Sap flow activities and maple syrup processing – April 2 to 8, 2016
In Ontario, the maple syrup processing season has shaped up to be a fantastic year for syrup quality and yield, with a full range of colour grades and flavour intensities. Sap harvest and syrup processing will continue for a week or two more. The trees in sugar bushes are transitioning out of dormancy now and will begin growth over the coming weeks as temperatures warm up.
In southern areas: sap harvest and syrup processing has finished now and maple syrup producers are still busy cleaning and sanitizing sap tubing and processing equipment. Once buddy off-flavoured sap appears due to advanced bud development, the off-flavour does not disappear and will not return back to good quality, even following freezing weather and snow fall. The chemistry of sap changes due to bud growth, making it unfit for making syrup.
After pulling spiles from trees, researchers have found it is best to leave the tap holes open to the air to dry. Filling the hole or covering the hole is not recommended, since it can seal wood decay organisms inside the tap hole, which can lead to wood rot within the sapwood.
Bud development on sugar maple trees
Mid-season and late areas: to the north and Ottawa Valley, very cold weather this past week has frozen the sapwood again and has stopped bud development. As much as a fresh foot of snow has accumulated in Algonquin area sugar bushes. As a result of the cold, the sap harvest season will be extended for another week or more in later areas.
Northern producers report their syrup crop yield ranges from 80 percent to more than 100 percent of a normal average yield. Many have exceeded the provincial average of 1.1 litres syrup per tap, similar to southern area producers. Hopefully these producers still have adequate firewood, wood pellets or fuel oil to keep processing new syrup, as well as enough food-grade storage containers for the finished syrup.
Sugar bushes that are located north of Wellington County, Peterborough and highway 7 to the east, may be processing new syrup when thawing conditions resume. The forecast indicates that ideal conditions for sap flow are expected after April 10 in central northern regions and after April 12 on St. Joseph Island.
Healthy sugar bushes = sustainable syrup production
For high-yielding sugar bushes, maple researchers have found that sap harvest does not affect the health of maple trees, where trees are assessed by producers to be free of stress prior to tapping and are in a healthy condition.
Vacuum-assisted sap harvest removes an estimated 10 to 15 percent of stored sugar from mature trees, leaving more than adequate reserves of sugar and starch energy in tapped trees to begin new growth in spring and carry the trees into summer.
As long as producers practice conservative tapping and monitor the health of their sugar bush during each unique growing season and winter, current syrup production methods are considered to be sustainable. Studies by maple researchers of sugar bush management and sustainable tapping practices are ongoing in Canada and the United States.
Regeneration and adaptability to climate
Seeds of trees represent a surge of effort by each species to reproduce and exist as the future generations of diverse forests. The genetic makeup of each seed presents a unique capability or opportunity, for adaptation of the species to the soil and environment, into which the seed germinates.
Among the thousands of mature seeds that fall from trees, those seedlings that contain the best genetic match to their surroundings will be the most competitive and most likely to survive to maturity.
In addition to soil conservation measures and a changing climate, the most adapted trees in the future will also have survived other stressors, such as repeated browsing by herbivores, the future dynamics of insect pests and diseases, invasive earthworms, air pollutants, highways and housing projects, volcanic activity and varying solar radiation.