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Internal decay is a common problem in poles or timbers of thin sapwood species. Several internal treatments have been developed to arrest this attack, and these systems are widely used in North America. Although these treatments have been evaluated in numerous independent field trials, there is no single test of all treatments. The objective of this study was to assess the chemical distribution and fungal colonization in Douglas-fir poles treated with each of 13 different internal remedial treatments over a 10-year period. Metam sodium treatments provided the shortest protective period, with little evidence of residual chemical 3 years after treatment. Methylisothiocyanate (MITC) in pure form provided a very high initial flush of active ingredient and a longer protective period extending from 5 to 8 years after treatment. Dazomet, which must decompose to produce MITC, took slightly longer to reach effective levels, but was still present at effective levels 10 years after treatment. Chloropicrin, which has strong interactions with wood, was associated with the highest chemical levels after 10 years. Borates took longer to reach effective levels in the poles and their protective zone was narrower than the fumigants, but boron was still present at effective levels 10 years after application. The results illustrate the different properties provided by each treatment, but also show that all tested remedial treatments were effective within certain limitations., Pressure treatment of large timbers and poles of thin sapwood species generally produces a shallow shell of protection surrounding the untreated heartwood core (Graham 1983). The treatment remains protective if [...]

Abstract The potential for using cinnamon oil as an antimold and stain compound was investigated on ponderosa pine sapwood. This material is available as a food grade additive and offers [...]

Abstract The potential for migration of boron from wood pressure-treated with disodium octaborate tetrahydrate (DOT) during rainfall events was assessed using sawdust, small blocks, and sections of Douglas-fir boards. Boron [...]

Abstract The thresholds of boron and fluoride against selected decay fungi (Postia placenta, Gloeophyllum trabeum, and Trametes versicolor) were determined in Douglas-fir sapwood and heartwood in non-soil contact exposures. Even [...]

Abstract The ability to treat Scots pine (Pinus sylvestris) and Norway spruce (Picea abies) with oilborne copper-8-quinolinolate or with waterborne chromated copper arsenate, ammoniacal copper zinc arsenate, or ammoniacal copper [...]

Abstract Molds are an increasingly important issue for all building materials, including wood. While washing with bleach is a commonly recommended method for removing molds, and the associated discolorations, there [...]

Abstract The residual protective effect of sodium n-methyldithiocarbamate (NaMDC) fumigant was investigated in Douglas-fir timbers in a bridge in western Oregon using fungal colonization and levels of methylisothiocyanate (MITC; the [...]

Abstract Oriented strandboard (OSB) manufacturers have developed 'enhanced' OSB subfloor products that they claim have improved thickness swell properties. Examples of these enhanced OSB panels were found to have reduced [...]

Abstract The potential of 17 hydroxylamine derivatives as wood preservatives was assessed on ponderosa pine sapwood blocks exposed to one of two decay fungi: Gloeophyllum trabeum or Trametes versicolor. Weight [...]

Abstract The decay resistance of China-fir (Cunninghamia lanceolata) was evaluated in several tests using white- and brown-rot fungi in an American Wood Preservers' Association soil-block test. Although there was some [...]