Testulea Gabonensis (Izombe)


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Scientific Name
Testulea gabonensis

Trade Name
Izombe

Family Name
Ochnaceae

Common Names
Ake, Akewa, Akewe, Isombe, Izombe, Magnenti, Mogongou, Mugongu, N’Gwaki, N’komi, Ngron, Rone, Zombe

Regions of Distribution
Africa

Countries of Distribution  [VIEW MAP]
Cameroon, Congo, Equatorial Guinea, Gabon, South Africa

Common Uses
Baskets, Bedroom suites, Boat building (general), Boxes and crates, Brush backs & handles, Building materials, Cabinetmaking, Carvings, Chairs, Chests, Clogs, Concealed parts (Furniture), Cooperages, Decorative veneer, Desks, Dining-room furniture, Domestic flooring, Door, Dowell pins, Dowells, Drawer sides, Excelsior, Figured veneer, Fine furniture, Floor lamps, Flooring, Flooring: industrial heavy traffic, Furniture , Furniture components, Furniture squares or stock, Furniture, Hatracks, Heavy construction, Interior construction, Interior trim, Joinery (external): ground contact, Joinery, Kitchen cabinets, Light construction, Living-room suites, Mathematical instruments, Millwork, Mine timbers, Moldings, Office furniture, Paneling , Paneling, Parquet flooring, Plywood corestock, Plywood, Radio – stereo – TV cabinets, Rustic furniture, Skis, Stools, Sub-flooring, Tables , Toys, Turnery, Veneer, Veneer: decorative, Windows

Environmental Profile

Status unknown in some areas due to inadequate information
Generally secure within most of its natural habitat, but note exceptions.
Extinct, Endangered, Vulnerable, or Rare within parts of its range
Data source is World Conservation Monitoring Center

Classified as either Extinct, Endangered, Vulnerable, or Rare in Cameroon. Its status in the wild in Equatorial Guinea and Gabon is listed as unknown due to insufficient information

Distribution Overview
Found mainly in Gabon. It also grows in Cameroon and throughout the equatorial forests of West Africa. usually scattered in dense primary forests and transitional zones.

Heartwood Color

Brown
Red
Yellow
Purple
Pink
Yellow to golden-yellow to orange
Reddish brown
Pale red to pink
Greenish to greyish

The heartwood varies from orange-yellow, gray-yellow, to pinkish-yellow with a gray hue.

Sapwood Color

White
Brown
Yellow
Green/Grey
Pinkish
White to yellow
Not clearly differentiated from the heartwood

Grain

Straight
Figure
Closed
Even
Stripe (figure)
Wavy
Interlocked
Weak (figure)

 

Straight
Striped figure
Weak figure
Wavy
Interlocked

May occasionally be slightly interlocked, producing a ribbon or wavy figure

Texture

Fine
Medium
Coarse
Fine
Even textured

A dark resinous substance is sometimes present in some cells.

Natural Growth Defects

Gum/resin exudation

Natural Durability

Durable
Perishable
Moderately durable
Resistant to termites
Non-durable
Non-resistant to powder post beetles
Susceptible to insect attack
Resistant to attack from termites (Isoptera)
Resistant to attack from powder post (Lyctid & Bostrychid) beetles
Durable
Very durable
Sapwood is susceptible to wood staining fungal attack
Resistant to wood staining fungal attack
Susceptible to marine borer attack
Sapwood is prone to stain
Resistant to attack from pinworms (ambrosia beetles)
Heartwood resistant to decay
Good weathering characteristics

Odor

No specific smell or taste

Kiln Schedules

Drying (speed) is fast
Kiln Drying Rate (in days) is rapid

Drying Defects

Collapse
Distortion
Moderate surface checking

The sapwood is prone to develop blue sap stain

Ease of Drying

Moderately Difficult to Difficult
Easy
Dries easily with little or no degrade

Kiln Drying Rate

Rapid (<10 days for boards < 32 mm, to <30 days for boards >= 63 mm)

Tree Identification

Bole/stem form is straight
Bole/stem form is cylindrical
Bole/stem form is buttressed
Bole/stem form is fluted

Tree Size

Tree height is 20-30 m
Bole length is 10-20 m
Tree height is 10-20 m
Bole length is 0-10 m
Trunk diameter is 100-150 cm

Product Sources
The timber is available in lumber form from large importers in the United States, and is usually priced in the moderately high range.

The ITTO reports that timber from this species is produced only occasionally and exported in negligible quantities.

Comments
General finishing qualities are rated as good

Blunting Effect

Slight dulling effect on cutting tools
Blunting effect on machining is slight

Boring

Fair to good results
Fairly easy to very easy
Good boring qualities
Easy

Bored surfaces are usually clean.

Carving

Fair to Good Results
Good results

Cutting Resistance

Easy to saw
Cutting Resistance with green wood is easy
Cutting Resistance with dry wood is easy
Low resistance to sawing
Cutting Resistance with green wood is moderate

Gluing

Easy to glue
Glues well

Mortising

Fairly Easy to Very Easy
Fair to Good Results
Easy to mortise

The wood responds well to mortising operations with ordinary machine tools.

Moulding

Fair to Good Results
Fairly Easy to Very Easy
Responds well to ordinary machine tools in moulding operations
Good finishing results
Easy to mould

Movement in Service

Fair to Good Stability – Medium Movement
Excellent Stability – Small Movement
Stable
Stable when seasoned
Holds shape well after manufacture

Nailing

Fairly Easy to Very Easy
Holds nails well
Easy to nail
Possible if prebored

Planing

Fair to Good Results
Fairly Easy to Very Easy
Planes well, to a good finish
Good planing properties
Easy to work with all types of tools
Easy to plane
Ease of planing is moderate

Resistance to Impregnation

Resistant sapwood
Resistant heartwood
Heartwood is resistant
Resistant to preservative treatment
Heartwood is extremely resistant

Resistance to Splitting

Satisfactory
Poor

Response to Hand Tools

Easy to Work
Responds Readily
Easy to machine
Responds well to hand tools

Routing & Recessing

Fair to Good Results
Fairly Easy to Very Easy
Routs well
Routing is easy

Sanding

Fair to Good Results
Fairly Easy to Very Easy
Good sanding finish
Yields relatively smooth surfaces
Good sanding properties

Screwing

Screwing yields good results
Easy to screw
Possible if prebored
Good screwing properties

Turning

Fair to Good Results
Fairly Easy to Very Easy
Good results
Easy to turn
Yields clean surfaces

Veneering Qualities

Bolt preparation requires steaming
Suitable for slicing
Moderately easy to veneer
Easy to cut

Steam Bending

Moderate
Good

Painting

Satisfactory results
Good results

Polishing

Fair to Good Results
Good results

Staining

Good staining qualities

Varnishing

Satisfactory
Good results

Strength Properties

Bending strength (MOR) = medium
Shrinkage, Radial = small
Max. crushing strength = high
Bending strength (MOR) = high
Shrinkage, Tangential = moderate
Max. crushing strength = medium
Density (dry weight) = 46-52 lbs/cu. ft.
Shrinkage, Tangential = small
Shrinkage, Radial = moderate
Shearing strength (parallel to grain) = medium
Modulus of Elasticity (stiffness) = medium
Modulus of Elasticity (stiffness) = low
Density (dry weight) = 38-45 lbs/cu. ft.
Very heavy
Shrinkage, Tangential = fairly large
Shearing strength (parallel to grain) = low
Modulus of Elasticity (stiffness) = very low
Density (dry weight) = 53-60 lbs/cu. ft
Dense
Compression strength (parallel to grain) = high
Bending strength (MOR) = very high

Numerical Data

Item Green Dry English
Bending Strength 11843 16696 psi
Density 46 lbs/ft3
Maximum Crushing Strength 5543 8535 psi
Shearing Strength 2043 psi
Stiffness 1441 1704 1000 psi
Specific Gravity 0.59 0.76
Weight 48 45 lbs/ft3
Radial Shrinkage 3 %
Tangential Shrinkage 6 %
Volumetric Shrinkage 10 %
Item Green Dry Metric
Bending Strength 832 1173 kg/cm2
Density 737 kg/m3
Maximum Crushing Strength 389 600 kg/cm2
Shearing Strength 143 kg/cm2
Stiffness 101 119 1000 kg/cm2
Specific Gravity 0.59 0.76
Weight 769 721 kg/m3
Radial Shrinkage 3 %
Tangential Shrinkage 6 %

References
Banks, C.H., Schoeman, J.P., Otto, K.P.,1977,The Mechanical Properties of Timbers with particular reference to South,Africa,South African Forestry Research Institute Bulletin,(Ed.,Schoeman, J.P. 1973 & Otto K.P. 1976,No.48

Bois et Forets des Tropiques,1990,Izombe (Testulea gabonensis,Bois et Forets des Tropiques No.225 (3) 65

Bolza, E., Keating, W.G.,1972,African Timbers – the Properties, Uses and Characteristics of 700 Species,C.S.I.R.O. Div. of Building Research

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 A. Wood Species from African Moist Forests,F.A.O. Forestry Department

Fortin, Y., Poliquin, J.,1976,Natural Durability and Preservation of 100 Tropical African Woods,International Development Research Centre, Canada

France – C.T.F.T.,1977,Promotion of African Timbers – New Species,CTFT,35 Leaflets

HMSO. 1981. Handbook of Hardwoods, 2nd Edition. Revised by R. H. Farmer. Department of the Environment, Building Research Establishment, Princes Risborough Laboratory, Princes Risborough, Aylesbury, Buckinghamshire.

ITTO. 1986. Tropical Timber Atlas, Volume 1 – Africa. International Tropical Timber Organization (ITTO) and Centre Technique Forestier Tropical (CTFT, 45bis, Avenue de la Belle Gabrielle, Nogent-sur-Marne Cedex, France.

ITTO. New Marketable Species Technical Notes. Prepared by Centre Technique Forestier Tropical (CTFT, Division of CIRAD, 45 bis, Avenue de la Belle Gabrielle, 94736 Nogent-sur-marne Cedex, France

Kline, M. 1986. Testulea gabonensis – Izombe. In A Guide to Useful Woods of the World. Flynn Jr., J.H., Editor. King Philip Publishing Co, Portland, Maine. 1994. Page 344.

Lincoln, W.A. 1986. World Woods in Color. Linden Publishing Co. Inc., Fresno, California.

Sallenave, P.,1955,Proprietes Phyiques et Mecaniques des Bois Tropicaux de l’Union Francaise,C.T.F.T

Takahashi, A.,1978,Compilation of Data on the Mechanical Properties of Foreign Woods (Part,III) Africa,Shimane University, Japan, Research Report on Foreign Wood No. 7

WCMC. 1992. Conservation Status Listing – Trees and Timbers of the World, World Conservation Monitoring Centre, Plants Programme, 219 Huntingdon Road, Cambridge, CB3 ODL, United Kingdom.