Ontario maple syrup production report for February 8 – 14, 2016

Sugar bush activities

Early in the week, alternating freeze and thaw conditions provided sap flow in southern area maple operations. Producers who completed some or all of the tapping in their sugar bush were able to collect sap. Several producers collected enough sap to complete one or two boils for syrup.

At the end of the week, deep freezing temperatures that are typical for mid-February occurred and will continue into next week, which has stopped sap flow for now in all regions. Frozen conditions will be a relief for many syrup producers who have decided to wait to tap their trees.  Producers will have time to prepare for sap harvest and have the sugar house cleaned and sanitized for processing syrup.

A number of syrup operators report they are still removing downed limbs and fallen trees due to previous windstorm damage and are busy making repairs to vacuum tubing systems before any tapping can begin. Chewing damage to tubing, caused mainly by squirrels is reported higher than normal at some sugar bushes.

Tighten support wires securely to prevent sagging along attached mainlines. Sags in sap tubing or upward slope can cause pooling of sap that can lead to fermentation and mould growth inside tubing, especially as milder sunny weather occurs later in the harvest season.

Shown last summer, a maple producer in the Waterloo region has installed heavy concrete blocks in strategic places in the sugar bush to act as anchor points for tubing support wires, where adequate anchorage is lacking.  Concrete blocks can be a better alternative to using large trees as anchors, to prevent injury to the trees by the tight pull of wires.

Tap trees with the future in mind

Plan for conservative tapping to help sustain the sugar bush for future syrup production.  Deeply frozen trunks can take a few days of milder temperatures to thaw adequately to allow drilling tap holes.  Wait for thawing temperatures to begin or resume tapping.

The photo below shows tap holes installed high within the tapping zone on the trunk, however, tap holes can be placed anywhere in the zone, up to three feet above the lateral collection tube.  Avoid drilling into old tap locations and underlying stain columns, which will persist above and below previous tap locations (see last week’s maple report).

Wait for frozen wood to thaw before drilling taps to prevent splitting of bark.  To help avoid drilling into previous tap holes and underlying non-conducting wood, old tap holes can be colour-coded with tree marking paint when taps are removed in spring (avoid oil based paint or nails).  When positioning a new tap hole, visualize the hidden stain column since you can’t see it through the bark.

Ontario maple colour classes

The province of Ontario has made changes to the maple syrup colour classes.  These regulatory changes came into effect January 1, 2016.  There is a transition period of two years.

Snow cover in the bush is important

Fortunately, many areas that were bare of snow in southern regions of the province have been receiving snowfall this past week to cover the forest floor. In addition to leaf litter, a layer of snow will act as an insulating cover to protect shallow tree roots from freezing damage.  Without adequate snow cover, deep freezing conditions could penetrate to the shallow roots and cause injury.

Roots of trees are far less winter-hardy than the above ground tree components and cannot survive temperatures below – 6 to – 7 ⁰C.  Unlike the trunk, branches and buds, tree roots don’t become dormant but remain in a state of readiness.  Roots can begin to grow whenever the soil temperature rises above zero to +5 ⁰C.  So a good layer of snow will help insulate shallow roots from periods of deep freezing.

Where moisture in the soil freezes, any encased roots will remain in a dormant-like condition until the soil thaws. Roots in frozen soil will not die as long as the surrounding temperature remains above – 6 to – 7 ⁰C.  Fracturing and heaving of frozen soil can cause significant damage to fine tree roots during winters that lack snow cover.

Temperature plunge

A fast plunge of ambient temperature, from relatively mild winter temperatures to deeply frozen temperatures that occurs quickly over a few days, such as the case this past week, will have many operators of commercial tree nurseries, fruit and nut orchards and grape vineyards very nervous about winter freezing injury to trees, shrubs and vines of all ages.

Although dormant, flower buds and vegetative buds can be killed when sudden sharp fluctuations happen.  A gradual drop in temperature over several weeks or months allow trees a chance to adjust to changing ambient conditions, unlike the fast freeze of this past week.  Sugar maple trees in Ontario are known to be very hardy to winter extremes.  We can check dormant maple buds in several weeks to see how maple trees fared this week’s freeze.