Grant T. Kirker

Community analysis of preservative-treated southern pine (Pinus spp.) using terminal restriction fragment length polymorphism (T-RFLP) analysis. Part 2: Bacteria field study

Abstract The effects of chlorothalonil (CTN), butylated hydroxytoluene (BHT), and ammoniacal copper quat (ACQ-C) on the fungal community on southern yellow pine (SYP) were assessed using terminal restriction fragment length polymorphism (T-RFLP) analysis over 15 months. Field stakes, treated with 0.25 and 0.37% ACQ-C, 0.1 and 0.25% CTN, 2% BHT alone, 0.1 and 0.25% CTN combined with 2% BHT, and untreated controls, were installed in two field sites in Mississippi. Stakes were sampled at 90-day intervals and rated for decay damage. Fungal DNA was extracted and amplified by non-specific (total fungi) and specific (Basidiomycete) primers and processes for T-RFLP. a-Diversity (richness and diversity) and b-diversity (similarity between communities) were calculated by means of T-RFLP data. The presence of wood preservatives slowed the initial colonization of field stakes by total fungi, resulting in lower richness and diversity that increased over time; however, preservatives increased the richness and diversity of Basidiomycetes. The b-diversity of treated samples was less similar in the early stages of exposure (3–9 months), but coalesced over time into equilibrium communities that were similar to communities on untreated controls. Basidiomycete species compositions were different among treated samples while control communities shared more than 75% of their species. Correlations were found between depletion of 0.1% CTN and increasing fungal diversity, but no other significant correlations were found.

Effect of fungal competition on decay rates in bicultured soil bottle assays

Abstract For decades, wood scientists and preservative formulators have employed the monocultured soil bottle assay to test efficacy of wood treatment in the laboratory as a rapid predictor of field performance. This study examines the effects of bicultured soil bottle assays on the decay by common wood decay fungi. Mycelial interactions were noted in early stages of colonization. With only two exceptions, a single fungus was apparent in each soil bottle, indicating dominance. The dominant fungi were not always the most efficient wood rots, and the rot type, white or brown, did not affect the dominance outcome on the preferred wood type.

Physical deterioration of preservative treated poles and pilings exposed to salt water

This report details the results of laboratory analyses of wooden pilings sent to the USDA Forest Products Laboratory in March 2011. These samples were removed from coastal wooden posts, poles, piles, and deck boards. A total of 22 samples, consisting of either core borings or surface fiber samples, were removed from four installations along the South Carolina coast. Methods focusing on the physical, chemical, and biological properties of the wood determined that the 22 specimen samples consisting of core borings and surface fiber samples were physically deteriorated by salt accumulation and not biological deterioration. This report presents the findings of these analyses and discusses the cause of the documented damage.

Northeastern United States species treated with copper-based preservatives: Durability in Mississippi stake tests

This paper reports on the ground-contact durability of lesser-used wood species of the northeastern United States after treatment with copper-based preservatives. Stakes (19 by 19 by 457 mm) cut from balsam-fir (Abies balsamea), eastern hemlock (Tsuga canadensis), eastern spruce (mixture of Picea glauca, Picea mariana and Picea rubens), red maple (Acer rubrum) or eastern white pine (Pinus strobus) were treated with one of four concentrations of chromated copper arsenate type C (CCA-C), copper citrate (CC), alkaline copper quat type C (ACQ-C) or copper azole type A (CBA-A) and placed into the ground at a test site in southern Mississippi. Similarly treated southern pine (Pinus spp.) stakes were included for comparison. The stakes were rated for decay and termite attack after 1, 2, 3, 4, 5, 8, 10 and 12 years. Eastern white pine and incised eastern hemlock and balsam-fir had durability similar to southern pine when treated with CCA or the other copper-based preservatives. Eastern spruce was less durable than the other softwood species, apparently because of low preservative uptake. Red maple had the least durability at all retentions and for all preservatives. This study indicates that several northeastern softwoods can be adequately durable when pressure-treated with CCA-C or copper-based preservatives.