Influence of moisture, nutrients, and distance from stream on early-stage mass loss of western red cedar leaf litter in headwater riparian forests

Western red cedar (Thuja plicata Donn ex D.Don) is a dominant species in forests of the Pacific Northwest in North America, but little is known about its decomposition in riparian habitat. We experimentally tested how early-stage mass loss of cedar leaf litter varied with distance from the stream (five distances from 1 to 40 m away) and responded to nutrient and water additions near four headwater streams in southwestern British Columbia. We ran three coarse-mesh litterbag trials in durations between five months to one year from January 2013 and January 2014. Litterbags were either untreated or given the following treatments: water additions during dry summer months, nitrogen and phosphorus additions, or additions of both. Control litterbags lost 21% initial mass over 12 months (January 2013 – January 2014), 20% over five months (January 2013 – June 2013), and 15% over eight months (June 2013 – January 2014). Rates of mass loss did not increase with water in any trial but did increase with nutrients in the 12-month trial. Litter located 40 m from the stream lost 7% more mass than that located 1 m away in this same trial. Our study indicates that cedar leaf litter mass loss responded primarily to nutrient additions.

Selfing and correlated paternity in relation to pollen management in western red cedar seed orchards

We used microsatellite genetic markers to evaluate the mating system of western red cedar (Thuja plicata Donn ex D. Don) under various seed orchard pollen management schemes. We primarily examined whether supplemental mass pollination (SMP) can reduce the observed selfing rates. Pollen blowing and “hooding” were also examined in smaller tests. Only SMP was consistently effective in reducing the selfing rate, from 30% to 20%. The correlation of paternity was quite high (60%–90%) in two of three orchards, and in these two orchards the application of SMP reduced this correlation by about 10% as well. The correlation of paternity is the fraction of full-sibling vs. half-sibling progeny, and unbiased estimates can be obtained with few loci, even single loci, in contrast to other types of paternity analysis. We also find the microsatellite amplicon sizes should be pooled into “bins” of 2–4 nucleotides, owing to unintended errors of assay; otherwise the estimates are biased. This new feature of mating system estimation was incorporated into the computer program MLTR.

Comparison of Drying Rates of Ground Western Red Cedar with Hemlock, Birch, Aspen, and Spruce/Pine/Douglas Fir

HighlightsWRC and SPF generate the largest fraction of small particles (<0.5 mm) during grinding.WRC is slightly low in total sugars, high in lignin content (should make durable pellets), and high in extractives.Aspen followed by WRC has the highest drying rate and the shortest drying time amongst all samples.Smoke point is similar for all wood species and is ~180°C.Abstract.Western red cedar () and yellow cedar () are among the most valuable tree species in British Columbia. These species make up about 20% of the coastal timber volumes and mostly are used as lumber for construction applications where resistance against decay is important. The use of red cedar for pellet production has been uncertain because it appears cedar has a tendency to cause fires in rotary drum dryers when compared to other wood species like pine and Douglas Fir. The scientific reasons for the reported fire incident are not known. The goal of the current study is to investigate the drying rates and the range of combustion temperature for western red cedar and five other wood species that either are used or have potential to be used for palletization purposes in British Columbia. Red cedar and Spruce/Pine/Fir (SPF) generate the largest fraction of small particles (<0.5 mm) during grinding. Almost 93% of cedar particles are less than 1 mm. Cedar has a high carbon content and low oxygen content that causes cedar has higher calorific value than other species. During a drying process, aspen following by cedar has the highest drying rate and the shortest drying time amongst all samples. The smoke point is similar for all wood species and is ~180°C. So, in the case of high temperature drying (beyond the smoke point) of mixed feedstocks with similar size, red cedar dries faster and starts smoking at dryer output. Keywords: Chemical composition, Drying rate, Physical characterization, Smoke point, Western red cedar.