Evergreen Broad-leaved Species Research Articles

Evolution of vegetation and climate since the last glacial maximum recorded at Dahu peat site, South China

Sporopollen analysis on a 346 cm peat record at Dahu, Jiangxi, chronologically constrained by 16 AMS 14C datings, provides an opportunity to reconstruct the vegetation evolution stages responding to climate change in South China since the last glacial maximum. The result shows that during 18330–15630 cal a B.P., broad-leaved forest dominated the area, corresponding to mild, cool and fairly humid climate. At the interval of 15630–11600 cal a B.P., several evergreen broad-leaved species appeared within the broad-leaved forest, indicating moderate and humid condition. During early Holocene, broad-leaved evergreen forest community was constructed as Castanopsis/Lithorcarpus principally developed, suggesting a warm and humid scenario until 6000 cal a B. P. Since 6000 cal a B. P., abrupt forest deterioration happened with an contemporary increase of fern and herb communities, representing a turnover to relatively cool and dry condition and as well, possible impact from human activities. Meanwhile, several relatively cool and dry events can be identified in the sporopollen record, they can be correlated to the North Atlantic Heinrich event, YD and Holocene millennial-scale oscillations, implying that the low latitude climate was coupled with high latitude influences. Moreover, the variations of temperature and humidity since LGM at Dahu were much smaller when compared with the records in north monsoonal China.

Changes in sapwood permeability and anatomy with tree age and height in the broad-leaved evergreen species Eucalyptus regnans

Increases in plant size and structural complexity with increasing age have important implications for water flow through trees. Water supply to the crown is influenced by both the cross-sectional area and the permeability of sapwood. It has been hypothesized that hydraulic conductivity within sapwood increases with age. We investigated changes in sapwood permeability (k) and anatomy with tree age and height in the broad-leaved evergreen species Eucalyptus regnans F. Muell. Sapwood was sampled at breast height from trees ranging from 8 to 240 years old, and at three height positions on the main stem of 8-year-old trees. Variation in k was not significant among sampling height positions in young trees. However, k at breast height increased with tree age. This was related to increases in both vessel frequency and vessel diameter, resulting in a greater proportion of sapwood being occupied by vessel lumina. Sapwood hydraulic conductivity (the product of k and sapwood area) also increased with increasing tree age. However, at the stand level, there was a decrease in forest sapwood hydraulic conductivity with increasing stand age, because of a decrease in the number of trees per hectare. Across all ages, there were significant relationships between k and anatomy, with individual anatomical characteristics explaining 33-62% of the variation in k. There was also strong agreement between measured k and permeability predicted by the Hagen-Poiseuille equation. The results support the hypothesis of an increase in sapwood permeability at breast height with age. Further measurements are required to confirm this result at other height positions in older trees. The significance of tree-level changes in sapwood permeability for stand-level water relations is discussed.

Does growth irradiance affect temperature dependence and thermal acclimation of leaf respiration? Insights from a Mediterranean tree with long‐lived leaves

Understanding the response of leaf respiration (R) to changes in irradiance and temperature is a prerequisite for predicting the impacts of climate change on plant function and future atmospheric CO2 concentrations. Little is known, however, about the interactive effects of irradiance and temperature on leaf R. We investigated whether growth irradiance affects the temperature response of leaf R in darkness (Rdark) and in light (Rlight) in seedlings of a broad-leaved evergreen species, Quercus ilex. Two hypotheses concerning Rdark were tested: (1) the Q10 (i.e. the proportional increase in R per 10 degrees C rise in temperature) of leaf Rdark is lower in shaded plants than in high-light-grown plants, and (2) shade-grown plants exhibit a lower degree of thermal acclimation of Rdark than plants exposed to higher growth irradiance. We also assessed whether light inhibition of Rlight differs between leaves exposed to contrasting temperatures and growth irradiances, and whether the degree of thermal acclimation of Rlight is dependent on growth irradiance. We showed that while growth irradiance did impact on photosynthesis, it had no effect on the Q10 of leaf Rdark. Growth irradiance had little impact on thermal acclimation when fully expanded, pre-existing leaves were exposed to contrasting temperatures for several weeks. When Rlight was measured at a common irradiance, Rlight/Rdark ratios were higher in shaded plants due to homeostasis of Rlight between growth irradiance treatments and to the lower Rdark in shaded leaves. We also showed that Rlight does not acclimate to the same degree as Rdark, and that Rlight/Rdark decreases with increasing measuring and growth temperatures, irrespective of the growth irradiance. Collectively, we raised the possibility that predictive carbon cycle models can assume that growth irradiance and photosynthesis do not affect the temperature sensitivity of leaf Rdark of long-lived evergreen leaves, thus simplifying incorporation of leaf R into such models.

Seasonal fluctuations and temperature dependence of leaf gas exchange parameters of co-occurring evergreen and deciduous trees in a temperate broad-leaved forest

Seasonal fluctuations in leaf gas exchange parameters were investigated in three evergreen (Quercus glauca Thunb., Cinnamomum camphora Sieb. and Castanopsis cuspidata Schottky) and one deciduous (Quercus serrata Thunb.) co-occurring, dominant tree species in a temperate broad-leaved forest. Dark respiration rate (Rn), maximum carboxylation rate (Vcmax) and stomatal coefficient (m), the ratio of stomatal conductance to net assimilation rate after adjustment to the vapor pressure deficit and internal carbon dioxide (CO2) concentration, were derived inversely from instantaneous field gas exchange data (one-point method). The normalized values of Rn and Vcmax at the reference temperature of 25 degrees C (Rn25, Vcmax25) and their temperature dependencies (Delta Ha(Rn), Delta Ha(Vcmax)) were analyzed. Parameter Vcmax25 ranged from 24.0-40.3 micromol m(-2) s(-1) and Delta Ha(Vcmax) ranged from 29.1- 67.0 kJ mol(-1). Parameter Rn25 ranged from 0.6-1.4 micromol m(-2) s(-1) and Delta Ha(Rn) ranged from 47.4-95.4 kJ mol(-1). The stomatal coefficient ranged from 7.2-8.2. For the three evergreen trees, a single set of Vcmax25 and Rn25 parameters and temperature dependence curves produced satisfactory estimates of carbon uptake throughout the year, except during the period of simultaneous leaf fall and leaf expansion, which occurs in April and May. In the deciduous oak, declines in Vcmax25 were observed after summer, along with changes in Vcmax25 and Rn25 during the leaf expansion period. In all species, variation in m during periods of leaf expansion and drought should be considered in modeling studies. We conclude that the changes in normalized gas exchange parameters during periods of leaf expansion and drought need to be considered when modeling carbon uptake of evergreen broad-leaved species.

Gradational Forest Change along the Climatically Dry Valley Slopes of Bhutan in the Midst of Humid Eastern Himalaya

Altitudinal forest and climate changes from warm, dry valley bottom (1250 m a.s.l.) to cool, humid ridge top (3550 m a.s.l.) along the typical dry valley slopes of the Bhutan Himalaya were studied. Annual mean temperature decreased upslope with a lapse rate of 0.62 °C·100 m−1 from 18.2 °C at the valley bottom to 4.3 °C at the ridge top. On the contrary volumetric soil moisture content increased from 14.7 to 75.0%. This inverse relationship is the major determinant factor for the distribution of different forest types along the altitudinal gradient. Based on the quantitative vegetation data from 15 plots arranged ca. 200 m in altitude interval (1520–3370 m a.s.l.), a total of 83 tree species belonging to 35 families were recorded. Three major formation types of lower and upper coniferous forests, and a mid-altitude evergreen and deciduous broad-leaved forest were contrasted. Including two transitional types, five forest zones were categorized based on cluster analysis, and each zone can be characterized by the dominants and their phytogeographical traits, viz. (1) west Himalayan warm, dry pine (1520–1760 m a.s.l.), (2) wide ranging east-west Himalayan mixed broad-leaved (1860–2540 m a.s.l.), (3) humid east Himalayan evergreen broad-leaved (2640–2820 m a.s.l.), (4) cool, humid east Himalayan conifer (2950–3210 m a.s.l.), and (5) wide ranging cold, humid conifer (3305–3370 m a.s.l.). Structurally, total basal area (biomass) increased from 15.2 m2 ha−1 in the pine forest (1520 m) to 101.7 m2 ha−1, in the conifer forest (3370 m a.s.l.). Similarly, soil organic carbon increased from 2.7 to 11.3% and nitrogen from 0.2 to 1.9% indicating dry, poor nutrient fragile ecosystem at the dry valley bottom. We concluded that low soil moisture content (<20%) limits downslope extension of broad-leaved species below 1650 m a.s.l. while coldest month’s mean temperature of −1 °C restricted the upslope extension of evergreen broad-leaved species above 3000 m a.s.l. Along the dry valley slopes, the transition from dry pine forest in the valley bottom, to a mixture of dry west Himalayan evergreen and deciduous east Himalayan broad-leaved, and to humid evergreen oak–laurel forests feature a unique pattern of forest type distribution.

Physiological basis of seasonal trend in leaf photosynthesis of five evergreen broad-leaved species in a temperate deciduous forest

The physiological basis of photosynthesis during winter was investigated in saplings of five evergreen broad-leaved species (Camellia japonica L., Cleyera japonica Thunb., Photinia glabra (Thunb.) Maxim., Castanopsis cuspidata (Thunb.) Schottky and Quercus glauca Thunb.) co-occurring under deciduous canopy trees in a temperate forest. We focused on temperature dependence of photosynthetic rate and capacity as important physiological parameters that determine light-saturated rates of net photosynthesis at low temperatures during winter. Under controlled temperature conditions, maximum rates of ribulose bisphosphate carboxylation and electron transport (Vcmax) and Jmax, respectively) increased exponentially with increasing leaf temperature. The temperature dependence of photosynthetic rate did not differ among species. In the field, photosynthetic capacity, determined as Vcmax and Jmax at a common temperature of 25 degrees C (Vcmax(25) and Jmax(25)), increased until autumn and then decreased in species-specific patterns. Values of Vcmax(25) and Jmax(25) differed among species during winter. There was a positive correlation of Vcmax(25) with area-based nitrogen concentration among leaves during winter in Camellia and Photinia. Interspecific differences in Vcmax(25) were responsible for interspecific differences in light-saturated rates of net photosynthesis during winter.

Changes in leaf morphology and anatomy with tree age and height in the broadleaved evergreen species, Eucalyptus regnans F. Muell

Relatively little is known about changes in leaf attributes over the lifespan of woody plants. Knowledge of such changes may be useful in interpreting physiological changes with age. This study investigated changes in leaf morphology and anatomy with tree age and height in the broadleaved evergreen species, Eucalyptus regnans. Fully expanded leaves were sampled from the upper canopy of tree ages ranging from 6 to 240 years, and tree heights ranging from about 10–80 m. There were significant changes in leaf form with increasing tree age and height. Leaf size and specific leaf area (SLA; leaf area/leaf mass) decreased, leaf thickness increased, and leaves became narrower relative to their length, with increasing tree age and height. Cuticle thickness and leaf waxiness, including wax occlusion of the stomatal antechamber, increased with increasing age and height. By comparison, there were no clear trends in stomatal frequency or stomatal length with tree age, although there were curvilinear relationships between an index of total stomatal pore area per leaf lamina and both tree age and tree height. The results support the hypothesis that leaves of E. regnans become more xeromorphic with tree age and height. The results are discussed in relation to their significance for changes in water relations in the canopy with age.

Carbon assimilation, nitrogen, and photochemical efficiency of different Himalayan tree species along an altitudinal gradient

In the area of Jumla region in Western Nepal, measurements of saturated leaf net photosynthetic rate (Psat), nitrogen content, leaf fluorescence, carbon isotopic composition, and water status were performed on woody coniferous (Pinus wallichiana, Picea smithiana, Abies spectabilis, Juniperus wallichiana, Taxus baccata), evergreen (Quercus semecarpifolia, Rhododendron campanulatum), and deciduous broadleaved species (Betula utilis, Populus ciliata, Sorbus cuspidata) spreading from 2 400 m up to the treeline at 4 200 m a.s.l. With the exception of J. wallichiana, Psat values were lower in coniferous than broadleaved species. Q. semecarpifolia, that in this area grows above the coniferous belt between 3 000 and 4 000 m, showed the highest Psat at saturating irradiance and the highest leaf N content. This N content was higher and Psat lower than those of evergreen oak species of tempe forests at middle and low altitudes. For all species, Psat and N content were linearly correlated, but instantaneous nitrogen use efficiency was lower than values measured in lowland and temperate plant communities. The values of carbon isotopic composition, estimated by δ13C, showed the same range reported for temperate tree species. The ranking of δ13C values for the different tree types was conifers < evergreen broadleaved<deciduous, suggesting tighter stomatal closure and higher water use efficiency for the evergreen types, confirming trends found elsewhere. No relevant differences of δ13C were found along the altitudinal gradient. Quantum yield of photochemistry at saturating irradiance, measured by leaf fluorescence (δF/Fm’), was highest in J. wallichiana and lowest in T. baccata. Overall, photochemical efficiency was more strongly related to species than to altitude. Interestingly, changes of .δF/Fm’ along the altitudinal gradient correlated well with the reported altitudinal distribution of the species.

The role of fire in the invasion process of evergreen broad-leaved species

Summary Since the early 1970s evergreen broad-leaved (=laurophyllous) species growing at the southern foot of the Alps (Ticino, southern Switzerland) have increasingly spread from gardens and parks into adjacent forests. To assess the capability of survival of these newly established populations, knowledge of their responses to disturbance within the local ecosystems is required. This paper highlights the relevance of different fire histories to the structure, abundance, species richness and composition of evergreen broad-leaved vegetation on comparable sites and relates these findings to other factors influencing the invasion process of laurophyllous species in the area. The results suggest that the growth and performance of evergreen broad-leaved species are heavily affected by forest fires. The capability of evergreen broad-leaved species to recolonise repeatedly burned sites is very low, suggesting that fires not only damage the affected individuals but also temporarily modify habitats previously suitable for colonisation by evergreens.

Litterfall and nutrient dynamics in a montane moist evergreen broad-leaved forest in Ailao Mountains, SW China

Montane moist evergreen broad-leaved forest, dominated byLithocarpus and Castanopsis species,is the most extensive stand of subtropical mountain in Yunnan Province, SWChina. Litter production, standing crop of litter on forest floor and nutrientreturn patterns were studied over nine years (1991–1999) in a stand ofprimary evergreen broad-leaved forest in northern crest of the Ailao MountainRange. There were significant yearly variations in litter production, which ismainly related with the masting year of canopy species, and exceptionalphysicalevents (strong winds and snow) in the natural forest. The mean annual smalllitterfall is 7.12 t ha−1 yr−1ofwhich leaf litter account for 65% of the total litterfall. The seasonality ofsmall litterfall was bia-modal, with the main one in the late dry season(April–May) and a lesser one in early winter (October–November).Decomposition quotient value was relatively low with 0.58 for total smalllitterfall. Mean large-wood (≥ 2.5 cm in diameter) ranged from0.21 to 1.41 t ha−1 yr−1 with amean of 0.52 t ha−1 yr−1.Concentrations of most elements in leaf and twig were slightly greater in wetmonths than dry months, except for C and K. Woody litter had low N and Pconcentrations compared with the leaf and reproductive parts. Nutrient returntothe soil through small litterfall decrease in the orderC>N>Ca>K>Mg>Mn>Al>P>Fe, while nutrient reserve inlitteron the forest floor was in the declining sequenceC>N>Ca>K>Mg>P>Fe>Al>Mn.

Weakening of climatic constraints with global warming and its consequences for evergreen broad-leaved species

Meteorological stations located in the lower areas of southern Switzerland have recorded a period with distinct milder winter conditions since 1970 as compared with the first half of the 20th century. The twofold set of climatic parameters, the absolute values and frequency of minimum temperatures as well as the length of the growing season have shifted towards warmer conditions in the last thirty years. In this paper, consequences of the lengthened growing season to 11 months are discussed. The detected climatic change supposedly favours species with evergreen broad-leaved growth form. With the analysis of 170 resurveyed releves the hypothesis of whether the group of evergreen broad-leaved species have succeeded in profiting from this weakening of climatic constraints was verified. Conspicuous changes have been observed not only in terms of the abundance and frequency of indigenous evergreen broad-leaved species, but also with a number of exotic species sharing equal characteristics and having succeeded in colonizing forest areas and establishing stands in the shrub layer. It is suggested that in areas with a minimum temperature above −10 °C and sufficient water supply throughout the year, evergreen broad-leaved species become increasingly competitive as soon as the growing season (days without frost) lengthens to about 300–320 days.

Species diversity in the progression of ecological restoration of artificial mixed forest after wind damage in Jinyun Mountain, Sichuan

The result indicates that #alpha#-diversity of woody-plants increases with artificial mixed forest succession while that of grassy-plants decreases. On different time-scales, #beta#-diversity is obviously different. This indicates that artificial mixed forest of wind-damaged slash has high species turnover rates, and evergreen broad-leaved species have replaced some coniferous species. It is concluded that artificial mixed forest of wind-damaged slash tends to become evergreen broad-leaved forest.

Stand Structure and Dynamics of Pinus densiflora Forests Damaged by Pine Wilt Disease in the Southern Part of Okayama Prefecture.

In order to explore the effects of pine wilt disease on the stand structure of Pinus denszflora forests in urban fringe areas of Okayama City, we researched two damaged forest stands and one undamaged forest stand. In one of the damaged stands, selective felling of dead pine trees were conducted, and in the other damaged stand, no operations to protect pine treees were conducted. Stand structures varied in the studied stands. Biomass in the two damaged stands were reduced by pine wilt disese damage. In the damaged stand where the selective felling operation was conducted, biomass of the understorey was remarkably reduced. In both the undamaged stand and the damaged stand without protection, evergreen broad-leaved species were abundant in small size classes and were predominate in the understorey. In the damaged stand with the selective felling operation, deciduous broad-leaved species were abundant in small size classes and were predominate in the understorey. It was thought that the selective felling operation disturbed the understorey of the stand and this disturbance caused the establishment of shade intolerant species. From the analysis of diameter increments, it was presumed that the grawth of remnant trees had been accelerated after the outbreak of the disease. It was assumed that the remnant trees had been released from the suppression because the canopy trees of P.densiflora were dead and thus decreased by pine wilt disease. From our research we concluded that pine wilt disease accelerated the succession of the pine forests.However, selective felling operations disturbed the forest stand and decelerated the succession.

Biomass, Productivity, Leaf Longevity, and Forest Structure in the Central Himalaya

Patterns of leaf characteristics, forest structure, tree species diversity, biomass, and productivity across a gradient of 3300 m and 15.7°C in mean annual temperature in Kumaun, in the Indian central Himalaya, were summarized and compared to values from other similar forests. Throughout the elevational gradient, the annual rainfall was high (100—300 cm), but not correlated with elevation. Evergreen species with a 1—yr leaf life—span dominated most of the elevational transect; above 1800 m, species with deciduous and multiyear evergreen leaves were also well represented. Although variability among sites within forest types was high, a number of consistent patterns were apparent. Forests of Pinus roxburghii and those at high elevations were most consistently different from other forest types. Leaf life—span was not strongly correlated with leaf mass, specific leaf mass, or leaf production efficiency (net primary productivity per unit leaf mass), contrary to relationships presented in the literature. Tree species richness and basal area were lower than for most similar types in Nepal. Biomass and productivity of the forests in Kumaun were relatively high, compared to mean values for similar forest types elsewhere. Measured values for most variables describing these forests (but not all) fell within the ranges for the variables in similar forests worldwide. The maximal values for forest biomass remained high, 500—600 Mg/ha, up to 2600 m elevation, but declined sharply in birch forest (°170 Mg/ha) above 3100 m. Net primary productivity (NPP) varied little (15—20 Mg°ha—1°yr—1) below 2700 m, despite a 10°C gradient in mean annual temperature and marked changes in basal area, tree density, growth form, and leaf characters. The level of productivity appeared not to be limited by rainfall, forest structure, leaf type, or temperature above an annual mean of 11°C. Leaf mass (LM) varied considerably among forest types, being 3.7—8.6 Mg/ha for deciduous species, 5.7—8.9 Mg/ha for P. roxburghii, and 10.0—28.2 Mg/ha for evergreen broad—leaved species. Leaf mass duration (leaf mass x months of the year with leaves present) was related directly to NPP and inversely to leaf production efficiency (NPP/LM). These data add substantially to the data base for forest properties, especially for broad—leaved evergreen forests.

943 INFLUENCES OF NODAL EXPLANT POSITIONS AND MEDIA OVERLAY ON MICRO PROPAGATION OF SHEPERDIA ROTUNDIFOLIA

Limited numbers of broad-leaved evergreen species grow well in the cold, dry plains of Colorado. The roundleaf buffaloberry, Sheperdia rotundifolia Parry, is a broad-leaved evergreen species that's adaptable to xeriphytic conditions of the Western states. Since little propagation information is available for this species, we studied procedures for clonal propagation with emphasis on tissue culture procedures. In this study, we evaluated the use of liquid media overlays on rapid propagation and the influence of node position on growth. A comparison of media overlay, transfer to fresh media and a control of no transfer (remained in same media) showed limited differences among treatments. Comparison of terminal, middle and basal node sections showed considerable differences. Sections from the middle produced more branches than the terminal and basal sections, though the branches were shorter than the terminal sections.

Plants at the Cretaceous-Tertiary boundary

Environmental selection determines to a large extent the morphology and anatomy of individual plants, and the composition and structure of vegetation. The intimate relation between vascular land plants, climate and substrate produces an abundant fossil record with a strong inherent signal reflecting, in particular, air temperatures, precipitation and evaporation, light régime and seasonality. Studies of palynomorphs, cuticles and plant megafossils in detailed sedimentological and stratigraphic context across the Cretaceous-Tertiary (K-T) boundary in North America, suggest sudden and traumatic vegetational disturbance, profound and long-lasting climatic change, and survivorship patterns that are palaeogeographically heterogeneous and possibly related to the ability of taxa to enter dormancy. Some of these changes are reflected in palaeosols. Major vegetational changes are also apparent in Europe, and Asia, although the precise timing of these events is less clear. The record, as presently interpreted, is one of ecological catastrophe, some selective extinction of broad-leaved evergreen species, and long-term vegetational restructing, expressed most strongly at middle and lower latitudes in the Northern Hemisphere.

Seasonal frost tolerance of some ornamental evergreen broad-leaved and coniferous tree and shrub species

Abstract The seasonal frost hardiness of several ornamental species was evaluated by exposing intact plants to controlled advective frost conditions in spring, midsummer, autumn, and midwinter. Cultivars of the evergreen broad-leaved species Camellia japonica, Daphne odora, Desfontainea spinosa, Grevillea × gaudi-chaudi, Hardenbergia violacea, Hypericum × moserianum, Nandina domestica, and Photinia serrulata × glabra ‘Rubens’ all developed limited winter frost hardiness with the most hardy (Camellia and Photinia) being killed at temperatures below-17°C. Generally, evergreen broad-leaved species from northern zones were more tolerant than Australasian species. Of the ornamental conifers examined, Cupressus macrocarpa was only moderately hardy in winter, being injured by temperatures lower than-8°C and killed below-14°C, whereas Juniperus chinensis tolerated temperatures down to-19°C without injury. The summer frost tolerance of all of these species was similar and all were injured or killed by temperatures in the-1 to-5°C range. Yucca filamentosa, a species with a xerophytic morphology, was damaged at-13°C but survived-17°C in summer and was not injured by winter temperatures down to-17°C. Lethal temperature values obtained in the controlled environment evaluations generally agreed well with hardiness zone ratings.

Comparison of Factors Determining Growth Rates of Deciduous vs. Broad-leaf Evergreen Trees

Growth rates of mature trees of two broad-leaved evergreen species (Quercus albocincta and Q tuberculata) and one deciduous species (Lysiloma divaricata) were monitored across a gradient in nutrient availability (soil pH in this study) and vegetation abundance in the Sierra Madre Occidental of northwestern Mexico. Seedlings of two of the species were also grown in the greenhouse in soil from extremes of the pH gradient. The abundance of Q. albocincta is negatively correlated with soil pH, while that of L. divaricata is positively correlated. Quercus tuberculata is most abundant at intermediate pH levels. Growth rates of seedlings and mature trees were not significantly different between evergreen and deciduous species, contrary to the predictions of a general model relating the distribution of growth forms to nutrient availability. Quercus tuberculata showed a significant positive correlation between growth and soil pH, while adult trees of the other two species showed positive correlations between growth and a measure of vegetation density, but not between growth and soil pH. However, seedlings of L. divaricata grown in the greenhouse did show a strong positive response to soil pH. The results are discussed in terms of the usefulness of correlations of growth with environmental parameters in understanding the causes of a distribution pattern. INTRODUCTION The association of broad-leaf evergreen plants with nutrient-poor soils in regions where deciduous plants dominate on relatively nutrient-rich soils is a well-documented pattern (Beadle, 1966; Monk, 1966; Specht, 1963, 1969; Webb, 1968; Whitmore, 1975; Goldberg, 1981). The advantage of the evergreen habit on nutrient-poor soils has been hypothesized to be due to the greater amount of carbon assimilated per unit of nutrient in long-lived leaves (Small, 1972; Schlesinger and Chabot, 1977). The disadvantage of evergreens on relatively nutrient-rich soils has been hypothesized to stem from low maximum growth rates due to both high carbon costs per unit surface area and low photosynthetic rates per unit surface area (see review of evidence in Goldberg, 1981). Low growth rates, in turn, are predicted to result in an inability to successfully compete in dense, rapidly growing deciduous vegetation on fertile soils (Grime, 1977; Goldberg, 1981). This general model predicts that deciduous species are excluded from nutrient-poor soils due to intolerance of low nutrient availability, while evergreen species are excluded from nutrient-rich soils through competition, and, in the absence of competition, should respond positively or not at all to increased nutrient supply. In the present paper I use data on growth rates of naturally occurring mature individuals of evergreen and deciduous tree species found over a gradient of nutrient availability and vegetation density to test two components of the model outlined above: (1) Maximum potential growth rate of evergreen trees is lower than that of deciduous trees. (2) Growth rate of deciduous trees is positively correlated with nutrient availability, while growth rate of evergreen trees is either not correlated or positively correlated with nutrient availability. These two predictions were also tested with seedlings of one evergreen and one deciduous species in a greenhouse experiment using soils from the extremes of a nutrient-availability gradient. Because plant species abundances are often determined at the seedling stage (Grubb, 1977; Werner, 1979), it is critical to know how well adult response to environmental factors matches seedling response. 'Present address: W. K. Kellogg Biological Station, Michigan State University, Hickory Corners 49060.

福岡市天神地域の後期更新世‐完新世たい積物の花粉分析学的研究 Ｉ

The writers attempted to clarify the late Quaternary stratigraphy and climatic change through the subsurface sections in the central part of Fukuoka City on the basis of pollen analysis. Four pollen zones were recognized, which respectively correspond to FG, RI, RII and RIIIb zones of NAKAMURA, J. (1952, 1967, 1975a, 1975b) and TSUKADA, M. (1963, 1967, 1974) in ascending order. In view of paleoclimate, these pollen zones represent respectively a climatic period.1. Cold period (FG zone): the peat layer (910-950cm) is mainly characterized by north temperate elements, such as Abies, Tsuga, Betula, Carpinus, Fagus, Ulmus, Tilia, Alnus, etc. and wholly excludes south temperate elements such as Celtis, Shiia, Cyclobalanopsis, Gleichenia, Pteris, etc. North temperate forest probably expanded to the low land with its lower boundary about 1000-1500m lower than that in the present day.2. Cold period (RI zone): the beds (838-895cm) consisting of irregular bodies of sands, silts and gravels hold very poor pollen records. The result is not effective to correlate this section decidedly with RI or LG zone (L zone) and so we tentatively correlate it to RI zone on the basis of the geological field data. In general RI is regarded as a transition zone between the cold period LG (L) and the next warm period RII.3. Warm period (RII zone): it is generally accepted that the colder forest of the former period was pushed away by such south temperate elements as Shiia and Cyclobalanopsis which became dominant. However there are small quantities of north temperate elements throughout these layers (680-838cm). While Celtis decreases at the upper part of these layers, Cyclobalanopsis and Shiia increase.4. Decreasing warm period (RIIIb zone): the peaty mud layer (365-400cm) is characterized by a large quantity of Pinus, while evergreen broad leaved species are not many. Cereal pollen were also recognized in the samples from. this section. The above facts suggest destruction of forest and agricultural activities by man as NAKAMURA, J. (1971, 1975b) and TSUKADA, M. (1974) pointed out.14C age of molluscan shells from about 4m level under the ground surface was 5540±100y.B.P. (KURI 185, T. SAKATA) and that of pieces of wood from 9.5m level, 20600±400y.B.P. (KURI 186, T. SAKATA). These 14C dates reinforce the correlation of our pollen zones to the zones FG, RI and RII.