Innovative Approaches to Increase Service Life of Poplar Lightweight Hardwood Construction Products

Abstract

During the second half of last century the forestry-wood chain has evolved and today ecosystem services in a sustainability framework are important. Forests are intended to provide services for the bio-economy, human health, biodiversity and climate control. An increased need for more renewable resources both for material and energy use has initiated extra interest for the potential to produce more lignocellulosic biomass, in short to increase wood production. One option is to provide in complementary production in planted forests. Both forestry and agriculture can take part in this. The cultivation of poplar hybrids in the temperate regions is a key option for the current and future bioeconomy. These fast-growing trees are producing lightweight hardwood with a low natural durability, but with an important potential as construction material especially as engineered wood products. All wood protection methods are of interest to be evaluated for this wood resource, making it suitable even for high quality applications. Poplar, for many reasons, has been nominated as hardwood with the best potential to perform similarly as softwoods for applications in wood construction. Benchmarking with wood species like spruce is relevant for several engineered wood products like plywood, LVL and even CLT. Wood treatments to increase durability have evolved from traditional wood preservation towards modification techniques such as thermally modified timber. Innovative poplar based products have been assessed on their performance and are designed to fit for purpose in relation to a specific combination of use class and service life. Introducing innovative poplar based construction product for green building requires adequate testing tools. Performance based assessment should allow to integrate different protective measures. Related to moisture dynamics and the linked fungal decay risk, opportunities to extend service life are manifold. Treatment can be differentiated e.g. for cladding (building envelope) and loadbearing construction components. Simple or sophisticated modification processes can alter the equilibrium moisture content. The use of wood based panels and new engineered wood products allow for better moisture control impacting fungal decay risk, but also alter the probability of insect damage. This paper intends to present several innovative poplar based construction products and show some cases of benchmarking in relation to an integrated service life approach.

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