Pinus Longaeva Research Articles

A 7,272-year tree-ring chronology for western Europe

Long tree-ring chronologies provide a unique calendrical record that is of value for archaeological dating, climatic and post-glacial studies. They also form a standard for the calibration of the radiocarbon time scale. The world's longest continuous tree-ring chronology is based on the bristlecone pine (Pinus aristata and Pinus longaeva) growing in the White Mountains of California1–3. The great age of living and sub-fossil trees of this species enabled a continuous tree-ring sequence of 8,681 years to be established, providing absolutely dated wood samples for the first radiocarbon calibration4,5. We have now established an unbroken west European tree-ring sequence spanning the past 7,272 years.

Paleobiogeography of Montane Islands in the Great Basin since the Last Glaciopluvial

The existing warm (Larrea) deserts of the Southwest are Holocene expansions replacing late—Pleistocene, evergreen woodlands of low—statured junipers, pinyon pines, and live oaks; these woodlands have been isolated by complementary contraction to the slopes of higher mountains that rise like islands from the modern desert sea. Because pinyon—juniper woodland is now so widespread on the similar fault—block mountains of the Great Basin, even as far north as southern Idaho, it would seem reasonable to suppose that the modern "cold" (Artemisia, Atriplex) deserts were similarly wooded during the last glacial. However, conclusive Neotoma macrofossil evidence (45 14C—dated assemblages are reported here) documents major latitudinal displacement of vegetation that precludes pinyon—juniper woodland in the northern and central Great Basin at that time. On the other hand, the entire Mohave Desert sector (south of °37°N) served as an extensive Pleistocene refugium for pinyon—juniper woodland, as documented by an additional 48 dated Neotoma deposits. During the Wisconsinan glacial in the southeastern corner of Oregon, a 42°27'N, there was a subarctic landscape of hyperboreal, prostrate shrublet—junipers (Juniperus horizontalis and J. communis) and widespread patterned ground, even at the near—basal elevation of 1460 m. The pleniglacial vegetation of the central Great Basin at 39°N in eastern Nevada and western Utah, was dominated by a regional subalpine forest of bristlecone pine (Pinus longaeva), associated with minor but consistent boreal juniper (J. communis) down to 1660 m, close to the base level imposed by pluvial Lake Bonneville. Spruce has not been recorded below 1900 m during the last glacial. At a lower range of elevation (1350—1525 m), available south of the southeastern rim of the Bonneville basin at 37°30'N. Pinus longaeva was replaced by limber pine (P. flexilis), Douglas—fir (Pseudotsuga), and montane red cedar (J. scopulorum); existing woodland juniper (J. osteosperma) was lacking, but the subalpine J. communis was present at this local base level. Theory of island biogeography, as applied to ecological islands atop the high mountains of the Great Basin, is reexamined in the light of the drastic vegetational displacements documented in the detailed Quaternary macrofossil record. Species/area plots of montane—subalpine conifers presently distributed on 54 Great Basin mountaintops show an overall insular pattern that is especially well developed on the subset of 38 ecological islands east of 116°W; the slope of z = 0.26 is close to the theoretical value for islands in equilibrium. All 11 taxa of montane—subalpine conifers that penetrate the Great Basin deeply have their main distributions in the Rocky Mountains; only three wide—ranging species occur also in the Sierra Nevada. A long sundering trough in the western Great Basin parallels and isolates the Cascade—Sierran uplift with low—elevation barriers that impede migration, but in the eastern Great Basin there are high connecting divides to the western Rockies, especially via an axial route southeast of the Bonneville basin. There is an east—west pattern of declining species richness of11 montane conifers in the Great Basin that correlates with distance from the rocky Mountain pool of 12 coniferous species. The pleniglacial subalpine forests in the lowlands of the central Great Basin had only one to three species of conifers (e.g., Pinus longaeva, Picea engelmannii, Juniperus communis). During the great late—glacial/Holocene (12 000—8000 yr BP) warming of climate, these shifted upward in elevation and were augmented in the east (but not in the west) by as many as five additional species of montane conifers. Macrofossil evidence indicted that the later Holocene arrivals dispersed across barriers of woodland and desert that by then isolated the shrunken montane islands. Moderately long—range transport of seeds by birds is deduced as follows: a northward latitudinal shift of 500—640 km during the Holocene is documented for several species of relatively thermophilous conifers, including the heavy—seeded, late—maturing pinyon pine. A 640—km migration in 8000 yr (80 m/yr) is indicated for pinyon, but the most generous estimate of its dispersal rate via the wind/gravity mode is a plodding 0.4 m/yr (3.2 km/8000 yr), orders of magnitude too slow. Seed dispersal by Clark's Nutcrackers and Pinyon Jays, however, is both the prevalent mode and amply swift enough to fit the known migrational history. Hence, the islands—in—equilibrium pattern indicated by the typically insular slope (z = 0.26) for montane conifers on the eastern set of mountaintops in the Great Basin is a reflection of Holocene immigration via sweepstakes dispersal being offset by extinction on the smaller islands. Both extinction and immigration of conifers are documented in the late—glacial/early—Holocene Neotoma record from the small Confusion Range in the east—central Great Basin of western Utah.

The determinate and indeterminate dwarf shoots of Pinus longaeva (bristlecone pine)

The dwarf shoot of the genus Pinus is normally regarded as a determinate short shoot, but the fate of the dwarf shoot apex after needle maturity and the origin of proliferated dwarf shoots remain controversial. To resolve these issues, 1- to 28-year-old dwarf shoots of P. longaeva were microscopically examined and experimentally manipulated. Eighty-eight percent of the lateral long shoots and all trunks had "proliferated dwarf shoots," or dwarf shoots that had become long shoots. On trunks 44.3% of the dwarf shoots had terminal buds, versus 6.6% on lateral long shoots. Most of these buds were microscopic, "interfoliar buds," derived from the original dwarf shoot apex. With advancing age of dwarf shoots there was no statistically significant change in the percentage of dwarf shoots with buds. The fate of the dwarf shoot apex depends upon the position of the dwarf shoot within its age-class and the type of long shoot. On lateral long shoots, only distal dwarf shoots have interfoliar buds and only these may spontaneously proliferate or be experimentally induced to proliferate into long shoots. Proximal dwarf shoots have a suberized apex. On trunks, both distal and proximal dwarf shoots often have buds and can thus proliferate. Dwarf shoot proliferations therefore arise predictably from interfoliar buds and not adventitiously.

Patterns and Levels of Genetic Variation in Great Basin Bristlecone Pine, Pinus longaeva

Patterns and Levels of Genetic Variation in Great Basin Bristlecone Pine, Pinus longaeva

Dendrochronology of Bristlecone Pine: A Progress Report

Dendrochronological studies of bristlecone pine, Pinus longaeva, have produced a continuous tree-ring sequence back to 6700 BC for the White Mountains of California and to 3258 BC for east-central Nevada.

Secondary Growth in Needle Leaves of Pinus longaeva (Bristlecone Pine) and Other Conifers: Quantitative Data

Needle leaves of Pinus longaeva can be accurately dated and remain alive on branches for 30 or more yrs, making this species ideal to study secondary growth in leaves. Field observations and regression analysis of needle age versus mean needle length both indicate primary (elongation) growth of needles is completed in the first year. Statistical analysis of cell counts for one- to 33-yr-old needles indicate production along the entire length of needles of 1.0-1.7 cell layers per year of secondary phloem, but no secondary xylem. Microscopic measurements and cell counts reveal that with advancing needle age phloem increases radially and transfusion tissue buckles, but the number of endodermal cells and xylem width do not change. Living phloem remains constant in amount (ca. 9 layers) with advancing needle age, indicating yearly replacement of old by new phloem. For comparison to P. longaeva, needle leaves were also studied for ten other conifer taxa with maximum needle longevities ranging from 3 to 19 yrs. In needles of each taxon no secondary xylem is produced, but secondary phloem production occurs throughout the post-elongation lifespan of the needles regardless of maximum needle longevity.

SECONDARY GROWTH IN NEEDLE LEAVES OF PINUS LONGAEVA (BRISTLECONE PINE) AND OTHER CONIFERS: QUANTITATIVE DATA

Needle leaves of Pinus longaeva can be accurately dated and remain alive on branches for 30 or more yrs, making this species ideal to study secondary growth in leaves. Field observations and regression analysis of needle age versus mean needle length both indicate primary (elongation) growth of needles is completed in the first year. Statistical analysis of cell counts for one‐ to 33‐yr‐old needles indicate production along the entire length of needles of 1.0‐1.7 cell layers per year of secondary phloem, but no secondary xylem. Microscopic measurements and cell counts reveal that with advancing needle age phloem increases radially and transfusion tissue buckles, but the number of endodermal cells and xylem width do not change. Living phloem remains constant in amount (ca. 9 layers) with advancing needle age, indicating yearly replacement of old by new phloem. For comparison to P. longaeva, needle leaves were also studied for ten other conifer taxa with maximum needle longevities ranging from 3 to 19 yrs. In needles of each taxon no secondary xylem is produced, but secondary phloem production occurs throughout the post‐elongation lifespan of the needles regardless of maximum needle longevity.

Variability in essential oils and needle resin canals of Pinus longaeva from Eastern California and Western Nevada in relation to other members of subsection Balfourianae

Mono- and sesquiterpenoids from wood and leaves of Pinus longaeva trees collected in various localities of eastern California and western Nevada were quantitatively analyzed by GLC. Concurrently the number and size of resin canals in foliage of the same trees and as well as Pinus aristata trees from Arizona, Colorado and New Mexico were determined. While some monoterpenes (mainly α-pinene and 3-carene) suggest that P. longaeva trees from the Panamint Mountains of California are P. aristata-like, the total chemical data and morphological data indicate that Panamint trees should be grouped with P. longaeva. A chemical latitudinal gradient is evidenced by the appearance of trees producing 3-carene in large amounts along the line joining the Panamint, Inyo and White Mountains of California. Pinus rzedowskii, well separated geographically and morphologically from the accepted members of subsection Balfourianae, is shown to be sufficiently distinct chemically, as to leave its suggested membership in the subsection an open question.

Longevity of needle fascicles of Pinus longaeva (Bristlecone pine) and other North American pines.

Variation in leaf longevity of gymnosperms has received surprisingly little attention despite its likely adaptive significance. Pinus longaeva, a pine of arid, subalpine environments in the western United States, has the record among conifers for needle longevity, with a maximum dwarf shoot (needle fascicle) retention time of up to about 45 years. Most low elevation pines have dwarf shoot retention times (DSRs) of two to four years. Literature data for the 37 species of Pinus native to the United States and Canada and field data for eight taxa (21 populations) of pines growing at various elevations in California each show a strong positive correlation between elevation and DSR, respectively, r=+0.65, df=35, p<0.001 and r=+0.82; df=19, p<0.001. We propose that extended needle fascicle longevity represents an adaptation to arid and especially high elevation environments. Field data from native stands and common gardens indicate that differences between taxa in DSR relate to both genetic and environmental factors. When grown at the same sites certain species (eg, P. longaeva, P. monophylla) had much longer DSRs than others, indicating a genetic basis for differences in needle fascicle longevity. For six of seven taxa that were each studied at more than one elevation there was a statistically significant increase in DSR in going from the lowest to the highest elevation site, indicating strong environmental control of needle fascicle longevity.The physiological control of dwarf shoot senescence and abscission is poorly understood. For P. longaeva dwarf shoots of a particular age class are not shed simultaneously; rather there is a more or less gradual attrition of dwarf shoots from the long shoot. Although different types of long shoots of pines are known to differ physiologically, for P. longaeva there was no consistent difference in DSR on various types of lateral long shoots (eg, vegetative, pollen cone-bearing, seed cone-bearing), nor was there a statistically significant difference in DSR on trunks versus on their lateral long shoots. In addition, for P. contorta ssp. bolanderi and P. muricata needle fascicle longevity was not affected by the degree of edaphically induced dwarfing (ie, stunting) of the trees.

Ecological Relationships of Bristlecone Pine

Functional relationships between bristlecone pine (Pinus longaeva Bailey)1 growth characteristics and environmental factors were investigated near Wheeler Peak and Bastian Peak in E-central Nevada. Because of bristlecone pine's intolerance to shading it constituted only a small percentage of the total tree cover on sites favoring good growth rates and dense timber stands. On such sites limber pine (P. flexilis James) and Engelmann spruce (Picea engelmanni Parry ex Engelm.) dominated the stands. On harsher sites bristlecone pine often formed essentially pure, although sparse, stands. Regression analyses (both simple and multiple) and analyses of variance revealed that bristlecone pines are faster growing, taller, straighter and less sensitive to climatic fluctuations on sites where moisture conditions are favorable. Organic carbon, clay and mean air temperature accounted for 83% of the variation in mean annual growth rates of bristlecone pine. Organic carbon and mean air temperature accounted for 55% of the variation in mean sensitivity (a measure of annual variation in ring width) of the trees. Maximum tree age is associated with harsh growing conditions which result in slow growth rates and dense, highly resinous wood. 1D. ?. Bailey (1970) demonstrated seveial important differences between the bristlecone pines and the Rocky Mountain bristlecone pines (Pinus aristata) as described by Engelmann. He proposed that the Great Basin population be considered a separate species, viz., Pinus longaeva Bailey. Nomenclature for other plant species follows Munz and Keck (1959). Introduction Bristlecone pine (Pinus longaeva Bailey) grows and attains great longevity on dry, rocky subalpine habitats in the southwestern United States. Trees over 3000 years old are common in particular habitats and several trees in excess of 4000 years have been reported in California (Schulman and Ferguson, 1956) ; only one bristlecone pine over 4000 years has been found in Nevada (Currey, 1965; Ferguson, 1970b). The longevity and esthetic appeal of the gnarled weather-beaten trees and their habitats have generated much interest among scientists and naturalists. Study of these ancient trees is contributing to many fields of science, including dendrochronology, climatology, geology and archaeology (Ferguson, 1968; Renfrew, 1973; LaMarche, 1974; Wilson, 1975). Yet, knowledge of the longevity and unique growth habit of bristlecone pine is still limited (LaMarche, 1969). The objective of this study was to identify environmental factors which might influence growth and distribution of bristlecone pine in E-central Nevada and to examine functional relationships between tree characteristics, environmental factors and soil properties. Study Area The study areas?Wheeler Peak and Bastian Peak?are E of Ely, Nevada, in the Snake and Schell Creek ranges, respectively, near the geographic center of the Basin and Range physiographic province of western North America. Near Wheeler Peak, bristlecone pine sites lie between 2900 m elevation and timbe rline (3200 m). Slopes are steep and covered with coarse, blocky, quartzitic glacial till. Soil derived from quartzite occupies interstices within the glacial till and supports sparse stands of bristlecone pine, Engelmann spruce (Picea engelmanni Parry ex Engelm.), limber pine (Pinus flexilis James) and scattered shrubs, herbs and grasses. On Bastian Peak, elevation 3274 m, bristlecone pine grows on soils derived from limestone. Slope gradients are steep on the E and W sides of the ridge but gentle to moderate near the crest. Limestone is exposed on the W side of Bastian Peak in

13C/ 12C ratio variations in Pinus longaeva (bristlecone pine) cellulose during the last millennium

δ 13C values are presented for cellulose samples prepared from two dendrochronologically dated Pinus longaeva (bristlecone pine) trees which grew during the last 1000 years. δ 13C variations for these lower forest border trees are similar to upper tree line ring-width variations for the same species and English high summer temperature variations for the same time period. However, the δ 13C variations appear to be unrelated to lower forest border ring-width variations and cellulose δ D variations for the same specimens.

Dendrochronology of bristlecone pine, Pinus longaeva

Since 1953 the Laboratory of Tree-Ring Research has conducted dendrochronological studies of bristlecone pine ( Pinus longaeva D.K. Bailey, sp. nov.) in the White Mountains of California. This research resulted in the establishment of a continuous tree-ring sequence of 8253 yr. The millennia-old pines have emerged as a unique source of chronological data and the precisely dated wood is essential to certain paleoenvironmental and geophysical investigations. Over 1000 dendrochronologically dated decade samples of bristlecone pine supplied to three C-14 laboratories have been used to calibrate the radiocarbon time scale for the past seven millennia, a development of far reaching consequences in the fields of archaeology and geology. In addition, recent advances in other methods of analyzing past climatic variability — techniques involving stable isotope ratios, amino acid racemization, remanent magnetism, and trace element abundances — have greatly increased the demand for wood of known age and, hence, for chronology development. Spanning the past 7500 yr, 1138 prepared decade samples, with a total weight of nearly 16 kg are available for study.

Variability in the essential oils of wood and foliage of Pinus aristata and Pinus longaeva

Variations in the monoterpenoid composition of the essential oil of wood, and of the mono- and sesquiterpenoids of foliage collected from more than 200 specimens of pines of subsection Balfourianae (P. aristata, P. longaeva and P. balfouriana) substantiate the previously reported morphological and chemical separation of P. aristata and P. longaeva and suggest a restricted intermediacy in northern Arizona and eastern California. On the basis of wood essential oil the limited population of P. aristata in northern Arizona, while exhibiting to a slight degree morphological intermediacy, is found to be practically identical to the main populations of P. aristata in Colorado and New Mexico. On the basis of foliage oil, however, the same population is clearly intermediate, but closer to P. aristata. The detailed chemical data suggest a distinct chemical status for the Arizona population, with selection for the present-day chemophenotypes being the dominant factor in their evolution. Analysis of monoterpenoids from P. balfouriana × longaeva hybrids indicates that incomplete selective elimination of 3-carene-producing P. longaeva chemophenotypes rather than gene exchange with P. balfouriana is responsible for the presence of abnormal P. aristata-like 3-carene-producing trees in eastern California. The latter trees could have resulted from limited gene exchange between P. aristata and P. longaeva by routes no longer available to them lying to the south of the Grand Canyon.

Water stress in bristlecone pine and associated plants

Abstract Measurements of leaf water potential taken in the Snake Range of Nevada indicate that bristlecone pine (Pinus longaeva Bailey) may be adapted to maintain lower internal water stress than some of its competitors. This characteristic may account in part for the tree's dominance on harsh timberline sites.

Holocene climatic variations inferred from treeline fluctuations in the White Mountains, California

Remains of dead bristlecone pine ( Pinus longaeva Bailey) are found at altitudes up to 150 m above present treeline in the White Mountains. Standing snags and remnants in two study areas were mapped and sampled for dating by tree-ring and radiocarbon methods. The oldest remnants represent trees established more than 7400 y.a. Experimental and empirical evidence indicates that the position of the treeline is closely related to warm-season temperatures, but that precipitation may also be important in at least one of the areas. The upper treeline was at high levels in both areas until after about 2200 B.C., indicating warm-season temperatures about 3.5°F higher than those of the past few hundred years. However, the record is incomplete, relative warmth may have been maintained until at least 1500 B.C. Cooler and wetter conditions are indicated for the period 1500 B.C.-500 B.C., followed by a period of cool but drier climate. A major treeline decline occurred between about A.D. 1100 and A.D. 1500, probably reflecting onset of cold and dry conditions. High reproduction rates and establishment of scattered seedlings at high altitudes within the past 100 yr represents an incipient treeline advance, which reflected a general climatic warming beginning in the mid-19th century that has lasted until recent decades in the western United States. This evidence for climatic variation is broadly consistent with the record of Neoglacial advances in the North American Cordillera, and supports Antevs' concept of a warm “altithermal age” in the Great Basin.

Recognizing site adversity and drought-sensitive trees in stands of bristlecone pine (Pinus longaeva)

Bristlecone pine has been called the world's oldest known living thing. The tree grows in mountainous terrain near timberline in three southwestern states. Because of the species' longevity, sensitivity to climatic fluctuations, and unique growth form, it has attracted considerable attention from both scientists and recreationists. This paper discusses bristlecone pine in relation to its environment in east-central Nevada and sets forth criteria for recognizing trees that may be old or sensitive to climatic changes.

Variability of the wood monoterpenoids from Pinus aristata

Striking differences in turpentine composition between California-Nevada-Utah populations and Colorado-New Mexico-Arizona populations of the Bristlecone pine ( Pinus aristata) were demonstrated by GLC analyses of the wood extracts. These differences are in line with Bailey's taxonomic division of Pinus aristata sensu lato into western Pinus longaeva and eastern Pinus aristata sensu stricto.

Recent Climatic Change and Development of the Bristlecone Pine (P. longaeva Bailey) Krummholz Zone, Mt. Washington, Nevada

Wood remnants above the present upper tree line are the basis for reconstruction of past changes in tree form and distribution. Living bristlecone pines (Pinus longaeva Bailey) on Mt. Washington, i...