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Teak Log Grading

Introduction
Grading is a value adding process as " adding value" is an action that adds worth to something through a specific process. Properly graded timber gives a value of worthiness and satisfaction to the buyer and graded timber of any species enjoys higher prices than ungraded timber. In the early days not many items of timber were traded and grading was mainly by rule of thumb.

Most countries and regions have their own sets of grading rules with different rules for different species; for softwoods and hardwoods. For example, the National hardwood Lumber Association(NHLA) Rules from the United States, the British Columbia Lumber Grading and Quebec Grading Rules from Canada, the Finish Grading Rules and the Malayan Grading Rules(MGR) are some of the well-known rules, to name a few. As a major teak producer, Myanmar has its own sets of grading rules for teak and grading of teak logs and lumber in Myanmar is done according to these rules. Until now there appears to be no collaboration regarding grading among the teak producers in the Region. Teak, whether in the rough or processed is still a natural product, and growth conditions are mainly influenced by soil and climate. Until a wonder technique has been perfected to produce finer specimens of trees, grading rules will remain the arbiter of what a piece of timber is worth.

Jungle Rejection Rules
The origin of the first modern grading rules for teak logs in Myanmar can be traced back to 1936. The Forest Department established the "Logging Rules and Standard for Jungle Rejection of Teak Logs" and the rules mention the measuring system. Logging system and system of rejection in the jungle. In short, the rules specifiy the calculation of defects for obligatory and optional timber. Mention of Grades is not noted in these rules.

Gallant Rules
The " Standard for Jungle Rejection " was followed in April 1998 by " Classification of Teak Logs ", popularly known as "Gallant Rules", as they were prepared by Mr. M.M. Gallant, Forest Economist of the Forest Department. This classification covers five grades; viz., five star( or AY), four star, three star, two star and one star. Like the standard for Jungle Rejection, and the Gallant Rules deduct five cubic feet per defect for scaling purposes. Star classes are graded according to the defect value and the limits determining the star class of a log are given in Table 1.

Table 1: - Star Classes and defect values

Star Class	Min. Length (Ft)	Min. Girth (Ft)	Min.Volume (Cu.Ft)	Defect
AY (5*)	15	6	-	0.5/50 Cu.Ft
4*	15	5	30	1.0/50 Cu.Ft
3*	12	5	30	2.0/50 Cu.Ft
2*	10	4	20	3.0/50 Cu.Ft
1*	10	4	20	5.0/50 Cu.Ft

Note - Logs are graded by calculating the defects per 50 Cubic Feet.

Grading Rules for Teak Veneer Logs
The late 1950s saw the rise of the teak veneer market started much earlier. The quality of the logs harvested then was very good and therefore logs graded under the Gallant Rules were also acceptable as veneer logs, mainly because of the superior quality of the logs. Logs inferior in quality to those harvested earlier, increased in quantity as time passed. Market conditions also pinpointed defects previously not recognized. Aesthetic value is now being considered in addition to other quality defects. A new set of rules prepared by the Myanma Timber Enterprise (MTE) came into being are called the "Grading Rules for Teak Veneer Logs" , and are currently applied. Defects considered in the Galant Rules and the Veneer Log Rules are shown below as comparisons:

Gallant Rules
Bear Bites; Bee Hole; Bend; Bird Holes; Buttress( no defcets); Doyo; Drag Hole; Ellipse; Flute; Holes(End); Knots; Shakes; Shatter; Snout(no defects); Sun Cracks, Inbark; Twist.

Veneer Log Rules
Bee Hole; Bump; Curvature; Elephant Skin; End Flute marks; Flutes; Green Band; Heart(Diagonal, Double, Spongy, Hole, End); Inbark; Knots(sound, Pin); Pig Eyes; Pitch Pockets; Shape(Elliptical, Triangular); Shake(Ring, Cup); Splits; Sun Cracks; Twist; Wavy Grain; Interlocked grain; Black Spots; sapwood pockets and Syphilis)

Permissible defects are scheduled according to the location and magnitude. These defects are then classified as either mild or serious. One serious defects (S) equals to mild(M) defects, and each grade limits 3(S) or 6(M). In the Veneer Log Rules, log scaling, i.e. estimating the net contents of a log, which equals the gross or full contents less deduction for defects, is not taken into account. This is one difference from the preceding rules but like its predecessors, each log has to be graded separately.

One of the disadvantages in the log trade is that one has to sell only what was extracted. Up to the mid-seventies, a larger percentage of First, Second and Third quality logs were available for export. What was not exported in log form was used in the local mills. The 1980s witnessed an entirely different scenario when fewer veneer logs were obtained and more sawing-quality logs become available.

The need for introducing rules for sawing quality teak logs that do not fit in the previous rules engendered a new set of rules for sawing quality logs that are inferior to the 1 Star Class. Gallant Rules require that logs are to be butted clean at both end. The same applies to veneer logs. But, the sawing quality logs sold today are unbutted and offered for sale as they come out of the forest. A comparison of dimensions is shown in Table (2).

Table 2: - Comparison Between Galant Rules and Veneer Log Rule

Gallant Rules	Min Dimension Length x Girth	Veneer Log Rule	Min Dimension
AY	L15' x G6'	Special	L15' x G6'
4*	L15' x G5' - min.30Cft	First	L8' x G4'-2"
3*	L12' x G5' - min.30Cft	Second	L8' x G4'-2"
2*	L10' x G4' - min.20Cft	Third	L8' x G4'-2"
1*	L10' x G4' - min.20Cft	Fourth	L8' x G4'
-	-	Sawing Grade - 1	L8' x G5'
-	-	Sawing Grade - 2	L8' x G5'
-	-	Sawing Grade - 3	L8' x G3' to 4'-11"
-	-	Sawing Grade - 4	L8' x G4'

Note - In veneer logs there is no minimum volume(vol) or cubic content specified provided that the length(L) and Girth(G) are met.

The sawing Grade Rules calculate the defect value as in Gallant Rules. But, there is no log scaling. Each Grade allows a fixed defect value. Grading is done according to the defect value considering the category of grade a log will fall into after the length and the girth are taken.

In addition, teak logs originating from different areas have different values. Area consciousness on the part of the buyers is very pronounced in this particular species. Teak logs from areas with heavy rainfall are less favored than logs from that of scanty rainfall. For instance, teak log from Yamethin, Pyinmana, Pyay, Minbu and Yaw are extremely popular. It has alos been noticed that teak from Northen Shan State, and Momeik are also favoured. The reason for the partiality is that there are no typical defects in teak logs from these areas and the colour, stripe and conformation of the logs rate from Good to Very Good. Incidence of beeholes is markedly less in logs from the above mentioned area. Area-wise characteristics of Myanmar Teak logs are mentioned Table (3) as bellows:

Table 3: Area-wise characteristics of Myanmar Teak Log

No	Area	Typical defects	Nature of Stripe	Sawing Yield %	Colour	Formation
1	Yamenthin	Not Promonent	V.Good	85	V.Good	Good
2	Pyinmana	Not Prominent	Good	60	V.Good	Good
3	Meikhtila	Heavy Suncracks	V.Good	95	V.Good	Fair
4	Pyau	Not Prominent	V.Good	90	V.Good	Good
5	Minbu	heavy Suncracks	V.Good	90	V.Good	Good
6	Pyin-Oo-Lwin	Not Prominent	V.Good	85	Medium	Good
7	Aunglan	Heavy Suncracks	V.Good	90	V.Good	Fair
8	Yaw	Not Prominent	V.Good	75	Good & Dull	Fair
9	Thayet	Heavy Suncracks	V.Good	80	V.Good	Fair
10	Zigon	Not Prominent	Good	50	Fair	Good
11	Kayah State	V.Heavy Suncracks	Good	80	Dull	Poor
12	N.Shan State	Not Prominent	V.Good	70	Good	Good
13	Lr.Chindwin	Not Prominent	Good	60	Good	Good
14	Shwebo	Pitch Pocket Black Spot	Thin	75	Good	V.Good
15	Mongmeik	Black Spot	Good	65	Good	V.Good
16	Pa-an	Not Prominent	Fair	60	Good	Good
17	N.Taung-Oo	Pitch Pocket	Poor	70	Good	Good
18	Kawkerik	Not Prominent	Poor	60	Good	Good
19	Myitkyina	Many Bee Holes Heavy Pitch Pocket Black Spot	V.Poor	10	Good	Good
20	W.Katha	Many Bee Holes	V.Poor	40	Good	Good
21	Bhamo	Many Bee Holes Many Pitch Pocket	V.Poor	10	Good	Good
22	E.Katha	Many Bee Holes Heavy Pitch Pocket Black Spot	Fair	65	Medium	V.Poor
23	Up.Chindwin	Many Bee Holes Heavy Pitch Pocket Black Pocket	Fair	35	V.Poor	Good
24	Myitha	Heavy Pitch Pocket Bee Holes Black Spot	Fair	40	V.Poor	Good
25	S.Toing-Oo	Pitch Pocket	Thin	50	Poor	Good
26	S.Shan State	Heavy Pitch Pocket Bee Holes Cracks	V.Good	95	Poor	Poor
27	S.Pegu	Bee Holes	Thin	50	Good	Good

Note - S=South, N=North,Up.=Upper and Lr.=Lower

The areas are classified as Good Area, Medium Good Area and Poor Area. Some characteristics variable on the different areas are mentioned in Table (4 ) as below:

Good Areas

Area	Colour	Stripe	Formation	Remark
Yamethin	Good	Little	Good	-
Pyinmana	Good	Little	Good	-
Meikhtila	Good	Many	Good	-
Pyi (Prome)	Good	Many	Good	-
Minbu	Good	Many	Good	-
Aung Lan	Good	Many	Good	-
Yaw	Good	Many	Good	Preferred in Hong Kong
Gantgaw	Good	Many	Good	- do -
Thayet	Good	Many	Good	- do -
Zigone	Good	Little	Good	Preferred in Japan

Medium Good Areas

Area	Colour	Stripe	Formation	Bee Hole	Remark
Mabein	Good	Medium	Good	-	-
N.Katha	Poor	Fair	Good	Fair	-
Shan	Good	Good	Good	-	Favor of HK & Japan
Chindwin	Good	Many	Good	-	Favor of HK
Shwebo	Good	Many	Good	-	Favor of HK
Myittha	Poor	Little	Good	-	Favor of Japan
Taung-Oo	Poor	Little	Good	-	Favor of Japan
Bago (Pegu)	Poor	Little	Good	-	Favor of Japan

Poor Areas

Area	Colour	Stripe	Formation	Bee Hole	Remark
Kayah	Poor	Many	Poor	-	-
Pa-an	Poor	Fair	Fair	-	-
N.Taung-Oo	Poor	Fair	Poor	-	-
Myitkyina	Poor	Many	Poor	-	-
Bhamaw	Poor	Poor	Fair	-	-
Kyankhin	Poor	Fair	Fair	-	-
U.Chindwin	Poor	Fair	Poor	-	-
Thibaw	Poor	Many	Poor	-	-

Note - N=Northern, S=South, U=Upper

Myanma Timber Enterprise (MTE) has specified the Defects Classification as follows:

Major Defects
Bee Holes, Green Band, Branch, Heart Hole, Doyo Hole, Pitch Pocket, Double Heart, Wavy, Bump, Twist, Culvature Diagonal Heart.

Minor Defects
Cup Shape, Ring Shape, Flute, Inbark, Sun Crack, Spongy, Pinknot, Black Spot, Elephant Skin, Triangle shape, Felling crack, Elliptical shape.

Additional Defects
Inbark hole, Star crack, Waving ring, Ring close, Deform Gallstore, Heart crack, Side hole, water stain, Flute mark, Color dark, Heart spongy, Pig eye, White spot, White band.