Frozen sugar bushes

Last week, cold winter weather persisted throughout the week across Ontario keeping maple trees frozen solid without a chance of sap flow.  Drilling holes and tapping trees was halted due to risk of splitting bark while the sapwood is frozen.  To ensure tree health is a priority, syrup producers are waiting until thawing conditions return to resume tapping maple trees.

Although the sap did not flow, producers were still busy preparing vacuum tubing in the bush.  Many have completed cleaning and sanitizing all processing equipment in the sugar house and bulk storage containers in readiness for sap flow and the new syrup crop.

Traditional to the maple syrup industry, many areas of the province began holding official first tapping ceremonies to mark the historical value and current value of Ontario’s maple syrup industry.

Longterm weather forecasts predict that cold winter conditions will continue into the coming weekend and sap flow is not expected.  Where trees have been frozen by deep cold, sapwood can require several days of thawing temperatures before sap will flow.  The only areas in the province that may see the first sap flow by next weekend are Windsor, Blenheim and the Niagara region where temperatures may warm above freezing in sunny sheltered sugar bushes.

While air temperatures are not expected to warm to thawing conditions, the increasing intensity of sunlight during March can sometimes induce sap to flow and sap tubing to not freeze sap where sugarbushes are sheltered from wind.  Maple syrup producers might consider planting windbreaks around the perimeter of their sugar bush this coming spring or fall to help encourage sap to flow sooner.

 Figure 1.  Modern sap holding tanks are constructed of tig welded stainless steel or food-grade plastic.  This large tank has been cleaned, sanitized and thoroughly rinsed with potable water and now stands ready to receive the first sap when thawing conditions begin.  Also note the washable walls, which are ideal for modern food processing facilities.

 Figure 2.  A sap releaser is in operating condition, clean and sanitized, ready to begin separating incoming sap from the vacuum tube system.  Once separated, fresh sap is then pumped to a large holding tank (Figure 1) while thousands of feet of sap tubing that spreads out into the sugar bush will remain under nearly constant vacuum.  Releaser tanks are intricate and precise, and can be operated mechanically or electrically at the sugar house, or remotely at distant sap collection tanks.

Figure 3.  Vacuum pumps draw sap in from the sugar bush into sap storage tanks.  Vacuum pressures (suction) can range from 15 to 26 inches of mercury.  Vacuum collection can double the yield of sap without affecting tree health.  Avoid dangerous situations of electrical shock by having electrical systems inspected and approved by a certified electrician. 

Conservative tapping reminder

Many syrup producers have not tapped their trees yet and are waiting until trees begin to thaw.  Leading maple researchers at Centre ACER Quebec, Cornell University and University of Vermont agree that following conservative tapping will help ensure the long-term sustainability of sugar bushes.

The objective of tapping is to minimize injury to the tree while maximizing the quantity of sap collected.   Proper tapping is particularly important where higher vacuum pressures of 22 to 26 inches of mercury are applied.

Commercial producers and hobbyists using bucket collection or gravity flow sap tube collection can also consider tapping conservatively to minimize injury to the trees.

Figure 4.  A sharp drill bit (left) is important to cut clean tap holes into maple trees to receive the spout.  A sharp bit makes work easier on the operator over a long day of tapping trees.  Carry several tapping bits in a Ziploc bag that have been cleaned and sanitized.  Sugar maple trees are also known as hard maple and can dull drill bits quicker than softer woods (dull bit right).  Drill 1.5 inches, no more than 2 inches deep into sapwood when tapping trees.