March 3, 2013

Ponderosa Pine

Becoming deeply familiar with this tree, the most regal of pines, will almost certainly lead to a richer, more fulfilling life, and offer many new ways of seeing the world.
Ponderosa Pine
Pinus ponderosa
Pinaceae (Pine Family)

Quick ID:  Luckily, ponderosas are pretty easy trees to pin down.  They're giant, regal evergreens with thick, straight trunks.  Branches of older trees are clustered toward the top, developing a distinctively massive bole (the part of the trunk below where the branches start).  A ponderosa's branches are relatively short for its stature, and turn up at the ends.  Needles are 5-10" long, in fascicles, or bundles, of 3 (sometimes 2 or 5 depending on the variety).
From a distance, it's easy to distinguish long-needled ponderosas from other, shorter-needled evergreens.    Up close, you can recognize them by their orange puzzle-piece bark with its deep black furrows.  Be sure to stick your nose into these crevices in spring and sniff the rich vanilla-scented sap running under the bark.
Like all Pinus members, the female cones are hard-scaled, as opposed to the soft paper-scaled cones of conifers like spruce (Picea).  They're armed with a poky prickle and open in fall to release tiny winged seeds.
According to the Utah Forest News, the oldest ponderosa in the world is in the Wah Wah Mountains, and is at somewhere around 940 years.  The National Register of Big Trees says the tallest (of the interior variety) is right here in Lolo National Forest and was 194' as of 1997. 

Range:  This is the most common pine in North America, and is widespread throughout the west, from BC to Mexico and east through the Black Hills.  It covers 38 million acres across 14 states.  Interior ponderosa is most common around 6000-8500', found randomly spaced in open grasslands at lower elevations, with stands becoming denser as elevation increases.  Check out the USDA range maps and some details on regional varieties here.

What's in a Name?  Ponderosa is also known as Western Yellow, Bull, Blackjack, Western Red, Sierra Brownbark, Heavy, and Western Pitch Pine.  According to Flora of North America"Its wood is more similar in character to the white pines, and it is often referred to as white pine. The taxonomy of this complex is far from resolved."  What we do know is this...  
1.  It was named for its heavy, "ponderous" wood in 1826 by the fascinating botanist David Douglas, from a specimen found near present-day Spokane.
2.  The common name "pine" (and genus Pinus) ultimately derive from the Sanskrit pituh, "juice, sap, or resin", the Greek pitys, "pine tree", and Latin pinguis, "fat".
3.  There are basically three varieties:  P. ponderosa var. ponderosa, found along the Pacific Coast, P. p.var. arizonica in the southwest, and the widespread interior variety, P. p. var. scopulorum (that's the one we have here in Montana, and the one I'm referring to in this post).  They differ in size and fascicle number, but also overlap in morphology and distribution, and vary by latitude.  As you can imagine...the taxonomy of this complex is far from resolved.
Ponderosa is the most commercially important timber tree in the west, and has played a huge role in the region's economic development since the early pioneer days.  The lumber was used intensively for building homes, railroads, telegraphs and mine bracing, and is still considered great for construction.  In 1949, the Montana Federation of Garden Clubs convinced the Legislature that the Ponderosa was the "King of the Forest".  It was adopted as the Montana state tree that same year, and we've all celebrated ever since.Equally important is P. pine's essential role in the ecology of western North America.  The behemoths create a mosaic of open stands filled with understory browse, interior woodland food and cover, and snags for cavity nesters and hunters.

Next time you're standing by one of these old trees, think about how incredibly well-adapted it is to the surface fires that naturally occur in this area.  The branches prune themselves up and out of reach.  Even then, the needles cluster tight around vulnerable growing branch tips, and open loosely farther up to discourage flames.  The bark is thick and insulative, as are the scales covering the buds.  The roots are deep, the size of lodgepoles themselves.  Regular low-intensity surface fire opens the canopy to light and burns up the thick layer of plant debris that builds up on the ground, encouraging graminoids (grasses) to germinate in the nutrient-rich, ashen soil.  It also thins out young trees, particularly the less fire-resistant ones.  It may go without saying that trees in crowded interior stands where fire has been suppressed are much more susceptible to catastrophic crown fires.  In the competition for space, they develop thinner bark and more compact foliage, and the closed canopy creates a dense understory of combustible "ladder fuels".
Anthropogenic factors like dense stands and stagnated nutrient cycling in the absence of fires, coupled with prolonged drought, have led to supreme stress on interior ponderosa ecosystems.  As a result, P. pine is susceptible to a slew of pests including Dwarf Mistletoe, insects like Pine and Bark Beetles (Dendroctonus and Ipsspp.) and wood decaying fungi like red rot and western gall rust.  The Forest Service has this to say:
"Besides unprecedented, large-acreage severe fires, other ecological consequences of fire suppression in interior ponderosa pine ecosystems include:

  • decreases in soil moisture and nutrient availability
  • decreases in spring and stream flows
  • decreases in animal productivity
  • increased concentrations of potentially allelopathic terpenes in pine litter
  • decreases in productivity and diversity of herbaceous and woody understory species
  • decreases in tree vigor, especially the oldest age class of pines, and
  • increased mortality in the oldest age classes of trees"

    The ecological changes in Ponderosa forests that have occurred in the last century as a result of fire exclusion, overstory logging and heavy grazing are a well-documented, fascinating and perhaps scary story that everyone in the west should be familiar with.  

Fire rolls through a Salmon River ponderosa pine stand in the River of No Return Wilderness, Idaho

Wild Gardening
Despite the complicated (and controversial) state of ponderosa forest ecology, the fact remains the this pine is extremely well adapted to the soils, temperatures and moisture regimes of the west.  Try planting P. pine to establish windbreaks or as an impressive ornamental, if you have the space (they grow 60-150' in cultivation).  You can collect not-quite-open cones in late summer, and dry them on racks to release the seeds.  Sow your untreated seeds in late fall; you'll have better luck if you start them in containers before you put them out in the ground.  You'll be providing food and cover for all sorts of wildlife, and will be rewarded with the company of the most awe-inspiring of trees.
You can read an incredibly detailed and fascinating account of ponderosa ecology here.
This blog entry was originally created for the Montana Natural History Center.  Check out the original blog post here.

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