Processes Underlying Discoloration of Redwood<i>(Sequoia sempervirens)</i>during Drying and in Use

Background: Sequoia sempervirens (D. Don) Endl.) (redwood) has the potential to be grown in New Zealand in commercial forestry operations and is valued for its naturally durable heartwood. A viable redwood industry based on planted forests can only be achieved if the timber produced meets quality expectations, in particular durability. Natural durability is highly variable among trees. Also, a within-tree pattern of low durability close to the pith has been observed. Natural durability is preliminarily caused by secondary metabolites deposited into the cell walls during heartwood formation. The exact nature of the compounds responsible for natural durability in redwood is unknown. Methods: Samples of heartwood from 22 different trees were obtained, ground and extracted using a range of solvents. The ability of some of these extracts to reduce the growth of two fungi (Gloeophyllum trabeum and Trametes versicolor) was tested in vitro. Information on the composition of the extracts was obtained using infrared spectroscopy and gas chromatography.

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“…facilitated by partial oxygen pressure, (low) pH, temperature and heavy metals (Zavarin and Smith 1962).…”

Section: Chemical Reactions Of S Sempervirens Heartwood Extractsmentioning

confidence: 99%

The chemistry and bioactivity of various heartwood extracts from redwood (Sequoia sempervirens) against two species of fungi

Davies

Altaner

2014

N.Z. j. of For. Sci.

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“…The development of non-microbial discolouration of lumber is a widespread problem for many hardwood and softwood species (Bailey 1911;Zavarin and Smith 1962;Cech 1966;Miller et al 1983;Charrier et al 1992;Schmidt and Amburgey 1994;. Such non-microbial discolourations can develop before the logs are sawn or after the sawing of the boards, and cause an undesirable blemish, thus reducing the wood value (Kreber and Byrne 1994;McLean 1995;Anon.…”

Section: Introductionmentioning

confidence: 99%