Roundwood [German version]

Table of contents

General:
Product information
Packaging
Transport
  Container transport
  Cargo securing


Risk factors and loss prevention:
Temperature Odor
Humidity/Moisture Contamination
Ventilation Mechanical influences
Biotic activity Toxicity / Hazards to health
Gases Shrinkage/Shortage
Self-heating / Spontaneous combustion Insect infestation / Diseases




Product information

Product name

German Rundholz
English Roundwood/round lumber/logs
French Bois de grume/Bois rond
Spanish Madera redonda
Scientific  
CN/HS number * 44 ff.


(* EU Combined Nomenclature/Harmonized System)



Product description

Roundwood is the term used to describe logs cut to specific lengths across the grain.

General information about wood:

Wood mainly consists of elongate, firmly intertwined, microscopically small cells. These cells consist of a cell wall and a cell lumen, as a result of which wood is a pore-filled material primarily consisting of cellulose, hemicellulose, lignin and water.

The following Figure shows the macroscopic structure of wood. In addition to the bark and phloem layers, the soft sapwood layers and the hard heartwood layers can also be distinguished. The soft, light-colored sapwood consists of living cells and transports water and nutrients, processes which occur in the outermost annual rings. The hard heartwood consists of dead cells and is often of a dark color due to the deposition of heartwood substances, such as tannins and colorants, resins and other lumber constituents, as well as storage materials.

Wood segment

Figure 1


In comparison to sapwood, heartwood has a lower water content, is heavier, harder and more durable. Trees with a large proportion of heartwood are known as heartwood trees, for example mahogany, cedar and oak. Sapwood trees which exhibit no difference in color and water content between the inner and outer wood are, for example, birch, willow and lime.

"Dressed" lumber is lumber from which the sapwood has been removed. Sapwood is highly susceptible to insect attack, while heartwood is less so.

Roundwood is classed into the following types:

roundwood logs, only cut to length, up to 30 metric tons in weight -
unbarked roundwood, logs without bark -
roundwood, sapwood removed; logs without sapwood -
roundwood, dressed; logs, dressed -
piles up to 24 m in length -
pit props -
burls -
pulp wood -


Roundwood is traded in solid m³ measures. These are calculated in accordance with the following formula:

(radius of trunk)2 · π · length of trunk


Example: A trunk is 4.20 m long and has a diameter of 0.30 m (corresponding to a radius of 0.15 m)

0.152 · 3.14 · 4.20 = 0.297 fm



Quality / Duration of storage

Measures for maintaining quality:

Mechanical means: sheet steel protectors are applied around the cross-section of the trunk in order to prevent splitting due to drying-out of the lumber. In the case of woods with a high tannin content, however, this may result in oxidative discoloration.
Chemical lumber preservatives: in order to inhibit splitting, oxidative discoloration and fungal attack, the cross-sections or bark-free surfaces of the logs are preserved immediately after felling with wax, paraffin, latex or lime, e.g. limba, Parana pine; limba is generally limed.
Sprinkler systems: Sprinkler systems may be set up to prevent deck cargoes of lumber from drying out. When setting up a sprinkler system, it must be borne in mind that the veil of water can be blown away by the wind.


Tropical lumber must have an FSC (Forest Stewardship Council) certificate. This certificate proves that the lumber has been felled from a managed forest and guarantees that the lumber originates from forestry operations which have been certified to operate responsibly by an independent and recognized certification organization.

Click on the link Wood species to find out more about the characteristics of different types of lumber.


Intended use

Roundwood is primarily used for the production of veneer, plywood and furniture and in papermaking.


Figures

(Click on the individual Figures to enlarge them.)

  Makore

Figure 2
Spruce

Figure 3
Beech

Figure 4
Pine

Figure 5
Acariquara

Figure 6



Countries of origin

This Table shows only a selection of the most important countries of origin and should not be thought of as exhaustive.

Europe Sweden, Finland, Russia
Africa Liberia, Ivory Coast, Ghana, Nigeria, Cameroon, Equatorial Guinea, Gabon, Congo, Zaire, Kenya, Tanzania
Asia Malaysia, Singapore, Sumatra, Philippines
America Canada, USA, Honduras, Mexico, Chile, Ecuador, Venezuela, Brazil, Argentina
Australia  


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Packaging

Depending upon weight and length, roundwood logs are transported individually or in bundles, sometimes unbarked. Individual logs may weigh up to 15 metric tons or more.

Strapping

Figure 7


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Transport

Symbols

Symbol, general cargo

General cargo



Means of transport

Ship, truck, railroad


Container transport

Container types which are suitable for lo/lo loading, such as open-top containers, flatracks.


Cargo handling

Lumber is loaded onto ocean-going vessels either dry from the quayside or lighters or directly from the water, the lumber in the latter case being known as rafted logs.

Rafted logs

Figure 8


It must be borne in mind that logs which fall overboard may sink if their density is too high ("sinkers").


Stowage factor

The stowage factor of the various species of wood is directly related to their density. A distinction is drawn between theoretical density and apparent density. Theoretical density is calculated purely on the basis of solid lumber, i.e. as if all cavities within a slab of lumber had been obliterated by compaction. Theoretical density is identical for all species of wood and is 1.50 g/cm3. Apparent density or bulk density is calculated from the weight and the volume of the lumber and differs from species to species in accordance with their differing structure. Comparisons can only be made between types of lumber with an identical water content. Fixed points are a water content of 0% (kiln dry lumber) and 15% (air dry lumber). Lumber is divided into the following categories by density:

very light species < 0.40 cm3
moderately light species 0.41 - 0.50 cm3
light species 0.51 - 0.60 cm3
moderately heavy species 0.61 - 0.70 cm3
heavy species 0.71 - 0.80 cm3
very heavy species > 0.80 cm3


Balsawood with a density of 0.14 - 0.44 g/cm3 is the lightest lumber, while quebracho (1.12 g/cm3), ebony (1.18 - 1.33 g/cm3) and guayac (1.20 - 1.30 g/cm3) are among the very heavy species.

"Sinkers" (heavy wood species such as jarrah) cannot be rafted due to their high density. Care must thus be taken during cargo handling as any logs which fall overboard will sink.


Stowage space requirements

Carriage as deck cargo is usual, provided that the particular species of wood are suitable.


Segregation

Oil-based paint, fiber or wire ropes


Cargo securing

Maritime transport: Especially for carriage as deck cargo on ocean-going vessels, the means of transport must have appropriate lashing means to ensure proper cargo securing.

The IMO Code of Safe Practice for Ships Carrying Timber Deck Cargoes must be observed for cargo securing on ocean-going vessels.

Road transport: Roundwood must be transported in vehicles having a headboard and side walls (stanchions) with sufficient strength and loading capacity. Gaps between the load and the headboard and side walls should be avoided. Gaps in the longitudinal direction in particular may result in slippage on hard braking. If there are gaps in the load, it must be secured in accordance with anticipated accelerations by direct securing (e.g. tight fit, loop lashing) and/or by frictional securing (e.g. tie-down lashing).

For load securing on road vehicles, see also chapter entitled Roundwood in the GDV Cargo Securing Manual.


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Risk factors and loss prevention

RF Temperature

Roundwood requires particular temperature, humidity/moisture and possibly ventilation conditions (SC VI) (storage climate conditions).

Favorable travel temperature range: < 10°C [1]

If the travel temperature is > 10°C, there is a risk that fungi and insects will be activated.

There is a risk of frost splitting at temperatures below freezing point (e.g. ilomba and African canarium). Tropical lumber should not be shipped to Europe during periods of heavy frosts.

Sprinkler systems (e.g. fire-fighting hoses provided with holes) are required to provide protection from solar radiation and so prevent drying-out and splitting of deck cargoes.

Sprinkler system

Figure 9



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RF Humidity/Moisture

Roundwood requires particular temperature, humidity/moisture and possibly ventilation conditions (SC VI) (storage climate conditions).

Designation Humidity/water content Source
Relative humidity 95 - 99% (rafted logs) [1]
70 - 80% (unrafted lumber) [1]
Water content 40 - 60% (rafted logs) [1]
20 - 30% (unrafted lumber) [1]
Maximum equilibrium moisture content > 95% (rafted logs) [1]
< 80% (unrafted lumber) [1]


Due to lumber's high pore content, it is regarded as a porous material having lumens (cavities) filled either with an air/water vapor mixture (gas phase) or with water/aqueous solutions (liquid phase).

Lumber may be divided into the following water content classes:

Water content Designation
0% Kiln dry lumber
6 - 10% Room dry lumber
10 - 12% Very dry lumber
12 - 15% Air dry lumber
15 - 20% Slightly dry lumber
20 - 25% Green lumber (forest dry)
30 - 33% Fiber saturated lumber
> 33% Water saturated lumber


Fiber saturation means that the cell walls (microsystem) are maximally filled with water, while water saturation means that all lumens (micro- and macrosystem) are maximally filled with water.

Air dry lumber is considered dry for shipment; its equilibrium moisture content is 70 - 80% at a temperature of 20°C.

The lumber "works", i.e. swells as it absorbs moisture and shrinks as it dries. In deck cargoes, drying as result of solar radiation may cause dry splitting, which gives rise to claims.

Sorption isotherm

Figure 10


Sheet steel protectors are applied around the cross-section of the log in order to prevent splitting due to drying-out of the lumber. In the case of woods with a high tannin content, however, this may result in oxidative discoloration. In order to inhibit splitting, oxidative discoloration and fungal attack, the cross-sections or bark-free surfaces of the logs are preserved immediately after felling with wax, paraffin, latex or lime.

Sprinkler systems may also be set up to prevent deck cargoes of lumber from drying out.

On the other hand, water washing over the deck, ice or precipitation may result in an increase in weight of deck cargoes of lumber of up to > 25%, which may jeopardize stability.

Due to the risk of moisture damage, rafted logs should not be transported/stored together with products which are dry for shipment (e.g. cocoa, coffee) or with unrafted lumber or cut lumber.


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RF Ventilation

Roundwood requires particular temperature, humidity/moisture and possibly ventilation conditions (SC VI) (storage climate conditions).

Rafted logs should not be ventilated in order to maintain the elevated relative humidity (> 95%). The hygrophilic layer of mold which subsequently forms, causing no damage to the lumber, grows over the burrows of insect lumber pests, so inactivating them. Growth of the blue stain fungi is also inhibited.

Unrafted lumber should be carefully ventilated in order to maintain an ideal relative humidity (avoiding drying-out, creating unfavorable living conditions for pests).


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RF Biotic activity

Roundwood displays 3rd order biotic activity.

Respiration processes are essentially suspended, but biochemical and microbial processes continue.


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RF Gases

Caution: wet logs in unventilated holds consume large quantities of oxygen. No access is permitted to the holds until they have been thoroughly ventilated and the O2 and CO2 contents of the hold air have been measured.


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RF Self-heating / Spontaneous combustion

No risk.


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RF Odor

Active behavior Roundwood releases a penetrating odor.
Passive behavior Roundwood is insensitive to foreign odors.



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RF Contamination

Active behavior Roundwood may cause contamination of other goods.
Passive behavior Roundwood is sensitive to contamination by fats and oils. Mahogany, in particular, is extremely susceptible to stains.

When not caused by fungal attack, discoloration may arise due to contact of the lumber with ferrous metals (e.g. staples and sheet steel protectors), with other moist lumber of certain species or with ship sweat containing iron. The resultant, usually deep, stains arising by a chemical reaction are bluish gray to inky black and may be confused with "blue stain", which is the result of fungal attack. Discoloration may result in severe depreciation.



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RF Mechanical influences

The staples and steel rafting spikes used on rafted logs leave holes and promote splitting. As a result, the bark may become detached in some wood species. The consequently accelerated drying-out of the surface creates more favorable living conditions for any insects which may be present.

Spikes

Figure 11


The use of unsuitable slinging equipment may cause tearing in the outer zones of the lumber and also result in depreciation.


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RF Toxicity / Hazards to health

Due to the O2 consumption of wet logs, an O2 shortage and a dangerously high CO2 concentration may arise in holds which are not ventilated for an extended period. For example, in one case, the O2 content fell from 20.95 vol.% to 2 - 5 vol.% after 4 days without ventilation. The TLV for CO2 concentration is 0.49 vol.%.

34 different species of wood contain irritants or toxins, so caution is required in the event of splinter injuries.


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RF Shrinkage/Shortage

Weight losses due to drying-out of the goods should be avoided (see also RF Insect infestation in this connection).

In the case of west African roundwood logs, which are rafted out to the ships lying in the roads, care must be taken to ensure that the individual log numbers are entered on the bill of lading. This is important for establishing the loss/recourse because this type of loading results in short quantities and the logs are of highly variable dimensions.


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RF Insect infestation / Diseases

The nature and duration of transport prior to shipment have a major impact on the reduction in utility value of tropical structural lumbers. Roundwood benefits from the protection of preservatives at sea only if it has been transported to the port of loading by land (truck, railroad) and loaded directly from the quayside onto the ship. Chemical preservatives are washed off on long journeys during the rainy season or by rafting, such that the logs may be infested by pests and fungi on acceptance. Ramin, ilomba, limba and obeche are particularly susceptible.

Insect infestation

Infestation with wood-destroying insects is not restricted to transport operations. New infestation or reinfestation occurring during transport may originate from other already infested lumber, but this is difficult to establish. No successful countermeasures are possible during storage on board. In several countries of origin, particularly susceptible wood species are treated with chemical agents as a precaution on felling, but complete protection is not achieved.

"Worminess" is the result of burrowing by wood-destroying insects (beetles, horntails and wood borers). The soft sapwood is particularly susceptible. Dressed lumber is consequently not at such high a risk.

Wood-destroying insects become highly active at temperatures of 27 - 30°C, with the high and low temperature torpidity thresholds respectively being 40°C and 4°C.

Particular attention must be paid to termite infestation of tropical roundwood. Termite-infested lumber has "galleries" or tunnel-like systems of passageways. Imported exotic hardwood logs must always be inspected for termite infestation. Termite-resistant wood species are, for example, jarrah, East-Indian rosewood, teak and izombé.

Rafted logs may be infested by bivalves and crustaceans (e.g. balanids). Destruction of the lumber by bivalve teredos proceeds very rapidly due to the large number of individuals, the quality of makore, for example, being degraded by teredo infestation. Only few wood species are considered teredo-resistant, e.g. jarrah, ekki, teak and acariquara.

Teredo (pileworm)

Figure 12
Teredo (pileworm)

Figure 13


Fungal attack

New attack by coloring fungi or further development of existing fungi, which is subsequently usually described as "blue stain", may result in considerable quality degradation during transport. The same applies to new attack and further development of existing wood-destroying fungi. In this case, the change in appearance is frequently described as "white, red and brown pocket rot". Light-colored lumbers are at the highest risk. Fungal growth during maritime transport generally leaves visible damage subject to the following conditions:

susceptibility of wood species (including sapwood)
water content in lumber, relative to dry weight, between 20% and almost complete saturation
temperatures above 10°C


In order to prevent damage of this type, susceptible roundwood is soaked in water to raise its water content above that suitable for fungal growth. Only superficial overdrying to below 20%, in which the water content within the lumber remains at a high level, or chemical treatment by spraying or dipping protect only the surface and are not generally capable of preventing internal "blue stain" which is only revealed on conversion of the log. If the moisture content of a previously dried fungus-sensitive lumber rises back to above 20%, e.g. due to rain during loading or dripping sweat on board, the risk of fungal development rises again at temperatures above 10°C because fungal spores are present on virtually all lumber. In properly dried lumber, i.e. lumber with a moisture content of below 15%, atmospheric humidity alone cannot raise the lumber's water content to the level necessary for fungal growth.

Inspection of the lumber during unloading is the only opportunity to determine the location at which blue stain has arisen and developed. Moisture during transport primarily has an impact on the periphery of the stowage block. Blue discoloration due to blue stain fungi (species common in tropical lumber are Lasiodiplodia and Dothiorella) may cause considerable damage, especially to the sapwood of unrafted lumber, during the voyage, in particular to ilomba and limba. Blue stain fungi find ideal living conditions on drying lumber, so rafted logs should not be ventilated.

Due to its content of sugar, starch and protein, the sapwood is preferred by the fungi. Rafted logs suffer little attack from these fungi as the nutrients have been either leached out or destroyed and they can only grow if the air content of the cell lumens is greater than 15%.

The risk of quality impairment due to fungal attack may be reduced by establishing unfavorable living conditions. Wood species at risk of fungal attack, e.g. ilomba and limba, may thus be stowed on deck as the change from hot to cold during the voyage rapidly makes the living conditions unfavorable for pests.

Alternatively, unfavorable living conditions may be established in the holds by not ventilating them. The resultant high relative humidities of above 95% suppress the metabolic activity of the blue stain fungi. While the growth of hygrophilic molds is indeed promoted by this atmosphere, the resultant surface growth (maximum depth of penetration into the lumber is 2 mm) is preferable to the blue stain fungi, which penetrate deeply into the lumber.


The following table shows the optimum temperature and humidity conditions for wood-damaging fungi and insects:

  optimum temperature lumber moisture content for lower growth threshold optimum relative humidity
Blue stain fungi 27 - 30°C (maximum 35°C) 30% (fiber saturation point) 85 - 95%
Wood-destroying fungi 33 - 40°C 20% 85 - 95%
hygrophilic molds 37°C moist to wet surfaces 95 - 99%
Wood-destroying insects 27 - 30°C at least 15% air in pores of the lumber > 75%



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