Assessing the performance of Chromated Copper Arsenic Treated and Untreated Naturally Durable Papua New Guinea Timber Heartwood in Marine Exposure
Creators: name: Galore, Elaine
Publisher: name: University of the Sunshine Coast, Queensland
Year: 2024
Subjects: PNG
CCA-treated
marine borers
Banksia sp.
Teredo sp.
Martesia striata
Hopea iriana (Hopea, heavy)
Homalium faetidum (Malas)
Vitex cofassus (Vitex, PNG)
Pometia pinnata (Taun)
Castanospermum australe (Blackbean)
Forestry sciences

description: Timber is one of the most important renewable resources, especially if it is obtained from sustainably managed forests. Heartwood durability is important for most exterior timber applications. While considerable research has delved into the resistance and durability of timber species from Papua New Guinea (PNG) against fungal and termite threats in terrestrial conditions, few studies have examined their performance in marine environments. Marine applications of naturally durable or preservative-treated timber are common in PNG; however, utilization is limited to a few timber species despite the availability of several other species that may have better durability and structural performance properties. There is a compelling need for comprehensive research to assess the performance of a broader spectrum of PNG timber species intended for marine applications.
description: This study assessed the marine borer community present at a test site in Queensland. The study also investigated the performance of five chromated-copper-arsenate (CCA)-treated and untreated PNG timber species at the same site and characterized their heartwood extractives and density. Extractive contents and density were assessed to determine their correlation to the selected woods’ durability performance. The species studied were Hopea iriana Sooten. (Hopea, heavy), Vitex cofassus Reinw. ex Blum (Vitex, PNG), Homalium foetidum Benth. (Malas), Pometia pinnata J. R. Forster &amp; G. Forster (Taun) and Castanospermum australe A. Cunn. ex Mudie (Blackbean). CCA-treated and untreated Pinus radiata D. Don (radiata pine) was used as a control species.
description: Marine organisms present at the site were assessed by exposing untreated radiata pine samples, removing samples monthly over 11 months (all samples were severely destroyed at 11 months), assessing and retrieving marine borer organisms. Teredinidae, especially Bankia australis (Calman) and Teredo spp. Linnaeus were the dominant species recovered. Pholadidae Martesia striata Linnaeus and Sphaeromatidae Sphaeroma terebrans Spence Bate were the other groups of marine borers recovered. Evaluation of added samples suggested that colonisation by marine borers occurs more frequently earlier in the year (January) than in the cooler months.
description: All samples were heavily fouled. CCA treatment prevented marine borer attack on most treated timber samples except two of the six Homalium foetidum samples which were assessed as having light marine borer attack. PNG timber species were lightly to moderately attacked after eight months of exposure and the untreated radiata pine (control) samples were heavily attacked to destroyed. Pearson correlations showed a significant (p = 0.035) relationship between total extractives and marine borer attack.
description: There was tendency for less-dense species to be more heavily attacked but the relationship was not significant (p = 0.07).
description: The results from this study will contribute to the more effective utilization of PNG species in marine applications. Additionally, the research will aid in identifying the marine borer community at the Scarborough Marina, leading to valuable insights for future marine