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Growing Sugar Maple Trees in New Zealand

 maple syrup harvest in wood

Ever since I was a little tot I've been fascinated by maple syrup. An aunt in Canada sent me a musical book about a family of bears and their maple syrup jug that played the Little Brown Jug jingle when you turned a handle. The thought that something so sweet and delicious could come out of a tree captured my young imagination. Thirty odd years later I've been doing my own impression of a bear filling my little jug. Thanks to the forethought of New Zealander Dave DeGray, I've been not only able to fill my jug, but a whole bucket of fresh sap from his secluded grove of sugar maple, right here in the coastal Tasman hills.

In 1984, Dave planted the first of 200 sugar maple trees, Acer saccharum, in a sheltered hollow on his 4-hectare property. Thirty years later and the trees are now a towering grove of graceful trunks, reaching upwards of 20 meters and carpeting the earth where 3m high scrub stood with a clean blanket of beautiful leaves.

Now an architectural designer, an early career in the US Forest Service and an active involvement in the NZ Farm Forestry Association fueled Dave’s interest in growing trees for timber, shelter, beauty and food. Obviously a man to take a long-term view of things, he planted the trees as a bit of an experiment and to benefit future generations with the knowledge of how and if sugar maples would be a viable crop for New Zealand. Before his grove was established, the received wisdom was that it could take up to 40 years before sugar maple trees could be tapped, however the remarkable growth rates Dave has achieved in Nelson have shown that some trees can achieve the tappable girth of 25cm within just 20 years.

maple syrup harvest 

Growing Conditions

The trees have not been bothered by any pests or diseases. The sugar maple is a long-lived tree that Dave believes could be tapped for at least 300 years once established. He knows of 160m old trees in India with a girth of over 1.5m. More of that long-term thinking led him to expound the idea of starting plantings of them now along suitable public land for inhabitants of future centuries to reap the benefit of. And before they are of a size to tap for syrup, they would indeed make a beautiful amenity tree. In autumn the grove glows with golden foliage clinging to the stately upright trees. The timber is also highly valued for its strength and resilience, being used in bowling alleys. You can see why the Canadians put the maple leaf on their flag.

Maple trees need good drainage, moisture levels, and reliable cold winters to produce well. The trees are harvested for sap in winter when the onset of frosts concentrate the sugars in the sap and the freezing action forces the sap to flow upwards from the roots during the warmth of the day. Dave has noticed the effects of climate change on the harvests from his grove over the last 30 years. "It used to be that we had good reliable frosts from the end of May through till September during the 80's but now the good frosts are often not happening until mid-June." If he was planting again now he would consider areas further south with good rainfall and more reliable frosts.

In the early years, the lower branches were pruned off in early summer to create straight tappable trunks and an open forest floor for ease of access. Apart from this initial pruning and leaf mulch, the grove has not received any fertilizers or irrigation.

maple syrup plastic bottle 

Harvesting Maple Syrup

Dave regards the tapping of the trees as part art and part science. Knowing when to tap is a judgment each winter based on the arrival of the frosts and weather conditions. Cold nights and warm days are the best to get the sap flowing. The sap flows fastest during the warmth of the day after a cold night. Traditionally on small homestead sugaring operations, metal buckets were hung on hooks from each tree but Dave’s son designed an ingenious stainless steel tap that plastic bottles are fitted to. On first sight, the grove of trunks fitted with taps and plastic bottles looks like an installation in a modern sculpture park.

When I joined the harvest, Dave had the help of visiting Canadian, Elizabeth Régnier, who was fascinated by the potential for sugar maple growing in New Zealand and was keen to help document the harvest. Elizabeth’s interest in the little grove in Tasman is proof that Dave's planting experiment is generating more than a little sweet syrup for the pancakes, it is delivering information that future farm foresters and environmentalists are finding value in. With much of the North American maple syrup harvest being damaged by acid rain, the purity of maple syrup in New Zealand is of increasing interest.

cooking down the maple syrup 

Processing Maple Syrup

Collecting the sap is just the first part of the process. The raw sap is a clear and slightly sweet liquid with a brix measurement of around 3%. To get to a finished syrup with a brix of 66.5% there is a lot of reduction to do. For every 30 parts of sap you will produce 1 part of finished syrup, and you do this by gently evaporating the sap in shallow pans over heat. Although it takes a while, sitting around pans of steaming syrup on top of a roaring fire is a not a bad way to pass winter evenings.

The sap slowly takes on subtle golden hues to become a light caramel color as it transforms into syrup. Scum that rises to the surface is skimmed off. The lighter in color the sap is, the better the quality of the syrup. It reaches boiling point at 106°C (about 228 degrees Fahrenheit) and is pasteurized at this point but needs to be kept in a sterile container and refrigerated or it will go off. When the temperature of the syrup gets close to boiling point it is a good idea to transfer the large shallow pans into saucepans to finish the syrup on the stove where it can be monitored more closely. It can quite quickly turn to maple candy if you let it get too hot. When cold, any sediment or “sugar sand” can be strained off.

Next week I’ll share some of the best recipes I’ve found to use the finished product.

maple syrup harvest

Photo courtesy Country Trading Co.