Torreya californica (California Torreya)

by Connie Barlow
(original page 2005; latest update 2022)

WIKIPEDIA: Torreya californica


  

The Santa Cruz Mountains are home to the biggest Torreya trees in North America.

ABOVE LEFT: Connie Barlow with STATE CHAMPION Torreya californica in 2005 (near Swanton).

ABOVE RIGHT: Jonathan Walton photographed this grove along a road above Los Gatos. He reports that the largest of all dozen stems visible is 72 inches in circumference. "They are growing on a rather dry site with poison oak, California bay (laurel), madrone, Douglas-fir, and coast live oak. No redwoods in this area."
_____

CHAMPION DIES; NEW CHAMPION NAMED IN 2014: The new champion (photos below) is not as big in circumference as the old (and Barlow suspects that the old champion was a merged set of 2 or 3 basal sprouts), but the new champion is healthy and has an extraordinary height of 105 feet! It is accessible via the Skyline-to-the-Sea Trail at Rancho del Oso, in Big Basin Redwoods State Park, which is near the coast north of Santa Cruz.

 

FOUR PHOTOS OF NEW CHAMPION BELOW (some photos are by Brian Kelly).

 


TABLE OF TOPICS

INTRODUCTION: Report, photos, and interpretations of 2005 SITE VISITS

Narrated VIDEO by Connie Barlow of photos taken in 2005

GROWTH HABITS of Genus Torreya in North America

PHOTO-ESSAY: Wide Range of Adaptive Growth Forms

(1) MULTI-STEMMED adaptations for shaded or steep habitats

(2) A profusion of BASAL SPROUTS for keeping the ROOTS alive

(3) BASAL SPROUTS from stump or root crown can REGROW a tree

(4) LOGGING the redwood canopy inadvertently helped the torreyas

(5) ABILITY TO LEAN without breaking or falling

(6) SLOW GROWTH and bark texture invite MOSS covering

(7) How MOSSES ACIDIFY Trees

(8) Torreyas search for light gaps HORIZONTALLY

(9) Shade v. Sun LEAF FORM adaptations

(10) Torreyas excel within BOULDER fields (and along ROADS)

PURPOSE of 2005 Site Visits

SITE-SPECIFIC PHOTOS and informational webpages

SUMMARY OF RESULTS from the 2005 Site Visits

Extracts from OTHER WEB PAGES on California Torreya

ASIAN TORREYA information



INTRODUCTION: Report, photos, and interpretations of 2005 site visits
to wild California Torreya (by Connie Barlow)

The map below uses green dots to mark the disjunct populations of California Torreya in the wild. All natural sites are in mountainous terrain, which affords this narrowly dispersed ancient conifer opportunities to track suitable microclimates by shifting altitude and local topography, along with shifts between northerly (cool) and southerly (warm) slope aspects or deep ravines and canyons while remaining on the same mountain. Short distance adjustments are crucial for this genus, as squirrels and humans seem to be the most active agents for seed dispersal.

  • MAY AND JUNE 2005, I, Connie Barlow, (webmaster of this site and proponent of "rewilding" the endangered Florida torreya to the Appalachian Mountains) visited 4 distinct regions in which the California species of genus Torreya grows in the wild.

The map shows 2 sites in the Coast Range and 2 sites on the west slope of the Sierras.

My aim in 2005 was to observe California torreya trees in their wild habitats in order to provide guidance for volunteer planters of the Torreya species native to the eastern USA: Florida torreya.

Through photos, commentary, and video summary, those site visits help planters of Florida Torreya discern habitat preferences of the genus and thus pinpoint similar environments in eastern states for planting seeds and seedlings.

NOTE ON FLORIDA TORREYA: Because Florida torreya was left behind in its peak glacial refuge, Holocene warming had already restricted the species to cool ravines alongside the only river that drains the southern Appalachians through Florida on its way to the Gulf of Mexico. By mid 20th century, human-caused additional warming had made this species of Torreya so vulnerable to native diseases that reproduction halted. In 1986, the Florida torreya was listed as critically endangered. In contrast, because California Torreya did not have to leave its preferred mountain habitats during the Ice Age, it is not (yet) facing extinction. But with continued climate warming, it too may need human "assisted migration" in moving poleward.


Narrated VIDEO by Connie Barlow of photos taken in 2005
during site visits to California Torreya trees

In 2018, I assembled my 2005 photos, along with relevant maps and other information into a 2-part video series, posted on youtube. My aim was to help other volunteer planters (and the officials implementing the Endangered Species Recovery Plan for Florida torreya) to "see" what this genus is capable of and its range of preferred habitats, such that the Florida species can be offered the best prospects for human-assisted migration poleward of its peak glacial refuge in northern Florida.

 

Part 1 (25 minutes)                                Part 2 (27 minutes)


Growth Habits of Genus Torreya in North America

Two early contributors to professional field studies of Florida torreya, Torreya taxifolia, were Mark Schwartz and Sharon Hermann. In 1999 they published a paper on their study of California torreya, Torreya californica, in the field: "Is Slow Growth of the Endangered Torreya taxifolia (Arn.) Normal?", Journal of the Torrey Botanical Society. Their final paragraph:

In aggregate, the results of this work suggest that the observed low growth rates of T. taxifolia might not be indicative of disease-induced stress. The similarity between T. taxifolia and T. californica growth rates and patterns is consistent with the hypothesis that T. taxifolia is growing normally within its environment. The infrequent expansion of terminal buds may simply be the way that these trees naturally grow in low light environments. Evidence of suppression and release growth pattern in tree rings, along with a preliminary observation that trees in high light environments grow more frequently than those in low light, support the hypothesis that growth in T. taxifolia is light limited. Given the continued lack of an identified primary disease agent, we recommend pursuing further tests of the light limitation hypothesis, and management to increase light levels above extant trees in the wild.
BARLOW COMMENT: This is a helpful paper. My own natural history observations in 2005 (at a greater number and diversity of sites than the quantitatively driven experimental approach undertaken by Schwartz and Hermann) would add two interpretations:
(1) Genus Torreya evolved as a definitive subcanopy species (as are other members of the yew family, Taxaceae). With the assistance of arbuscular mycorrhizae (and perhaps receiving photosynthates from canopy trees via the fungal network) it is capable of living a very long time in a seemingly stunted state, until a canopy opening enables growth and eventually also seed production on the individual branches that can access sufficient sunlight.

(2) With rare exceptions, Torreya seems to do best on extremely steep slopes, where the usual canopy giants (Coast Redwoods, Douglas-fir, various pines) are either not found or cannot sustain many years of growth before falling. Exceptions occur wherever a torreya happens to be growing when a road is excavated right alongside, thus releasing it into sun. As well, natural boulder fields (or boulders resulting from mountainous road excavations) with patches of soil too shaded for canopy species to establish offer opportunities for torreya to grow unimpeded by an overstory.

See my interpretive PHOTO ESSAY, which follows.


PHOTO ESSAY: Wide Range of Adaptive Growth Forms

(1) Multi-stemmed adaptations for shaded or steep habitats

ABOVE LEFT: Torreya on a steep slope of a narrow canyon, beneath redwood and Douglas-fir canopy, shows a steady multi-generational sequence of basal sprouting and regrowth. (Coast range NW of Napa Valley, 2005)

ABOVE RIGHT: This old torreya is growing on a very steep slope. Long ago it sent up a basal sprout to access additional sunlight. (Santa Cruz mountains, Scott Creek, 2005)

ABOVE: Two examples of triple-stemmed torreyas at Sequoia Kings Canyon National Park. The photo at right shows the beginning of an extremely steep fall-off into a sunny canyon — which this torreya has accessed for its superb growth. (Harold Wood in photo by Connie Barlow, 2005)

ABOVE: Look carefully at this Christmas-tree-form of a young torreya along a road winding upslope in Yosemite National Park. There are multiple leaders (probably from a total of at least 6 basal stems) producing dense growth in response to this secure patch of sunlight.


(2) A profusion of basal sprouts for keeping the roots alive

ABOVE: Fires northwest of Napa Valley (left) and north of Santa Cruz (right) show profusions of basal sprouts emerging from torreya root crowns in the full-sun habitats. The tree's purpose for a multi-leader flush has nothing to do with shooting up into a now-open canopy. Rather, the purpose is to quickly maximize sunlight-capturing leaves in order to send photysynthates to the vast root system unharmed by the fire. Those roots would otherwise die of starvation. Hence, the above-ground regrowth may seem stalled into shrub form, but this is overall a superb evolutionary adaptation.

ABOVE LEFT: This fallen torreya log shows charring on the left. The two chunks of charcoal Barlow pulled out from underneath. A few seedlings are struggling in deep shade nearby (a flash camera made this photo). But a few tens of meters across this deep ravine to the opposite side is where numerous multi-age regrowth and fresh seedlings/saplings abound. (Coast Range, Diamond Mountain, near Calistoga, northwest of Napa Valley)

ABOVE RIGHT: Elsewhere in the same ravine are several big redwood stumps (timber harvest), with canopy tree replacements also entailing Douglas-fir and tanoak. In this photo, the green-needled specimen is torreya. The brown-needled branchlet is Coast Redwood, with a drought-resistant string-like form to its right (which is typical of the high branch-tip regions of this canopy giant). The conifer cone is an old Douglas-fir that has lost the delicate 3-tip bract on each scale. The hairy "acorn" seed cap downward from the cone is the cap not of an oak seed but of a tanoak, genus Notholithocarpus, whose seed was (and is) a much valued food by Indigenous peoples.

 
Baseline Documentation for
Assessing Fire Resilience

PHOTO LEFT: Connie Barlow in Sequoia National Park in 2005 with a 2-stemmed torreya on a steep slope.

This photo can serve as BASELINE DOCUMENTATION for assessing whether variously aged torreyas can survive (or resprout) after severe fire.

Autumn 2021, the KNP Complex fires that killed many ancient sequoias also burned in this area.

By 2023, it should be evident on a return visit whether (and which) torreyas survived and/or resprouted from its base.

PHOTO DETAILS: Notice that torreya self-prunes lower branches that are shaded by its own extending canopy. Several young seedlings and saplings are visible near right. About 50 feet to the left is the big triple-stem torreya pictured earlier on this page.


(3) Basal sprouts from stump or root crown can regrow a tree

ABOVE: A giant Coast Redwood is reborn in just a few centuries when its replacement basal sprouts grow to sizes large enough to merge. (Prairie Creek State Park, CA, 2020 photo by Connie Barlow)

ABOVE: Two examples of redwood basal regrowth following logging of the original tree. A side of the original stump is visible in the photo at right. In general, a "fairy ring" demarcates a circumferance just a bit larger than the original old-growth giant. (Photos along Freshwater Creek inland from Eureka, by Connie Barlow, 2019)

ABOVE: Coast Redwoods are no longer abundant in the Scott Creek valley bottom where the Torreya giants are found. These two redwoods have interesting stories:

ABOVE LEFT: A "fairy ring" of basal resprouts rises from the stump of what would have been an immense original redwood. It seems that the ancient conifer genera (or their immediate ancestors) that survived mass extinctions (including the one that demolished the dinosaurs) shared a number of tricks to survive difficult times. Resprouting from the basal crown and lignotuber (but not the roots) is a skill shared by Coast Redwoods and torreyas.

ABOVE RIGHT: Lee Klinger stands on the old narrow-gauge railroad right-of-way that had been excavated on the first topographic bench above the current floodplain of Scott Creek. This was the only intact giant redwood we encountered during our entire on-foot exploration. It was obvious why the tree had not been cut: Not far above the top of this photo, an old injury had disfigured the usual perfect redwood stem form. As well, then as now, timber operators sometimes leave intact edge-side trees to prevent the logging road or rail from eroding on a slope.
     This section of Scott Creek was
scalped of its redwoods within a few years following the 1906 San Francisco earthquake that destroyed wooden buildings in the resultant fires. Coast redwoods grow enormously fast; so this individual would have been half its present diameter when the loggers came through. What was bad news for the redwoods became an extraordinary gift for the torreyas: suddenly, they had all the sun to themselves.


(4) Logging the redwood canopy inadvertently helped the torreyas

ABOVE: Lee Klinger is standing by a large Torreya, beyond a multi-stemmed Bay Laurel growing out of an old lignotuber. (The bay tree is amplified in size by the telephoto lens.) Although the Torreya has dead, moss-covered lower branches, its tall canopy looked healthy from a distance. Because it is vertical (not leaning), it probably was only a seedling or sapling in the early 20th century when the redwoods were harvested.

ABOVE: This is the second biggest torreya that Lee and Connie encountered along Scott Creek. They measured a circumference of 125 inches, and Lee estimated its height as 80 feet. Moreover, as evident in the upward view at the right (and also the view from the road directly below), it has a very healthy canopy in full sun.

ABOVE LEFT: View from the road of the torreya pictured in the two previous photos. Observe that its apparently unimpeded full sun habitat during its life has given this tree the same verticality and conical form as a typical conifer tree in full sun. Torreya varies from this standard conifer form only as shade demands it — and torreya's inability to compete with the fast-growing canopy trees usually does force alterations in its form and stature.

ABOVE RIGHT: Clinging to the downslope of the old railraod grade, here is another torreya whose form and canopy fullness suggests an unimpeded history of full-sun upward growth. These tall, vertical specimens are the inadvertent beneficiaries of redwood logging a century earlier.

ABOVE: Connie photographed these two large torreyas while standing on the road. The vertical tree (yes, we did obtain permission from Cal Poly to explore the property) suggests a history of full sun growth. As well, the road has enabled this tree to maintain low, leafy branches on this side, rather than self-pruning during its skyward journey.
    The leaning tree has a smaller diameter and thus probably grew from a seed decades later, and thus spent its early years probing horizontally for a patch of sun away from its older companion. Notice the young vertical stem emanating from the main trunk perhaps 5 feet above the ground. Its thickness and vigor indicate that it has accessed sunlight.

   The century ago REDWOOD LOGGING along Scott's Creek watershed north of Santa Cruz is discussed by Connie (with photos) at timecode 19:08 of the video at left.


(5) Ability to lean without breaking or falling

A clue that torreyas are strong contenders at a young age in subcanopy shade is the number of tall trees that are leaning — including the current national champion (as of 2014) and the slowly dying champion that I (Connie Barlow) visited in 2005.

ABOVE: Seen from particular camera positions, the late-champion (left) and the current champion (right) both reveal that they began their life journeys for many years leaning outward from canopy shading.

ABOVE LEFT: Another leaning view of the previous champion Torreya in the Santa Cruz Mountains (along Scott Creek). In 2005 Connie Barlow took this photo of Lee Klinger, founder of Sudden Oak Life in California.

ABOVE RIGHT: The mid-section of the late champion branched into 3 main stems. Take another look at the top of the above left photo: Do you see signs of multiple stems beginning there — and perhaps all the way to the base? And does this suggest that the tree may actually be the result of two or more merged basal regrowths? • In 2012 Stephen A. Garland contributed a photograph he had taken in Mariposa County of a pair of large sibling stems that had indeed begun to fuse together. Click to view the photograph and caption of documentation of early-stage basals fusing.

In contrast, Frank Callahan reported:

• 3 January 2016 email from Frank Callahan: Email from Steve Auten and National Champion nomination by Frank Callahan (1992). The critical measurements are: just under 21' in circumference @ 4.5" - 96' tall - crown spread = 68' - Total points = 364. Steve Auten reports the age from this single trunk tree to be 230-250 years old, however the center 12" is rotten.

• 15 December 2016 email from Frank Callahan: "Here is the data on the former National Champion Torreya californica at Swanton. It was just one tree not conjoined trunks! This is not an old tree: probably 250 years, considering the rotten center." Frank's email contained a string of emails among Steve Auten (Ranch Operations Manager, Swanton Pacific Ranch, College of Agriculture, Cal Poly State University), Jim West, and others. Auten reported in an email to Frank dated 15 March 2016: "We did cut the Torreya. It was one tree [not 2 stems]. Varied fire damage with rotten center. Rotten diameter is approximately 12 inches. Aged at approximately 250 and 230 years on two different counts (does not include any estimation of rotten center). Due to fire damage and compression/tension issues, the three rounds we cut broke into smaller sections."

MORE DELIBERATION IS NEEDED: Barlow suggests that the 12 inches of rotten core might have been where the basal merging could have been detected.


(6) Slow growth and bark texture invite moss covering

While exploring the Scott Creek giant torreyas in 2005, Lee Klinger educated Connie about the acidic dangers of rain seeping through mossy tree bark.

  ABOVE: Look again at the top of the previous champion in the photo directly above. Notice so much moss covering the bark.

LEFT: Here is the mid-section of the dying champion along Scott Creek. This is where the canopy stem distinctions divide.

Might this growth form have made it easier for rainwater made acidic while seeping downward through the moss to penetrate inward, along the old sutures of the several melded trunks?

Is this what doomed the tree?

ABOVE: Close-ups of the moss-bark intersections of the dying champion at Scott Creek.

Observe how the moss-covered living bark has bulged over a long barkless section of the lower trunk. The patch of orange in photo left reveals a section of the living bark.

But the PHOTO RIGHT shows a close-up of that patch. A severe crack has developed; and thus dooms the tree to yet another locus of fungal entry.


(7) How mosses acidify trees

  As of 2022, Lee Klinger is still using lime and other minerals to reverse California's epidemic of "sudden oak death". His business name: Sudden Oak Life. He desribes this practice as "fire mimicry" because it results in renewed health of struggling trees similar to the outcome of Indigenous forest tending by setting periodic ground-level fires. Both methods reverse the ill effects of bark and soil acidification. Liming is, however, the only option where the density of dwellings and the overgrowth of untended forests preclude attempting to use and control a ground-level fire.

LEFT: Torreya seedlings in the foreground, a moss covered log mid-ground, and moss-free young redwoods at the back. The grayish-green patches on those redwoods (and close-up below) are crusts of lichen. While lichens also acidify rainwater, dense mosses retain moisture much longer.

TOP RIGHT: Again, redwoods are moss-free, but their Big-Leaf Maple companions host so much moss that ferns are visible on the branches in the distance.

ABOVE: Young or fast-growing redwoods tend to show reddish bark. Redwoods in less favorable conditions tend to look gray-purple. Slowed growth reduces bark shedding — and thus crustose forms of lichens can accumulate. (Redwood branchlets on left; Douglas-fir on right.)


(8) Torreyas search for light gaps horizontally

Shade is so extreme in a northeast-facing deep ravine near the top of Diamond Mountain (northwest of Napa Valley) that many of the torreyas there had directed their main stems to search for light patches not by growing up but by growing outward — nearly horizontally.

  It appears that a treefall episode pushed this torreya stem over — revealing not the roots but its "lignotuber".

The lignotuber size is proof that this stem did not arise from a seed. Rather, it began as a basal sprout arising from the lignotuber, possibly after a fire destroyed the previous main stem(s).

While this stem is rather young, the "tree" may be a century or more old.

The tree still lives so long as the rootstock remains healthy enough to continue sending forth replacement stems.

A torreya need not wait for a treefall in order to begin exploring its surrounds.

PHOTO BELOW: This moss-covered stem long ago initiated a downslope direction. The "seedling" near its base is almost certainly not a true seedling but a basal sprout. The tree's hidden lignotuber would easily have spread to this distance.

ABOVE: The next 5 photos will be different views of the same stem. Notice the white patch of missing moss on the top of this close-up of the stem. Then make sure you also see it in the rest of this photo sequence.

ABOVE: Notice the two sturdy stems growing vertically off the main leaning stem.

ABOVE: A closer view of a more distant section of the main leaning stem.

ABOVE: Even closer, but from a different camera view, such that 2 of the upright stems frame a cut redwood stump. The telephoto view also shows a living redwood at far left.

ABOVE: Another view, with the redwood stump and tall living redwood directly behind.

ABOVE: This is the final photo of the sequence, showing the full reach and plethora of skyward stems. (The white patch is easily visible.)

   The best way to get a sense of the habitat (steep slope and deep shade) that made extreme leaning of California torreya adaptive is at timecode 7:11 of this 2018 video narration of both Coast Range sites by Connie Barlow:

VIDEO: Florida Torreya's California Cousin Has Clues for Ex Situ Plantings - pt 1 of 2.


(9) Sun v. Shade leaf form adaptations

Torreya excels in adapting its leaf abundance and orientation in accordance with whatever amount of sunlight any particular habitat offers.

ABOVE LEFT: In its usual subcanopy position, Torreya grows leaves like a yew, genus Taxus, and both are members of the yew family: Taxaceae. (Sequoia National Park, 2005)

ABOVE: Torreya adopts more of a Douglas-fir leaf fullness and orientation when it gains access to unimpeded sunlight. Indeed, the long downward branchlets off the horizontal branches echo the growth form of Norway Spruce. (Yosemite National Park, 2005)

   LEFT: Orientation and fullness are not the only features that vary greatly according to sunlight access. Even the needle length differs markedly. Advice: Beware of keys to species distinctions within genus Torreya that use leaf dimensions as an element.

BOTTOM LEFT: These seeds were developing in Yosemite National Park, full sun, on 19 May 2005.

BOTTOM RIGHT: The open edge of the forest at the Swanton station (north of Santa Cruz) had a female tree producing seeds in abundance. The seeds are much farther along in development because this is a month later (15 June 2005) and at an elevation only 50 feet above sea level.

SEEDS ONLY DEVELOP ON BRANCHES OF FEMALE TREES THAT ACCESS SUFFICIENT SUNLIGHT.


(10) Torreyas excel within boulder fields (and along roads)

   All 3 photos depict the same tree. This torreya has both a road and a boulder field to insure that it has no competition for a full share of sunlight.

For the best visuals of the landscape and plant associates at this site in YOSEMITE NATIONAL PARK, visit Connie's video narration of these and additional photos at timecode 17:28 of:

VIDEO: Florida Torreya's California Cousin Has Clues for Ex Situ Plantings - pt 1 of 2".

ABOVE & BELOW: These photos show the context of this remarkably lush torreya tree. This habitat is both a roadside and a boulder field created by roadbuilding into a steep cliff. Notice that the "tree" is actually multiple stems. Are they sibling basal sprouts of about the same age, growing from a torreya cut and cast down during roadbuilding?
    Or did the torreyas on the upslope cast multiple seeds into this spot — perhaps before seed-loving rodents reoccupied the finished construction site? Or might a rodent have gathered the seeds and cached them here? Whatever the source, who but a torreya could establish seed in total shade and then grow at an angle before catching enough sun to straighten up and continue in glory?

BELOW: Two more sets of torreya trees with fast-growing, straight growth forms indicative of excellent habitat — thanks to the road-side boulder field.

ABOVE LEFT: View up the mountain while standing on the road. There is one small, brushy Torreya (center bottom of photo) where vegetation begins at top of road cut; blueish manzanita foliage is to its immediate right. The tall trees are California Live Oak and the short brushy shrubs are California Bay Laurel.

ABOVE RIGHT: Elsewhere on the upslope, we encountered a small torreya with the kind of shaggy bart indicating slow-growth and great age. Something other than shade is its challenge in this site. Perhaps the slope has been subject to too many slides or avalanches to have deep soil to retain snow melt. Notice that it got its start in the safety of rocks (albeit small rocks).

   LEFT: This photo was taken by Jonathan Walton along a road above Los Gatos. (It is also posted at the top of this lengthy webpage.) The largest of all dozen stems visible is 72 inches in circumference.

"They are growing on a rather dry site with poison oak, California bay (laurel), madrone, Douglas-fir, and coast live oak. No redwoods in this area," he reports.

It would be fascinating to explore the bases to discern how many of them might share the same root system. Clearly, this set benefitted enormously from the boulder-making roadbuilding, followed by steadfast access to sunlight.


Purpose of 2005 site visits

CONNIE BARLOW EXPLAINS: I visited these sites with the goal of getting a sense of the habitat and life association preferences of the California torreya, with the hope that this would give me (and others, via photographs here) a better sense of what the mountain habitat preferences for the "Florida" species (Torreya taxifolia) might be. In turn, this would improve our success rate when planting Florida Torreya into Appalachian Mountain sites and other northward locales.

   The thesis is that Florida torreya (along with many other plants) migrated to Florida as the Ice Ages set in, but has been unsuccessful in this current interglacial in returning to the Appalachians from its "pocket refuge" in Florida. Its sudden failure to thrive and reproduce in its localized Florida habitat beginning in the 1950s supports this thesis, as does the fact that all other species of genus Torreya — in California, Korea, Japan, and China — live in mountain habitats.

My hypothesis as I began my California quest for Torreya was that direct access to mountains is the key reason that the California, Japanese, Korean, and Chinese species of Torreya are not endangered. I found that California torreya is indeed "rare, though locally abundant," as reported in the literature. I believe it is "locally abundant" because it has been able to altitudinally compensate for rises in temperature during this interglacial.

Its large seed, however, may be the reason that it is "rare". A large seed cannot waft on a breeze from one favorable habitat to the next. Rather, Torreya depends on squirrels to distribute its seed and thus to carry out the shifts in range (in contrast to other conifers, such as Douglas-fir and Redwood, whose seeds are easily airborne).

Possibly tortoises and other creatures that are now extinct played important roles distributing torreya seeds in North America for millions of years prior to the end-Pleistocene extinctions, but today squirrels (and humans) are the only seed carriers who remain. This thesis is presented in "Bring Torreya taxifolia north now, by Connie Barlow and Paul S. Martin, published in Wild Earth in 2004. This article led to the establishment of Torreya Guardians, which in turn has led to substantial controversy about using "assisted migration" as a climate adaptation strategy for helping forest trees and endangered plants move their ranges in pace with climate change.

PAGE UPDATE: In 2022 Barlow updated this webpage (initially created in 2005) for a second purpose: There may be citizens on the West Coast who choose to collaborate in helping California Torreya track ongoing rapid climate change — and not simply by slow adjustment in altitude and aspect in its current mountain homes. Rather, there may be interest in "assisted range expansion" poleward.

   Foresters make a 3-fold distinction in the types of assisted migration, with the "assisted species migration" (a.k.a. "species rescue") being the most radical.

The actions taken by Torreya Guardians made Florida Torreya the type-case example of the latter.

ABOVE: "Preparing for Climate Change: Forestry and Assisted Migration", by Mary Williams and Kasten Dumroese, 2013, Journal of Forestry.

Certainly there are already good reasons to engage in "population rescue" for geographic subsets of California torreya that have already topped out of their ability to move upslope. The Coast Range populations of California torreya that Barlow visited in 2005 had already reached their upslope and aspect (north or northeast) topographic limits.


Site-specific photos and informational webpages

PHOTOS FROM CONNIE BARLOW'S 2005 SITE VISITS:
  • Sequoia and Yosemite National Parks
  • Coast Range of north Napa Valley (Stevenson State Park)
  • Coast Range of northwest Napa Valley (Diamond Mountain Road)
  • Coast Range by Santa Cruz (Scotts Creek watershed)
  • HIGH RESOLUTION CALIF PHOTOS
    __________
  • PHOTOS FROM OTHER CALIFORNIA SITES:
    Los Gatos and San Jose

    Mt. Tamalpais State Park, Marin County

    Bolinas Ridge, Marin County

    King Mountain Open Space, Larkspur (Marin County)

    Sonoma County

    Mariposa County

  • Please let us know if you have additional information, and especially personal experience, with California or Asian species of Torreya growing in the wild. Email Connie Barlow.




  • Summary of Results from the 2005 Site Visits
    of California Torreya

    Conclusions as of June 22, 2005 (by Connie Barlow)

    NOTE IN 2022: The text below has not been altered since it was written. Barlow decided to archive the early results this way, and also because her conclusions have not changed.

    1. SUNLIGHT REQUIRED FOR SEED PRODUCTION:
    Genus Torreya thrives in sun, but in cool habitats, such as one finds at high elevations (4000 feet in the Sierras) or on the steep slopes of Coast Range ravines. Torreya seems to require access to direct sunlight in order to produce its large seeds.

    2. STUMP SPROUTING AS A HOLDING PATTERN:
    Although Torreya thrives in full sun, it can't expect to have it: other species easily overtop a Torreya. Stump sprouting, followed by stem dieback without reproduction, and then another round of stump sprouting seems to be a HOLDING PATTERN by which established rootstock waits out conditions too shady to support seed development. When Torreya is growing as an understory tree beneath a much higher canopy, it is simply waiting for the canopy to open by windfall, fire, or (on steep slopes) landslides. Immediately following such an event, the influx of sun allows the established rootstock to send a stem quickly upward, and (in females) to begin producing viable seeds, which disperse locally. The new seedlings may have an opportunity to establish in sunlight before the habitat returns to the deep shade of high canopy conifers or evergreen oak and bay laurel.
        Repeated stump sprouting from established rootstock is all that remains of the once-locally abundant, though geographically limited, population of Torreya taxifolia in northern Florida. The easily observable difference between Florida Torreya resprouting and California Torreya reprouting is that the Florida species is plagued by stem cankers and by leaf browning that begins near the stem (not the branch tips). California Torreya growing in deep shade may assume a short and spindly growth form, but I saw no cankers on any trunk and only one instance of leaf death not associated with the natural shedding of old leaves as branches continue to lengthen. Indeed, when a Torreya tree is in full sun, its branches depart from the yew-like flatness and assume a bushiness that resembles Douglas Fir.

    3. COAST RANGE CONSTRAINTS AND OPPORTUNITIES:
    Genus Torreya is neither fast growing nor capable of producing a canopy as tall as that of competing trees that share its cool, Coast Range ravine habitats — notably Douglas Fir and Redwood. Thus, persistence of Torreya in the Coast Range seems to depend on Torreya's ability to linger in shady habitats (perhaps for centuries) as spindly, non-seeding trees that vegetatively replace their own dying stems by stump sprouting, until an overshading tree of a taller species happens to fall or a fire opens up the canopy. Acidification of soils and root rot may be the proximate causes of Torreya's failure in these situations to ever look like anything more than "saplings" (and droopy ones at that), and it is also the reason why stump sprouts can look quite healthy, because there is enough root to support very small growth forms, but not large ones. Thus, there is NOTHING WRONG with a Coast Range slope full of spindly Torreyas that grow under mature conifer forests with ground otherwise barren of understory vegetation — provided that every few centuries or so, fires revivify the soils or landslides open the canopy, at which time fresh stump sprouts enter a growth spurt and sexually reproduce, with some of the seed sprouting in places still favorable for successful development of rootstock, sufficient to weather out another shady period before the next slide or fire disturbance. In the wild, Torreya is thus adapted for spurts of sexual reproduction amidst long episodes of sexual quiescence.

    4. SIERRA MOUNTAINS CONSTRAINTS AND OPPORTUNITIES:
    Torreya also grows in steep ravines in the Sierras (as witnessed by the site I visited in Sequoia National Park), and there it is subject to the same constraints and opportunities as noted above. However, I also visited south-facing, steep dry slopes in which a canopy (of broadleaf, mostly evergreen oaks and laurels) was generally less than 30 feet tall, sometimes less than 20 feet tall. In these DROUGHT-STRESSED circumstances, Torreya has an opportunity to join others in the canopy as a sexually reproducing tree. Because the Sierra sites (unlike the Coast Range) are richly endowed with surface rocks and boulders, Torreya's LARGE SEED gives it a unique opportunity to germinate and establish in the shadow of rocks and boulders, eventually breaking through into sunlight.

    5. THE SYMBIOTIC ROLE OF NATIVE AMERICANS
    Because Torreya may require periodic fires to foster sexual reproduction as an understory tree, Native Americans may have played a symbiotic role in this tree's success. Active fire-suppression during the 20th century probably has been cumulatively detrimental, both in depriving Torreya of growth-spurt opportunities and through acidification of soils. My companion for the Santa Cruz area outing, Lee Klinger (his website for healing trees is
    "Sudden Oak Life" (www.SuddenOakLife.org), was convinced that the ancient Torreya specimens with gigantic trunk girths growing on the flat river terraces of Scotts Creek achieved such size only through the assistance of the Native inhabitants who may have favored Torreya for its big edible seed, just as they are known to have assisted oaks with edible acorns and redwoods that could provide shelter (in trunk bole caves created by intentional burning) and spiritual sustenance. In Scotts Creek watershed, we also found evidence that the Natives had "limed" the big redwoods, by depositing crushed shells at their base. For the very large Swanton Creek specimens, therefore, a continuation of the arborcultural assistance to which these giants have become accustomed may be a wise strategy.

    NOTE: On 8 October 2005, the Garden Section of the San Francisco Chronicle published an article that features the ideas and ongoing success of Lee Klinger's "SUDDEN OAK LIFE" project, and thus the efficacy of using lime and other techniques to counter soil acidification that stresses mature trees and thus makes them highly susceptible to the proximate cause of "Sudden Oak Death": the fungal-like Phytophthora ramorum.

    6. SUGGESTIONS FOR T. TAX ASSISTED MIGRATION:

    Although the species of Torreya now struggling in Florida demonstrably can grow in shady conditions, it may be a wise choice in effecting "assisted migration" northward for planters to seek out sites of recent disturbance or treefall for planting seed, and then to assist the seedling by weeding out plants that threaten to overtop it. Steep slopes are ideal, and if you can find surface rocks and boulders, plant Torreya seeds amidst them, especially in places where plants that need sun for germination and early growth would be unable to grow. For the long-term, after rootstock is established, human tending should not be necessary, and the tree could rely on windfall, slope slumpage, and perhaps the rare fire to occasionally (geologically speaking) open up canopy for growth spurts and sexual reproduction.


    Extracts from Other Web Pages on California Torreya


    1. General information:
    "http://www.fs.fed.us/database/feis/plants/tree/torcal/


    2. Local knowledge of Torreya californica: http://www.tarol.com/torreya.html

    [EXTRACT from the website]

    Finding these trees requires a bit of knowledge. First of all, where to look? California Torreya grow amongst incense cedar and live oak in shady ravines and rocky gorges between 2,000 and 6,000 feet in elevation in the Sierra Nevada and slightly lower in the coastal ranges. I have found them growing in three nearby locations. The closest is about two miles up the Doyle Springs Trail near Camp Wishon in Sequoia National Forest. Next closest would be along the Crystal Cave Trail in Sequoia National Park. The third area is near Boyden Cave in Sequoia National Forest near Kings Canyon National Park. There, near the parking area, is a beautiful specimen, the largest I have seen!

    Second, how do you identify this tree? At first glance its foliage looks like that of a white fir. Its needles are deep green, flattened, and 1-2 inches long. Their needles are aromatic and this has led to them sometimes being called a "stinking cedar." Their fruit is a modified cone, blue-green, plum-like, and about 1 inch long. They are small trees, rarely attaining heights of 60 feet and 2 feet in diameter. They grow slowly, however, so although they do not reach a great size, they can live to be several centuries old. Their branches are slender and they spread out making for a slightly ungainly appearance. Unlike other conifers, they are dioecious, meaning that there are separate male and female trees. The fruits hang from the tips of the outer branches from the female trees in late summer and autumn. Male trees produce pollen but never fruit.

    Once you find a California Torreya tree you'll find it is adapted to its foothill environment. They can sprout permanent new trunks from their base when they are cut or burned, thus they are adapted to foothill fires. Their wood is durable and flexible and was used by Native Americans for making hunting bows. Their seeds were harvested and roasted for eating and their roots were used for making baskets.

    3. Other locations: http://www.botanik.uni-bonn.de/conifers/ta/to/californica.htm

    [EXTRACT from website]

    USA: California. Rare and local along mountain streams, protected slopes, creek bottoms, and moist canyons of the Coast Range and Sierra Nevada, at 0-2000 m elevation (Hils 1993). See also Thompson et al. (1999). Arno and Gyer (1973) indicate that it can be found in "draws and basins on Mt. Tamalpais in Marin County;" along "the road entering Yosemit Valley from El Portal" (Yosemite National Park); at "the entrance to Boyden Cave in Kings Canyon" (National Park); and "the trail to Crystal Cave and near Clough Cave in Sequoia National Park."

    I have only found it in one location so far, on the road towards Giant Forest a few miles beyond the Foothills Visitor Center in Sequoia National Park. My notes report: "Here I find what is definitely the most prickly conifer I have ever encountered. This is a decent-sized little grove. They're growing amidst evergreen oaks, blue oaks, tanoak, a few small incense-cedars, and an understory with a xeric analogue of ladyfern, shrub oak, and probably poison oak. There's active regeneration, trees and seedlings growing both above and below the highway. Within 100 m of the sample point there are probably 50 stems taller than breast height, the largest being the one that I photographed the bark of, which has a dbh of about 25 cm. These trees are growing on a south- or southeast-facing slope. It seems to be a relatively dry microsite, but the torreyas are on locally concave topography. Slopes are 60-70%. We only find fruits on the largest, sun-grown specimen. Seedlings, of which the smallest I can find are about 15 cm tall, basically look the same as the larger plants except that their needles are shorter, about 1.5-2 cm vs. 4 cm on sun foliage in the mature trees." [photo: "californica2.jpg" caption=Tree in Sequoia National Park, CA [C.J. Earle, 24-Mar-01].

    4. More Locations and Plant Associations: http://reference.allrefer.com/wildlife-plants-animals/plants/tree/torcal/distribution-occurrence.html
    [EXTRACT from website:]

    California torreya is endemic to California. Its range has two distinct parts: one in the Coast Ranges and one in the Cascade-Sierra Nevada foothills. In the Coast Ranges, it is distributed from southwest Trinity County south to Monterey County. In the Cascade-Sierra Nevada foothills, it is distributed from Shasta County south to Tulare County [8]. Although not rare, it is not an abundant species. Local occurrence is widely scattered throughout its range [3], and trees are often infrequent in these localities [8].

    LISTED IN THESE ECOSYSTEMS. NOT OFFICIALLY ENDANGERED.

  • FRES20 Douglas-fir
  • FRES21 Ponderosa pine
  • FRES24 Hemlock - Sitka spruce
  • FRES27 Redwood
  • FRES28 Western hardwoods
  • FRES34 Chaparral - mountain shrub

    KUCHLER PLANT ASSOCIATIONS :

  • K001 Spruce - cedar - hemlock forest
  • K005 Mixed conifer forest
  • K006 Redwood forest
  • K007 Red fir forest
  • K011 Western ponderosa forest
  • K012 Douglas-fir forest
  • K025 Alder - ash forest
  • K029 California mixed evergreen forest
  • K030 California oakwoods
  • K033 Chaparral

    SAF COVER TYPES:

  • 207 Red fir
  • 213 Grand fir
  • 221 Red alder
  • 224 Western hemlock
  • 229 Pacific Douglas-fir
  • 230 Douglas-fir - western hemlock
  • 232 Redwood
  • 234 Douglas-fir - tanoak - Pacific madrone
  • 243 Sierra Nevada mixed conifer
  • 244 Pacific ponderosa pine - Douglas-fir
  • 245 Pacific ponderosa pine
  • 246 California black oak
  • 249 Canyon live oak

    HABITAT TYPES AND PLANT COMMUNITIES:
    California torreya is plastic is its habitat requirements, and occurs in many diverse plant communities. In the Coast Ranges, it grows in chaparral and various coastal forests such as redwood (Sequoia sempervirens). It is associated with canyon live oak (Quercus chrysolepis) and California bay (Umbellularia californica) woodlands in both coastal and inland foothill regions [10]. Inland populations are most commonly found in the ponderosa pine (Pinus ponderosa) belt [3,8]. It is rare in chaparral communities of the Cascade-Sierra Nevada. It is not a dominant or indicator species in community or vegetation typings.

    LISTED AS A THREATENED SPECIES IN IUCN RED LIST
    http://www.redlist.org/search/details.php?species=34026
    Much of the population outside protected areas has declined. The species is relatively common in the Sierra Nevada but less so in the coastal ranges. The expansion of agriculture is mainly responsible for the decline.

  • 5. EXTRACT from 1973 book Discovering Sierra Trees by Stephen F. Arno (Yosemite/Sequoia Natural History Association).

    Finding California torreya requires considerable knowledge of where to search and what to look for. The species reaches its best development on cool shady slopes and in canyons of the coastal mountains in Lake and Mendocino counties; it inhabits draws and basins on Mount Tamalpais in Marin County. Also, it grows in various rocky gorges and ravines scattered along most of the western slope of the Sierra Nevada between 2000 and 6000 feet elevation. Torreyas line the road entering Yosemite Valley from El Portal. Other good places to find them include the entrance to Boyden Cave in Kings Canyon, and the trail to Crystal Cave and near Clough Cave in Sequoia National Park.

    In the south-central Sierra, torreya typically occupies rocky gulches too low and hot for Douglas-fir or areas beyond Douglas-fir's southern limits. In Sierra canyons, torreyas rarely attain two feet in diameter and 60 feet in height. Small size, coupled with their dense crowns, gives them a youthful appearance. Nevertheless, trees only 1 to 1.5 feet thick are likely to be two centuries old. Torreyas and coast redwood are notable among the world's conifers in their ability to sprout permanent new trunks from cut or burned stumps. In this respect, torreya, like the chaparral shrubs, is adapted to foothill fires.

    Note: another source reports that California torreya "prefers moist, shaded, north-facing slopes (but found in open, sunny, exposed locations), usually near watercourses between 2,000 and 6,000 feet on the western slope.

    6. EXTRACT from the 1999 book Conifers of California by Ronald M. Lanner (Cachuna Press).

    California nutmeg is an evergreen widley but sparsely scattered up and down the Coast Ranges and along the west side of the Sierra Nevada and Cascades. Never forming a continuous forest, but found rather as isolated trees or in small groups, the nutmeg is usually seen tucked into shaded ravines or rocky gorges, beneath a canopy of pines or other conifers. Where it is stunted by growth on serpentine soil, it is a shrub of the chaparral. But throughout most of its range it grows as a modest-size forest tree 30 to 50 feet tall. One giant near Fort Bragg in Mendocino county reached a height of 141 feet before it was illegally felled.

    Habitat: California nutmeg is found on moist, rocky microsites within the shade of tall, coniferous forests; it grows as a shrub on serpentine substrate. It has a wide array of associates and ranges from about 2000 to 7000 feet.

    Distribution: It grows in the Coast Ranges from southwest Trinity county to Fremont Peak in Monterey County. It is also found in the Cascades and Sierra Nevada, ranging from Shasta County south to Tulare County.

    7. USFS "Fire Effects" species page on Torreya californica contains useful information.- https://www.fs.fed.us/database/feis/plants/tree/torcal/all.html
    EXTRACT: Male California nutmeg bear their microsporophylls within strobili. In contrast, the ovules of female trees are not contained within strobili but are solitary [16]. Male strobili begin growth the year prior to flowering, while females trees develop ovules in one growing season [21]. Torreyas are wind pollinated [16]. Male trees must normally be within 75 to 90 feet (23-27 m) of female trees in order to effect pollination [24]. Seed production is erratic. Good seed crops may be followed by crop failure the following year [10]. Seeds mature in 2 years [19]. Being heavy, seeds usually fall near the parent plant; wind dissemination is rare [17]. Seed predation by Steller's and scrub jay is high [10]. Seeds require a 9- to 12-month stratification period before germination [21]. In one study, seeds stratified for 3 months before planting took an additional 9 months to germinate under greenhouse conditions. Ninety-two percent of seedlings germinated at that time. [15]. Temperature regimes during the stratification period were not noted. Seeds sometimes germinate without stratification but do so slowly [21].

    Growth of trees in the understory is slow [10]. Sudworth [24] reported trees from 4 to 8 inches (10-20 cm) in diameter were 60 to 110 years of age, while those from 12 to 18 inches (30-46 cm) in diameter were 170 to 265 years old. The growth rate needs further study, however, as rates of over 1 foot (30 cm) per year have been reported in cultivars [3]. Preliminary data obtained from tree-ring counts of saplings on the El Dorado National Forest shows some trees attained heights of 4.8 feet (1.5 m) in 28 years [10].

    California nutmeg sprouts from the roots, root crown, and bole following damage to aboveground portions of the tree [3,10,19]. Some nutmegs reproduce by layering [21], but the layering capacity of California nutmeg is unknown.

    SUCCESSIONAL STATUS: California nutmeg is very shade tolerant [9] and is found in late seral and climax communities [3]. Following disturbance such as fire or logging, sprouts growing from surviving perennating buds appear in initial communities [10].


    Torreya in Korea

    1. In Bija-Rim Forest: http://www.lifeinkorea.com/Travel2/cheju/225

    [EXTRACT from website]

    This forest contains 2,500 Torreya nucifera, aged 300-600 years old, and is said to be the best area in the world for this single species of trees growing so densely together. Because the trees are evergreens, people can enjoy the dense forest all year long. Several rare parasitic plants grow within the trees. The trees blossom around April and fruits ripen in autumn. The fruits are widely used for medicinal purposes and food. The quality of the wood is excellent and is used for high-class furniture and stone checker boards.The Pija tree has been designated as Natural Monument #374 for protection.

    A natural nutmeg grove (Torreya nucifera community) on Mt. Hallasan (designated Natural Monument #384), extends over 448 thousand square meters. One of the few natural nutmeg groves in the world, it contains 2,570 trees ranging fromn 500 to 800 years of age. They measure from 7 to 14 meters in height, 0.5 to 1.4 meters in diameter (measured a meter from the ground), and 10-15 meters in width at the crown. In the past, nutmeg was valued as vermicide and its wood was popular for high quality furniture and paduk (go) boards for the wealthy. The area is also noted for many rare orchids which grow naturally. These include Nadop'ung-nan (Aerides japonicum Reichb. fil.) P'ung-nam (Neofinetia falcate hunb Hu), K'ongjjagae-ran (Bulbophyllum drymoglossum Maxim.), Huk-nanch'o (Bulbophyllum inronspicuum Maxim.), and Pija-ram (Sarcochilus japonicus, mig.)

    "The New Millennium Nutmeg":
    This 813-year old tree inhabits this nutmeg grove. It is the oldest nutmeg in Korea and the oldest of all evergreen trees on Jeju Island. This tree is a witness to the indomitable spirit of Korea's ancestors in overcoming hardships imposed by the environment and isolation, and was named the "New Millennium Nutmeg." Local residents wish the spiritual power of this noble tree to bring everyone happiness, prosperity, and health in the coming millennium.


    Torreya in China

    1. [Connie Barlow writes for this website]: I could find very little on the internet on Chinese species of genus Torreya. But Peter Wharton, Curator of the David C. Lam Asian Garden at the University of British Columbia Botanical Garden (Vancouver, BC) reported to us in January 2005 of sitings he made on a recent trip to China:

    "Very excited to see Torreya yunnanensis in the wilds of central southern Yunnan (Ailao Shan, 2475m)."
    2022 UPDATE: Visit the genus section of our Natural History of Torreya taxifolia webpage, which provides photos and information about Asian species.



    USFS FEIS page on Torreya californica describes the slow subcanopy growth in this way:
    Growth of trees in the understory is slow [10]. Sudworth [24] reported trees from 4 to 8 inches (10-20 cm) in diameter were 60 to 110 years of age, while those from 12 to 18 inches (30-46 cm) in diameter were 170 to 265 years old. The growth rate needs further study, however, as rates of over 1 foot (30 cm) per year have been reported in cultivars [3]. Preliminary data obtained from tree-ring counts of saplings on the El Dorado National Forest shows some trees attained heights of 4.8 feet (1.5 m) in 28 years [10].

    Habitat types and plant communities: ... occurs in many diverse plant communities. In the Coast Ranges, it grows in chaparral and various coastal forests such as redwood (Sequoia sempervirens). It is associated with canyon live oak (Quercus chrysolepis) and California bay (Umbellularia californica) woodlands in both coastal and inland foothill regions [10]. Inland populations are most commonly found in the ponderosa pine (Pinus ponderosa) belt [3,8]. It is rare in chaparral communities of the Cascade-Sierra Nevada. It is not a dominant or indicator species in community or vegetation typings.

    The Gymnosperm Database offers site-specific information:

    Sequoia-Kings Canyon National Park: I have found it on the road towards Giant Forest a few miles beyond the Foothills Visitor Center. My notes report: "Here I find what is definitely the most prickly conifer I have ever encountered. This They're growing amidst evergreen oaks, blue oaks, tanoak, a few small incense-cedars, and an understory with a xeric analogue of ladyfern, shrub oak, and probably poison oak. There's active regeneration, trees and seedlings growing both above and below the highway. Within 100 m of the sample point there are probably 50 stems taller than breast height, the largest has a dbh of about 25 cm. These trees are growing on a south- or southeast-facing slope. It seems to be a relatively dry microsite, but the torreyas are on locally concave topography. Slopes are 60-70%. We only find fruits on the largest, sun-grown specimen. Seedlings, of which the smallest I can find are about 15 cm tall, basically look the same as the larger plants except that their needles are shorter, about 1.5-2 cm vs. 4 cm on sun foliage in the mature trees." I also have a report that they occur in Sequoia National Park on the lower part of the trail from Potwisha campground to Marble Falls (Roy Malahowski email 2011.03.13), and Arno and Gyer (1973) state it can be found at the entrance to Boyden Cave in Kings Canyon and along the trail to Crystal Cave and near Clough Cave in Sequoia National Park.

    California coastal parks: Arno and Gyer (1973) indicate that it can be found in "draws and basins on Mt. Tamalpais in Marin County." Samuel P. Taylor State Park near Point Reyes has some very large trees, including two that were 30.25 and 32.3 m tall in November 2011 (Steve Sillett email 2011.11.19). The trees can also be found, at an unusually low, dry location, on the trails of Low Gap Park in Ukiah (Mark Hedden email 2017.07.10).



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