Acer saccharum Seeds | Sugar Maple
LATIN NAME: Acer saccharum
COMMON NAME: Sugar Maple
Plant Profile
Acer saccharum is the tree that makes maple syrup, and it is also one of the best hardwood timbers in North America. It grows to thirty-five metres in the forest, with a straight trunk and a broad, rounded crown, and it can live for three hundred years. The leaves are five-lobed with shallow sinuses, dark green above and lighter beneath, and they turn yellow, orange and red in October.
The species dominates the northern hardwood forest from Nova Scotia to Minnesota and south along the Appalachians, usually on moist, well-drained slopes with beech, birch and hemlock. It is shade-tolerant and regenerates under a closed canopy, which is why a sugarbush can be worked for generations without replanting. The wood is hard, close-grained and light-coloured, and it is sold as hard maple.
Science & Biotechnology
Sap flow depends on a freeze-thaw cycle that few other trees exploit. In late winter the sap in the trunk is under positive pressure, generated by starch converted to sugar in the wood and by water drawn in from the roots. On a freezing night the gas in the wood contracts and pulls sap in; on a warm day it expands and pushes sap out of any wound. A taphole therefore runs on warm mornings and stops at night.
The sap is about two per cent sucrose, so forty litres are needed for one litre of syrup, and the boiling is an evaporation problem as much as a chemistry one. Sucrose dominates over glucose and fructose, which is unusual among trees and is why maple syrup tastes mild rather than caramelised. The sugar content varies with the tree, the season and the weather, and a warm winter gives a short, poor run.
Uses & Benefits
Syrup and sugar are the main products, and the industry is worth hundreds of millions of dollars in Quebec, Vermont and New York. The wood goes to furniture, flooring, bowling pins, butcher blocks and musical instruments, and the figured grades, bird’s eye and curly, are sold at a premium for veneer.
The tree is also planted as a street and shade tree, though it suffers from road salt and from compacted soil. In medicine the sap was used as a spring tonic and the bark as a cough remedy by several Indigenous nations, and the leaves were used to wrap food for cooking.
Growing from Seed
Seed needs cold and should be sown fresh. Stratify at 4 degrees for three months, then sow at 15 to 20 degrees; germination is in two to four weeks, and the seedlings are slow, reaching twenty centimetres in the first year. The species needs a mycorrhizal partner to grow well, so use soil from under a mature tree where possible.
Plant in deep, moist, well-drained soil with a pH near neutral, in sun or in light shade. The tree is hardy to about minus thirty, but it is sensitive to drought, to salt and to soil compaction, and it should not be planted in a narrow street pit. Protect the trunk from string trimmers, since the bark is thin and wounds invite decay.
Our Take
A forest tree rather than a garden one: grow it for the timber and the autumn colour, and tap it only if you have several mature trunks.
Related Reading
Gardeners who grow Sugar Maple often pair it with these related subjects: