Some possible reasons:
) The sugar levels in Acer s. varies widely by genotype, so genetics may play a part.
) The sugar comes from starches that accumulated in the summer previous and are converted to sucrose in the late fall & winter. The enzymatic activity that is involved with this conversion increases in a linear relationship with temps as they fall (more cold = more sugar).
) I'm not sure how your temperatures vary in spring, but sap runs depend on freeze thaw cycles. Runs occur when night temperatures are below freezing and day temps are above freezing. Runs stop as long as temperatures remain either above or below freezing and stop altogether when night temps no longer drop below freezing.

Perhaps you'll find some clues in the above?

Al

Further to tapla's comments.
The best sap does come from >32ºF days & 60ºF) for a period of a few days, the sap becomes too bitter for syrup.

The industry works well in the NE because there is a clearly defined season of optimal production. In NC, there is too much climatic variability to make a viable industry of it and makes it difficult for the hobbiest to string together enough good sap production days to produce enough syrup/tree to justify the effort.

Simon

All of the information makes sense, but it also tells me that, if the weather conditions are conducive, I could tap a tree or two for sap collecting as a demo for kids. Perhaps not this winter since we're having spring-like temps, but at some point. In other words, it is possible.

Thanks.

When I was a kid in northwestern Pennsylvania, there was a sugar maple at the playground. Every year, one of the teachers stuck a tap into it to collect sap for a maple syrup experiment, and we'd spend all recess waiting in line with paper Dixie cups to drink the sap straight out of the tree.

This does not have to be an involved process.

Mad gallica: that's exactly what I needed to know. I knew it could be done!!