Excessive pitch can sometimes be a sign of insect infestation. You might want to have a closer look for crawly critters .. jmho

The sap-sucking insects that cause sap to flow are not a problem in a healthy tree. In fact, the sap is a defense mechanism against those insects, and is a sign of a healthy plant. Look for other signs of declining health before you panic. These signs include - shedding bark, excessive cone production, shedding needles, thatch ants climbing the trunk, white fuzzy coating on the needles, mushrooms (conchs) growing on the bark, dropping whole branches, and lack of 'growth fissures' on the trunk. Growth fissures on Douglas-fir trunks appear as vertical cracks in the outer layer of bark, and the interior zone of the crack is a ruddy red, giving the appearance of stripes. If the fissures don't have a vibrantly colored zone of new bark in the interior of the fissure, then the tree is not growing. If you have any doubt about the health of a tree on your property, call the Master Gardener's Association or County Extension Office. Sometimes they know arborists that will give a free tree health assesment. Make sure they are ISA-certified. If you call a tree removal service, they might not be certified arborists, and remember that they only make money if they cut your trees down. I've included a link below for the International Society of Arboriculture where you can verify that an arborist is certified.

Sap (and pollen) from Douglas-firs is a fact of life in the Pacific Northwest. Use bug and tar remover to remove the sap from the car. And, when the Douglas-firs are producing pollen (watch the allergen alert websites), make sure you wash the car really well because the pollen is high in sugar, and fungus grows on it. If there's a green layer on your car paint, it's the fungus, and it can harm the paint finish on your car if you don't get it off.

Here is a link that might be useful: International Society of Arboriculture

Thanks so much for your thoughtful reply. I contacted the tree service that we use and they suggested they could prune off the ends of branches to remove many of the cones. Not helpful. This tree is 4 feet in diameter, 80 to 100 feet high! It has some dead twiggy branches on it high up. Three years ago we built a small wall in front of it and I think DH and the helpers cut through a large root and I am afraid that they damaged the tree. There are some woodpecker holes drilled into the trunk but it looks quite good.

Yes, you don't want to be cutting or filling under trees you want to be sure to keep healthy.

Yeah, naughty naughty you, Dotty!

But seriously, if you are concerned, bejoy seemed to give some good advice, though in my experience, it takes a heck of a wallop to severely disturb Doug firs, they are pretty robust around here.