Biogenic Formaldehyde: Content and Heat Generation in the Wood of Three Tree Species

Global trends in allowable formaldehyde (CH 2 O) emissions from nonstructural wood-based composites require a renewed consideration of biogenic CH 2 O from wood. Increment cores from living Virginia pine ( Pinus virginiana ), yellow-poplar ( Liriodendron tulipifera ), and radiata pine ( P. radiata ) trees were used to measure CH 2 O and CH 2 O generation due to heating (200 °C, 10 min). Significant variations within and between trees of the same species were observed. Tissue types (juvenile/mature, heartwood/sapwood) sometimes correlated to higher CH 2 O contents and greater heat-generation potential; however, this did not always depend upon species. Heating increased CH 2 O levels 3–60-fold. Heating with high moisture levels generated more CH 2 O than that generated from dry specimens. Radiata pine generated extraordinarily high CH 2 O levels when heated, far exceeding the other species. It was suggested that pine extractives might catalyze CH 2 O generation, perhaps in lignin. Regarding wood-based composites, findings suggested that compliance with emissions regulations may be complicated by CH 2 O generated in the hot press. If we could reveal the precise mechanisms of CH 2 O generation in wood, we could perhaps manipulate these mechanisms for beneficial purposes.