Conifers Archives - Page 12 of 17

July 11, 2014December 13, 2019

The Ecological Staircases of Mendocino County

Original Publication DATE: 11/7/2012

A sequence of five elevated marine terraces along Jug Handle Creek in coastal Mendocino County constitutes a nationally and internationally famous ecological staircase. So outstanding is the combination of canyons, terraces and ancient dunes, tall redwoods and firs, bishop pine forest and dwarfed pines and cypresses that…It has become a Mecca for naturalists, botanists, ecologists, pedologists (soil scientists), geographers and nature-oriented laymen. It is being praised as the best preserved ecological showplace of coastal landscape evolution anywhere in the northern hemisphere.
–Hans Jenny 1973

Throughout the Pleistocene, as the climate fluctuated, sea levels rose and fell in conjunction with the size of the polar ice caps thus allowing oceanic wave-action to cut coastal terraces around the world. Subsequent tectonic forces then slowly pushed these terraces upward. What we now witness in coastal Mendocino County is, as Jenny states, the best preserved ecological showplace of coastal landscape evolution in the Northern Hemisphere.

Through other dynamic processes, beach materials like sand, gravel, clay and other rock have been deposited on the terraces at varied depths. Directly adjacent to the Pacific Ocean on the first step, wind sculpts coastal scrub and grassland on coastal bluffs or “Bonsai” beach and bishop pine forests just inland. A bit further up the staircase, out of reach of the salty air, ample precipitation, Pleistocene and Holocene sand dunes, and deposition of nutrient-rich conifer needles offers the abiotic needs for trees with deep roots and tall shoots. However, the most amazing staircase story begins just to the east of the ancient dunes.

July 10, 2014

Bristleconing: from Charleston to San Francisco

Original Publication DATE: 7/7/2012

Spring Mountain National Recreation Area

Rising from the lowlands at the edge of the Mojave and Great Basin deserts, the Spring Mountains are renowned for flora and fauna found nowhere else in the world. This endemism occurs because these mountains exhibit extreme vertical relief, temporal isolation, and a geographic position on the boundary of two deserts. Charleston Peak, the highest mountain in the range at nearly 12,000′, is a stark contrast to the desert 9,000′ below. Vertical relief is a barrier to migrations and, as a result, relict species have persisted and new species have evolved. It is postulated that at least 25 species (15 vascular plants, 1 mammal, 9 invertebrates) are endemic to the Spring Mountains (Spring Mountain Conservation Agreement 1998).

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July 9, 2014

Conifer Rarity in Southern California

Original Publication DATE: 3/17/2012

Work occasioned a trip to southern California which, of course, also required me to spend some time with a few regionally endemic conifers. I had never visited the Torrey pine or Cuyamaca cypress, so in planning the trip to Palm Springs for a conference, Allison and I took a few extra days–looping south toward the Mexican border–to see North America’s rarest pine and cypress.

Torry Pine (Pinus torreyana)

Rarity is a new endeavor for the Torrey pine. Though it is the current record-holder for “rarest North American pine” it has not always been that way. It is an ancient pine, whose lineage (or at least that of a near ancestor) extends back as far as the Oligocene or Miocene with a range that extended as far north as Oregon (Kral 1993). In the Pleistocene, the species probably ranged throughout the coastal basins of Southern California but became restricted to coastal San Diego County and Santa Rosa Island over the last 12,000 years or so, during Holocene warming (Waters and Schaal 1991). Its closest extant relative is probably the Coulter pine (Pinus coulteri).

San_Diego_2012074_pano — Charismatic specimens are sculpted by the pervasive wind, fed by moist coastal fog, and nourished by the sandstone on which they root.

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July 9, 2014

High Pressure in the Siskiyou Wilderness

Original Publication DATE: 12/16/2011

The winds were blowing across southern California and the skies were clear in the north. This unseasonal weather, cultivated by a high pressure system sitting over most of the West coast, motivated a 24 hour whirlwind into the Siskiyou Wilderness. My goal was to search for an unusual population of Alaska yellow-cedar documented and collected by Overton and Butler in 1979. I had discredited this report for several years because it did not fit within the parameters of my expectations for the species’ regional ecological amplitude–reported at a mere 3115 feet. If true, this would be over 2000 feet lower than any other regional population. In the fall I made it to the HSU Herbarium to look at the specimen and, sure enough, it was properly identified by the duo. I had to find this unusual place. The high pressure was the excuse to escape the stress of the end of 2011, get into the mountains, and attempt to find another outlier in the Siskiyou Wilderness.

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July 6, 2014

Larix Lyallii | Derivations on a survival regime

Original Publication DATE: 8/10/2011

Conifers possess highly derived adaptations that allow them to flourish on continental land masses north and south of the 45th parallel—to the arctic tree line. They also grow in similar regions with decreasing latitude, like the various cordilleras of western North America. Though they comprise less than 1% of all plant species (~630), they define 30% of the forests on Earth. In order to survive in colder climates conifers must be able to handle temperature and moisture extremes. As a cat preens its fur, most conifers care for their needles. These waxy progeny are coddled when energy is diverted from other tree functions to maintain needles—often for many years. This heavy investment must allow needles to endure both high and low temperatures while at the same time regulating water loss during the warmer months. Also, because most conifers are evergreen, they are not inhibited by late spring or even summer frosts which might otherwise kill the leaves of a less cold-adapted species. Angiosperms–many of which are deciduous–generally inhabit lower elevations and warmer regions where they spend less time and energy in leaf production and maintenance and can therefore allocate resources to grow faster and pioneer oft-disturbed landscapes more rapidly. It it these two generalized survival regimes that had me confused on a recent backpack into the Pasayten Wilderness where there is a conifer that has blazed a unique path for survival on the edge of the Washington State alpine tundra.

The alpine tundra of the Pasayten Wilderness is characterized by small hummocks decorated with diminutive heaths and grasses with the much taller conifers surviving on only the fringes of this landscape.

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