Select Page

The Pacific Madrone (Arbutus menziesii) is perhaps our second most favorite tree growing here (second only to our Coast Redwoods).  Recently, however, we’ve realized our Pacific Madrones are likely the most at risk of disappearing from Curbstone Valley, permanently.

 

Pacific Madrone has prolific displays of red fruit throughout fall and winter

Arbutus menziesii is native to the Pacific coast, ranging from British Columbia, southward to California’s central coast.  This species becomes less common south of Santa Barbara county, but isolated stands can be found as far south as Baja Mexico.

Arbutus, from Latin, means strawberry tree, and was named such by naturalist Archibald Menzies for its red strawberry-like fruits.

The color and texture of individual fruits bear some resemblance to strawberries

The Pacific Madrone is renowned for its crooked beauty. This evergreen tree produces masses of creamy white flowers in the spring, later followed in autumn and winter by a profusion of red berries.  The exfoliating bark in summer is a rich orange-to-red color, often peeling in large sheets.

 

The exfoliating bark and red fruits of Pacific Madrone

The leaves are thick, oval, 7-15 cm long and 4-8 cm broad, and arranged spirally; they are glossy dark green above and a lighter, gray-green beneath.

The flowers are relished by bees, and the berries are favored by birds, especially quail, band-tailed pigeons, and dark-eyed Juncos, of which we have very large populations residing here all year – one of whom loves to admire himself in the side-view mirror of my truck, for hours at a time!  Deer favor young shoot and seedling growth, and as this species is prone to heart rot with age, other wild creatures find shelter in the cavities produced within mature trees.

Pacific Madrone showing exfoliated bark

Native peoples had varied uses for Arbutus menziesii.  The Cowichan and Pomo used an infusion of the bark to treat small wounds and sores, and chewed the leaves to treat sore throats.  The Miwok made a cider that was used to treat stomach ailments, and as an appetite stimulant.  A number of tribes used the berries as food, either raw in small quantities, or they were steamed, dried, and stored for later use. [1]

 

A sheet of exfoliated bark from Pacific Madrone

Arbutus menziesii however has been known to be in decline throughout its range since the late 1960s. [2]

Pacific Madrones are frequently found in association with Douglas Fir, Tanbark Oak, and Redwood, all of which are present on this property.  Our Madrones, however, are primarily restricted to a southern slope above one of the creeks, with a few scattered specimens along the west-facing slope near the main house.  It’s clear that of the few remaining Madrones still growing here that few, if any, could be considered healthy.

 

Branch die-back on a Pacific Madrone

In the last year alone at least four substantial trees have fallen on the south slope, and at least three others can be seen standing, but are clearly dead, completely defoliated.  Of the those that remain, only three have been seen with healthy green canopies, and producing fruit, although they can be difficult to find amidst the over-story growth, as they tend to lean and stretch outward, growing through bay laurels, or oaks, as they reach for light.

As our Madrones clearly aren’t thriving, we wanted to try to find out why.  Until we know what’s killing them, how can we preserve them?  However, the problem clearly is not a simple one.  Apparently there are more than 21 known species of fungus that are associated with disease in Pacific Madrones, although the two most prevalent are reported to be the Arbutus Canker (Nattrassia mangiferae) and Madrone Canker (Fusicoccum aesculi).  Another important culprit is a root rot in mature Madrone trees caused by the fungus Phytophthora cactorum (a fungus in the same genus as Sudden Oak Death).

Dead for some time, the roots of this Madrone are gone, although the rest of the trunk wood is still sound

However, Madrones are also susceptible to Phytophthora ramorum, the causative agent of Sudden Oak Death.  Symptoms of a number of fungal diseases that afflict Pacific Madrones often appear first in the canopy of trees, often beginning at the branch tips, and severe disease can result in die-back of entire branches, ultimately killing the tree.  Unfortunately, infection with Fusicoccum or Phytophthora, without laboratory testing, can be virtually impossible to differentiate, as their observable symptoms overlap.

 

This tree is now completely defoliated

Arbutus menziesii naturally favors growing in dry soils, and in cultivation supplemental irrigation and fertilizer both contribute initially to lush growth, but result in a shortened lifespan.  This is not a good candidate for a lawn or garden tree primarily for that reason.  The Madrones growing here though are in undisturbed naturally forested areas.

Conditions here clearly once favored the growth of this Madrone...

However, Pacific Madrone depends on periodic fire to eliminate or at least significantly reduce the conifer over-story, which enhances both light and air circulation in the understory, permitting Madrones to thrive.  Fires that result in repeated top-kill  of Madrones will encourage burl development in these trees, which in turn enhances Pacific Madrone survival, as the burls nutritionally sustain root-crown sprout growth after fire.  Oak-Pacific Madrone-Douglas-fir and Redwood forests, where Pacific Madrone naturally occurs, historically experienced understory fires at intervals between 5 and 25 years.

...but the extent of moss on this Madrone stump suggest conditions are now too dark, and too damp

The last significant fires in this area though were probably those associated with Redwood logging activities in this region more than a century ago.  Most importantly, as with many California native plant species, fire favors Pacific Madrone seedling establishment. [3]

Pacific Madrone bark with moss

Ironically, in areas managed for conifer timber production today, the Pacific Madrone is considered a “weedy” tree species, because it out-competes replanting of timber species due to its ability to resprout from its burls after disturbance. [4]

So it seems a combination of numerous and pervasive pathogenic fungal diseases, coupled with a century of fire suppression, are at least partially to blame for the decline of Pacific Madrone in this area.

Speaking of seedlings, therein lies our other observation.  Of the trees that have fallen here, and even below the more healthy Madrone specimens still growing here, despite abundant fruit-set each year, we’ve found absolutely no seedling Madrones in the understory growing as replacements.  None.  In fact, the only ‘small’ Madrone we’ve observed here thus far, is this rather sad (and dead) looking ‘Charlie Brown’ specimen near one of the southwestern oriented mountain ridges in the center of the property.

Although now dead, this young Madrone exhibited the classic crooked and contorted architecture this species is known for

It seems clear, here at least, the rate of Pacific Madrone loss is far outpacing the rate of replacement, and with so few Madrones left on this property, we’re wondering how much longer they will continue to grow here.

This Madrone snapped just 5 feet above its roots during our massive October 2009 storm

Apparently Madrone seedling germination rates in the wild are very high (close to 90 percent), not that we’ve ever once seen a seedling in the three years we’ve been here.  So where are they?  The caveat is that mortality of Madrone seedlings is also very high, reportedly between 90-100 percent!  That at least helps to explain why we’re seeing little in the way of understory replacement of Madrones here.

There are no seedlings present to replace this fallen Madrone

Seedlings are commonly killed by a variety of factors, including drought, fungi associated with damping-off, root rot, desiccation during early growth before the seedlings are established, smothering by deep leaf litter, frost heaving, and predation by slugs, and of course our ever-ravenous deer. [5]

 

The over-story canopy has become dense. Unable to compete, two madrones fell here last year

Further digging in the literature revealed that soil disturbance actually favors seedling establishment.  Seedlings and young trees however with their fragile root systems, once sprouted, resent disturbance and are often killed by it.  Studies have shown that seedling establishment is poor in areas with low light, heavy litter-fall, damping-off fungi, and predation on the forest floor.  So it seems, looking critically at where our Pacific Madrones have previously grown, in the absence of fire, and the presence of increasingly dense forest canopies, the conditions that once favored their growth are no longer present in those areas.  Barring a catastrophic alteration of our forest canopies, our ‘hands off’ approach to restoration (except for invasives) could cause the Pacific Madrones growing here to soon disappear.  Perhaps it’s time to reconsider that approach.

Beetle art on Pacific Madrone

It seems clear that trying to re-establish new Madrones where they’ve been growing previously, will likely doom them to failure as the canopies of Douglas Fir and Redwood are too thick, and the litter on the forest floor too deep, and too damp to enable their survival.  Careful forest management, under professional guidance, may be necessary to help maintain suitable growing conditions where our Madrones once grew.

However, last year we removed a number of dead trees, and did open up an area where the orchard and gardens were installed.  Up-slope of this area is drier, and brighter along the south-facing slope, devoid of routine supplemental irrigation, and now protected from deer by the perimeter fencing.  Two somewhat healthier Madrones are growing just outside the fence perimeter up-slope, so this may be our best area at the moment to attempt to establish some young trees, just inside the fence line away from browsing deer.

 

This somewhat healthier Madrone is growing just outside the double fence

Although we could source Pacific Madrones that have been nursery propagated as replacement trees, we’d prefer to try propagating them ourselves.  If we’re successful, we’d expect that plants produced from seed endemic to the property would likely be better adapted to the growing conditions here than a tree sprouted in a nursery in Oregon or Washington.

 

We collect these, and a few other fruits to try propagating a few trees ourselves

The Madrone berries have been abundant this fall, and we should have enough seed to engage in a little trial-and-error survival-of-the-fittest experimental gardening.  I’ve collected some recently fallen berries during my walks around the property, and now need to separate the seed from the fruit, and cold stratify the seeds for 60 days.  At that point the seeds can be sown into a sandy medium, and hopefully at least some will sprout.  For more regarding propagation of this species see this article.  The reality is, at the rate we’re losing these beloved trees, we have little to lose.

Although we’d love to see many more of these trees growing here, for now we’ll be happy if we can succeed in establishing just a few healthy specimens on the property.  It’s going to require a long-term multi-factorial approach, but for now I’m crossing my fingers they’ll sprout, and that by next November we’ll have some young Pacific Madrones ready to transplant back into the woods.  We’ll let you know how that project transpires along the way…

Pacific Madrone

MADRONO

“Where, O where, shall he begin
Who would paint thee, Harlequin?
With thy waxen burnished leaf,
With the branches’ red relief,

With the poly-tinted fruit,
in thy spring or autumn suit, —
Where begin, and O, where end, —
Thou whose charms all art transcend?”

~ Bret Harte

————-

[1] Daniel E. Moerman’s Native American Ethnobotanical Database

[2] Farr DF, Elliott M, Rossman AY, Edmonds RL 2005.  Fusicoccum arbuti sp. nov. causing cankers on pacific madrone in western North America with notes on Fusicoccum dimidiatum, the correct name for Scytalidium dimidiatum and Nattrassia mangiferae.  Mycologia 2005 May-Jun; 97(3): 730-41

[3] USDA Forest Service: Fire Effects Information System (FEIS)

[4] USDA Natural Resources Conservation Service

[5] Tappeiner, John C., II; McDonald, Philip M.; Hughes, Thomas F. 1986. Survival of tanoak (Lithocarpus densiflorus) and Pacific madrone (Arbutus menziesii) seedlings in forests of southwestern Oregon. New Forests. 1: 43-55.