Earth’s oldest living things!

Westgard Pass

A view down towards Westgaard Pass.

I’ve mentioned before that I am never happier than when I am in the field, especially when it’s an extended insect collecting trip. One problem I face on these trips, however, is the conflict between my desire to stay focused on the task at hand (collecting insects) versus indulging my broader natural history interests—landscapes, botany, geology, etc. The urge to explore increases the further west I go, as the landscape becomes more diverse and unfamiliar, and reaches its zenith in the king of landscapes that is California.

Ancient Bristlecone Pine Forest

Approaching Ancient Bristlecone Pine Forest from the south.

During our Great Basin collecting trip last August, field mate Jeff Huether and I visited the White Mountains near Bishop to look for Crossidius hirtipes nubilus, an isolated subspecies of longhorned beetle (family Cerambycidae) known only from the vicinity of Westgaard Pass. At 7,282′ elevation, the landscape around Westgaard Pass is beautiful enough, but we also knew that lying another 3,000′ above us was one of the most stunning landscapes that anyone even remotely interested in natural history could possibly imagine—Ancient Bristlecone Pine Forest (ABPF)!

Ancient Bristlecone Pine Forest

Entering the Ancient Bristlecone Pine Forest.

While Jeff had previously visited this magical place, I’d not yet had the chance despite my five years in California back in the 1990s (too many places, not enough time!). I had mentioned this to Jeff earlier in the trip, so with small but adequate series of C. hirtipes nubilus in our bottles Jeff suggested we take a break from insect collecting and visit ABPF. I was excited enough about the prospect of seeing these ancient trees, but I could not have anticipated just how bizarre and otherworldly a landscape we were about to see!

Bristlecone Pine Ancient Forest

Bristlecones growing in the harshest sites tend to be the longest-lived.

ABPF is, of course, named for the Great Basin bristlecone pines (Pinus longaeva) that occur here, one of three closely related pine species found in scattered, high mountain localities across the western U.S. and widely regarded to be the longest-lived of any non-clonal organism. The oldest known individual tree in the world, measured in 2012 at 5,062 years of age, is a bristlecone that occurs at this very site (although its identity and precise location are kept secret—for sadly obvious reasons), and nearly two dozen additional trees exceeding 4,000 years of age are known to occur here as well. True—there are clonal plants such as creosote bush and quaking aspen that are believed to survive as distinct genotypes for longer periods of time. However, the individual plants themselves are short-lived and quickly replaced by new sprouts from the clonal root mat. A 6,000-year old clonal patch of aspen may be technically older than a 4,000-year old bristlecone, but in my mind only the latter is bona fide ancient!

Ancient Bristlecone Pine Forest

Most older bristlecones have trunks with large sections of exposed dead wood.

In the White Mountains, bristlecone pines are restricted to exposures of white dolomite (giving the mountains their name), usually between 10,000′ and 11,500′ in elevation. We could see the sharp demarcation between the white dolomite—heavily colonized by bristlecones—and non-dolomitic bedrock colonized by shrubs but devoid of pines as we approached ABPF from the south.

Bristlecone Pine Ancient Forest

Dead bristlecones stand with main limbs intact for centuries.

Great Basin bristlecones occur also in the Inyo Mountains and other high mountains sites in Nevada and Utah. Most of these other sites have milder climates that offer more favorable growing conditions for the trees, and as a result the trees at these sites grow faster but—ironically—also die younger (Lanner 1999). Greater moisture availability and soils with more organic matter favor denser stands of trees as well as a richer shrub layer. This results in a greater fuel load that can carry fires, which are generally absent in the White Mountains groves with their widely spaced trees and sterile, rock substrate. Moreover, the harsh, dry conditions in the White Mountains inhibit the growth of fungi that can penetrate and colonize trunks at injury points, and there is a general lack of other threats that exist at milder sites such as bark beetles, sapsuckers, and even porcupines!

Bristlecone Pine Ancient Forest

Bristlecone Pine Ancient Forest

Unlike other pines growing at high elevations, such as whitebark pine (Pinus albicaulis), which develops an almost shrubby, beaten-down form in the face of constant battering by fierce winter winds, Great Basin bristlecones grow solidly upright and develop massive branches supporting a spreading crown. As the trees get older, their outer branches become long and pendulous, drooping under the cumulative weight of numerous, tightly packed needle clusters that can remain on the tree for up to 40 years! (The needles of most pines are shed after just a few years.)

Pinus longaeva male catkins

Bright, reddish-brown male catkins emerge near the tips of the densely needeled branches.

Most of the trees at ABPF grow on steep slopes of barren dolomite with virtually no soil layer, and the trunks of older trees usually bear large sections of exposed dead wood. Over the course of their very long lives, erosion of the rocks on the steep slopes around them gradually exposes roots, killing them and resulting in death of the trunk sections and branches that they feed. In many cases nearly the entire trunk is dead, but the tree lives on in a narrow ribbon of living bark snaking or spiraling up the trunk and connecting the last surviving roots to a single living branch.

Pinus longaeva sapling

A bristlecone sapling represents the promise of enduring life in the face of harsh conditions.

Eventually death does come, but it can take centuries for the dry, cold air to decompose the standing carcass and even millenia for the hard, resinous wood to break down completely once the tree finally does fall. The oldest existing wood at ABPF has been dated to more than 9,000 years old! It is almost incomprehensible to imagine stepping over a log that began life as a sapling shortly after the last glacial retreat and the arrival of the first humans to step foot in North America!

Pinus longaeva cone

Bristlecones are named for, well.. the bristles on their cones!

Why do Great Basin bristlecones live so long? It’s tempting to presume that the dry, high elevation environment, with its long, harsh winters and short, cool growing season enables an unusually slow metabolism that somehow translates to longevity. There is no evidence to support this, however. Perhaps characteristics such as its extremely decay-resistant wood play a part, but there are a few other species of pine that are also extraordinarily long-lived, yet still fall far short of the great ages that can be attained by Great Basin bristlecone pine. These include limber pine (Pinus flexilis), which co-occurs with Great Basin bristlecone pine in the White Mountains, but this species maxes out at about 2,000 years of age. Likewise, Rocky Mountain bristlecone pine (Pinus aristata) in Colorado can reach around 2,500 years of age. (Interestingly, limber pine occurs here as well, but in this area it reaches at best only about 1,500 years of age.) Even Great Basin bristlecones themselves growing at other sites, as noted above, are unable to match the longevity of the trees growing here in the White Mountains. Perhaps, as California conifer expert Ronald Lanner remarked, the question is not why these trees “live so long”, but why they “take so long to die”.

Bristlecone Pine Ancient Forest

A raven perches atop a fine, massively trunked specimen.

REFERENCE:

Lanner, R. M. 1999. Conifers of California. Cachuma Press, Los Olivos, California, 274 pp. [description].

Copyright © Ted C. MacRae 2014

These are a few of my favorite trees

Adrian Thysse recently posted a video of a talk by Wayne Maddison titled “Jumping Spider Melodies,” given November 2012 at the Joint Annual Meeting of the Entomological Society of Canada and the Entomological Society of Alberta. It was a fascinating talk that revealed some interesting correlations between the phylogeny and geographical patterns of distribution of jumping spiders—those bright-eyed, bouncy, almost kitten-like darlings of the spider world. One quote from the talk, however, that stood out for me above all others went something like “Scientists have a rational motivation to seek truth and an emotional motivation to seek beauty.” I think this is true especially for biologists and natural historians—who among us that studies that natural world in adulthood didn’t start out with a love of the outdoors as a child? For me it was the woods that ignited my passion, and still today nothing rejuvenates my spirit like the overwhelming beauty and solitude of the forest.

Shortleaf pine (Pinus echinata) | Wayne Co., Missouri

Shortleaf pine (Pinus echinata) | Wayne Co., Missouri

Wintertime especially is when I enjoy my visits to the forest. Far from the cacophony of summer, my mind is free to explore the open canopy, to examine the fabric of the landscape and ponder its history—unhurried, without objective. During the summer, trees are host plants—I see them not for what they are, but for the beetles that might be on them. I identify them, sample them, assess them for where their guests might be. In winter though, without beating sheet in hand, without collecting vials in the pocket, I see trees as works of art—freed from their summer cloaks, living skeletons on a living landscape.

Honey locust (Gleditsia triacanthos) | Wayne Co., Missouri

Honey locust (Gleditsia triacanthos)

Different trees are my favorite at different times for different reasons. Blazing hot orange sugar maples (Acer saccharum) at peak fall color, stately white oaks (Quercus alba) with their ash-gray branches, broad-crowned post oaks (Quercus stellata) dotting a remnant savanna, or even gnarled, ancient red-cedars (Juniperus virginiana) clinging tenuously to life on the edge of a dolomite bluff. Most often for me, however, the beauty is in the bark. The deeply fissured, reddish plates of shortleaf pine (Pinus echninata), the terrifyingly thorned trunks of honey locust (Gleditsia triacanthos), the shaggy, peeling strips of shagbark hickory (Carya ovata). Even in their winter nakedness, the bark of these trees gives them year-round personality that is lacking in lesser-barked trees.

Shagbark hickory (Carya ovata) | Wayne Co., Missouri

Shagbark hickory (Carya ovata)

Honey locust (Gleditsia triacanthos) - thornless individual | Wayne Co., Missouri

Honey locust (Gleditsia triacanthos) – thornless individual

The tree in this post were photographed during November 2012 while hiking the Wappapello Section of the Ozark Trail in the Ozark Highlands of southeastern Missouri (Wayne Co.). 

Copyright © Ted C. MacRae 2013

Great Smoky Mountains National Park

Is there any question why these are called the Smoky Mountains?

Last week I attended the Entomological Society of America (ESA) meetings in Knoxville, Tennessee. It was my first ESA attendance in more than ten years, so I took full advantage of the opportunity by speaking at the insect macrophotography symposium, presenting a poster on my soybean insect research, and enjoying face-to-face conversations with an extraordinary number of colleagues—some of whom I had not seen since my last ESA meeting and many more for which this was my first opportunity to meet them in person. I admit to having grown a little complacent in recent years about the importance of regular personal contact in cultivating these relationships—my attendance at this year’s ESA reminded me of that fact, and I’ve renewed my commitment to make ESA attendance a priority in the coming years.

Of course, no meeting should be all work and no play, and for me the chance to sample the local natural or cultural history is an added benefit of meeting attendance. This year’s destination for such was a no-brainer—located less than an hour’s drive from Knoxville, Great Smoky Mountains National Park is the largest federally protected area east of the Mississippi River. Straddling some of the highest peaks of one of the world’s oldest mountain ranges, the park has been designated an International Biosphere Reserve by the United Nations due to its rich biota.

One afternoon is not nearly enough time to even scratch the surface of the park’s 800 square miles, but it’s enough to get a taste of the diverse habitats they encompass and whet the appetite for further exploration. Highly recommended for those short on time is Clingman’s Dome—the park’s highest point at 6,643 ft. An observation tower allows spectacular vistas (provided the day has good visibility) of the surrounding mountains and the evergreen forests that cloak them. Unfortunately, the view has been marred in recent years by the accidental introduction of an exotic woolly adelgid (a relative of aphids) from Europe and its subsequent establishment on the forest’s Frazier firs. Dead trunks rise from the forest like tombstones—ghostly reminders of what has been lost. The starkness of the high elevation forest contrasts with the lush mixed hemlock forest that dominates the park’s lower elevations, and the 2.4-mile Alum Creek Trail provides an intimate experience with this rich forest and its thick understory of native rhododendron. I hope the following slide show imparts some essence of the experience, and larger versions of each photo can be seen by clicking on the thumbnails in the gallery that follows.

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Copyright © Ted C. MacRae 2012

North America’s second-rarest pine

Jeffrey (L) and Washoe (R) pines at Galena Creek Park

During last year’s trip to Lake Tahoe, I made it a goal to find all of the 11 conifer species occurring naturally in the Lake Tahoe Basin.  It took some effort, some good references (Arno 1973, Graf 1999, Lanner 1999, and Peterson 1975), and the help of an especially knowledgeable associate at the U.S.D.A. Forest Service headquarters in South Lake Tahoe, but I succeeded in my quest and later wrote two posts covering the Lake Tahoe conifers (Trees of Lake Tahoe – The Pines, Trees of Lake Tahoe – The “Other” Conifers).  In the first of the posts covering the six species of pines, I added the following footnote:

Two additional species of pine – Washoe pine (Pinus washoensis) and single-leaf pinyon pine (P. monophylla) – are often treated as occurring in the Lake Tahoe area. However, they are of sporadic occurrence on the eastern slopes of Mount Rose, and thus do not occur within the Tahoe Basin proper.

Of these, I am quite familiar with single-leaf pinyon pine.  Widespread on isolated mountain ranges throughout the Great Basin into eastern and southern California and Baja California Norte, I have encountered it during many of my field trips out west and reared a number of buprestid species from its tough, scrubby branches (including 2 specimens of the rarely encountered Phaenops piniedulis).  The other species, Washoe pine, was a new one on me, and it is, in fact, the second-rarest species of pine in all of North America (Torrey pine, Pinus torreyana, being the rarest).  Well, that was all it took to make me commit to finding this species on this year’s return to Lake Tahoe.

Washoe pine cones surround a larger Jeffrey pine cone.

Washoe pine grows only in a few locations, primarily in northern California with the best stands found in the Warner Mountains in Modoc County.  In the Tahoe area, Washoe pine grows only on the eastern slope of Mt. Rose in Nevada, where it is limited to the upper reaches of Galena Creek (Graf 1999, Lanner 1999).  It is apparently very similar to Jeffrey pine (P. jeffreyi) – the most common pine in the Tahoe area – but seems to be more closely related to ponderosa pine (P. ponderosa), which occurs at lower elevations and barely makes it up to the Tahoe area (some authorities even question the distinctiveness of this species, instead considering it a high elevation variety of ponderosa pine).  All three species are 3-needled and grow into tall, pyramidal trees with widely spaced horizontal branches.  Like ponderosa pine, the bark of mature trees forms broad yellowish plates separated by black fissures (the bark of Jeffrey pine is often more reddish with plate more narrowly separated).  The resin of Washoe pine is also chemically similar to that of ponderosa pine, both of which differ from the heptane-producing resin of Jeffrey pine.  However, Washoe pine cones more closely resemble those of Jeffrey pine, being somewhat smaller but sharing the “inward-curved” prickles on the scale tips that make them easy to handle (those of ponderosa pine point outwards, making them very prickly to handle).

Ponderosa (L) and Washoe (R) pine cones. Note smaller size and outward-pointing spines of ponderosa pine cone.

Jeffrey (L) and Washoe (R) pine cones. Both have inward-pointing spines, but Washoe pine cone is smaller and more loosely built.

None of my references had any specific locality information for Washoe pine beyond what I’ve stated above, but a little bit of Google snooping through conservation action plan documents revealed that the species occurred at Galena Creek Park, so early in the morning daughter Madison and I made the one-hour drive from South Lake Tahoe to the park.  Arriving at the park, I was disappointed to find nobody manning the headquarters, no maps in the park information board – indeed, no information whatsoever about the occurrence of Washoe pine within the park and where it might be found.  The only clue that there was something special about the pines at this place were the wooden signs around the parking and picnic areas stating “Collection of pine cones prohibited.” I reasoned that it would be very difficult to distinguish the species by its needles, bark, or form, but that the pine cones should be easier to distinguish. I also had no idea whether the pines would occur close to the parking area or if we would need to hike into the area to find them.  So, we just began picking up pine cones.  For a time, all of the pine cones seemed to be typical Jeffrey pine (abundant in the area) with an occasional ponderosa pine (just making up the 6,200′ of elevation in this area).  Ever concerned that I might be missing a subtle difference, I studied each “Jeffrey” pine cone carefully looking for any reason to regard it as truely smaller than normal.  Within about 15 minutes, however, we found it!  Picking up the pine cone, it had the compact build and inward-pointing spines of a Jeffrey pine, but it was smaller and a little more loosely built.  I looked at the trees above and could see no difference from what I would expect for a Jeffrey pine.  Further looking revealed numerous cones of the same type – each tree we found them under was otherwise indistinguishable from Jeffrey pine (at least to this eastern U.S.-based wannabe botanist).  Nevertheless, it was clear that we had found Washoe pine, and that it was quite abundant within this small watershed that we were exploring.  Jeffrey pine was also common in the watershed, and an occasional ponderosa pine could be found.  I took photos of mature individuals of each of the three species, identified conclusively by way of the cones found underneath them, to show how similar in appearance the three species are.

Pinus ponderosa

Pinus jeffreyi

Pinus washoensis

Madison and I later hiked out of the watershed into the higher elevations of Mt. Rose (from where these ants were photographed) – we noticed that almost immediately upon hiking out of the watershed the Washoe and ponderosa pines disappeared, and only Jeffrey pines were seen.  Although I have seen it many times before, I was still hoping to see single-leaf pinyon pine, but none were seen.

REFERENCES:

Arno, S. F. 1973. Discovering Sierra Trees. Yosemite Association, Yosemite National Park, California, 89 pp.

Graf, M.  1999. Plants of the Tahoe Basin.  Flowering Plants, Trees, and Ferns.  A Photographic Guide. California Native Plant Society Press, Berkeley, 308 pp.

Lanner, R. M.  1999. Conifers of California.  Cachuma Press, Los Olivos, California, 274 pp.

Peterson, P. V., and P. V. Peterson, Jr.  1975. Native Trees of the Sierra Nevada.  University of California Press, Berkeley, 147 pp.

Copyright © Ted C. MacRae 2010

Bicycle ride around Lake Tahoe

Overlooking Emerald Bay from Emerald Bay Pass.

Perhaps some of you have by now deduced that, in addition to insects and natural history, I have a second passion – cycling! In fact, I raced bikes competitively as an amateur for seven years (going by the local nickname “BugMan“) before hanging it up at the end of 2008.  However, even though I’m not racing anymore, I still ride as much as ever, only now it’s purely for the fun of it!  I’m a dedicated roadie, riding year-round and averaging around 5,000-6,000 miles a year.  I love the speed and the smoothness of the road and the opportunity it provides to cover long distances and enjoy the sights (not to mention the resulting freedom to eat like a horse and stay relatively trim!).

One of my most memorable cycling experiences was in 1995, when I joined a group that rode the entire circuit around Lake Tahoe.  I was living in Sacramento at the time and was a relative newbie – the 72-mile ride with 3,500 feet of climbing at elevations ranging from 6,200 feet at lake level to more than 7,000 feet near Carson Pass was without question the most difficult ride I had ever attempted at that point.  Now, as a seasoned ex-racer, such a ride is not extraordinarily difficult for me – in fact, I do rides in the 60-80 mile range with as much climbing or more almost every weekend.  Still, my memories of the challenge and the unbelievable scenery have kept that ride high in the ranks of my most epic, and since we began going back to Lake Tahoe two spring ago I’ve wanted to do it again.  It would not have been possible during our first trip back, as the roads still had quite a bit of snow on them; however, last year the roads were clean and dry, and I resolved to bring my bike with me on this year’s trip in the event that such was again the case.  Madonna del Ghisallo (patron saint of cycling) must have been smiling down upon me, because this year the roads were again in beautiful condition, despite the amount of snow blanketing the surrounding landscapes.  It made for one of the most beautiful bike rides I have ever done in my life.

There was a comforting familiarity to the ride, despite the 15 years since the last – the stunning landscape that I have come to cherish so dearly, the massively shaded solitude of the west shore, lunching on California cuisine in a quaint village along the north shore, and the long climbs and screaming descents through open Jeffrey pine forests along the east shore.  It was also different – I was by myself, yet despite that I was stronger and briming with confidence; not only a seasoned cyclist, but also much more knowledgeable of and closely attuned to the natural history of the area.  I didn’t fear the climbing, I relished it!  I didn’t overcome the challenge, I enjoyed it!  I stopped at a few places to take photographs (taken with my small point-and-shoot, for obvious reasons) and share some of them here – I hope they give you a tiny taste of the flavor of that day.

Near the summit of Emerald Bay Pass, looking back at Mt. Tallac.

High point on Emerald Bay Pass.

The descent to Eagle Falls at Emerald Bay.

 This is an avalanche zone (note deep snow deposits on steep slopes on left side – these extend high up the mountain here).  Moments after taking this photo, an avalanche fell onto the road right as I was descending by this spot. At ~35 mph there was no stopping – I rode right through it as the initial snow drop hit the pavement and then watched in amazement as the main drop dumped onto the road behind me.  It was not big enough to bury anything, but I surely would have crashed had I gotten there just a moment or two later!

Overlooking Emerald Bay from Emerald Bay Pass.

Emerald Bay is a glacial scour formed during the last glacial period ending only 10,000 years ago. Fannette Island, Lake Tahoe’s only island, is thought to be a resistant rib of granite rock that was overridden by the glacial ice. Lateral glacial morraines enclose each side of the bay, and an incomplete terminal morraine connects Emerald Bay to the main lake. Last year, I stood atop the outermost rock of the left side of the terminal morraine and took photographs looking back in this direction

Grove of sugar pines at D. L. Bliss State Park.

Sugar pine, Pinus lambertiana, is among my favorite of all pines.  More common on the west shore due to their preference for higher levels of moisture, their towering, ragged, asymmetrical crowns with long, pendulous cones (usually a foot or more in length) hanging from the branch tips are immediately recognizable from afar.  These majestic trees are the world’s tallest pine and bear the longest cones in the genus; they stand in defiant contrast to the uniformly symmetrical crowns of the more common Jeffrey pines (Pinus jeffreyi) and white firs (Abies concolor) that surrounded them.  For a more thorough treatment of the trees of Lake Tahoe, please visit my three-part series covering the pines, the “other” conifers, and the deciduous trees.

Some might think it was still a little too early in the season for bike riding.

Looking west across Lake Tahoe from Logan Shoals Overlook.

The east shore in Nevada is decidedly drier than California’s west shore.  The forest on the Nevada side is a more open, fire-mediated landscape dominated by Jeffrey pine, as opposed to the denser forests on the west shore with higher incidence of shade-tolerant trees such as white fir and incense-cedar (Libocedrus decurrens).

View of Cave Rock (left center) from Logan Shoals Overlook.

Cave Rock was and still is a sacred place for people of the Washoe tribe, whose ancestors occupied Lake Tahoe during the summers and performed religious ceremonies inside the largest of its caves.  These caves, sitting several hundred feet above the current lake level, were carved by wave action shortly after Lake Tahoe’s formation nearly 3 million years ago when lake levels were much higher than they are today.  The first of two highway tunnels was blasted through the rock in 1931 (much to the dismay of the Washoes), and the second was added in 1957.

Looking north along Lake Tahoe's east shore from atop Logan Shoals Overlook.

Copyright © Ted C. MacRae 2010

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Trees of Lake Tahoe – The “Other” Conifers

The inviting openness of the Sierra woods is one of their most distinguishing characteristics. The trees of all the species stand more or less apart in groves, or in small, irregular groups, enabling one to find a way nearly everywhere, along sunny colonnades and through openings that have a smooth, parklike surface.–John Muir, The Mountains of California (1894)

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In a previous post (Trees of Lake Tahoe – The Pines), I discussed the six species of pine that can be found within the Tahoe Basin. These include Jeffrey pine (Pinus jeffreyi) – dominant around the lake at lower elevations, lodgepole pine (P. contorta ssp. murrayana) – common in meadows at lower elevations and replacing Jeffrey pine at higher elevations, ponderosa pine (P. ponderosa) – uncommon in the basin due to its preference for lower elevations, sugar pine (P. lambertiana) – the magnificent giant of high quality mesic sites along the western shore, western white pine (P. monticola) – co-occurring with lodgepole pine at higher elevations, and whitebark pine (P. albicaulis) – covering the highest peaks with its gnarled and twisted form.  In this post, I will cover the five “other” coniferous trees that can be found growing in the Tahoe Basin.  These other conifers belong to several different genera in two gymnospermous families – the Pinaceae and the Cuppressaceae.  Together with the pines, these trees comprise what John Muir described as one of the most diverse and appealing coniferous forests in the world. I am most inclined to agree with him.  The diversity of conifers found in the Tahoe Basin is reflective of the wide range of conditions occurring there as a result of differences in elevation (from 6,200 ft to more than 10,000 ft), exposure, and moisture.

Family-level identification of Tahoe Basin conifers is relatively straightforward – those with needle-shaped leaves belong to the Pinaceae (the pine family), while those with scale-like leaves belong to the Cuppressaceae (the cypress family).  There are other characters that distinguish members of these two families, but leaf shape is the most useful for purposes of field identification.  Nine of the eleven species of conifers found in the Tahoe Basin belong to the Pinaceae, while only two are members of the Cuppressaceae.  Within the families, the genera can be distinguished most readily by the following characters:

Pinaceae

  • Pines (Pinus) – needles linear, arranged in bundles or clusters of up to 5 needles held together at the base by sheath of papery bark (discussed in Trees of Lake Tahoe – The Pines).
  • Firs (Abies) – needles more or less flattened, growing directly and singly from the branch and with a plump base that leaves a round depression on the branch.  Cones upright, on upper branches.
  • Hemlocks (Tsuga) – needles more or less flattened and growing directly and singly from the branch like firs, but narrowly stalk-like at the base where they are joined to tiny wooden pegs.  Cones pendant, on outer branches.

Cuppressaceae

  • Incense-cedars (Calocedrus) – scale-like leaves 4-ranked, twigs branching in one plane to form flat sprays, cones > ½” in length, consisting of two large scales separated from a closed center.
  • Junipers (Juniperus) – scale-like leaves arranged in circles of 3, twigs not forming flat sprays, cones < ½” in length, berrylike.

There are three additional coniferous genera in the Sierra Nevada – each represented by a single species and found along the western slope – that do not occur in the Tahoe Basin.  These include: Douglas-fir (Pseudotsuga menziesii) – widespread at elevations from 2,500 ft to 6,000 ft (higher at the southern end of its range); giant sequoia (Sequoiadendron giganteum) – primarily in Giant Sequoia National Monument, and California nutmeg (Torreya californica) – of scattered occurrence.

White fir (Abies concolor)

As old age creeps on, the bark becomes rougher and grayer, the branches lose their exact regularity, many are snow-bent or broken off,…but throughout all the vicissitudes of its life on the mountains, come what may, the noble grandeur of the species is patent to every eye.

p1020574_2p1020575_2p1020587_2

White fir is second only to Jeffrey pine as the dominant conifer at the lower elevations within the Tahoe Basin¹.  It is immediately recognizable as the only non-pine member of the Pinaceae to occur at these elevations – red fir and mountain hemlock are found only at higher elevations in the basin.  Young trees have a nearly perfect pyramidal shape, with silvery gray bark that is thin, smooth, and p1020588_2covered with resin-filled blisters that can be “popped” to shoot out the resin. Older trees develop a more cylindrical and slightly irregular crown, and the bark becomes thick and roughly furrowed, changing to a dark gray or brown color. The foliage has a gray frosted appearance from below, and crushing the needles releases a delightful citrus smell that I found myself partaking in repeatedly. In the narrow elevational zone where white fir and red fir co-exist, white fir may be recognized by its more flattened needles (cannot be “rolled” in the fingers) which are distinctly twisted near the base, causing them to appear 2-ranked. White fir was seen throughout the Tahoe Basin at elevations below around 7,500 ft, and especially along the western shore and southern shores where the greater moisture and protection of north and east facing slopes are to this species liking.

¹ This post by Watching The World Wake Up provides an excellent introduction to the characteristics and distribution of white fir and its relatives. It also contains what must be the best tangent to ever appear in a botanical blog – the connection made between white fir and the alluring Salma Hayek (annoyingly mispelled “Selma” Hayek), softly singing Siente Mi Amor, is pure brilliance!

Despite its “noble grandeur,” white fir may be regarded as somewhat of a pest species. The suppression of fires that have been the hallmark of 20th century forest management have encouraged the replacement of pines throughout the Sierra Nevada by this species. White fir does not tolerate fire as well as the pines with which it occurs, but unlike those species it does well in shadier conditions. The suppression of fires has resulted in dense stands of white firs growing up in the spaces between the pines. Since it tends to retain its lower branches as it grows, when fires do occur the white firs can act as “fire ladders” that allow the fires to reach the upper canopies of the pines. Pines are not as shade tolerant as firs and are thus unlikely to become established beneath the dense canopy of firs. The result of these fire suppression policies are mixed-conifer forests that are denser and contain a much higher proportion of white fir than in the past, making the forests more vulnerable to stand-replacing fires as well as stress-induced insect and disease outbreaks. These counterproductive management policies are beginning to change – and I saw two controlled burns taking place during the week while I was in Lake Tahoe – but there is still much progress yet to be done if we are to once again see large expanses of the “inviting openness” that so captivated John Muir.

Red fir (Abies magnifica)

This is the most charmingly symmetrical of all the giants of the Sierra woods, far surpassing its companion species [white fir] in this respect… Happy the man with the freedom and the love to climb one of these superb trees in full flower and fruit.

p1020785_2I suspected I had seen this magnificent relative of the white fir in the higher elevations at Heavenly Ski Resort on my first trip back to the area last year, but lacking any real knowledge or field guides at the time it remained only a suspicion. When I returned to Heavenly this year, I was ready for it, and I recognized it instantly when I reached elevations around 8,000 ft. The massive trees with deeply reddish bark were unmistakable, and my only disappointment in seeing this species was that I was unable to approach them closely enough to allow a more thorough examination of their needles and bark. Like the white firs I saw at lower elevations, these massive trees had developed a bit of irregularity in their long, cylindrical crowns.

Younger trees can appear more similar to white fir because of their thin, smooth gray bark with elliptical resin blisters. However, in trees both young and old, the foliage is a more boldly colored blue-green than the paler foliage of white fir. p1020784_2Both species develop thick, deeply furrowed bark as they age, but the bark of red fir is distinctly reddish-brown or reddish purple, compared to the dark gray or brown bark of white fir – almost ashen in appearance. In the hand, the needles are not so flattened as white fir – almost quadrangular in cross-section and able to be rolled in the fingers – nor are they distinctly twisted near the base. The photo at right shows a stately red fir on the left next to a Jeffrey pine on the right at Lakeview Lodge on the California side of Heavenly (elevation 8,250 ft – the highest at which I saw the latter species).  I found this species growing in the company of western white pine (Pinus monticola), lodgepole pine (P. contorta ssp. murrayana), and mountain hemlock (Tsuga mertensiana), as well as in groves of its own kind (unfortunately, seen only from my perch upon a ski lift).

Mountain hemlock (Tsuga mertensiana)

The Hemlock Spruce is the most singularly beautiful of all the California coniferæ. So slender is its axis at the top, that it bends over and droops like the stalk of a nodding lily. The branches droop also, and divide into innumerable slender, waving sprays, which are arranged in a varied, eloquent harmony that is wholly indescribable.

p1020804_2I hadn’t a clue whether I would succeed in finding mountain hemlock – I knew it was a denizon of the snowy high mountains, though less common than some of the other high country conifers, and I didn’t recall noticing anything that might be this species during last year’s visit to the slopes of Heavenly. Of course, being a long-time resident of the Midwest I have little experience with hemlocks in general – eastern hemlock (T. canadensis) is on occasion planted in urban landscapes here, but mountain hemlock is markedly different from that species, as well as its Pacific counterpart western hemlock (T. heterophylla), due to its needles growing out of the twigs in all directions rather than in two flat planar sprays. Additionally, the needles are square in cross-section like spruce (Picea), a genus that does not now occur in the Sierra Nevada. These features caused 19th century botanists to suspect that mountain hemlock might have originated from an intergeneric hybridization event, as evidence by John Muir’s reference to it as “Hemlock Spruce.” However, no crosses between genera in the Pinaceae have ever been substantiated, and no compelling evidence of the presumed crossing events proposed for mountain hemlock has been brought forth (Lanner 1999).

p1020803_2Perhaps being primed by the readings I had done beforehand, I knew instantly I had found this species while riding a ski lift and seeing what looked at first like small junipers, but with a Tolkienesque appearance due to the gracefully nodding leader and drooping branch tips.  My hurried attempts to snap photographs of the trees from the moving ski lift produced nothing but skewed views marred by lift cables and passing cars, but once at the summit I was able to ski down to a little grove next to the ski run for closer inspection.  I immediately noticed the many cones clustered at the branch tips and was struck by their pine cone-like appearance. They were quite large – nearly 2” long (massive by hemlock standards).  Sadly, the only examples I would see of this species would be these small trees that only hinted at the charms of the massive specimens with trunks up to six feet in diameter that so enamoured John Muir.  Like the rare Washoe pine (Pinus washoensis) that occurs just outside Tahoe Basin on the eastern slopes of Mt. Rose, attempts to find some of these graceful 100-footers will have to await my next year’s visit.

Incense-cedar (Calocedrus decurrens)

Casting your eye over the general forest from some ridge-top, the color alone of its spiry summits is sufficient to identify it in any company.

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The incense-cedar is my favorite of all the Tahoe Basin conifers. The bright, cinnamon-red bark of mature trees, deeply-furrowed, fibrous and peeling, is reminiscent of California’s two most iconic conifers – redwood (Sequoia sempervirens) and giant sequoia (Sequoiadendron giganteum), respectively the world’s tallest and most massive trees. Incense-cedar is neither as tall as redwood nor as massive as giant sequoia – p1020590_2indeed, it is not even very closely related (redwood and giant sequoia belong to yet another coniferous family, the Taxodiaceae, containing also the graceful but much smaller resident of southeastern U.S. swamps, baldcypress – Taxodium distichum). Nevertheless, old trees – veterans of centuries of fires and storm damage – are stunning specimens to behold, their massive, buttressed trunks often draped in yellow-green mosses and bearing deep basal fire scars, their spired crowns often broken and forked.  Their flattened sprays of foliage give the tree a delicate, lacy appearance in beautiful contrast to its grizzled, gnarled bark. Indeed, even in death these trees stand out for their stark beauty.

Incense-cedar is common at lower elevations in the Tahoe Basin, especially down close to the lake and in the communities ringing the shore. It rarely forms “stands” like white fir and the pines, p1020670_2but rather most often occurs singly – as if to emphasize their distinctiveness. I found it most common along the western shore, where it grows scattered amongst white fir and Jeffrey, sugar, and ponderosa pines. Some of the most massive incense-cedars I have ever seen were found down near the lakeshore along the Rubicon Trail in Emerald Bay State Park. Common on these trees were what I take to be incense-cedar mistletoe (Phoradendron libocedri) (family Santalaceae), which is apparently rare in the Tahoe Basin but known to occur in the mesic forests of the west shore.

Incense-cedar is another of the so-called “wrongly named” conifers – it is not a true cedar (thus, the hyphen in the name), a group of conifers belonging to the genus Cedrus in the family Pinaceae that is found across Eurasia². While somewhat resembling the true cedars, incense-cedar’s closest relatives are restricted to China and Taiwan. p1020640_2Early botanist-explorers, when they first encountered this tree, named it for what it most resembled to them – the old world cedars. This distinctiveness makes older trees the easiest Tahoe Basin conifer to identify. Even it’s cones that litter the ground under mature trees are unique – slender, spindle-shaped, and about an inch long, with the two longest scales bending back at maturity in a manner resembling a wide-open duck’s bill with the tongue sticking out. Young trees resemble Sierra juniper by their scale-like leaves and peeling bark, but the flattened, yellow-green sprays of incense-cedar and shiny reddish coloration of the bark of twigs and younger branches are immediately distinctive.

² There are actually numerous examples of such wrongly named conifers – Douglas-fir (Pseudotsuga menziesii) is not a true fir; eastern redcedar (Juniperus virginiana), western redcedar (Thuja plicata) and Alaska-cedar (Chamaecyparis nootkatensis) are not true cedars; and baldcypress (Taxodium distichum) is not a true cypress. Long live scientific names!

Like white fir, the Sierra Nevada has seen a bit of a population explosion of incense-cedar due to the fire-suppressive forest management practices of the past century. Despite the thick, fire-resistant bark of older trees, the thin-barked seedlings and saplings are intolerant of fire and grow more slowly than the fire-adapted pines. As a result, the frequent low-intensity fires of the past kept seedling establishment to a minimum, resulting in spot occurrences of mature, fire-resistant specimens. The suppression of these fires, combined with the ability of incense-cedar to germinate in shade and thick layers of duff, have allowed this species to increase in incidence throughout the Sierra Nevada. Along with white fir, it is gradually replacing the pines. This may seem like a good thing from the perspective of foresters and loggers, who value the wood of incense-cedar for its use in making pencils and cedar chests, but from an ecological perspective this has the same negative consequences discussed above for white fir.

Sierra juniper (Juniperus occidentalis ssp. australis)

Its fine color and odd picturesqueness always catch an artist’s eye, but to me the Juniper seems a singularly dull and taciturn tree, never speaking to one’s heart.

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This was another conifer that I didn’t recall seeing on my previous visits, but from what I had read I really hoped I did. Gnarly and burly, mature specimens have a weather-beaten, picturesque quality that is unmatched by any other Tahoe Basin conifer save whitebark pine (P. albicaulis). While I did not find this tree to be common in the Tahoe Basin, I did find it in the most surprising of places – Emerald Bay overlook, where I had gazed in admiration at Lake Tahoe on so many previous occassions. This enduring dweller of exposed granite crags grows where no other trees can, anchored to crevices with only the tracest amounts of soil, p1020613_2seemingly thriving on nothing more than rock, snow, and sunshine. Old trees, with their massively short trunks supporting wind-pruned crowns, cannot be mistaken for any other Tahoe Basin conifer. The wood, it seems, is almost as hard as the granite upon which the trees grow, accounting for John Muir’s impression of this tree as without expression – not even the strongest Sierra winds evoke the slightest of shudders or the quietest of whispers in its unyielding bows.

I did not find this species commonly in the areas of the Tahoe Basin that I visited (which were mostly lower elevation sites below 7,000 ft). In addition to the specimens seen at Emerald Bay State Park, I also found this species near Upper Truckee River before the climb to Echo Summit, and I found a number of fine mature specimens outside of the basin proper at Pyramid Creek Geological Area.  Where I did find it, Jeffrey pine was the most common associate, but in most cases the trees stood alone in their own starkness.  Among the Tahoe Basin conifers, the small scale-like leaves are recognizable to almost any easterner as those of juniper, immediately placing it in the family Cuppressaceae alongside incense-cedar.  Even the young trees can be distinguished from that species by their non-glossy foliage borne on twigs that radiate out from the branches in all directions.  p1020602_21The bark of young trees is shreddy and peeling like that of incense-cedar, but it is dull brown to reddish-brown rather than the shiny purple-red color of incense-cedars.

Sierra Nevada populations of Juniperus occidentalis are considered a separate subspecies due to differences in reproduction and elevational preference.  Trees in nominotypical populations, found in northeastern California and up through eastern Oregon and Washington, are found at somewhat lower elevations (4,000 ft to 5,000 ft) and have cones of both sexes on the same tree; while those of subspecies australis, limited to higher elevations (usually from 6,500 ft to over 10,000 ft) in the Sierra Nevada, have either all male cones or all female cones.

REFERENCES:

Arno, S. F. 1973. Discovering Sierra Trees. Yosemite Association, Yosemite National Park, California, 89 pp.

Graf, M. 1999. Plants of the Tahoe Basin. Flowering Plants, Trees, and Ferns. A Photographic Guide. California Native Plant Society Press, Berkeley, 308 pp.

Muir, J. 1894. The Mountains of California. The Century Co., New York, xiii+381 pp.

Lanner, R. M. 1999. Conifers of California. Cachuma Press, Los Olivos, California, 274 pp.

Peterson, P. V., and P. V. Peterson, Jr. 1975. Native Trees of the Sierra Nevada. University of California Press, Berkeley, 147 pp.

Copyright © Ted C. MacRae 2009

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Winter botany quiz #4

Back to botany mode¹, and in that vein there are a couple of botanically-oriented carnivals with new issues just out.  The first is Berry Go Round #15 at Mary Farmer’s A Neotropical Savanna. An expert botanist herself, Mary presents a nice selection of March blog posts with themes ranging from spring (or not), tropics and the Southern Hemisphere, evolution and extinction, research, and food. The second is Festival of the Trees #34 at Seabrooke Leckie’s the Marvelous in Nature. A naturalist of many talents, Seabrooke has collected posts on trees from around the world and introduces them with her usual sagacity.  I have contributions in both of these carnivals, but of course, you’ve already read them!

¹ One caveat – it occurs to me that I needn’t be apologetic every time I switch to botany mode – the name of my blog is, after all, Beetles In The Bush 🙂

On to business – it’s quiz time again, and while much of the country moves into spring mode, winter hasn’t yet lost its snowy grip completely.  These pictures were taken in the waning days of winter, and I have my suspicions that somebody out there is going to ace this test considering the abundance of clues that have been dropped over the past week or so. In addition to the plant identities, bonus points to anyone who can identify a key commonality among them. As usual, comment moderation has been turned on for the next couple of days or so to give all an equal shot.

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Copyright © Ted C. MacRae 2009

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Trees of Lake Tahoe – The Pines

The coniferous forest of the Sierra are the grandest and most beautiful in the world, and grow in a delightful climate on the most interesting and accessible of mountain-ranges…–John Muir, The Mountains of California (1894)

During the early 1990’s while I lived in Sacramento, I spent a lot of time exploring the nearby Sierra Nevada – my first true mountain experience after cutting my entomological teeth in my beloved Ozark Highlands.  The beauty of the Sierra is overwhelming (this should be obvious after my last several posts), and it didn’t take long for the deep, clear, blue waters of Lake Tahoe to capture my heart.  One year ago, I returned to Lake Tahoe for the first time since moving back to St. Louis in 1995.  That visit was much too short – only 3 days, but that was more than enough time to rekindle my love affair with Lake Tahoe.  My wife shared those feelings, and together we made a commitment to return to Lake Tahoe every year from then on.

And return we did.  Our primary goals last week were skiing (to invigorate the body) and relaxation (to rejuvenate the mind) – typical goals for working professionals who spend much of the year consumed by the demands of job and family.  In addition, I had another goal of my own – to learn as many of the trees and shrubs that occur in the Tahoe Basin as possible.  I hadn’t done a very good job of this during the time that I lived in California – in those earlier days of insect collecting, I was content to call a pine a pine and a fir a fir and leave it at that.  Over the years, however, I’ve become more and more interested in understanding host plant associations for the woodboring beetles that I study, and to do that I need to become a better botanist.  With a whole week to explore the Tahoe Basin during this year’s trip, I figured I should be able to gain a solid understanding of most of the trees and a good portion of the shrubs that occur in the area.  Maybe, if I was really lucky, I could actually succeed in finding and recognizing every species of conifer known from the Basin.

To make a long story short – yes, I did succeed in building a solid understanding of most of the trees that occur in Tahoe Basin, including all 11 coniferous tree species.  At this point, I have to acknowledge once again the considerable help given by a particularly knowledgeable associate at the U.S.D.A. Forest Service headquarters in South Lake Tahoe.  Without her focused insight on distinguishing characters and locations, I may not have enjoyed the same level of success.  From my discussions with her and what I had gleaned from my readings up to that point, I knew I would have to explore a range of habitats and elevations to find everything I was looking for, always with field guides and camera in pocket.  This post represents the first of a two-part treatment of the coniferous trees that occur naturally in the Tahoe Basin and covers the six species of pine¹ (family Pinaceae, genus Pinus). The second part in this series will cover the remaining conifers in other genera.

¹ Two additional species of pine – Washoe pine (Pinus washoensis) and single-leaf pinyon pine (P. monophylla) – are often treated as occurring in the Lake Tahoe area. However, they are of sporadic occurrence on the eastern slopes of Mount Rose, and thus do not occur within the Tahoe Basin proper.

In the treatments that follow, click on any of the photos to see enlarged versions for a better view of the characters discussed.

Jeffrey pine (Pinus jeffreyi)

p1020604_2p1020665_2p1020576_3This is the dominant conifer and pine species in the Tahoe Basin. It is very closely related to ponderosa pine – so much so that some authors have treated it as a variety or synonym of the latter. Here, I follow the opinion of Conifers of California by Ronald M. Lanner (1999), who notes important differences in the chemical composition of its oleoresin (containing an explosive hydrocarbon p1020586_2called normal heptane) in addition to the subtle phenotypic characteristics. At a distance, the species can be recognized by its tall, straight massive trunk and relatively long, symmetrical crown. The bark is generally reddish brown with narrow plates between deep fissures. Like other species in the hard pine subgenus, old trees cease adding height after their crown flattens out (as seen in the photo above, which at first caused me to think it might be sugar pine). This species and ponderosa pine are the only Tahoe Basin pines that bear needles in bundles of three, and their length (up to 10″) and blue-green color also help to distinguish at a distance these two species from the other Tahoe Basin pines. p1020784_2I found the beehive shaped cones of Jeffrey pine to be the most reliable character for distinguishing this species from ponderosa pine – they are more robust, more tightly constructed, and easy to handle because the prickles of open cones curve inward.

This species was the dominant pine at lake level around the entire perimeter of the lake.  It also dominated the forests I saw at Spooner Lake (elevation 7,200′), and I saw a few specimens as high as about 8,000′ elevation at Heavenly Ski Resort.  The photo at right shows this species (right) standing next to red fir, Abies magnifica (left) on the California side of Heavenly. I also found it outside Tahoe Basin on the western slope of the Sierra Nevada down to Pyramid Creek Geological Area at an elevation of about 6,200′.  At that point, ponderosa pine began to take over and dominated at lower elevations.

Ponderosa pine (Pinus ponderosa)

p1020690_2p1020643_2p1020644_2Despite the widespread occurrence of this species across the mountainous west, I knew this species was not common in the Tahoe Basin as it prefers somewhat lower elevations than Jeffrey pine. The U.S.D.A. Forest Service representative told me that I should be able to find this species in Emerald Bay State Park, and that proved to be the case. This species is so similar to Jeffrey pine that it is more useful to discuss the differences only. The photograph in Winter botany quiz #3 shows the more yellow, larger plates of the bark on mature trees that is usually cited as a distinguishing character, but I found this to be unreliable in deciding whether a large tree represented this species or Jeffrey pine.  On several occasions I made a judgment based on the bark and then had to change my mind after looking at the fallen cones underneath.  Furthermore, this character was useless for younger trees that have not yet developed the distinctive plating. Another character often cited is the shape of the crown, which in ponderosa pine is generally shorter and less symmetrical than that of Jeffrey pine and results in the branches starting higher up the trunk in mature trees. I didn’t develop any confidence in this character either. It was not until I started focusing on the fallen cones beneath each tree that I developed a consistent sense of which species was which. In contrast to the robust cones of Jeffrey pine, those of ponderosa pine were almost always slightly smaller, with a more open structure and – most obvious – were very prickly to hold due to the prickles of open cones curving outwards.  p1020663_2The photo at right shows the distinctly outward pointing prickles and more open structure of a ponderosa pine cone (left) versus the distinctly inward pointing prickles of a Jeffrey pine cone (right).

Within Tahoe Basin proper, I didn’t see any trees that I thought represented this species outside of Emerald Bay State Park, where it occurred together with Jeffrey pine in mixed stands.  At higher elevations, Jeffrey pine took over exclusively, while at lower elevations (outside Tahoe Basin, on the western slope of the Sierra Nevada), ponderosa pine eventually took over.  I saw both species in the area of Pyramid Creek Geological Area (about 6,200′ elevation – the same as lake surface within Tahoe Basin).

Sugar pine (Pinus lambertiana)

p1020715_2p1020647_2p1020632_2If there was any pine that I most looked forward to finding on this trip, it was this one². In contrast to the straight, narrow-crowned Jeffrey pines that dominate the Tahoe Basin, mature sugar pines have a ragged quality to them that makes each one unique.  Or at least that was the feeling that I got from my readings. p1020719_2I had seen the giant cones of this tree before up around Tahoe City, but I had never before made the effort to find and recognized the tree itself – to say unequivocally “Wow, that’s a sugar pine!” The wonderfully knowledgeable U.S.D.A. Forest Service associate had told me I might be able to find it along the Vikingsholm and Rubicon Trails at Emerald Bay State Park, but better stands could be found further north along the west shore at D. L. Bliss and Sugar Pine Point (of course) State Parks.

In addition to its distinct crown – tapering, frond-like branches that arch upwards in the upper crown and droop gracefully at the tips, while spreading horizontally below – sugar pine is immediately recognizable from a distance by the long, pendulous cones (usually a foot or more in length) hanging from the branch tips. It wasn’t long into my hike on the Vikingsholm Trail before I spotted the distinctive cones on a tree down by Vikingsholm Castle. Up close, the bark of mature trees is dark reddish and narrowly fissured, similar to Jeffrey pine but not so distinctly “plated.” p1020581_2Younger trees not yet bearing cones lack such distinctive characters, but they can still be recognized by their needles in bundles of five (about 4″ in length, much shorter than Jeffrey and ponderosa pine) – which places them in the soft pine subgenus – and smooth, gray bark. There are three soft pine species in the Tahoe Basin, but the other two – western white pine and whitebark pine – are found at higher altitudes than lake level. After hiking at Emerald Bay State Park, I drove up to D. L. Bliss State Park, and even from the road the towering asymmetrical crowns were immediately recognizable.  Rising like giant monuments, these largest of pines were full of character and stood in defiant contrast to the uniformly symmetrical crowns of the Jeffrey pines and white firs (Abies concolor) that surrounded them.  I would see this species along the entire western shore – just uncommonly enough to make each new sighting a delight.  This species appears to favor the greater moisture of the western shore, as I only saw a single tree of this species while driving the eastern shore in Nevada.

² I equally looked forward to seeing whitebark pine, but I knew I would find good stands of this hauntingly beautiful species on the high peaks at Heavenly Ski Resort, where I had seen and recognized it for what it was during last year’s trip.

Western white pine (Pinus monticola)

p1020797_2p1020796_2p1020787_2I wasn’t sure I would find this species at first – my readings suggested, and the U.S.D.A. Forest Service associate confirmed, that I would need to visit higher altitudes than around the lake to find this species. I held out hope that I might see it on my final day during the trip, when we went skiing at Heavenly Ski Resort. This species is another member of the soft pine subgenus, with its needles in bundles of five and looking very similar to those of the closely related sugar pine. I learned, were I to find it, that its crown of horizontal branches would appear more tightly and neatly layered, and that the upward arching branches of the upper crown would not droop at their tips. I also learned that the cones, smaller than those of sugar pine, would cluster erectly at the tips of the branches rather than hanging pendulously. My skepticism at being able to find and recognize this tree would prove to be unfounded. As soon as I reached the upper elevations of the ski resort, the robust, mature trees of this species were immediately recognizable – the crown shape and shape of the hanging cones were unmistakable. The foliage and young bark resembles that of sugar pine, but older trees quickly develop a thick, deeply-fissured, dark, purplish-brown bark that has a checkered appearance. They’re not as tall as sugar pine, but stouter and more robust. The trunks of some of the trees I saw were as massive as the largest ponderosa pines I had seen down near Vikingsholm Castle. I saw this species at elevations above about 8,000′ on both the California and the Nevada sides of Heavenly Ski Resort.

Lodgepole pine (Pinus contorta ssp. murrayana)

p1020733_2p1020582_21p1020635_2In the Jeffrey pine dominated zone around the Tahoe Basin, lodgepole pine is the second most common pine species. It is also one of the most easily recognized species due to its thin, flaky bark – light, brownish-gray in color and almost appearing orange from a distance, brown and gray mottled up close. I recognized this as something different right away when I started noticing nearly uniform stands in the wet meadow areas around the southern lake shore. It’s not as big as the Jeffrey and other pines I’ve discussed, and although the trunk is straight as in the others, the crown tends to be narrower. It has the shortest needles of any of the Tahoe Basin pines – only about 2″ – and is also the only pine in the area with its needles in bundles of two – all other Tahoe Basin pine species have needles in bundles of three (Jeffrey and ponderosa) or five (sugar, western white, and whitebark).  p1020731_2This gives the foliage a finer, more delicate appearance, as seen in the photo at right with lodgepole pine on the right and Jeffrey pine on the left.  Lodgepole pine cones are quite small, only about 2″ in length, with an open structure and distinctive dark tips that contrast strongly with the brown scale bases.

I found this species sporadically throughout the forests along the Vikingsholm and Rubicon Trails when I hiked Emerald State Park; however, the best stands were seen in the meadows along the Upper Truckee River near the city of South Lake Tahoe and while cross-country skiing around Spooner Meadow near Spooner Lake in Nevada (elevation about 7,000′). This species likes moisture and is the dominant pine in the many wet meadow areas that are found in the Tahoe Basin. The photo below was taken at Spooner Meadow and shows the stands of lodgepole pine in the meadow, with Jeffrey pine taking over on the elevated hillsides. p1020738_2I also saw this species commonly at much higher elevations (about 8,000-9,000′) at Heavenly Ski Resort, where it took on a more stunted, windswept growth form that at first made me think I was seeing whitebark pine.

The Sierra Nevada-Cascade populations of this species are assigned to subspecies murrayana, while populations in the Coastal Range and Rocky Mountains are assigned to the nominate subspecies and subspecies latifolia, respectively. The three populations lost contact with each other when their ranges shrank during the Pleistocene glaciations, resulting in subspecific divergence before expanding their ranges northward again as the ice sheets retreated. A fourth subspecies in Mendocino, bolanderi, is believed to have evolved from a soil race or ecotype of coastal lodgepole.

Whitebark pine (Pinus albicaulis)

p1020794_2Whitebark pine is without question the most grotesquely beautiful of the Tahoe Basin pines. Growing only at the highest elevations, it develops a spectacular windswept form through endless pounding by fierce alpine winds and heavy snowpacks. Nearly pure stands of this tree were seen near the summits at 9,000-10,000′ elevation on both the California and the Nevada sides of Heavenly Ski Resort. It is usually encountered as a multistemmed plant with upswept branches and twisted, crooked trunks, a result of its unique association with Clark’s nutcrackers, who live almost exclusively on a diet of pine nuts. These birds harvest the seeds, which do not exit the cone as in most other pines, and cache them in groups of usually 3-4, relying on their memory to find their caches at a later date. p1020793_2Lanner (1999) refers to a 1990 study at Tioga Pass in the Sierra Nevada, in which it was estimated that each adult nutcracker cached an average 89,000 seeds and each juvenile about 34,000 seeds. In years when abundant seed crops are produced, the nutcrackers cache many more seeds than they or their offspring can utilize. It is these unrecovered caches that allow regeneration of whitebark pine, and the majority of trees that grow from them are members of stem clumps. Whitebark pine has no other mechanism for dispersing its seeds and is thus completely dependent upon Clark’s nutcracker for its regeneration.

p1020792_2Up close, whitebark pine needles are relatively short (usually about 2″ in length) and stout, and their bundles of five immediately distinguish this species from lodgepole pines which may grow with them and mimic their windswept form. The yellow-green needles lack the bluish cast of western white pine needles. The bark on the branches is smooth like the other soft pines but had a slightly reddish cast rather than the silvery gray color of sugar and western white pine or the flaky, orange-gray appearance of lodgepole pine.

In part two of this series, I’ll treat the remaining conifers of the Tahoe Basin, which include Abies and Tsuga in the Pinaceae and Calocedrus and Juniperus in the Cupressaceae.

REFERENCES:

Arno, S. F. 1973. Discovering Sierra Trees. Yosemite Association, Yosemite National Park, California, 89 pp. (at only $5, this is an excellent, informative book with beautiful ink drawings).

Graf, M.  1999. Plants of the Tahoe Basin.  Flowering Plants, Trees, and Ferns.  A Photographic Guide. California Native Plant Society Press, Berkeley, 308 pp.  (another excellent resource for plants specific to the Tahoe Basin).

Lanner, R. M.  1999. Conifers of California.  Cachuma Press, Los Olivos, California, 274 pp. (the ultimate resource for conifers in California).

Peterson, P. V., and P. V. Peterson, Jr.  1975. Native Trees of the Sierra Nevada.  University of California Press, Berkeley, 147 pp. (this compact field guide was in my pocket at all times).

Copyright © Ted C. MacRae 2009

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