Madrone trees have glossy, dark green elliptical-shaped leaves. This tree drops some foliage throughout the year. Madrone trees shed leaves most heavily in summer and early fall. The madrone tree also sheds bark in summer and early fall. Even during this time of heavy leaf loss, madrone trees retain some leaves on each branch so no area is completely bare. Rake up the leaves as they fall, or leave them to turn crispy underfoot. Leaves break down and provide a natural mulch layer under the tree.

Pacific madrone (Arbutus menziesii), is native to the Pacific Northwest. It is a member of the Ericaceae plant family which makes it a relative of Rhododendrons, Huckleberry, Salal and Heather. In California they are called Madrona and in Canada, Arbutus. It doesn't follow any of the tree rules. It is broadleaved, yet it is an evergreen. It seems to have no sap, mature wood is hard as steel and like a reptile, it sheds its bark every year as it grows. The tree is a symbiont. They prefer poor soil, don't like to be watered, survive fire and drought, but transplanting will probably kill them. The tree cannot assimilate nutrients through the roots on its own. To survive, it must live symbiotically with a root fungus called a Mycorrhiza. This is why watering, fertilizing and transplanting Madrones put them in jeopardy. If these activities disturb the fungus, the tree will die of starvation.

There are three major groups of diseases that cause problems for Pacific madrone (Arbutus menziesii): foliage diseases, branch dieback and trunk canker diseases, and root diseases. Insects generally are not a serious threat to madrone health. Excessive sap dripping occurs because of inappropriate pruning, mechanical injuries, or canker development.

The other common situation is when people invade an area where madrone is growing. We put in driveways, trenches, home sites. We run over the ground with heavy equipment, backfill over the existing soil surface, then install lawns and water them daily, all of which damage or kill roots. Dense stands of trees are suddenly exposed to full sun, leading to sunscald and bark injury. These impacts may be unavoidable. But the stress on trees is cumulative, and it shouldn’t be a surprise when they decline in health.

Here is a publication to check out:

https://extension.oregonstate.edu/forests/tree-care/whats-wrong-my-madrone

Hope this helps!