The landscape is showing little or no foliage change yet.

With a day off from school and a clear blue sky overhead, I decided to set off this morning on a hike along a section of the Mid-State Trail that would take me over the Crow Hill Ledges in the Leominster State Forest. The trail offers several terrific views, perfect places to enjoy the fall foliage.

Only there wasn’t any. Or not much, anyway. It seemed maybe only 10 percent of the leaves had changed color so far, and they weren’t especially bright, either. This is traditionally the peak period, so what gives?

The short answer is no one knows.

Traditionalists will point out that some years are spectacular, others aren’t. Some years the foliage peaks early, other years later. Some years are too wet. Others are too dry. Mother Nature can be fickle that way.

Phenologists – the scientists who study timing in nature are just beginning to turn their attention to this fall phenomenon. They agree that the quality of a foliage season is dependent on several factors, making it difficult to find any kind of a trend, and to be able to come up with a credible trend requires years of reliable observation and documentation.

Here are a few things they’ve found.

The growing season in the Northern Hemisphere has been extended by 6.5 days between 1982 and 2008. At the Harvard Forest in Petersham, Mass., researchers report that the leaves are changing – on average – three days later than 20 years ago.

So what does this mean?

In part, it fits in with other changes that can be linked with global climate change. It’s also slow and gradual, so it’s not as if our spectacular autumns are gone forever. They just might be a week later than we’re used to.