AU764729B2 - Method for inhibiting sapstain in wood - Google Patents

Description

14-AUG-2001 16:56 FROM A.J.PFIRKTO0628274P0/0 TO 0061262832! 34 P.04/30 64 4 4723358 Regulation 3.2

AUSTRALIA

PATENTS ACT, 1990 COMPLETE SPECIFICATION FOR A STANDARD PATENT

ORIGINAL

Name of Applicant: Actual Inventor: Address for service in Australia: Invention Title: NEW ZEALAND FOREST RESEARCH INSTITUTE LIMTED CHEMCOLOUR INDUSTRIES (NZ) LIMITED ROBIN NICHOLAS WAKELING A J PARK, Level 11, 60 Marcus Clarke Street, Canberra ACT 2601 METHOD FOR INHIBITING SAPSTAIN IN WOOD The following statemnent is a full description of' this invention, including the bcst mcthod of performing it known to me/us G:,\WEST-W-lEAVADOCS\NXC\33446954. I RE\',\EIVED TIME 14AUG, 14 5 2 RECIVD IM 14 AG.1452PRINT TIME 14, AUG. 15:14 14-AUG-2001 16:57 FROM A.J.PARK TO 0061262832734 P.05/30 W \CALOUN\ oNX\SPECS\826252 64 4 4723358 METHOD FOR INHIBITING SAPSTAIN IN WOOD FIELD OF INVENTION The invention relates to the prevention of the development of sapstain in logs or sawn timber pieces.

BACKGROUND

Once a tree is felled the logs are subject to degradation by fungi. The hyphae of the fungi may penetrate and grow through the wood resulting in staining of the wood. The staining is known as "sapstain", or "blue stain" and is of microbial origin. Such staining devalues the quality of the wood.

Colonisation of the log with sapstain causing fungi occurs immediately or soon after felling of the tree. Under optimal conditions the hyphae of sapstain causing fungi can move radially (from the log's surface towards log's centre) in the order of 1 to 4 mm per day, and move longitudinally (from log ends) in the order of 5 to 10 mm per day. This varies enormously depending on the fungal species, the tree species, the climate, and the way the logs are handled. A log may be infected with sapstain causing fungi well below its surface.

typically within I to 4 days of the tree being felled during the summer, and under some circumstances it is possible that infection from sapstain fungi will be present in the standing tree before felling well below the surface, for example due to infection from damage caused by pruning or log extraction during thinning operations, and therefore in such instances any harvested logs will contain infection immediately upon felling the standing tree.

For mechanically harvested logs the problem of infection with sapstain causing fungi is exacerbated by the introduction of sapstain fungi by the spiked rollers on the harvester head and other log holding equipment that can damage the logs surface. For hauler based operations where logs are felled in hilly country, the logs cannot be extracted rapidly enough to allow effective treatment to prevent sapstain. Logging operations therefore increase the incidence of infection of logs with sapstain causing fungi and/or place a limit RECEIVED TIME 14 AUG 14 52. PRINT TIME 14 AUG 15 14 RECEIVED TIME 14. AUG. 14:52. PRINT TIME 14. AUG. 13/06/2003 15:31 PAJ PARK WELLINGTON NEW ZEALAND 0061262837999 NO.880 o011i wwuiouvcMflSPS\262520MAPL on the speed with which trees may be felled and then treat harvested logs subsequently treated so as to prevent their infection by sapstain causing fungi and development of sapstain Antisapstain treatments applied to the exterior of the logs by for example spraying typically do not make contact with internal sapstain fungi and therefore surface application is of limited efficacy. Some antisapstain treatments are mobile and can diffuse into the log but.

typically do not move fast enough to "catch-up" with internal sapstain fungi and kill them.

Any tree felling operation that cannot extract logs and treat them at a central processing facility within a few days, if not a few hours, in summer months cannot guarantee sapstain free logs.

""SUMMARY OF INVENTION

**S

*o 15 The invention provides a method for treating logs from felled trees against sapstain, that o***may be applied later than at least some conventional antisapstain treatments and yet still provide effective inhibition of sapstain development, or which at least provides a useful alternative in the prevention of sapstain development In broad terms in one aspect the invention comprises a method of treating a log or piece of sawn timber including the steps of: exposing the log or timber piece to a fnumigant effective against any existing sapstain 2. fungi in the log or timber piece, and (ii) applying an antisapstain treatment to the log or timber piece to inhibit regrowth or infection of sapstain fungi in the log or timber piece.

Preferably the method includes exposing the log or timber piece to the fumigant prior to melanisation of any existing sapstain fungi in the log or timber piece.

2 COMS ID No: SMBI-00293340 Received by IP Australia: Time 13:36 Date 2003-06-13 13/06/2003 15:31 AJ PARK WELLINGTON NEW ZEALAND 4 0061262837999 NO.880 D012 Typically the log or timber piece will have a sapstain level of less than 10%, more preferably less than and most preferably less than 1% at the time of treatment.

References to "sapstain levels" are well known in the art and are generally expressed as percentages. They can either refer to the percentage sapstain surface cover on a veneer peeled from a log using an industrial peeler, or the percentage sapstain surface cover of sawn timber sawn from a log using a commercial sawmill.

DETAILED DESCRIPTION OF INVENTION There is a delay between infection of wood by sapstain fungi and the development of the pigment melanin. Melanin is produced inside fungal hyphae and when fungal hyphae are present in or on the wood in sufficient concentration, the wood is stained, usually grey, blue or black or intermediate shades thereof, the colour being affected by the diffraction of light by the pigment The present invention recognises that fungal infection of wood by sapstain fungi is not in itself a problem if it can be killed before melanin development causes sapstain. The invention recognises that a window of opportunity for antisapstain treatment exists even after infection by sapstain fungi, if the treatment of the invention is carried out before melanisation of the fungal hyphae.

In the method of the invention preferably the fumigation step is carried out first, followed by application of the antisapstain treatment to the fumigated wood. Alternatively however it is possible that the antisapstain treatment may be applied to the wood for example by spraying, prior to carrying out the fumigation step on the wood in a fumigation chamber or vessel, and it is also possible that fumigation and application of the antisapstain treatment may be carried out together.

Typically logs will have been debarked prior to treatment according to the method of the invention. Typically the treatment is applied to wood containing less than 10%/ sapstain at the time of treatment, and more preferably to wood with less than 5% sapstain and most preferably less than 1% sapstain.

Preferably the fumigant is a halogen containing fumigant, more preferably methyl bromide, methyl iodide, chloropicrin, or sulphuryl fluoride. Other suitable fumigants may include phosphine, vapam (methan-sodium), formaldehyde, sulphur dioxide, ozone, nitrous oxide, 3 COMS ID No: SMBI-00293340 Received by IP Australia: Time 13:36 Date 2003-06-13 14-AUG-2001 16:58 FROM A.J.PARK TO 0061262832734 P.08/30 W CALJ4UNNK\SPCS\8262( 64 4 4723358 ammonia, dimethylsuiphide, chloroform, azinphos methyl, formatanate hydrochloride, etaconazole. iodomethane, ethylene oxide, camphor, naphthalene, dichiorodifluorometharie, freon. methyl isothiocyanate, paradichlorobenzene, Mylone (dazornet), sodium bisuiphite.

tridampam (NIN dirnethylthiuramdisulphide), sodium N-methyldithiocarbamate, orthophenyl phenol, Vanicide TH (hexahydro-l,3,5.triethyl-s-triazine), Thymol. carbon disulphide. smokes produced from wood, oil and other substances.

The period of exposure to the fumigant, and the atmospheric concentration of the fumigant, will depend on the fumigant being employed, the moisture content of the log being treated, and the ambient conditions during which exposure of the log to the funigant occurs. The fumigant may comprise several fumigants and may be applied as a gas, smoke, vapour, liquid, solid, or combination thereof.

In one form the antisapstain treatment may be applied to the logs within 2 days followingexposure to the fumigant, more preferably within 24 hours following exposure to the fumigant, and most preferably immediately following or concurrently or before exposure to the fumigant.

*Antisapstain treatments suitable for use in accordance with the invention are known to :20 those skilled in the art. They include. but are not limited to, compositions including V chlorothalonil (tetrachloroisophthalonitrile). carbendaziim (methyl benzidazol-2vicarbamate), quaternary ammonium compounds didecyldimethyl ammonium chloride and didecyldimethyl ammnonium bromide), benomnyl (methyl I -(butylcarbonyl) benzimidazol-ycbaa), ope- quinolinolate, methylene bis thiocyanate, 2(thiocyanomethylthio) benzothiazole, triazoles azaconazole, flusilazole.

propiconazole and hexaconazole ((RS)-2-(2,4-dichlorophenyl)- 1-(1 H-I,2,4-triazole- 1-yl) hexan-2-ol)), methyl benzimidazol-2-yl carbamate, 2-(diiodomethylsulphonyI)-toluene..

fenpropimorph, and isothiazolinones 2n-octyl isothiazolin-3-one).

Preferably the antisapstain treatment applied is able to penetrate the surface of the wood, more preferably the antisapstain treatment comprises methylene bisthiocyanate, and most 4 RECEIVED TIME 14. AUG. 14 :52 PRINT TIME -14. AUG.. 15: 14 04-JUL-2003 15:31 A J PARK 64 4 472 3358 P.03/06 preferably the antisapstain treatment is the formulation

SENTRY

T M which is described in our published PCT international patent application WO 99/55505.

The antisapstain composition may include methylene bis-thiocyanate (MBT), a quaternary ammonium salt, and an organic solvent, as a solution or microemulsion which is effective to cause the antifungal activity to penetrate the surface of the wood.

The antisapstain composition may be an aqueous formulation.

Alternatively the antisapstain composition may be an oil in water microemulsion.

The antisapstain treatment may comprise: 0.05-1% of methylene bistbiocyanate, 0.1-10% of an organic solvent, 0.1 to 15% of a quaternary ammonium salt, and up to 99.75% water.

Preferably the solvent comprises dimethyl sulphoxide, N-methyl pyrrolidone, or dimethyl *0oo formamide.

25 Alternatively the antisapstain composition may comprise 1-10% w/w methylene bisthiocyanate dissolved in a vehicle containing 10-90% w/w dimethyl sulphoxide, N-methyl pyrrolidone, or dimethyl formamide, and 10-90% w/w of a quaternary ammonium salt as a surfactant.

Alternatively the antisapstain composition may comprise 1-10% w/w methylene bisthiocyanate dissolved in a vehicle containing 10-90% w/w dimethyl sulphoxide and 10-90% w/w benzalkonium chloride.

COMS ID No: SMBI-00322209 Received by IP Australia: Time 13:26 Date 2003-07-04 14-RUG-2001 16:59 FROM A.J.PARK a TO 0061262832734 P.10/30 W\CALHoUN\NXK\SPECS\S262\5 64 4 4723358 Preferably the antisapstain composition includes an isothiazolone.

Even more preferably the isothiazolone is 2-n-octyl-isothiazolin-3-one.

The concentration of the antisapstain treatment applied to log or timber piece is preferably between 5 and 15%w/v, more preferably between 7 and 12%w/v.

The method may include carrying out all of the fumigation and antisapstain steps more than 3 days after the felling of the log or timber piece, preferably more than 5 days after the felling of the log or timber piece and most preferably more than 10 days after the felling of the log or timber piece.

The method may include exposing the log or timber piece to the fumigant at a concentration of at least 300 pans per million for at least four hours and may also include exposing the log or timber piece to the fumigant at a concentration of greater than 500 parts per million.

The method may include exposing the log or timber piece to the fumigant at dosage consisting of a fumigant concentration of at least 300 parts per million for an exposure time of at least four hours, or to an equivalent fumigant dosage consisting of a fumigant Sconcentration and exposure time equivalent to fumigation at a concentration of at least 300 parts per million for at least four hours where fumigant dosage is calculated as dosage length of exposure to fumigant (hours) x concentration of fumigant (parts per million).

Alternatively the method may include exposing the log or timber piece to the fumigant at dosage consisting of a fumigant concentration of at least 300 parts per million for an exposure time of at least three days, or to an equivalent fumigant dosage consisting of a fumigant concentration and exposure time equivalent to fumigation at a concentration of at least 300 pars per million for at least three days where fumigant dosage is calculated as dosage length of exposure to fumigant (hours) x concentration of fumigant (parts per million).

6 RECEIVED TIME 14. AUG. 14:52 PRINT TIME .14, AUG. 1 14-AUG-2001 16:59 FROM A.J.PARK a TO 0061262832734 P.11/30 w\CALWOUN\NXK\rPECS\826252( 64 4 4723358 Yet another alternative method may include exposing the log or timber piece to the fumigant at dosage consisting of a fumigant concentration of at least 500 parts per million for an exposure time of at least three days, or to an equivalent fumigant dosage consisting of a fumigant concentration and exposure time equivalent to fumigation at a concentration of at least 500 parts per million for at least three days where fumigant dosage is calculated as dosage length of exposure to fumigant (hours) x concentration of fumigant (parts per million).

Rates of application of the antisapstain treatment required will depend on the antisapstain treatment being applied, the moisture content of the logs or wood to which the antisapstain treatment is applied, and the ambient conditions in which the logs or wood are to be stored.

The preferred concentration of the SENTRY T composition to be applied to logs is between and 15%w/v, and the most preferred concentration is between 7 and 12%w/v.

Logs may be covered with impermeable sheets and then sulphuryl fluoride or methyl bromide introduced to achieve a concentration of between 80 and 300 grams per cubic meter (ppm) (under some circumstances it may be desirable to user higher concentrations of fumigant up to 1000 grams per cubic meter) for between 1 and 3 days (under some circumstances it may be desirable to expose logs to fumigant for longer periods up to 7 20 days) depending on the log age. The logs are then treated with an antisapstain composition such as the SENTRYTM composition at a concentration within the range 5-15%w/v, depending on the destination of the logs, usually after removal of bark.

Alternatively logs may be treated with an antisapstain treatment such as the SENTRYTM composition at a concentration of between 7%w/v and 15%w/v, usually after removal of bark, followed by storage of logs in a ships hold or any other confined space or under impermeable sheets, followed by introduction of sulphuryl fluoride or methyl bromide or another fumigant to achieve an atmospheric concentration of between 80 and 1000 grams per cubic meter (ppm) for between 1 and 10 days depending on the log age.

A pressure above atmospheric pressure can be applied either before, during or after introduction of the fumigant into the atmosphere; or a vacuum or negative pressure can be 7 RECEIVED TIME 14. AUG. 14:52 PRINT TIME 14. AUG. 15: 13 14-AUG-2001 16:59 FROM R.J.PARK TO 0061262832734 P.12/30 \CALHOUN\NXK\SPECS\826252( 64 4 4723358 applied followed by release of the vacuum or negative pressure, possibly followed by application of a pressure above atmospheric pressure, before, during or after introduction of the fumigant into the atmosphere to increase the rate of fumigant penetration into logs.

By combining a fumigation step with a post fumigation application of an antisapstain treatment, or by combining an antisapstain treatment step with a post antisapstain treatment of a fumigant, the development of sapstain can be inhibited in logs even when this combined exposure to fumigant and application of an antisapstain treatment is applied several days after the felling of the tree and harvesting of the logs.

The antisapstain treatment is applied post-fumigation, or even concurrently with the fumigation step, or the fumigation step can be carried out shortly after the antiapstain treatment. The fumigant is a gas, liquid, solid, or combination thereof, capable of ready volatilisation and/or dispersion in the atmosphere surrounding the logs under the conditions of use.

A list of such fumigants includes, but is not limited to, halogenated hydrocarbon fumigants such as ethylene dichloride, tiichloroethylene, methylbromide and the like, and inorganic halides such as sulphuryl fluoride. The list of halogens includes fluorine, bromine, iodine :'20 and chlorine. Effective fungicidal gases, vapours, smokes, liquids, solids, or combinations thereof, diffuse into the wet wood.

In its simplest form the treatment includes covering logs with tarpaulins and venting gas, S vapour, smoke, or combinations thereof, under the tarpaulin amongst the logs. The gas, vapour, smoke, or combinations thereof, preferentially moves into all the voids in the logs surface especially those associated with damage and where infection with sapstain causing fungi is most likely to occur. The fumigant then moves preferentially into dry or drying wood and then moves by diffusion into wet wood until all the wood potentially containing sapstain causing fungi is treated. The fumigation step may take several hours or days depending on several factors such as the potential depth of fungal infection, the nature of the gas, vapour, smoke, or combinations thereof, being applied, the concentration of the fumigant, the duration of exposure of the fumigant to the logs surface, the age and extent of 8 RECEIVED TIME 14. AUG. 14:52 PRINT TIME- 14, AUG, 15: 13'.1, 14-RUG-2001 17:00 FROM FA.J.PARK TO 0061262832734 P.13/30 W\CALHOUN\NXK\SPECS\826252( 64 4 4723358 wicaumouwinx,<isPess2s2 64 4 4723358 damage to the logs being treated and the extent of moisture loss from logs and on the temperature, pressure and humidity.

Methods of fumigation which allow greater control of these variables-may be employed.

For example a truck and trailer unit bearing the logs to be treated may be driven into a tunnel, the truck detached, driven out and the trailer unit with logs sealed in the tunnel. The gas, vapour, smoke, or combinations thereof, may then be introduced into the tunnel, left for the required time, vented with recycling or scrubbing of the gas, vapour, smoke, or combinations thereof, followed by removal of the trailer unit bearing the logs from the tunnel. Under some circumstances it may be advantageous to raise atmospheric temperature and/or raise pressure slightly above atmospheric pressure inside the tunnel.

The antisapstain treatment is applied to the fumigated logs. The antisapstain treatment should be applied shortly after the fumigation step. Common antisapstain treatments are known to those skilled in the art. Most advantageously an antisapstain treatment which has some ability to penetrate the surface of the fumigated log can be applied.

Alternatively antisapstain treated logs may be placed in a ships hold or other confined space, or under impermeable sheets prior to fumigation. The gas, vapour, smoke, or combinations thereof, may then be introduced into the confined space or under the impermeable sheets, left for the required time, vented with or without recycling or scrubbing of the gas, vapour, smoke, liquid, solid, or combinations thereof, followed by removal of the logs.

The combined fumigation step with a post fumigation application of an antisapstain treatment results in the killing of fungi, or at least the inhibition of pigmentation of hyphae of the fungi, eg by melanisation.

Typically New Zealand summer logs do not contain any sapstain before 7 to 10 days and at this stage the detection of sapstain requires the sawing up of logs into transverse sections followed by close inspection or by close inspection of the first veneer from a peeler log, often with concurrent microscopic analysis. After 10 to 20 days the development of 9 RECEIVED TIME 14. AUG. 14:52 PRINT TIME -14. AUG. 15 :13' 14-AUG-2001 17:00 FROM A.J.PARK .W\CALHOUN\NXK\SPECS\826252( 64 4 4723358 TO 0061262832734 P.14/30 sapstain may be more apparent but is rarely greater than 10%. In the absence of effective treatment the sapstain will continue to develop in these logs to levels which significantly devalue the logs or render them unsaleable. By the method herein described logs from trees felled several days earlier, and containing sapstain that cannot be effectively treated by conventional approaches, may be effectively treated to prevent the formation or continued development of sapstain. Other variations falling within the scope of the present invention will suggest themselves to those skilled in the art.

The following examples further illustrate the invention.

EXAMPLE 1 Materials and Methods: A number of 3.9 metre long radiata pine peeler logs, felled and de-barked over two days, were delivered to a spray booth facility. Two sets of logs containing eight logs each were selected at random. For each set three treatments were applied: four logs were designated for fumigation and antisapstain treatment, hereafter referred to as SentryPlus and four logs for antisapstain treatment only The two remaining logs served as untreated controls. To simulate logs of different ages and degrees of fungal infection, the two sets of logs were stored untreated for 9 and 16 days.

r -i r 0 to *.t After the pre-treatment storage period the four S log billet replicates of each set were treated by spraying with the antisapstain composition of Table 1, and were then stacked in an outside storage area on bearers in a pyramidal stack for twelve weeks.

Constituent Constituent Active w/w of Function active N-methyl pyrrolidone N-methyl pyrrolidone 25.9 Solvent/surfactant Synthecol Quad HC Benzalkonium 51.8 Solvent/surfactant Chloride Methylene bis Methylene bis 6.5 Fungicide thiocyanate thiocyanate Kathon 893 F 2-n-octyl-isothiazolin- 1.3 Fungicide RECEIVED TIME 14. AUG. 14:52 PRINT TIME 14. AUG. 15:13 14-AUG-2001 17:01 FROM A.J.PARK a TO 0061262832734 P.15/30 w\CALHOUN\NXK\SPECS\826252 64 4 4723358 3-one SI -one I I TABLE 1 SENTRY T ANTISAPSTAIN COMPOSITION After the pre-treatment storage period the SP log billet replicates were fumigated with methyl bromide vapour. Methyl bromide is a liquid under pressure, but when introduced into the tarpaulin/chamber, the atmospheric pressure causes it to vapourise. A separate fumigation chamber was used for each pre-infection holding period. The fumigation schedule aimed for was 1000g/m methyl bromide for five days, but the level of methyl bromide was monitored and topped up if necessary.

After fumigation, the fumigated logs were also sprayed with the antisapstain composition of Table 1 and similarly stored outdoors in a pyramidal stack for 12 weeks prior to assessment.

Assessment Results: Before rotary cutting of the logs into veneer, the tag labels were removed and each log was cross cut into three 1.3 metre long log billets. The billets were clearly identified as either the end or middle portions of the original log. A visual assessment for percentage cover of sapstain and other fungal discolourations was determined for the first complete veneer sheet, approximately 2 metres long, of each log S 20 billet. In this way the surface of the logs were assessed to a depth of up to approximately five millimeters. If assessment of the first veneer sheet revealed that no sapstain was present, then this was indirective of there being no antisapstain deeper in that particular log.

S The results are shown in Table 2: Pre-infection period Mean percentage surface fungal degrade (days) S SP Untreated control 0 60.0 9 60.0 6.3 16 58.8 16.3 RECEIVED TIME 14. AUG'14:52 PRINT TIME 14. AUG. 15: 13.. 14-AUG-2001 17:01 FROM A.J.PARK W\CALHOUN\NXK\SPECS\8262S2C 64 4 4723358 TO 0061262832734 P.16/30 TABLE 2 Fungal degrade on S and SP treated logs after 9 and 16 days pre-infection The mean percentage of fungal degrade for the S treatments were similar to the untreated control (Table In contrast, SP treated logs showed 6.3% fungal degrade for the nineday-old logs and 16.3% for the 16-day-old logs.

EXAMPLE 2 Materials and Methods: Twenty nine freshly felled 3.9 metre long radiata pine peeler logs were selected at random over three different days. On each of the first two days four logs were allocated for each of the S and SP treatments used in Example 1. Five logs felled on the first day served as controls.

The three different days on which the logs were felled represented pre-treatment holding periods of 3, 5 and 9 days. Logs collected on the first two days were held in a marshalling area in the forest, until the third set of logs was felled. All logs were then transported to the treatment site and de-barked.

The S logs were sprayed with the antisapstain composition of Table 1. The SP logs were fumigated with methyl bromide vapour as described in example 1 except that fumigation took place in one container.

.5.5.5

S

S

S

Pre-infection Mean percentage surface fungal degrade period (days) S SP Untreated control 0 69.0 3 22.0 12.8 64.0 17.4 9 70.6 14.4 RECEIVED TIME 14. AUG, 14:52 PRINT TIME 14. AUG. .15:13- 14-RUG-2001 17:01 FROM A.J.PARK A TO 0061262832734 P.17/30 W\CALHou,\NXE\SPKCS\8e26S2C 64 4 4723358 TABLE 3 Fungal degrade on S and SP treated logs after 3, 5 and 9 days ofpre-infection Results: The logs were assessed as described in example 1. The results are shown in Table 3. Logs given the S treatment had. after 5 and 9 days pre-treatment holding period, mean percentage degrade of 64% and 70.6% respectively, which was similar to the untreated controls. Mean percentage degrade for a pre-treatment holding period of 3 days was 22%.

For all the pre-treatment holding periods. SP treated logs had a substantially lower rate of fungal degrade compared to the S treatment.

EXAMPLE 3 Materials and Methods: 156 pruned radiata pine peeler logs and unpruned A grade sawlogs 3.9 metre long with small end diameter 35-50 centimetres were delivered to the treatment site within 24 hours of felling and allocated at random to the 9 treatments shown in Table 5. Log replicates per treatment were either 10 or 16 depending on the treatment.

Additional logs were left untreated to serve as controls.

Logs intended for the SP treatment were held for 7 days after felling and logs for S treatment were held for 3 days, to allow for fungal colonization to occur, prior to debarking and treatment.

The S logs were sprayed with the antisapstain composition of Table 1. The SP logs were fumigated with methyl bromide vapour and then sprayed with the antisapstain vapour.

The S and SP logs were stored on a wharf for approximately 4 weeks, transported on the deck of a ship from New Zealand to the Philippines over a period of approximately 4 weeks, and then held in the Philippines for approximately 4 weeks. All other treatments were held on the New Zealand wharf for the duration prior to assessment.

13 RECEIVED TIME 14. AUG. 14:52 PRINT TIME 14. AUG., 15:13 14-RUG-2001 17:02 FROM A.J.PARK W\CALKoUN\XK\SFSC\82622 64 4 4723358 TO 0061262832734 P. 18/30 Assessment Results: The logs were then veneered as in Example I and the percentage cover of sapstain on veneers recorded. The fIrst veneer from each log was assessed for percentage cover of sapstain and other discolouration. Assessment of the S and SP logs was carried out in the Philippines 12 weeks after treatment. The other treatments were assessed in New Zealand after 14 weeks. Table 5 gives the percentage cover of stain on the first whole veneer of each log.

Treatment Holding Stain on first veneer Period Log Number S2 3 4 15 6 7 8 9 10 11 12 13 14 15 16 Mean Pruned logs 7daySP 7days 0 5 5 0 5 0 0 0 0 0 10 0 10 0 5 3 3davS 3days 25 25 35 25 15 40 25 15 15 15 24 Control 90 90 80 90 90 90 90 90 90 60 86 Unpruned logs 7daySP 7days 0 0 0 5 0 5 0 0 0 5 0 0 5 5 5 5 2 3dayS 3days 15 25115140 10140 15 20 23 Control 60180190140 40190 90 90 73

S.

*5S*

S

*5 5*

S

S

TABLE 5 Fungal degrade on pruned and unpruned logs The improved efficacy that results from fumigation prior to antisapstain treatment is clearly demonstrated. SP treated logs had a mean stain cover of 3 and 2% for pruned and unpruned logs respectively compared to 24 and 23% for S treated logs.

It is known that the degree of fungal pre-infection increases as the holding period increases.

Radial sapstain penetration rates are in the order of 3 mm per day in the summer and on this basis it would be expected that the depth of pre-infection would be approximately 21 un.

The results therefore indicate that pre-infection of this depth is effectively killed by the fumigation step. In contrast, S only did not kill 3 days worth of pre-infection (approximately 9 mnm). The ability of the SP treatment to control sapstain in 7 day old 14 RECEIVED TIME 14,AUG, 14:52 PRINT TIME .14. AUG. .15:13 14-AUG-2001 17:02 FROM A.J.PPRK W\CALI40UN\NX\SPECS\8262S2i 6 735 TO 0061262832734 P. 19/30 unpruned logs is an especially impressive result. This is because the rate of movement of sapstain infection into the log through branch stubs is much faster compared to penetration across thc growth rings. Rates of penetration of sapstain fungi through longitudinal wood elements, as occurs along the length of a branch (radially into the log), is in the order of mm a day. This suggests that the fumigation step was able to kill pre-infection up to approximately 70 mm in unpruned logs.

00 0000 *000 00 0@ 0 @0S0 0S *0 0 0@ @000

S

SS

0 0 000 0

S

ego. S.

0 @000

S

@005 06 0 00 0000 0 @000 J- PRIT TIME 14. N'A UG.15 12T 2 RECEIVED TIME'" 14. AUG. 52

Claims (26)

1. A method of treating a log or piece of sawn timber including the steps of: exposing the log or timber piece to a fumigant, effective against any existing sapstain fungi in the log or timber piece, and (ii) applying an antisapstain treatment to the log or timber piece to inhibit regrowth or infection of sapstain fungi in the log or timber piece.

2. A method according to claim 1 including exposing the log or timber piece to the fumigant prior to melanisation of any existing sapstain fungi in the log or timber piece.

3. A method according to claim 1 or 2 including fumigating the log or timber piece 15 and then applying the antisapstain treatment to the fumigated log or timber piece.

4. A method according to claim I or 2 including applying the antisapstain treatment to the log or timber piece, and then fumigating the log or timber piece. 20 5. A method according to claim 1 including applying the antisapstain treatment and fumigant simultaneously.

6. A method according to any one of the preceding claims wherein the log or timber piece is a log and including debarking the log before treatment.

7. A method according to any one of the preceding claims wherein the log or timber piece has a sapstain level of less than 10% at the time of treatment.

8. A method according to any one of the preceding claims wherein the log or timber piece has a sapstain level of less than 5% at the time of treatment. 16 COMS ID No: SMBI-00293340 Received by IP Australia: Time 13:36 Date 2003-06-13

14-RUGi-2001 17:03 FROM1 A.J.PARK aTO 0061262832734 P.21/30 64 4 4723358 9. A method according to any one of the preceding claims wherein the log Or timber piece has a sapstain level of less than 1% at the time of treatment. A method according to any one of the preceding claims wherein the fumigant is a halogen containing ftimigant. 11. A method according to claim 10 wherein the fumigant includes one or more of methyl bromide. methyl iodide, chioropicrin, and suiphuryl fluoride. 12. A method according to any one of claims I to 9 wherein the fumigant includes any one or more of phosphine, vapamn (rnethan-sodium), formaldehyde, sulphur dioxide, ozone, nitrous oxide, ammonia, dimethylsuiphide, chloroform, azinphos methyl. formatanate hydrochloride, etaconazole, iodomethane, ethylene oxide, camphor. naphthalene, dichiorodifluoromethane, freon, methyl isoihiocyanate, paradichlorobenzene, Mylone (dazomet). sodium bisuiphite, tridampam (NN dimethylthiuramdisulphide). sodium N- meihyldithiocarbarnate, orthophenyl phenol, Vanicide TH (hexahydro- 1,3,5 rtriethyl-s-triazine), thymol, carbon disulphide or smokes produced from wood or oil. 13. A method according to any one of the preceding claims including exposing the 20 log or timber piece to the fumigant as a gas, smoke, or vapour, or as a solid, or liquid, or as a combination thereof 14. A method according to any one of claims I to 3 and 6 to 13 including applying the antisapstain treatment to the log, or timber piece within two days following exposure to the fumigant. A method according to any one of the preceding claims wherein the antisapstain treatment includes at least one of chlorothalonil. (tetrachloroisophrhalonitrile), carbendazim (methyl benzidazol-2-ylcarbamate), a quaternary amimonium compound, benomyl (methyl 1 -(butylcarbonyl) benziniidazol-2ylcarbanate), copper-8 quinolinolate, methylene bis thiocyanate, 2(thiocyanomethylthio) benzothiazole, a triazole. methyl benzimidazol-2-yl carbarnate, 2-(diiodomethylsulphonyl)-toluene, fenpropimorph, and an isothiazolinone. 17 RECEIVED TIME 14. AUG. 14 :5 2 PRINT TIME 14. AUG. 15:1 77 13/06/2003 15:31 AJ PARK WELLINGTON NEW ZEALAND 4 0061262837999 NO.880 1015 W\CALQOUU1C\8PECS\B2625aCOMPLeTE

16. A method according to claim 15 wherein the antisapstain treatment also includes at least one of didecyldimethyl ammonium chloride, didecyldimethyl ammonium bromide, azaconazole, flusilazole, propiconazole, and hexaconazole ((RS)-2-(2,4-dichlorophenyl)-I- (1H-1,2,4-triazole-l-yl) hexan-2-ol) and 2n-octyl isothiazolin-3-one).

17. A method according to any one of claims 1 to 15 wherein the antisapstain composition includes methylene bis-thiocyanate (MBT), a quaternary ammonium salt, and an organic solvent, as a solution or microemulsion which is effective to cause the antifungal activity to penetrate the surface of the wood.

18. A method according to claim 17 wherein the composition is an aqueous formulation. 15 19. A method according to claim 17 wherein the composition is an oil in water microcmulsion. A method according to any one of the preceding claims wherein the antisapstain treatment is a composition comprising: 0.05-1% w/w ofmethylene bisthiocyanate; S* 0.1-10% w/w of an organic solvent, C 25 0.1 to 15% w/w of a quateriary ammonium salt, and up to 99.75%w/w water.

21. A method according to claim 20 wherein said solvent comprises dimethyl sulphoxide, N-methyl pyrrolidone, or dimethyl formamide. 18 COMS ID No: SMBI-00293340 Received by IP Australia: Time 13:36 Date 2003-06-13 13/06/2003 15:31 AJ PARK WELLINGTON NEW ZEALAND 4 0061262837999 NO.880 [016 w\cALHOUN\NcK\sPECS\82252COMPLET8

22. A method according to any one of claims 1 to 19 wherein the antisapstain composition comprises 1-10% w/w methylene bisthiocyanate dissolved in a vehicle containing 10-90% w/w dimethyl sulphoxide, N-methyl pyrrolidone, or dimethyl formamide, and 10-90% w/w of a quatenary ammonium salt as a surfactant.

23. A method according to any one of claims 1 to 19 wherein the antisapstain composition comprises 1-10% w/w methylene bisthiocyanate dissolved in a vehicle containing 10-90% w/w dimethyl sulphoxide and 10-90% w/w bezalkonium chloride.

24. A method according to claim 23 wherein the antisapstain composition includes an isothiazolone.

25. A method according to claim 24 wherein the isotbiazolone is 2-n-octyl- isothiazolin-3-one. S. 26. A method according to any one of claims 19 to 25 wherein the concentration of the antisapstain treatment applied to log or timber piece is between 5 and

27. A method according to claim 26 wherein the concentration of the antisapstain 20 treatment applied to log or timber piece is between 7 and 12%w/v.

28. A method according to any one of the preceding claims including carrying out all of the fumigation and antisapstain steps more than 3 days after the felling of the log or timber piece.

29. A method according to any one of the preceding claims including carrying out all of the fumigation and antisapstain steps more than 5 days after the felling of the log or timber piece.

30. A method according to any one of the preceding claims including carrying out all of the fumigation and antisapstain steps more than 10 days after the felling of the log or timber piece. 19 COMS ID No: SMBI-00293340 Received by IP Australia: Time 13:36 Date 2003-06-13 14-AUG-2001 17:04 FROM A.J.PARK aTO 0061262832734 P.24/30 W\CALHoum\NxK\sPecss262S2eC644 723

31. A method according to any one of the preceding claims including exposing the log or timber piece to the fumigant at a concentration of at least 300 parts per million for at least four hours.

32. A method according to claim 31 including exposing the log or timber piece to the fumigant at a concentration of greater than 500 parts per million.

33. A method according to any one of claims I to 31 including exposing the log or timber piece to the fumigant at dosage consisting of a fumigant concentration of at least 300 part per million for an exposure time of at least four hours, or to an equivalent fumigant dosage consisting of a fumigant concentration and exposure time equivalent to fumigation at a concentration of at least 300 parts per million for at least four hours where fumigant dosage is calculated as dosage length of exposure to fumigant (hours) x concentration of fumigant (parts per million).

34. A method according to any one of claims I to 31 including exposing the log or timber piece to the fumixigant at dosage consisting of a fumigant concentration of at least 300 parts per million for an exposure time of at least three days, or to an equivalent .20 fumigant dosage consisting of a fumigant concentration and exposure time equivalent to fumigation at a concentration of at least 300 parts per million for at least three days where fumigant dosage is calculated as dosage length of exposure to fumigant (hours) x concentration of fumigant (parts per million).

35. A method according to any one of claims 1 to 31 including exposing the log or timber piece to the fumigant at dosage consisting of a fumigant concentration of at least 500 parts per million for an exposure time of at least three days, or to an equivalent fumigant dosage consisting of a fumigant concentration and exposure time equivalent to fumigation at a concentration of at least 500 parts per million for at least three days where fumigant dosage is calculated as dosage =length of exposure to fumigant (hours) X concentration of fumigant (parts per million). RECEIVED TIME 14. AUG. 14:52 PRINT T'IME '14.AUG. .15:12 13/06/2003 15:31 AJ PARK WELLINGTON NEW ZEALAND 4 0061262837999 NO.880 D017 W\CALHOUIN\NXK\SECS\8ae252COMPLET

36. A log or timber piece as treated by the method of any of the preceding claims. COMS ID No: SMBI-00293340 Received by IP Australia: Time 13:36 Date 2003-06-13