North American and European conifer species evaluated for use as wood components in growing media: a mini review

A review of the scientific literature was conducted to determine which tree species have been used to derive wood components in growing media and their effect on plant growth. Details on wood processing methods are summarized as well as the criteria used to evaluate their suitability as growing media components. Both conifer and hardwood species spanning four continents have been evaluated as substrate components in research trials over the past five decades. The majority of reports indicate that wood products produced from conifer species are more successful than products derived from hardwoods. While not fully understood, it appears that some coniferous species have chemical compositions that are less detrimental to plant growth compared to the hardwood species tested. Chemical composition (i.e phenols, terpenes, lignin percentages, etc.) and biostability (decomposition) varies by tree species, seasonality of harvest, and method of wood processing and manufacturing. Currently in North America, Pinus taeda is the most utilized tree species in commercial wood fiber production, while in Europe, Pinus sylvestris and Picea abies are most commonly used, with other species being more limited in their usage. Understanding the successes and limitations of wood species/products from previous research can help guide current and future research efforts to better optimize and utilize wood products as suitable components in growing media.