The lovely red living phloem of the Mission Manzanita. The non-red parts are heartwood,

In manzanitas and other smooth-bark trees, the bark layer peels away each year. This prevents fungi, parasites, and epiphytes, such as mosses and lichens, from persisting on the tree’s trunk and stems.

According to Sherwin Carlquist, an expert on wood anatomy in California native plants, the rich, reddish coloration of manzanitas—which varies among species from orange to mahogany to dark purple—comes from tannins (and other compounds) manufactured by, and deposited in, the cells of its exterior bark. Tannins are bitter compounds toxic to some organisms; when present in the bark, they most likely serve to deter such organisms (insects, birds, bacteria, etc.) from penetrating the stems and feeding on the tissue within. So the coupling of shedding bark and tannic compounds appears to be an adaptive advantage that discourages stem herbivory.

https://baynature.org/article/why-is-manzanita-bark-so-smooth-and-red/

You can see where there is no living tissue, the lichens have taken hold.

Although I didn't pick up the leaves, this one is the rare Del Mar Manzanita, Arctostaphylos glandulosa ssp. crassifolia. It is of course only rare because both we and it like to live in the same places.