Fall is full of important things to do in the garden.

Forget about weeding and such. How about the worthy jobs of looking at autumn leaves and collecting the fallen ones to put in the compost? Or what about drying pumpkin seeds?

Autumn leaves signal the end of the growing season. Their bright colors are the aftereffects of photosynthesis, the process that means “to transform with light.” That is just what happens inside leaf cells as chlorophyll uses the sun’s light to transform water and carbon dioxide into food for the growing plant.

Throughout the summer, green plants produce a continual supply of chlorophyll to keep the transformation going. But when days get shorter and nights get cooler, plants slow their production of chlorophyll. As the amount of chlorophyll declines, the green color of plant leaves starts to fade and other pigments begin to shine through.

One pigment, carotenoids, for example, are found in most green plants, and are necessary for capturing sunlight. When chlorophyll fades, the carotenoids that are left create yellow and sometimes brilliant gold color. We see carotenoids at work in big-leaf maples this time of year.

A second pigment, anthocyanin, is produced in the leaves of only a few kinds of trees. It creates shades ranging from pink to red to purple, as in our native vine maples.

When the colorful pigments finally fade, leaves turn brown from the remaining tannin. Tannins are found in almost all trees, and are especially abundant in Oregon white oak, which keeps its autumn color to a conservative brown.

Weather plays a part in the show of autumn leaves. The most vivid color tends to unfold when autumn days are sunny and nights are cool but above freezing. The red-color anthocyanins are produced in strong light when sugars are trapped in the leaf as stems begin to shut off in preparation to drop. If the weather holds, enough sugars are produced to create brilliant red and orange color in the leaf. Rainy weather blocks warmth and sunshine, and so inhibits sugar production. Leaves fade without much color change. Likewise, early frost can kill leaves, turning them brown.

If you want to plan your own run of fall colors, consider planting Norway maples or tulip trees for yellow and gold color, sugar maples and sweet gums for bright orange and red, and scarlet oak, which is a bit tricky in our damp climate, but provides a brilliant deep red.

Once autumn leaves have fallen, consider breaking them down in your compost before putting them on your garden beds. Leaves are nitrogen-poor but rich in minerals, so most kinds make a great addition to the compost pile.

However, do note that some leaves, including oak and laurel, are especially slow to break down.

Chop the fallen leaves into tinier pieces to hasten the decomposition. If you don’t have a chipper, you can run over the leaves with a mulching lawn mower that has a collection bag. Or shred them, then rake them up.

If you want to store shredded leaves for later, put them in garbage bags or cans. Layer shredded leaves into your compost pile to add air and a carbon source to the pile. This is especially handy in the winter, as compost tends to get matted down and suffer from a shortage of bulk “brown” materials.

Place shredded leaves in the flowerbeds as mulch. They do a great job of building organic matter in the soil and protecting flower bulbs and perennials from hard winter freezes. Don’t wait for autumn rains to do this easy task. Raking, shredding or grinding up dry leaves is much easier than working with sodden matted ones.

Note – do not add walnut leaves to a compost pile, as they contain material that affects the growth of certain other plants.

While you’re checking out the autumn leaves or shredding them up for the compost, you might want to nibble on dried and roasted sunflower or squash seeds.

Food preservation expert Nellie Oehler, family and community development faculty with the Oregon State University Extension Service, recommends the following procedures:

For sunflower seeds, cut the spent flower heads, leaving a stem about one foot long. Hang each of these upside down in a dry location with good air circulation. Tie a cloth bag or a worn out, clean pair of panty hose around each head to catch the seeds, which might drop during drying.

For pumpkin and other winter squash seeds, wash and remove all clinging fiber from the seeds. Pumpkin and winter squash seeds can be dried in a dehydrator at 115 to 120 degrees until crisp or in a warm oven for an hour or two. Stir the seeds frequently until they are crisp.

For seasoned roasted seeds, try mixing two cups of the dry seeds in a bowl with a half-teaspoon of Worcestershire sauce, 11/2 tablespoons melted butter or margarine and a teaspoon of salt. Place the coated seeds in a shallow baking pan and roast in a hot oven at 300 degrees for 10 to 15 minutes or until crisp. Stir the seeds frequently, assuring that all are dry.

Cool the seeds after roasting in a plastic bag or container, removing as much air as possible. For long-term storage, store them in the refrigerator or freezer to prevent rancidity.

Cathy Peterson belongs to the Clatsop County Master Gardener Association. “In the Garden” runs weekly in Coast Weekend. Please send comments and gardening news to “In the Garden,” The Daily Astorian, P.O. Box 210, Astoria, OR 97103 or online to peterson@pacifier.com

Welcome to the world of the Douglas fir forest.

That’s the invitation from a new set of learning cards designed by the Benton County office of the Oregon State University Extension Service.

The 50-card set describes common plants, animals and fungi found in the Douglas fir forests of the Willamette Valley. Photographs, drawings, maps and clearly written descriptions on each laminated card help students get to know the life of the local forests.

Accompanying each set of illustrated field cards is an educator’s guide designed for fourth- through sixth-grade students, and all activities are benchmarked to the Oregon Educational Standards. There are also suggested sites for local field study and supplemental materials helpful for educators.

The set of Douglas Fir Ecology Field Cards is the first in a series that the OSU Extension Benton County office will produce to explore the Willamette Valley’s oak woodlands, prairies, riparian bottomland forest, wetlands and urban habitats.

The Douglas Fir Ecology Field Cards and Educators Guide can be purchased at the OSU Bookstore or ordered for $35, plus $5 for shipping and handling. Contact the Benton County office of the OSU Extension Service, 1849 N.W. Ninth St., Corvallis, OR 97330; telephone (541) 766-6750; or visit the Web site at http://extension.oregonstate.edu/benton