Kern River Washingtonia filifera - native or naturalized?

[Alex High]

Hello all,

I have recently learned of a population of Washingtonia filifera growing along the Kern River in Kern County, California. I actually first saw the palms when I was scrolling through the photos for Sequoia National Forest and came across a photo of what looked like a native grove of filifera growing along a river lined with steep cliffs. The abundance of grasses and trees on the cliffs made me wonder about the location of the photo, clearly different from the Sonoran Desert ecosystem where the palm is normally found. I forgot about these palms until I saw these photos of them in the IPS magazine this year. It lists them as being a native population "at the northern limit of the species' natural range in California." I was shocked. It turns out they are growing along the Kern River in the Kern River Canyon, right near the entrance. There is one main grove with a number of palms growing sporadically along the river and on the cliffs.

Main grove:

https://www.google.com/maps/@35.4412215,-118.7936388,3a,47.8y,323.53h,84.98t/data=!3m6!1e1!3m4!1sgDWJRcdBblJQz1hPUwcpgg!2e0!7i16384!8i8192!5m1!1e4?entry=ttu

Sporadic palms:

https://www.google.com/maps/@35.4423552,-118.7924008,3a,19.4y,10.46h,81.68t/data=!3m6!1e1!3m4!1sAQgA_2ly84xVyPuZntRI9w!2e0!7i16384!8i8192!5m1!1e4?entry=ttu

https://www.google.com/maps/@35.4442098,-118.7909585,3a,46.9y,312.14h,69.03t/data=!3m6!1e1!3m4!1s51jUSgbeQghdDuYFpKV15g!2e0!7i16384!8i8192!5m1!1e4?entry=ttu

And recently I began to research the palms, trying to find out if they are indeed native or simply naturalized. So I began searching for old photos of the canyon's entrance, where the palms are today, and in almost all of the old photos I found, there are no visible palms. There are several possibilities to explain this. One is, of course, that the palms were simply never there. The photos are also black and white and some are grainy so there may well be palms simply not visible in the shots. Another is that most were removed by PG&E, who constructed a hydro-electric plant next the canyon's entrance in 1921 and a water bypass right above the main grove of palms sometime prior to 1905, which creates a waterfall after heavy rains (which may have led to additional palm growth). They also constructed several buildings (which are now gone) right by the river, next to where the main grove looks to be now. Another possibility is that many of them were taken out in floods that came through. Unlike most of the springs/streams that California fan palms are often found along, the Kern River is large and powerful, and was prone to frequent flooding from storms and snow melt upstream (prior to the construction of dams). You can even see many of the palms half-submerged in the first street view image above, from all the rain of this past winter. Here is an image below that shows how high the flood waters reached in 1868, for example. A flood like that could surely take out even mature Washys, and it would take a while for them to re-establish. The first few photos show the canyon before and after the construction of the water bypass. I put first the same view in modern times with the palm grove for reference.

Water height during the 1868 flood:

This was the only photo I could find where it looks like palms might be visible. It's undated but looking at the cars it looks like it might be from the 60s-70s(?). Clearly the palms that were there had been there for a while as they look to have some size.

Close-ups:

I also found references to the palms in this book, A Flora of Kern County, California, from 1967. The author, Ernest C. Twisselmann, noted "eight spontaneous trees" and called them naturalized, although it is not clear if that is a known fact or just an observation as they are not officially known to be native to the county. So clearly there were palms back then, not sure if eight is an official count or an estimation, but there are clearly many more than that today. But that could be for a number of reasons such as those listed above, and some other palm oases have grown dramatically over the last century or so, while others have dwindled. I could only get these snip its from Google Books, I would love to read the whole section on the palms. I may actually buy the book, these palms have become somewhat of an obsession. Here is what I could find:

The setting of the groves very much makes them look native, with them all clumped together and the occasional outliers. Additionally, though they are far from the next closest native grove, that is nothing unusual. There are outlying groves in southern Nevada and central Arizona that are also pretty far from the area of Southern California/northern Baja where they're found in abundance, and some of these groves are also outside of the Sonoran Desert. They are also pretty far from any other California fan palms that could have lead to them becoming naturalized, and of course many of the palms are clearly decades if not at least a century old, so there were many less filifera in the area when they would have first germinated. And curiously there are some robusta nearby, which are notoriously weedy and naturalize with ease most everywhere, yet they do not seem to have naturalized at all in the river which is right behind them, and they certainly have not mixed at all with the filifera grove. So I am very curious to get your all's thoughts, I know @Josue Diaz has mentioned the palms in previous posts so I'd love to get his input. What do you think: native or naturalized? Thanks 🙂

[kylecawazafla]

Great post! It looks like you've done as much online research as possible, and I doubt someone will be able to provide more insight, so good luck! I don't think an online poll would provide a meaningful answer to your question. Given the amount of effort you've put into this, can you tell me if there are still Avicennia marina var. resinifera in Mission Bay, San Diego?  Jokes aside, the natural world is always changing and I'm sure the boundaries that species grow within is always in flux. 

[Alex High]

1 hour ago, kylecawazafla said:

Great post! It looks like you've done as much online research as possible, and I doubt someone will be able to provide more insight, so good luck! I don't think an online poll would provide a meaningful answer to your question. Given the amount of effort you've put into this, can you tell me if there are still Avicennia marina var. resinifera in Mission Bay, San Diego?  Jokes aside, the natural world is always changing and I'm sure the boundaries that species grow within is always in flux. 

LOL! Thank you so much, I appreciate it, it was fun researching it and I will continue to do so. I think I will buy the book A Flora of Kern County, California, which discusses the palms. I find outlying palm populations like this very interesting! And that's a good point you make, especially true with Washingtonia. Just as groves dwindle and die, new ones are born by animals distributing the seeds.

[kylecawazafla]

I hope you get an answer to your question. I've heard Brahea armata are native to within a few miles of the CA border, and would love to see a wild Brahea in California. Definitely interesting to see plants growing where you don't expect them to grow. 

[kylecawazafla]

Just FYI, the street view of those Washingtonia filifera on the Kern River was just updated, so you can see many of their trunks inundated by the June 2023 snowmelt! 

[Alex High]

19 hours ago, kylecawazafla said:

I hope you get an answer to your question. I've heard Brahea armata are native to within a few miles of the CA border, and would love to see a wild Brahea in California. Definitely interesting to see plants growing where you don't expect them to grow. 

Thanks, I hope so too! I just bought the book A Flora of Kern County, California, so I will share its info on the palms when it arrives, can't wait to read it. As for Brahea armata, the closest known wild specimen is just 7 miles south of the California border, with larger groves (usually mixed in with filifera) starting to appear 20-30 miles south of the border. Here is the lone specimen documented 7 miles south of the border on iNaturalist. No doubt a bird or other animal could bring seed across one day and armata could become California's second native palm, and there may already be some wild Brahea armata growing in some of the canyons along the border, where there are lots of filifera. I totally agree, it's so interesting learning about palms on the edge of their growing range and in unexpected places.

https://www.inaturalist.org/observations?place_id=any&subview=map&taxon_id=135433

https://www.inaturalist.org/observations/100635726

 

18 hours ago, kylecawazafla said:

Just FYI, the street view of those Washingtonia filifera on the Kern River was just updated, so you can see many of their trunks inundated by the June 2023 snowmelt! 

I saw that, some of the palms were more than half submerged, crazy! Must've happened countless times over the years with all the floods that have come through the canyon. It looks like all the rain has helped the palms growing up on the cliffs too, their crowns now look healthy and lush after suffering from drought for the past couple years.

April 2021:

June 2023:

[Nopalez]

I was passing through the area not too long ago and I recall seeing some Pineapple Palms (Phoenix canariensis) growing near this grove of Washingtonia in the canyon, certainly naturalized in the area. Curious how the filifera and Pineapple palms are located there, but no robustas are present. This was the only picture of them I could find but you can see them just upstream of the SoCal Edison plant. There are about 4 or 5 there

[JubaeaMan138]

20 hours ago, Nopalez said:

I was passing through the area not too long ago and I recall seeing some Pineapple Palms (Phoenix canariensis) growing near this grove of Washingtonia in the canyon, certainly naturalized in the area. Curious how the filifera and Pineapple palms are located there, but no robustas are present. This was the only picture of them I could find but you can see them just upstream of the SoCal Edison plant. There are about 4 or 5 there

Pineapple palms 🤣

[Josue Diaz]

wow, not sure how I missed this since I was even tagged in it! lol 

In my opinion, they are native to this canyon. Washingtonia filifera's range naturally extends throughout the Colorado & Mojave deserts. Kern Canyon dissects the southern Sierra mountain range and connects the San Joaquin Valley in the west to the Mojave Desert to the east. iNaturalist has observations of Washingtonia filifera in the Mojave desert near the mouth of the Kern Canyon on that end as well. If you take into account some of the other Mojave desert flora that also "spill into" the canyon, it wouldn't take much to deduce that these are just naturally occuring populations. Yucca brevifolia is an iconic mojave desert species that occurs in that canyon, as well as Larrea tridentata, Opuntia basilaris, Acacia greggii, Chilopsis linearis, Atriplex hymenelytra, Mimulus bigelovii, Escholzia glyptosperm... all plants that are fairly restricted to the Mojave desert. 

I think another test might be to do some research as to whether local tribes utilize palm for basketry or food - looks like the Tübatulabal people have lived in this area for many thousands of years, perhaps their oral history would give some clues.  

[hbernstein]

I wonder if they were originally introduced to by area's indigenous people. As I understand it, a number of Washingtonia populations were possibly established in that way.

[awkonradi]

1 hour ago, hbernstein said:

I wonder if they were originally introduced to by area's indigenous people. As I understand it, a number of Washingtonia populations were possibly established in that way.

I imagine humans have assisted palm (and other plant) dispersal worldwide, since long before grain-focused agriculture emerged about 12,000 years ago.  In the present day USA, I imagine humans assisted Washingtonia dispersal in the southwest, and Caribbean palm dispersal in south Florida.  I think it's natural for children to play with seeds, and for adults to willfully sew them.

[Silas_Sancona]

As mentioned -at least a few times- in the past when this subject ..or others related to California's flora -past and present- ( ..and future, potentially ) have come up, Palms have been part of the flora in the state -and region- for ....Quite some time...

As soon as i find it, there's a passage in an ecology book i've held onto since my sister had it for a college course that describes a time in the past when the Central Valley was a warm, shallow sea ...Perhaps similar to the present day Gulf ( of CA )  When flora,  presently restricted to say N. and central Baja / areas of Sonora ( ..and possibly Sinaloa, ...northern-most part of the state at least,  ..and Chihuahua )  were present in CA ( As noted in the book. )  was more common in the " state " ( ...Because there were no state / country boundaries at that time obviously, lol )

Distant relatives of present day Persa and Ficus species in N. Mexico, ..and ..at least one palm species ( ...Could it have been Washingtonia? ...maybe Brahea,  Perhaps both???  ...or some now extinct sp. of Sabal?? ) that grew along the shores of that ancient sea, alongside the above- mentioned Genera, and likely others that could be considered  more " tropical " than what is present in the same areas presently.

As far as i'm concerned, whether located along the Kern River, in / near Anza Borrego, ...whatever.. group of them,  Washingtonia filifera  specimens currently restricted to any of those sites likely represent relict populations that found the best spots to " weather " the -more recent- last ice age climate. Could there have some movement of seed / plants by indigenous groups?  Possible for sure, but, that would have occurred more recently, rather than wayy back in time when W. f. / or any other regional palm sps. would have already been present within the " state ".

Consider populations of W. f. here in W. Cen. AZ native as well since there are  plenty  of presently native plant species here which are direct hold outs / recent, re-establishers from a time our area's climate and vegetation assemblage  closely resembled  areas of Cen. / S. Sonora and N. Sinaloa ( Say the foothills just east of ..or around Hermosillo, Guaymas / Alamos, and the area of Sinaloa near the Sinaloa / Sonora state line for example ) Mountain areas of both S. Cal -at least-,  and AZ,  would likely have resembled higher elevation areas in Sonora, and neighboring Chihuahua when the climate of was warmer..

There are other clues as well that i've mentioned in past threads related to what this section of North America's climate resembled in the past as well: Mex Blue Oak ( S. AZ / Mexico ) and Englemann Oak ( S. Cal )  are directly related, even though they are presently separated by the S.E. CA / Central AZ Deserts.. Coulter Pine? ..believed to have arose from a natural hybrid between Ponderosa ..or a distant relative of.... and a Mexican Pinus sp.

Ocotillo once grew as far west to be mixed within the " soft " Salvia- centric Chaparral areas of coastal S. Cal, possibly as far north as the interior south central coast ...say east of San Luis Obispo / Paso Robles / Salinas. Other " semi desert / semi tropical " plants currently seen just south of the CA / Baja border likely were present ...or at least much more present.. as well ..at least in the southern 3rd of CA ( Santa Barbara to San Diego county area ).

If present day humans aren't dumb enough to wipe themselves out beforehand, ..and the current direction of where things may be heading in the not to distant future continues,  some distant relative may see the direct effects of a resurgence of this ...more " tropical " flora re establish itself in a warmer California ..and Arizona / neighboring states.

As far as the noted " Pineapple " Palm / any other Phoenix sp / other palm sps / genera not already native to the region / continent / Hemisphere? ...if they're growing in natural areas, they need to be taken out,  period.   Would happily lead a group to do just that.   They do not belong here ..outside of one's garden / park. 

Want to " spread some palmy love, here, or in CA? " toss around CA Fan,  some Brahea armata / edulis / Sonoran native Brahea sp seed,  or Sabal uresana seeds instead

 

[Darold Petty]

I was told once that coyotes eat the fruit and thus disperse the seeds over a wide geographic range.

[Silas_Sancona]

2 hours ago, Darold Petty said:

I was told once that coyotes eat the fruit and thus disperse the seeds over a wide geographic range.

Critters ..or the wind may disperse seed over a distance, but, those seeds may ...or may not... survive past germination if the " new " area's prevailing climate factors aren't ideal at X given period of time, outside of the most ideal " micro-level " spot..

An good example?  I've found the occasional Manzantita seed in both Coyote and Peccary scat at San Tan Regional Park ( Blue " B " on the map ).. There are no Point Leaf Manzanita recorded anywhere in the San Tans, and it will not grow anywhere on the valley floor ( Too hot / dry ..Not cold enough in winter ). Nearest population of that species is up at Oak Flat, above Superior, 35 miles to the east ( Point A )

Even closer to the foothills / out in the open desert, just beyond any possible UHI influence from Queen Creek / San Tan Valley town limits, or areas just below the foothills east of Hwy 79,  ( C and D on the map ) ..still too dry / winters too mild for Manzanita.



During the last Ice Age, vegetation in the valley resembled what you encounter on a walk about up at the Flat, or pretty much any other mid- elevation area in the foothills around the valley / or out near Joshua Tree, Mountains around San Diego, or east of Los Angeles..  Manzanita, Pinyon / Juniper,  AZ Cypress, ..and various local Oaks, etc..  Pines, other than Pinyon,  likely would have been growing where interior chaparral now occupies, at least here, during that time.

** Note that Point Leaf Manzanita is currently present both in the mountains of AZ, and the mountains around S. Cal. A pretty reasonable clue the populations were likely connected via the empty region between each major population center at some time in the past. 

Saguaro may experience a similar " break up " in the future, ...some of the population moving north ..and /or west,  while a different section moves east out of this part of AZ. Plants now more common with the hot, subtropical coastal plains region of Sonora proper may be what moves north into our section of the Sonoran Desert next. **

Now that it is too warm / dry, at valley elevation,  each time a Manzanita seed ..or seed from a majority of those plants finds their way down into the valley, they aren't going to survive.   Washingtonia ..or Brahea.. seeds ( ..or seed from other, more " cold sensitive " plant genera / families dispersed into the area by animals )  would suffer the same fate, just in the reverse. They would only succeed in that ideal spot where any potential set back from winter cold isn't much of a factor / spot stays wetter in summer, ...compared to landing ..or being " deposited " in a spot where the same plant might be more exposed to those chillier winter / long, hot and dry summer negative factors impacting potential establishment / eventual recruitment and spread. 

Spores from " tropical " ferns ( ...and possibly any finite seed that could be dispersed by wind, like those from various Orchids,  and / or some Bromeliads, like Tillandsia sps native to Sonora / N. Sinaloa / Chihuahua ) are carried north into AZ ( and TX ) at times pretty much each year, but will only sprout and continue growing up here where if they land in that perfect spot ...and the climate in that spot stays ideal as they reach reproductive age. 


 

[Josue Diaz]

A recent photo shared by CHP in Kern County, and what do you see here! The grove in question haha

 

[SM458]

If they are brought by native bird droppings. Then this could constitute Filifera farthest natural range. 😅