Impacts of Climate Change on the Timing of the Production Season of Maple Syrup in Eastern Canada.

Maple syrup production is an important economic activity in north-eastern North-America. The beginning and length of the production season is linked to daily variation in temperature. There are increasing concerns about the potential impact of climatic change on this industry. Here, we used weekly data of syrup yield for the 1999-2011 period from 121 maple stands in 11 regions of Québec (Canada) to predict how the period of production may be impacted by climate warming. The date at which the production begins is highly variable between years with an average range of 36 days among the regions. However, the average start date for a given region, which ranged from Julian day 65 to 83, was highly predictable (r2 = 0.88) using the average temperature from January to April (TJ-A). A logistic model predicting the weekly presence or absence of production was also developed. Using the inputs of 77 future climate scenarios issued from global models, projections of future production timing were made based on average TJ-A and on the logistic model. The projections of both approaches were in very good agreement and suggest that the sap season will be displaced to occur 15-19 days earlier on average in the 2080-2100 period. The data also show that the displacement in time will not be accompanied by a greater between years variability in the beginning of the season. However, in the southern part of Québec, very short periods of syrup production due to unfavourable conditions in the spring will occur more frequently in the future although their absolute frequencies will remain low.

Treatment of odorous sulphur compounds by chemical scrubbing with hydrogen peroxide--stabilisation of the scrubbing solution.

To slow down the hydrogen peroxide decomposition in basic aqueous conditions, the addition of stabilizers and co-stabilizers in the scrubbing solution was investigated. Results found with sodium silicate (Na2SiO3) were quite promising but several problems still remained. Based on these observations, this study focused on the research of a better stabilizer. Several ways were investigated: the use of silicate solutions employed in pulp industries, the addition of co-stabilizers to sodium silicate, or the use of an another stabilizer (the poly-alpha-hydroxyacrylic acid). Experiments revealed that the poly-alpha-hydroxyacrylic acid is the best stabilizing compound.