Indicating Past Fires

I’m chopping firewood and remembering all the old native Pacific madron trees (Arbutus menziesii) that used to grace pockets of the forest around my house. The trees rarely occur in pure stands. Some had trunks three feet or more in diameter at breast height (DBH). (I don't know who's breast.) Over the past 22 years all but a handful have died a natural death and were resurrected as firewood.

At only 80-100 years, these are so short-lived trees compared to the mixed coastal oak (Quercus agrifolia), Douglas-fir (Pseudotsuga menziesii), tanoak (Lithocarpus densiflorus), the California coast redwood (Sequoia semperviren) – with a DBH of 8-25 feet - and California bay trees (Umbellularia californica) in “my” forest. This is because the madrone, while drought resistant, is a colonizer of fire-scorched earth. They are among some of the first trees to sprout after a fire. It is said the seeds need fire to germinate. (However, most germination in nurseries is done by freezing the seed before planting in flats or tree tubes.) These trees at first grow more rapidly than the Douglas fir trees associated with a more mature forest. They help to stabilize the soil. Eventually the Douglas fir trees grow above the madrones and shade them to death.

To maintain madrone in a mixed Douglas fir, oak, and redwood forest, the tree needs fire. Not a firestorm in the tops of mature trees, but frequent fires about every five to 50 years. Pacific madrone depends, on these periodic fires to eliminate or greatly reduce the beginning of a Douglas fir overstory.

However, the forest here hasn’t burned in over 100 years. (A 1/2-acre fire last week a mere two miles from my house was quickly extinguished. What a close call and a relief!) The amount of “kindling” (dead trees and shrubs as well as the invasion of foreigners along parts of the forest’s edge like Scotch broom (Cytisus scoparius), which act like little balls of standing gasoline because they burn so easily and hot) on the ground is tremendous. When the next fire comes the burning grasses or Scotch broom will leap up the trunks of the trees to form a crown, or canopy, firestorm. Nothing, except the noble redwoods, will be left. Including my house.

This photo is of one of the few Pacific madrone trees left on the property as it snakes toward sunlight from beneath the maturing Douglas fir trees.

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Taproot Myths Revealed

This is a photograph of a young tan-oak seedling, sometimes called tanbark trees as their bark was stripped off and used to tan animal hides. These trees used to be classified as a species of Quercus (oak), now reclassified by botanists with time on their hands as Lithocarpus densiflorus. Don’t ask me why. This seedling has a stem with a few leaves five inches above ground and seven inches of a taproot, all I could dig out. (Click on the photo to see a much larger image.)

In my book, Roots Demystified, change your gardening habits to help roots thrive, I talk about how few trees actually grow with taproots. Oaks are an exception, for awhile.

Some Californian and western oak trees (including the tanbark oak), begin growing with a taproot, which then naturally atrophies. The loss of the taproot can begin as early as the first or second season. When the young seedling of a blue oak is a mere three inches high the taproot can already extend 40 inches into the soil. After a number of years, the taproot withers, to be replaced by heart roots (which angle down from the base of the tree) and many laterals, with vertical sinker roots. In Spruce (Picea spp.), Hemlock (Tsuga spp.) and Cedar (Cedrus spp.) trees, at less than eight years, the lateral and oblique roots take over the role of support and the taproot declines. (From: “Natural Root Forms of Western Conifers”, S. Eis; From: Proceedings of the Root Form of Planted Trees Symposium, page 24, 1978.) After the taproot atrophies, the new root system grows more horizontal and oblique roots and resembles a fibrous root system.

In my photograph the roots are about as long as the stem and leaves. However, much of the tiny taproot was left in the ground judging by the thickness of the bottom of this seedling as it was dug with a spading fork. The seedling sprouted in deep shade which probably accounts for the extended length of the stem.

Any oak planted from any container or balled-and-burlapped stock has effectively had its taproot destroyed and forms a fibrous (heart roots) root system.

I think the sturdiest oaks are grown like nature, from seed placed where you want a specimen for your grandchildren to climb on.


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A SOD Story, attachment to "my" forest.

Not the loss of lawns, which I can easily get over. But Sudden Oak Death syndrome (SOD).

SOD is decimating “my” forest. This alien disease first appeared in Marin county—the county just south of me—in 1995, although some say it may have been here since the mid ‘80s. It is caused by the water mold disease called Phytophthora ramorum.

The devastation of the tan oak along this ridge is enormous. As I drive home, the last three miles of the forest reveal hundreds of small and large dead and dying trees—some as high as 30 feet. It looks like a botanical firebombing. The dead trees stand out because they don’t loose their dead leaves for years, if not a decade or more. These sentinels are possibly a harbinger of things to come. SOD is decimating “my” forest. 

(A list of potential native host plants is at the end of this blog.)

Already the California bay laurel on this property is looking pretty shaggy and there is die-back on some of the limbs. Tan oaks and California bay tress make up 80% of the trees surrounding my house. Some say “this may merely be one of nature’s ‘house cleanings,’ removing genetically weak or damaged trees and leaving the healthier, stronger ones to produce better, sturdier offspring.” Well, I’m looking at a dead 40-foot high by 50 wide dead tan oak tree just 40 feet from my office and it’s not a pretty picture. I keep telling myself it wouldn’t be so bad if the leaves would fall off so the tree doesn’t look so miserable. But I still resent the death of these trees. These trees may follow the way of the elms that once graced so many yards and streets and the chestnuts that once were the major forest tree in the Eastern woodlands. But I hate it when it’s happening in my forest.

There will be a cascading effect on plants and animals as these trees die in greater numbers. As an example, the acorn woodpecker makes good use of the nuts from this tree. Squirrels nest in it. More than 300 species of animals; including 170 species of birds, 80 or more mammals and 60 varieties of amphibians and reptiles, and more than 5,000 insects make a home out of the habitats provided by the coastal live oak and tan oak trees, according to Bill Tietje, a natural resources specialist with the University of California Cooperative Extension. An acre of oak woodlands can have 10 to 100 million individual invertebrates which help to digest the decomposing oak parts to recycle nutrients for new growth. In the words of John Muir, “When we try to pick out anything by itself, we find it hitched to everything else in the universe.”

The death of tan oaks has been a great struggle at learning how to be unattached to the flow of nature (and mankind for that matter.) Sometimes as I drive home I simply gaze in a way that seems to selectively block out the view of the brown-leaved ghosts of the oak. I use to return from a trip out of state or the country and wonder in amazement at why I went somewhere else when it’s so beautiful here. Now when I return, I’m shocked at the death in the forest that I’ve forgotten about when I traveled. The forest may not cry, but I do. 

The ecological changes that happen will be slow and I probably won’t see the recovery or replacement of this wonderful tree in my lifetime. So the tragedy seems so personal. I am only one piece of the ecology but a very selfish one that doesn’t want to witness the slow demise or partial downfall of this tree that was here long before me. I just can’t let go.


This is the list of those trees and plants known to be host plants for the disease in California.

Scientific Name Common Name(s)
N= Native, MH = Grows around my house.

Acer macrophyllum Bigleaf maple - N
Adiantum aleuticum Western maidenhair fern - N
Adiantum jordanii California maidenhair fern - N
Aesculus californica California buckeye - N, MH
Arbutus menziesii Madrone - N, MH
Arctostaphylos manzanita Manzanita - N. MH
Rhamnus californica California coffeeberry - N
Heteromeles arbutifolia Toyon - N
Lithocarpus densiflorus Tanoak – N, MH
Lonicera hispidula California honeysuckle – N, MH
Pseudotsuga menziesii var.
menziesii & all nursery
grown P. menziesii Douglas fir - N, MH
Quercus agrifolia Coast live oak - N, MH
Quercus chrysolepis Canyon live oak - N
Quercus kelloggii California black oak - N
Quercus parvula var. shrevei
& all nursery grown Q. parvula Shreve’s oak - N
Sequoia sempervirens Coast redwood - N, MH
Trientalis latifolia Western starflower - N
Umbellularia californica CA bay laurel, Oregon myrtle – N, MH
Vaccinium ovatum Evergreen huckleberry - N, MH


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Note: I somehow lost the usual section "Post a comment". To leave a comment, simply click on the area/button that says "___ Comments". Clicking on the title of a Post under "Blog Archive" also gets you to a view that gives the option of leaving a comment. I hope to figure this out soon. Robert

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