Today I picked a pint of lovely raspberries. My fall crop. They never fail to fruit. Overhead my dogwood turned maroon. A friend brought a bag of her extra tomatoes. Every serious backyard gardener has too many squash and big cucumbers, which are given to neighbors. The fall harvest.

Fall is the season when old societies harvested the gift of food to sustain them through the winter. In earlier times, 90% of the population would be involved in some kind of agriculture. Today only about 2% of the population is engaged in farming. Supposedly though, many more than that are engaged in cooking and serving in restaurants.

Fall is also the time for our most special gift of foliage colors which so delights us here in New England. The trees engage us with their continuous and changing display of yellows, reds and browns.

Each tree variety has a slightly different time when it colors. Some are early like our native dogwoods and sugar and red maples. Some are late like the beech, oak and Japanese red maple, which ends the season in a true blaze of glory. And it is one of my very favorite trees

Leaves turn yellow when no more chlorophyll (green) is manufactured, and the yellow pigment, which is always there, becomes visible. Chlorophyll is manufactured only when there is enough light. That is why plants grown in dark or shady places often have yellowish leaves.

Red color is different. It is caused by a pigment called anthocyanin, which is produced when sugars accumulate in the leaves. In the sun, the leaves manufacture sugar, but on cold nights it can’t easily flow down to the roots, so the anthocyanin is produced. Then the red color appears. Often the sunny side of a tree will have more brilliant color than the shady side.

We have one of the best climates for these displays. The colors are most vivid when days are warm and sunny, but the nights go below 45 degrees. “Peak foliage season” is usually when the sugar and red maples are in full red or orange color, complemented by the yellow birches. When it is too warm or too dry, the colors are dull and the leaves fall sooner.

There is a particular health hint that each fall tree tells us. It a tree color turns much earlier than the others of like genetic variety, it is not well. Or it may be very dry, especially if the leaves curl. Give dry trees a really good watering. Additionally, if one branch colors early, take note. That branch is sickly even if the rest of the tree is OK.

So savor the colors and the harvest, for the golden days of fall pass too soon.

Ruth S. Foster is a landscape consultant and arborist. Gardening info can be found on her website:

Credit: Ruth S. Foster