29 October 2010

Lovely Larchiness

Larches have become one of my favorite trees since my move to Montana five years ago.  My first autumn here, I took a drive east on Highway 200, and I remember asking my friend, "What's wrong with all those trees?" as we passed hillsides covered with yellow-needled larches.  I thought they were dying.  Little did I know!  Now I'm married to a botanist and naturalist whose favorite tree is the larch, which means I've learned lots about these amazing trees in the past couple of years.  And the more I learn about them, the more I am fascinated by them.

Alpine larches at Glen Lake
Though there are about 10 different species of larch worldwide, we have just two types of larches (or tamaracks) here in western Montana, the western larch (Larix occidentalis) and the alpine larch (Larix lyallii).  What makes these trees unique among conifers is that they are one of just a handful of genera that are deciduous.  In the fall the needles turn a glorious golden color that splashes across the landscape, a bright contrast to the deep greens of the pines and firs and spruces.  In the spring, that same bright contrast is evident, but this time the color is the vivid green of new growth.  Whether it be spring or fall (or, for that matter, anytime in between), the lovely larch is worth searching out.  

In Donald Peattie's A Natural History of Western Trees, he writes, "Concerning the Alpine Larch the fact which even most naturalists know best is that they have never seen it.  And so scattered is its growth, so wild and inhospitable its favorite haunts at timber line . . . that most people would not know where exactly to begin to look for it."

Yet here in western Montana, we can (comparatively) easily walk among the Larix lyallii.  If you haven't yet done so, I highly recommend you change that.  One of the easiest spots to reach, after just a two-and-a-half-mile hike, is Glen Lake in the Bitterroot Valley.  Carlton Ridge/Lolo Peak is another great spot for alpine larches.  This year my husband and I took our alpine larch pilgrimage to the Bass Creek Overlook, just as the colors were peaking at the end of September.  (A word to the wise:  this trail gets pretty steep--but the larches are worth it!)

Alpine larches at Bass Creek Overlook
Besides being a place that provides fairly easy access to the alpine larch,  we in western Montana are also near one of the very few places where Larix lyallii and Laruix occidentalis hybridize.  This happens not only because the ranges overlap here (there are quite a few places where this is the case), but because of of the unique geography of the area.  In places like Carlton Ridge (just below Lolo Peak), where there are steep, north-facing slopes, alpine larches creep down the slope while western larches creep up, and the two species hybridize.  Now seeing a hybrid larch is definitely worth putting on the bucket list!

Alpine larches, which are found at elevations of 4,000-8,000 feet, tend to turn golden and shed their needles about a month before their lower-elevation (2,000-7,000 feet) counterparts.   But if you missed the alpine larches changing color, do not despair!  You still have time to enjoy the changing colors of our western larches (which also  have the advantage of being much easier to get to).  There are even a few in various yards around Missoula, if you know where to look.  So now is the time to go take a walk in the Rattlesnake, or Pattee Canyon (see below--this was taken just yesterday, on on October 28th), 

Western larches at Pattee Canyon
or along the Kim Williams trail.  Or, if you don't mind a little driving, Seeley Lake has some spectacular old-growth larch stands, including what is claimed to be the largest Larix in the world.  

Aside from their deciduous nature, larches can be identified by their clusters of needles, which are found in groups of 15-30 on western larches and 30-40 on alpine larches.

alpine larch needles
western larch needles

Western larches have thin, scaly bark when they are young, but as they mature the bark thickens--up to 3-6 inches thick on old-growth trees.  As the trees age, the bark darkens to a reddish-brown, and comes to look very much like the puzzle-bark of Ponderosa pines (though without the intoxicating vanilla fragrance).  The thick bark helps protect the larch from fires, as does its ready ability to create new needles.  Larch trees are also able to sprout new branches from the side of their trunks, yet another unique adaptation that gives this species a high survival rate from forest fires. 

While there are a plethora of fascinating facts about larches, what may be most important to note is that they are here, in western Montana, and that we have the good fortune to be able to see them with so very little effort.  So don't just drive by their changing beauty at 75 mph on the freeway--take the time to seek them out, walk among them, and absorb their loveliness.  And if you want to share your favorite larch-viewing place, that would be wonderful!

22 October 2010

Spotlight On...Rubber Rabbitbrush

Rubber Rabbitbrush
Chrysothamnus nauseosus
Asteraceae (Sunflower Family)
Quick ID:  
In general, Rabbitbrush appears similar to Big Sagebrush--a scrubby shrub with grayish-tinged, woolly leaves.  Like sagebrush, it's found in dry, open plains or disturbed sites, and grows about 1 to 6 feet high.  The leaves are linear and alternate on flexible stems.  The yellow flowers bloom late (August-October), blanketing the plains and slopes with the type of brilliant display most flora exhausted months ago.  Being in the Asteraceae family, each flower is actually a loose cluster of mini-blooms known as "disc flowers", like the ones in the eye of a sunflower or daisy.  The "ray flowers" that we know as petals in other Asteraceae species are absent in Rabbitbrush.  
Found up to 10,000', from Canada to Mexico, east of the Pacific mountain system and stretching to the Great Plains.  Look for it growing near dryland bunchgrasses and shrubs like Big Sagebrush (Artemesia tridentata), Basin Wildrye (Leymus cinereus), Mountain Mahogany (Cercocarpus ledifolius) and Bluebunch Wheatgrass (Pseudoregenaria spicata).
What's in a Name?
A quick note on taxonomy:
It's the most fickle sport among scientists, always in flux and impossible to keep up on.  It's not so easy to remember all this archaic Latin binomial nomenclature, and once you think you've got it down, a new taxonomical relationship is discovered or refuted, groups are shuffled around, and the 15 syllable name you've been proudly slipping into casual conversation and engraving onto your garden signs is now obsolete.  So if you're the type to stick with what you know and ignore all the newfangled monikers, I, for one, won't judge you.
That said, Rubber Rabbitbrush is technically known as "Ericameria nauseosa (Pallas ex Pursh) G.L. Nesom & Baird", but in my heart of hearts, it will always be Chrysothamnus.  Chryso- means gold, -thamnus a thicket.  The "nauseous" root in the specific epithet is in reference to the strong smell the plant gives off, rather than the idea that ingesting it will make you sick.  In fact, the plant's thick latex has been used for centuries as a sort of chewing gum (hence the "Rubber" part).  It provides shelter for and is eaten by rabbits and other small mammals.
In some southern parts of the country, Rabbitbrush is known almost exclusively as Chamisa, from the Spanish word for brush or kindling, and ultimately derived from the Latin chama (-->flamma-->"flame").        
The presence of Rabbitbrush, which often grows on very poor soils, and is considered a useful indicator that land is eroded or overgrazed.  It can be an important winter forage for antelope, mule deer and elk on depleted rangelands, but is sometimes reported to be toxic to livestock.
The plant has a few adaptations that allow it to thrive in arid, inhospitable places.  It's tolerant to a wide range of soil types, alkalinity, salinity, cold and drought.  The felt-like fuzz covering the stems (technically known as trichomes) acts as insulation and reduces water loss.  The light gray stems also reflect more heat than dark green leaves would, keeping the shrubs cool as a cuke in the harsh summer sun of the open prairie.
Historically, Rabbitbrush has been used to make yellow or green dye, and prepared as a tea to help coughs and colds.  The flexible twigs are good for baskets, and the seeds can be ground and used much like cornmeal.  
People have been looking for a way to use the natural latex found in the roots and inner bark to produce rubber since the 1930s, but haven't found a commercially viable way to extract it.  There is currently an investigation underway by the University of Nevada, looking at the potential of Rabbitbrush as a multi-use industrial crop for biomaterial and bioenergy applications.  Here's the interesting project summary.

Wild Gardening:  Plants need about 4' of space, and take about 4 years to mature.  They tend to produce about a million branches, generally arising from a common point and not overtaking neighbor plants.  Overwatering or fertilizing can produce leggy, sprawling plants.  New plants sprout up from the roots and can be divided, and the seeds germinate easily.
Being a late bloomer, Rabbitbrush fills an important niche both as an ornamental perennial and a fall pollen source for bees, flies and butterflies.  To see this plant in late fall, spilling over with brilliant color and buzzing with hundreds of hungry and deprived insects, is really incredible.  It tolerates fussing-over, but seems to delight in neglect: no extra water, no soil amendments, no pruning or deadheading.  The soft, pale branches complement the muted palette of a xeric landscape perfectly, and provide a safe haven for nesting birds and other small animals.

    Spotlight On... features Montana native plants that are currently on display in our natural areas.  Have a plant that you'd like to see featured?  Let us know!