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Aboveground live biomass, surface area, and net production have been estimated in two 0.36-ha stands each of white fir (Abiesconcolor), red fir (Abiesmagnifica), and mixed red and white fir in Sequoia National Park in the southern Sierra Nevada of California. Estimates are based on regressions developed from dimension analysis of 12 individuals of each fir species harvested in the adjacent Sequoia National Forest. The white fir forests are the largest and most productive of the several fir forests measured. The net production values of 1630–2200 g•m−2•year−1 are 1.3–2.7 times higher than for red or mixed fir forests and are at the high end of values reported from other highly productive coniferous forests of the western United States. The high productivity of these forests is attributable in part to the high proportion of aboveground biomass in leaves (4%), which remain on branches for up to 24 years or more, coupled with a high tolerance to shading. Production per unit leaf area is comparable to productive coast redwood and ponderosa pine stands. The biomass of white fir forests (59–97 kg•m−2) is in the range of other coniferous forests of the Pacific Northwest. The red fir forests are lower in height, smaller in biomass (40–67 kg•m−2), and lower in production (810–1030 g•m−2•year−1), consistent with the higher elevation and greater climatic stresses of their typical habitats. In growth form, the two species are similar, with red fir showing a more rapid increase in leaf biomass with stem or sapwood diameter increase than white fir and greater bark production. All-sided leaf area indices of 15–21 m2•m−2 for white fir and 17–25 m2•m−2for red fir are similar to values reported for mixed fir forests of comparable rainfall in Oregon.

Simple regressions of single band thematic mapper simulator (TMS) reflectance data against stand basal area and leaf biomass show that the spectral feature most strongly related to vegetation amount is visible reflectance (TM bands 1, 2 and 3), which decreases as conifer basal area increases. Principal components analysis of TMS spectral data for sample stands, and stepwise multiple regression of transformed axes, showed the first principal component, interpreted as scene brightness, to be the composite spectral feature most correlated to vegetation amount. TMS data showed some ability to discriminate spectrally between coniferous forest stands dominated by different species. Dense stands of large timber dominated by red fir (Abies magnified var. shastemis) had a different average spectral reflectance from white fir (Abies concolor) dominated stands, particularly in TM bands 4 (0.76-0.90μm) and 6 (10-4-12-5μm).

MaleIps paraconfususselected a host, ponderosa pine (Pinus ponderosa), over a non-host, white fir (Abies concolor), only after the beetles had bored through the outer bark and into the phloem. Males, when given a choice between bark discs of these tree species in petri dishes, bored readily through the outer bark of either species. However, the beetles penetrated no more than 1 mm into the phloem of white fir, but they bored extensively in the phloem of ponderosa pine. The beetle’s preference for the pine over fir phloem was apparent with intact samples of phloem with the outer bark removed and with ground phloem. No preferences were apparent for the ground or intact pine or fir outer bark, with the phloem removed. The beetles bored preferentially in fissured as opposed to smooth outer bark of either tree. Beetles did not feed in the outer bark but did feed in the phloem of either species. In field experiments beetles attracted to logs of pine and fir bored through the outer bark of each species in nearly equal numbers. In white fir they re-emerged and departed soon after penetration of the phloem, whereas in ponderosa pine they continued excavation of tunnels in the phloem. In contrast, few beetles penetrated even the outer back of incense cedar (Calocedrus decurrens), another non-host species.

Several wood structural characteristics were measured in 15-year-old Abiesconcolor (white fir) from four populations along an elevational transect in the central Sierra Nevada region. The trees had been growing in a plantation near Placerville, California. Growth rings were narrower at breast height, latewood percentage tended to be greater, and tracheids were shorter in trees from higher elevation populations. Proportion of family variance components was greater than population for specific gravity and spiral grain angle. The characteristics that showed greatest population components of variation would be largely determined by durations and rates of shoot and radial growth. Presumably, length of the growing season would exert stronger selection pressure on these variables than on other characteristics of wood structure.

SUMMARY Sparassis radicata Weir was found to be heterothallic with a bipolar type of mating system. Multiple alleles for incompatibility occur at the locus for heterothallism. Tests were negative for the production of extracellular oxidases on gallic or tannic acid media and with gum guaiac solution. The optimum temperature for growth on 3.0% malt extract agar medium was 23-25 C. Studies of some basidiocarps and cultures labeled Sparassis crispa Wulf. ex Fr. from Europe and Japan show they are conspecific with S. radicata. Specimens and isolates labeled S. crispa from southeastern United States differed from the European and Japanese specimens and from isolates labeled S. crispa. Apparent dikaryotization of single basidiospore isolates of S. radicata from Arizona by dikaryotic isolates labeled S. crispa from Europe and Japan offers additional evidence for the conspecificity of these fungi. Descriptions of basidiocarps and cultural characters are given for S. radicata and for specimens and cultures labeled S. crispa. Sparassis radicata Weir, a basidiomycete currently placed in the family Sparassidaceae (Aphyllophorales), was described by Weir in 1917. Weir studied some aspects of the life history and decay relationships of S. radicata, and found the fungus to be associated with a brown cubical decay of roots of some western conifer species. No other studies have been made on the fungus and most aspects of its biology are unknown. Field studies have revealed that S. radicata is rather common in coniferous forests of southern Arizona. The fungus has been collected on ponderosa pine (Pinns ponderosa Laws.), Douglas fir (Pseudotsuga menziesii (Mirb.) Franco), white fir (Abies concolor (Gord. et Glend.) Lindl.), and southwestern white pine (Pinus strobiformis Engelm.) in Arizona (Gilbertson et al., 1974). These tree species are important in

White fir cones were sampled for insect damage from wild stands in California and Nevada during 1984–1986. Insects were recovered from cones and seed damage was partitioned by insect species. The important phytophagous insects were separated into guilds: the cone- and seed-mining guild, Dioryctria abietivorella Groté, Eucosma prob. siskiyouana (Kearfoot), Cydia prob. bracteatana (Fernald), Barbara sp.; the seed-feeding guild, Megastigmus pinus Parfitt, M. rafni Hoffmeyer, Earomyia abietum McAlpine; and the scale- and bract-feeding guild, Asynapta hopkinsi Felt, Dasineura prob. abiesemia Foote, Resseliella conicola (Foote), Strobilomyia abietis (Huckett). Total damage by insects varied by year and site, reaching a maximum of 47% in 1986 on one site and a minimum of 12.5% in 1984 on another. Abortion and incomplete development also were major factors in the production of sound seed. Populations of white fir cone and seed insects varied with cone crop but also were affected by the occurrence of cone crops on alternate hosts. During most years, the seed-mining guild insects were the major cause of seed damage.

From energy budget data for a branch of ponderosa pine given by Gates, Tibbals and Kreith, entropy fluxes into or out of the branch due to solar radiation, infrared radiation, transpiration and convection are calculated. Net entropy flow into the branch is negative. Assuming that the entropy in the branch is at steady state, the entropy production in the branch of ponderosa pine is calculated and shown to be positive. A positive entropy production indicates that the Second Law of Thermodynamics is certainly valid in the branch. Entropy productions in other conifers, blue spruce and white fir, and in a single pine needle in a horizontal position are also calculated. The entropy production (Sprod) increases linearly with the solar energy absorbed by the plant surface (Esolar); Sprod≈(30.6 Esolar)×10−4. The ratio (Sprod/Esolar) does not differ between deciduous leaves reported earlier and conifer branches. The theorem of oscillating entropy production proposed earlier holds also for conifer branches and will be of universal nature, applicable to all plant leaves.

The factors influencing leaf litter decomposition and nutrient release patterns were investigated for 3.6 years in two mixed conifer forests in the southern Sierra Nevada of California. The giant sequoia–fir forest was dominated by giant sequoia (Sequoiadendrongiganteum (Lindl.) Buchh.), white fir (Abiesconcolor Lindl. & Gord.), and sugar pine (Pinuslambertiana Dougl.). The fir–pine forest was dominated by white fir, sugar pine, and incense cedar (Calocedrusdecurrens (Torr.) Florin). Initial concentrations of nutrients and percent lignin, cellulose, and acid detergent fiber vary considerably in freshly abscised leaf litter of the studied species. Giant sequoia had the highest concentration of lignin (20.3%) and the lowest concentration of nitrogen (0.52%), while incense cedar had the lowest concentration of lignin (9.6%) and second lowest concentration of nitrogen (0.63%). Long-term (3.6 years) foliage decomposition rates were best correlated with initial lignin/N (r2 = 0.94, p 2 = 0.92, p 2 = 0.80, p

Litterfall was measured for 4 years and leaf litter decomposition rates were studied for 3.6 years in two mixed conifer forests (giant sequoia–fir and fir–pine) in the southern Sierra Nevada of California. The giant sequoia–fir forest (GS site) was dominated by giant sequoia (Sequoiadendrongiganteum (Lindl.) Buchh.), white fir (Abiesconcolor Lindl. & Gord.), and sugar pine (Pinuslambertiana Dougl.). The fir–pine forest (FP site) was dominated by white fir, sugar pine, and incense cedar (Calocedrusdecurrens (Torr.) Florin). Litterfall, including large woody debris −1•year−1 compared with 4355 kg•ha−1•year−1 at the FP site. Compared with other temperate coniferous forests, annual variability in litterfall (as computed by the ratio of the annual maximum/minimum litterfall) was extremely high for the GS site (5.8:1) and moderately high for the FP site (3.4:1). In the GS site, leaf litter decomposition after 3.6 years was slowest for giant sequoia (28.2% mass loss), followed by sugar pine (34.3%) and white fir (45.1%). In the FP site, mass loss was slowest for sugar pine (40.0%), followed by white fir (45.1%), while incense cedar showed the greatest mass loss (56.9%) after 3.6 years. High litterfall rates of large woody debris (i.e., 2.5–15.2 cm diameter) and slow rates of leaf litter decomposition in the giant sequoia–fir forest type may result in higher litter accumulation rates than in the fir–pine type. Leaf litter times to 95% decay for the GS and FP sites were 30 and 27 years, respectively, if the initial 0.7-year period (a short period of rapid mass decay) was ignored in the calculation. A mass balance approach for total litterfall (

A survey was made of the yeasts occurring in slime fluxes ofQuercus kellogii (black oak),Abies concolor (red fir) and in certain mushrooms and dead logs in the mountains of the Yosemite region of California. Most of the 134 isolates identified were found to be non-fermentative or poorly fermentative (fermenting glucose only and usually weakly). The isolates were placed in the following genera:Pichia (34),Debaryomyces (35), imperfect forms ofHansenula (39),Endomyces (3),Saccharomyces (2),Candida (11),Trichosporon (7),Torulopsis (1),Cryptococcus (1) andSporobolomyces (1). Four new species have been described,Pichia silvestris, Pichia quercibus, Pichia carsonii andDebaryomyces fluxorum. P. quercibus andP. carsonii are unusual representatives of the genusPichia in that they form a very primitive pseudomycelium and lack pellicles on malt extract. To accommodate such species an amended diagnosis of the genusPichia has been proposed byPhaff in an accompanying paper.Saccharomyces pastori, of which 12 isolates were obtained, has been transferred to the amended genusPichia asP. pastori (Guilliermond) nov. comb.

Methods were developed to standardize sampling of the Douglas-fir tussock moth. Population density was estimated in terms of the number of eggs or larvae per 1,000 sq. in. of branch area of Abies concolor (Gord. and Glend.) Lindl. The density of eggs and larvae varied significantly in different parts of the tree crown. In an outbreak, egg masses were concentrated on inside branches near the bottom of the crown, but in light populations they were most common on outside branches in the top of the crown. Larvae were found over the entire tree, but they were especially concentrated on foliage in the top. Mean density of larvae in the middle crown was representative of the whole tree. Egg density is estimated from whole branches sampled representatively from three crown levels; however, density of larvae is estimated accurately from 17-in. twig samples taken from just the middle crown. Because eggs are clumped in masses and larvae are dispersed over the foliage, larval density can be estimated with much less sampling than can egg density for the same precision.

Attacks by Scolytus ventralis on white fir were correlated both with periods of low precipitation and with medium to heavy infestations of true mistletoe. Trees were seldom attacked when the "running mean precipitation" was above 54 in. Attacks were significantly more frequent and were often a year or more earlier on trees with substantial amounts of mistletoe. Broods were seldom produced, however.Data suggest that heavy mistletoe infestation rendered trees more susceptible to beetle infestation, possibly by creating moisture stress in infected trees.

1. Radial changes throughout the years 1944 and 1945 were studied in seventeen species of trees at Moscow, Idaho, in a region originally covered with prairie. Subsequent to their establishment in an arboretum the trees have not been irrigated, and all have become sufficiently adjusted to the environment to show approximately normal growth. 2. The groups of eight evergreen conifer (Abies concolor, Picea engelmannii, P. pungens, Pinus monticola, P. ponderosa, P. strobus, Pseudotsuga taxifolia, and P. t. var. glauca) and eight deciduous dicots (Acer pseudoplatanus, A. saccharophorum, Fagus grandifolia, Fraxinus americana, Juglans nigra, Quercus borealis, Robinia pseudoacacia, and Ulmus americana) that were studied began to grow at approximately the same time in both years. During the early part of the grand period of growth the evergreens grew more rapidly than the deciduous dicots, but in the later part of this period the relation was reversed. The evergreens shrank the most in response to drought in summer...

Epicuticular waxes of five cultivated varieties of Picea pungens and six other species of conifers were examined directly with a scanning electron microprobe. The quality, quantity, and distribution patterns of surface wax deposits varied between species, within species, within plants, and within individual leaves. Two basic types of wax were observed, structural and amorphous. Structural wax is associated with glaucousness and the blue foliage color in Picea pungens and other species. The degree of occlusion of the stomatal pore by surface waxes also varied from heavily occluded to completely free of wax. Wax in the epistomatal chamber may be another resistance barrier to gas exchange by ccnifer needles. NUMEROUS FUNCTIONS or adaptive roles have been suggested for the surface waxes of plant leaves. These include modification of the rate of moisture and other gaseous exchange with the atmosphere, protection against mechanical and pest damage, and protection against ultraviolet radiation and air pollutants. Despite the potential significance of these and other postulated physiological functions of the surface waxes, experimental evidence for specific functions is lacking. An understanding of the physical and chemical properties and patterns of natural variation of leaf surface waxes is basic to a determination of function for these materials. Several investigators have examined certain physical characteristics of the wax deposits on the foliage of xerophytic coniferous species with which we are mainly concerned. Mueller, Carr, and Loomis (1954) used a double replica technique to make indirect observations of Picea pungens var. glauca needles with the electron microscope. They showed a net-like pattern of wax deposition which was altered by aging and weathering. Leyton and Juniper (1963) found two morphological types of wax on Scotch pine. The portion of the needles enclosed by the basal sheath lacked the waxy projections which occur on the exposed surface of the needle. Eglinton and Hamilton (1967) reviewed the chemical properties of plant surface waxes which are complex mixtures of long chain alkanes, alcohols, ketones, aldehydes, acetals, esters, and acids. Considerable chemical variation exists between species suggesting their usefulness for taxonomic purposes. ' Received for publication 22 February 1971. Journal article No. 5388, Michigan Agricultural Experiment Station. This research was supported in part by Grant No. AP Al 00736 from the United States Public Health Service (JWH) and by McIntire-Stennis Cooperative Forest Tree Research Funds. Little is known about either chemical or physical variation patterns for epicuticular waxes within a species. However, Barber (1955) has reported that the variation patterns in visible glaucousness of Tasmanian Eucalypts are genetically controlled and are related to the environment in the native habitat, especially to frost conditions. Our study of the surface waxes focuses on their physical characteristics with particular reference to their patterns of distribution and associations with stomates and degree of needle glaucousness. MATERIALS AND METHODS-One-year-old needles were removed with forceps from three trees of each of the following 3-year-old grafted varieties of blue spruce; Picea pungens var. glauca Thomsen c.v. Hoopsii, c.v. Kosteri, c.v. Moerheimi and c.v. Pendula. The plants were grown in the greenhouse to obtain needles on which the epicuticular waxes were relatively undisturbed by weathering. Second and third year needles were sampled from var. Thomsen to observe the effects of weathering on the waxes. Seven other conifers 8-10 years old, grown under field conditions, were sampled in a similar manner. These were Picea pun,sens, Picea glauca, Abies concolor, Pinus strobus, Pinus nigra, Pinus sylvestris, and Pseudotsuga menziesii. The needles were affixed to polished carbon discs with rubber cement, coated with a gold-palladium alloy (60:40) about 200 A thick, and examined directly under vacuum with an Applied Science Laboratory EMX-SM scanning electron microprobe operated at 15 KV and 2.0 nanoamps. The beam diam for the instrument was 2000 A. Replicate needles of each tree and species were examined at levels of magnification ranging from 100 X to 5000 X to verify consistency of surface wax

IN NOVEMBER, 1941, Cornell University received fromii Norwich, New York, the basal end of the trunk of a white fir tree (Abies concolor L.) that had fallen "in a mysterious manner." The tree, an ornamental specimen grown in a cemetery, was about 40 years old, 25 feet tall, and 12 inches in diamiieter at the base. It was found fallen, separated cleanly from the stump just below the ground level. The break was nearly transverse and remarkably smooth (fig. 1, 3), suggesting to local people that it hlad been sawed down or that some animal had gnawed it down. It seemed probable that the fall was the result of a break in tissues along a line of incomplete graft union and members of the staffs of the Departments of Forestry and Botany went to Norwich and dug up the stump for further evidence of the cause of the fall. When the basal section of the trunk is fitted to the stump, a transverse furrow is evident in the bark along the line of break (fig. 2) and the trunk just above the line of break is seen to be slightly greater in diameter than the stump. The undulate surfaces of separation show, on opposite sides of the pith, a projecting hump and a concavity (fig. 1, 7). Both of these facts supported the view that the fall was the result of graft-union failure. Aniatomical study of the region of the break confirmiied this view and demonstrated the presence of a possibly new type of failure of anatomical union of stock and scion. Slight color differences of the inner bark indicated the probability that a different species was used as stock but these could not be used in identification, and wood characters also proved of no value. Bailey (1935) states that varieties and forms of firs are grafted on seedlings of the particular species, if these are available; if not, on those of .4bies balsamea (L.) AMill., A. concolor Lindl. and Gord., and A. alba Mill. (= A. Picea Lindl.; A. pectinata DC.). Though foliage forms of white fir are grafted on seedlings of the same species, it seemiis unlikely that the stock in this tree was of that species because of the differences in bark color, rate of growth, and a probable incompatibility. It is unlikely that the balsam fir was used because of the lack of vigor of growth of this species. That the European white fir was used is possible since at the time this tree was planted-about 1900-much grafted fir nursery stock probably came from Holland. Detailed anatomical study disclosed the story of the method of grafting used and the progress of growth to the fall of the tree. Perfectly preserved in the heart of the tree is the region of grafting, with the cut surfaces of stock and scion, the thread which held stock and scion together, and the callus 1 Received for publication February 26, 1945. tissue which closed the wound areas (fig. 8). The surfaces of rupture and the furrow in the bark show the position of the cambium layers of both stock and scion (fig. 7, 14-16) and the structural basis for the extraordinary break in the tree. The grafting method used was that known as "lateral," in which the scion was applied to the side of the stock. In preparation of the stock for grafting the cut was made extremely deep, well bevond the pith (fig. 10) so that less than half of the stem remained at that point. The position of the pith (fig. 8) determines the depth of the cut, as does also the absence of the pith in a transverse cut higher up (fig. 9). This doubtless accidental condition may have been in part the cause of the graft-union failure. The-scion, applied obliquely to the cut, was tied in by a linen thread (about 0.3 mm. in diam.) (fig. 11) which is preserved in position, overgrown by the later-formed xylem of stock and scion (fig. 8, 12). The lower part of the cut-surface of the stock, resin-coated, is clearly seen in the dissection (fig. 8), as is also the short oblique cut by which the top of the stock seedling was later removed (fig. 8, 12). Overgrowth by callus and xylem and phloem took place rapidly on these surfaces, both inward from the sides and downward over the top (fig. 8, 9, 12, 13). Some bark remains on this overgrowth adjacent to the scion (fig. 8). Overgrowth was so extensive and continued so long-three to six years-that it is clear that there was no close contact of the upper cut-surfaces of stock and scion; the tying-in of the scion was defective above, and the two plant-tops apparently stood apart, held together tightly only at the base of the union (fig. 11, 12). Callus development rapidly covered most of the wound surface of the stock, leaving contact with only the very base of the scion. Similarly most of the cut surface of the scion became callused. From the beginning, therefore, there was contact of vascular tissues over only a small part of the possible surface, and the cambium margins failed to unite. The failure of cambium union was probably due to incompatibility of stock and scion but may have been in part because of the early establishment on both stock and scion of callus that almost completely enclosed each wound area independently. The margins of the cambium cylinders lay close together but remained unfused. The position of the ends of the cylinders is evident from the form of the annual rings (fig. 16). The in-turned ends of the cambia formed tracheids which, similarly, were bent inward at right angles or lay horizontallv in the tree (fig. 4, 5). Thus there was no interlocking of the cells of the stock and scion, and horizontally lying vascular cells separated the stump of the tree from the trunk (fig. 4, 5, 14, 15). Contact between

Isozyme patterns of L-leucine-amino-peptidase (LAP), esterase, and peroxidase in extracts from conifer seeds (eight species of Pinus, Abies concolor Hoopes, and Pseudotsuga taxifolia Britt.) indicated that certain specific isozyme patterns might be useful in systematic studies of conifers. The isozyme patterns of LAP from these seeds showed an apparent phylogenetic relationship. Eight different LAP bands were detected, and all eight species of Pinus displayed the same three LAP bands. The two slowest moving LAP bands were found to be common to all 10 species, whereas the mobility of the other LAP bands varied among species. Isozyme patterns of esterase from seeds of Pinus, Abies, and Pseudotsuga varied from species to species, and no species displayed the same number of bands. The number of esterase bands detected varied from 5 to 16, and no phylogenetic relationships were apparent. The banding patterns of peroxidase from these conifer seeds, which ranged from three to nine bands, also appeared to be species specific, and no common trends or homologies were apparent.

The behaviour of amitrole (3-amino-l,2,4-triazole) in 3-year old seedlings of Pinus ponderosa (ponderosa pine) and Abies concolor (white fir) is described. Visual symptoms of amitrole action appeared as a chlorosis of young needles, the extent of which varied with time and species. Maximum chlorosis was obtained when the application was made during the stage when no visible growth occurred. The greater susceptibility of ponderosa pine seedlings could be accounted for by the lower resistance to uptake of the herbicide into the needles and not by any difference between the conifer species in the metabolism of amitrole. The translocation and metabolism of amitrole in the two conifer species are discussed. In both of the conifer species amitrole was converted into three metabolic products two of which were found to be identical with the previously described Unknown I and II. Two types of treatment, on exposed phloem and on the needles, provided the possibility for a direct study of the site of amitrole metabolism. This site appeared to be in the stem. Amitrole was the mobile, toxic compound in both species and was translocated in both symplast and apoplast. A circulation of the herbicide in the plant was observed. From the phloem amitrole diffused relatively slowly into the xylem, and during this lateral translocation part of the amitrole was metabolized. The rate of this detoxification process seemed to be dependent upon how fast amitrole moved from phloem to xylem and vice versa. This rate seemed to show a positive correlation with the intensity of the cambial activity. The translocation of amitrole to the roots was greatest when no visible growth could be detected.

which the fully formed telescoped shoot remains in a state of suspended growth; the first growth phase, during which the telescoped shoot elongates rapidly and gives rise to numerous cataphylls; and, the second growth phase, during which shoot elongation is completed and a new unelongated axis bearing many needle primordia is formed. The shoot tip of Abies consists of 4 clearly definable cytohistological zones; the apical initials, the sub-terminal mother cells, the peripheral zone, and the

Vegetation of the southwest slope of the Santa Catalina Mountains of southeastern Arizona was sampled and transects prepared for 1,000—ft (305 m) elevation belts on granite and gneiss soils from the summit forests (2,440—2,750 m) to the base of the mountains (900 m). Transects also represented subalpine forests above 2,750 m in the Pinaleno Mts. and vegetation of the valley plain or bajada below the mountains, and samples were taken from volcanic soils below 900 m in the Tucson Mts. Principal community—types from high elevations to low are: subalpine forest (Picca engelmanni in the Pinaleno Mts. and Abies lasiocarpa), montane fir forest (Abies concolor, Pseudotsuga menziesii), pine forests (Pinus ponderosa, P. strobiformis), pine—oak forests (P. ponderosa, Quercus hypoleucoides), pine—oak woodlands (P. ponderosa, P. chihuahuana, Q. hypoleucoides, Q. arizonica), pygmy conifer—oak scrub (Pinus cembroides, Juniperus deppeana, Q. arizonica, Q. emoryi, Arctostaphylos pringlei, A. pungens, monocot shrubs), open...

The transpiration rate of Abies concolor (Gord. & Glend.) Lindl. differed considerably between top and bottom sun branches for trees 28 m high or more. This difference changed with the time of day, tree height, time of year, and exposure to sun and shade. The transpiration of 1966 (new) needles was more rapid than for 1-year-old needles and differed according to sun and shade exposure and position on the tree. By mid-August of two different years, the transpiration rate of young and old sun needles of A. concolor was reduced drastically even though air temperatures remained above 18 C and relative humidity dropped to low levels by midday.

In the central Oregon Cascades, grand fir morphology varies from that of typical Abies grandis to that of populations with a variety of morphological types, some closely resembling A. concolor Low-elevation populations west of the Cascade crest, mostly on river terraces, resemble A grandis. High-elevation west-side populations, disjunct from those at low elevations and occupying ridge tops and steep, dry slopes, include trees with some traits of A. concolor. Populations on the east flank of the Cascades show a greater but widely variable influence of A. concolor. East-side populations vary locally with aspect, being most like A. grandis on north slopes, but they do not clearly vary with elevation. Incidence of characteristics resembling A. concolor increases from north to south within the study area, although this pattern shows deviations not associated with obvious changes in topography Periderm color and needle morphology show the same general relationships between the populations sampled. Either "maxim...

Spectroradiometric analyses were made to examine the light-filtering capacity of coniferous forests and to establish the lower limits of light energy for growth of Pseudotsuga menziesii (Mirb.) Franco, Abies concolor (Gord. and Glend.) Lindl., and Pinns ponderosa Dougl. Light energy (400–750 nm) was recorded periodically on clear days in June and July at 48 points under four mixed conifer stands and segregated into four spectral bands (blue, 400–450; green, 500–550; red, 650–700; far-red, 700–750 nm). Minor changes in the proportion of light in one band to that in another occur throughout the day, but in general the 400- to 700-nm range appears rather uniformly absorbed by a coniferous forest canopy. Averaged for an entire day, only the far-red band showed a significant proportional increase under a coniferous canopy compared to unfiltered sunlight.The relation between the energy received in each of the spectral bands and the total recorded in the 400- to 700-nm range was linear. The sampled canopies transmitted up to 25% of full sunlight. Beneath the canopies, the ratio of blue to total energy (400–700 nm) was 0.1540. Green, red, and far-red had ratios of 0.1853, 0.1220, and 0.1207.Terminal growth of 34 seedlings was measured at the light-sampling points to provide a means of establishing lower limits of light energy for survival. The lower limit for Abies and Pseudotsuga was 1.85 langleys (ly) per day (400–700 nm). Pinus grew only where the light energy exceeded 36.8 ly/day.An interaction with moisture appears to influence the minimum requirements for light energy of a species. Where moisture was adequate throughout the growing season, the lower limit of light for Pseudotsuga seedling establishment was 1.85 ly/day; where moisture became limiting, the minimum light requirement increased to 6.64 ly/day.

Recent years have seen the publication of life history studies for several kinds of soricid shrews, and we now have some idea concerning some of the salient biological features of these animals. There is an abundance of species of shrews, sometimes several species living in one locality, and it is a reasonable assumption that their habits are different. Also, it is not unlikely that some geographically widespread species will differ within themselves ecologically as well as morphologically, such differences reflecting responses to variations in their environments. As natural history studies of shrews gradually become more extensive and detailed, it may be possible to discover discrete biological differences among the various kinds and also to learn to what degree the environment may alter the biology of any one kind. The data here are not extensive, but concern one species, Sorex trowbridgei , in the Sierra Nevada of California. In some respects, especially with regard to the reproduction, trowbridgei appears to vary from some species of Sorex studied by other investigators. It is hoped that this account may serve also to describe any biological characteristics of trowbridgei that may be different in other parts of its geographic range. Habitats .—The Trowbridge shrew is common in the coniferous woodlands of the Sierra Nevada up to elevations of 5000 feet in Plumas County and at least to 6000 feet in Tuolumne County to the south. This forest is comprised of large coniferous trees ( Pinus lambertiana, P. ponderosa, Pseudotsiiga menziesii, Abies concolor , and Libocedrus decurrens ); the less conspicuous woody plants are smaller deciduous trees ( Quercus kelloggii and Acer macrophyllum ) and shrubs ( Quercus vaccinifolia, Alnus rubra, Ceanothus spp. Cornus spp., and Ribes spp.). The ground litter is composed of the decaying debris from these plants and provides the home and hunting ground of trowbridgei . …

To better understand root-soil water interactions, a mature white fir (Abies concolor) and the surrounding root zone were continuously monitored (sap flow, canopy stem water potential, soil moisture, and temperature), to characterize tree hydrodynamics. We present a hydrodynamic flow model, simulating unsaturated flow in the soil and tree with stress functions controlling spatially distributed root water uptake and canopy transpiration. Using the van Genuchten functions, we parameterize the effective retention and unsaturated hydraulic conductivity functions of the tree sapwood and soil, soil and canopy stress functions, and radial root zone distribution. To parameterize the in-situ tree water relationships, we combine a numerical model with observational data in an optimization framework, minimizing residuals between simulated and measured observational data of soil and tree canopy. Using the MCMC method, the HYDRUS model is run in an iterative process that adjusts parameters until residuals are minimized. Using these optimized parameters, the HYDRUS model simulates diurnal tree water potential and sap flow as a function of tree height, in addition to spatially distributed changes in soil water storage and soil water potential.

A chimera of red and yellow periderm color is described from a population intermediate between Abies concolor and A. grandis. Its formation probably followed changes in properties of apical initials, rather than in cells produced later in development. Apparently only a single genetic change can control this red–yellow periderm color difference.

THE light transmission and reflectance character-istics of white fir (Abies concolor) were investi-gated as part of a seed viability testing program. The viability of this seed is typically 30 to 50 percent and, therefore, any means of eliminating nonviable seeds will conserve expensive seed and nursery space and also reduce operating costs associated with over-planting. The reflectance characteristic of the seed was used to segregate a single sample into lots. Each lot was germinated and the results show a strong correlation between the reflectance parameters and viability.

Food selection by larvae of Hemerocampa pseudotsugata McDunnough was studied in an outbreak on white fir, Abies concolor (Gordon and Glendenning) Lindley, in northern California. Caterpillars fed more on new foliage of white fir when it was available than on old foliage. Old needles were almost totally unacceptable to early instars but were eaten by late instars. After a late spring frost killed back most of the new growth on white fir, many caterpillars shifted to and fed on new needles of ponderosa pine, Pinus ponderosa Lawson. However, when given a choice of fir or pine in the laboratory, larvae strongly favored new foliage of white fir. A shortage of preferred food stimulated mobility among early instars. When caterpillars were fed only frost-damaged foliage which contained no new growth, many died, apparently from starvation.

The fir engraver beetle, Scolytus ventralis LeConte (Coleoptera: Scolytidae), was first described from two specimens collected at Vancouver, Washington, but the species has been subsequently recorded throughout the western United States and British Columbia.20,55 Its primary hosts are true firs, Abies; specifically white fir (A. concolor), California red fir (A. magnifica), and grand fir (A. grandis).34 It has also been observed on occasion attacking subalpine fir, Douglas-fir, Engelmann spruce, mountain hemlock, and Western larch.20,55

This paper interprets plant community dynamics within three major vegetation regions - the Sonoran desert, the Encinal and coniferous forest - which extend from 700 m to the summit (2 766 m) on the south slope of the Santa Catalina Mts., Arizona. On the bajada, Larrea tridentata and disturbed desert scrub communities have been degraded by overgrazing and Carnegiea gigantea reproduction is failing on many sites. In the Spinose, suffrutescent desert scrub on protected lower mountain slopes Carnegiea is reproducing but mature populations are periodically decimated by freezing temperatures. In the desert grassland, graminoids or Agave schottii dominate, the former favored by fire, the latter by fire protection. In the Encinal above 1 220 m an open oak woodland dominated by Quercus oblongifolia is transitional to the pine, oak woodland where fire and drought result in several community segregates. A relict Cupressus arizonica forest is restricted to certain canyons. Above the Encinal (2 100 m) a Pinus ponderosa-Q. hypoleucoides forest is replaced by a less xeric P. ponderosa forest. In the latter a dense pine understory develops with fire protection and savanna-like pine stands are favored by fire. At higher elevations a mature Pseudotsuga menziesii, Abies concolor forest dominates the north-facing slopes where fire plays a significant factor in its perpetuation. An even-aged subalpine Abies lasiocarpa stand on the north slope below the summit suggests post-fire origin. In the Pinaleno Mts. to the northeast, mixed conifer and spruce, fir forests complete the vegetation gradient typical of these southwest mountain ranges. Here fire and windthrows interact in maintaining a mosaic of pure or mixed even or uneven-aged stands.

Four populations of Abies concolor, white fir, were sampled along an elevational transect in the central Sierra Nevada mountains of California. This paper is based on data taken during the first two years' growth in a nearby nursery at Placerville, California. Ten of the thirteen growth, size, and needle morphological characteristics had significant differences between population samples, while eleven characteristics had significant differences between open-pollinated families within the population samples. High-elevation population samples were smaller in size and needle measurements, had fewer adaxial stomatal rows, blunter needle tips, and a shorter growing season. Most characteristic values were distributed ecotypically between the two lower- and the two higher-elevation population samples. Analyses of the patterns of variation demonstrated that characteristics of size and growth showed greater differentiation between population samples than did characteristics of needle morphology. It was concluded that the differences between characteristic patterns were caused by the more intense selection pressures acting upon the characteristics of size and growth. No consistent differences were discovered between these population samples in terms of total amounts of within-population genetic variation. The failure to find differences in intra-population variation may be due to the high rates of migration that probably exist within such a transect, and the fact that none of the populations included in this study are truly marginal. There were large differences between characteristics for total within-population variation; a positive but non-significant correlation was found between high coefficients of variation and those characteristics with much differentiation between populations. It is postulated that the maintenance of this intra-population variation was caused by microhabitat adaptations and gene flow. Evidence for increased genetic variation within open-pollinated families due to pollen immigration is presented, and its implications discussed.

Forest compositional patterns in Yosemite National Park, California, were related to environmental factors through numerical classification of forest types, arrangement of forest types along elevational and topographic gradients, and development of regression models relating basal area of common tree species to environmental variables. The eight forest types are differentiated primarily by elevation zone and secondarily by topographic setting. Lower montane forests (1200–1900 m) were divided into the Abies concolor/Calocedrus type occurring primarily on mesic sites and the Pinus ponderosa/Calocedrus type predominantly on xeric sites. Upper montane forests (1900–2500 m) included the Abies concolor/Abies magnifica type on mesic sites, the Abies magnifica/Pinus type on somewhat more xeric sites, and Juniperus occidentalis/Pinus jeffreyi woodlands on granitic domes. Subalpine forests (2500–3300 m) embraced three types: Tsuga mertensiana/Pinus forests on mesic sites, monotypic Pinus contorta forests on drier sites, and Pinus albicaulis/Pinus contorta groves at treeline. Regression models consistently included elevation and soil magnesium content as explanatory variables of species basal area totals. The two Abies spp. were negatively correlated with soil magnesium levels, whereas other montane species (e.g. Calocedrus decurrens, Pinus lambertiana, and Pinus ponderosa) exhibited positive correlation with soil magnesium. Topography and soil physical properties were only infrequently incorporated into species regression models.

The formation of wound resin in sapwood and phloem by parenchyma cells not normally associated with resin production has been identified as an important induced defense response of conifers to bark beetles and their associated fungi (Reidet al. 1967, Berryman 1972). Early work on conifer defenses focused on the preformed resin canal system in unwounded pines (see reviews by Rudinsky 1962, Stark 1965, Callaham 1966, and Smith 1972). The true firs (Abies spp.), on the other hand, normally lack such resin canals in the xylem or phloem. The only preformed (in advance of wounding) resin is localized in cortical blisters (Bannan 1936).