | Volumetric Shrinkage | 10 | | % | |
Bending strength (MOR) = medium Max. crushing strength = medium Density (dry weight) = 38-45 lbs/cu. ft. Shrinkage, Tangential = small Shrinkage, Radial = small Resists denting and marring Max. crushing strength = high Hardness (side grain) = medium Density = high Density (dry weight) = 31-37 lbs/cu. ft. Compression strength (parallel to grain) = high Bending strength (MOR) = very high Bending strength (MOR) = high
Chudnoff, M.,1984,Tropical Timbers of the World,U.S.A. Department of Agriculture, Forest Service, Forest Products,Laboratory, Madison.Erfurth, T., Rusche, H.,1976,The Marketing of Tropical Wood B. Wood Species from S. American Tropical,Moist Forests,F.A.O. Forestry DepartmentTakahashi, A.,1975,Compilation of data on the Mechanical Properties of Foreign Woods (Part 2,Central and South America,Shimane University, Japan, Research Report on Foreign Wood No.4
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