Many families set up a tree in their homes as part of their holiday celebrations. In doing so, they continue a tradition that predates Christianity.

To celebrate the winter solstice, early people used evergreen boughs or entire trees in rites intended to secure protection of their homes and the promise of spring.

The earliest record of a cut and decorated Christmas tree is a diary from 1605 that describes a fir tree in Strasbourg, Germany, hung with paper roses, apples, candies and cookies.

One of the first “Christmas trees” in the United States was a wooden pyramid covered with evergreen boughs that was decorated by children in a German church settlement at Bethlehem, Pa., on Christmas Day, 1747.

Since then, the use of a tree as part of the Christmas holiday celebration in the United States has grown — today, more than 30 million cut trees are bought every year. Though at one time all Christmas trees were wild trees, almost all trees sold today are raised in farms where they are planted and grown for six to 12 years for harvest as Christmas trees.

When choosing your tree, look for indicators of age and deterioration, such as excessive needle loss, a musty odor, discolored foliage, brittle needles or wrinkled bark. When in doubt about the freshness of a tree, choose another one. If none of the trees on the lot look fresh, go to another lot.

When you find your tree, ask the lot proprietor to cut two inches or so off the trunk. If the seller is unable to do so, you will need to do it yourself. This allows the trunk to take up water.

The tree will be very thirsty at first, tapering off a little after a few days. Always keep water in your tree’s reservoir, and you should have a green tree to take you through the holidays.

Tracy offers curbside tree pickup after the holidays. Please take advantage of this free service — your old tree will be recycled and put to good use.

• UC Certified Master Gardeners are available to answer your gardening questions from 9 a.m. to noon Tuesdays, Wednesdays and Thursdays at 953-6112. Questions for Heather Hamilton can be submitted to ucmastergardener@gmail.com.