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1.
Abstract. The growth and survival of coniferous trees (particularly Abies sachalinensis) and broad-leaved trees (particularly Quercus crispula) were followed over a 15-yr period in a 15.5-ha area in a northern mixed forest in Japan, and the coexistence of the two groups was simulated by a density-dependent projection matrix model. The density-dependent model assumes that the density effect of mother trees due to one-sided competition for light on smaller-sized tree regulates the demographic functions. The mother tree densities of conifers and broad-leaved trees have stronger negative effects on the recruitment and survival of seedlings of their own group than of the other group. These results support the idea of reciprocal replacement for conifer and broad-leaved trees. Simulations using the density-dependent model showed that the two groups will co-exist within a particular range of recruitment rates. However, the density of both groups did not affect the growth rate of any tree, and equilibrium DBH-distributions from density-dependent matrices were quite different from present distributions both for conifers and broad-leaved trees. On the other hand, equilibrium DBH-distributions of conifer and broad-leaved trees from density-independent matrices were quite distinct from each other, reflecting different survivorship curves of the two dominants. These results suggest that density-dependent processes are not so important for shaping population structures in this northern mixed forest. 相似文献
2.
Abstract. Bischofia javanica is an invasive tree of the Bonin Islands in the western Pacific, Japan. This species has aggressive growth, competitively replacing native trees in the natural forest of the islands. The aim of this study was to examine seed and seedling factors which might confer an advantage to the establishment of Bischofia over native trees. During a 5‐yr period we compared the demographic parameters of early life history of Bischofia and Elaeocarpus photiniae‐folius, a native canopy dominant, in actively invaded forests. Predation of Elaeocarpus seeds by in troduced rodents was much higher before (27.9–32.9%) and after (41.3–100%) dispersal of seeds than that of B. javanica. Most Elaeocarpus seeds lost viability ca. 6 mo after burial in forest soil while some seeds of Bischofia remained viable for more than 2 yr. Seedling survival in the first 2 yr was much higher in Bischofia (16%) than in Elaeocarpus (1.3%). The high persistence of Bischofia in the shade, coupled to its rapid acclimation to high light levels, is an unusual combination because in forest tree species there is generally a trade‐off between seedling survival in the shade and response to canopy opening. Compared with a native canopy dominant, greater seed longevity, lower seed predation by introduced rodents, longer fruiting periods and the ability to form seedling banks under closed canopy appear to have contributed to the invasive success of Bischofia on the Bonin Islands. 相似文献
3.
Abstract. We examined the response of tree seedling emergence and survival to the dieback of Sasa and canopy gap formation in an old‐growth forest near Lake Towada, northern Japan. Synchronous death of Sasa occurred in 1995. We established four types of sampling sites differing in forest canopy conditions (Closed or Gap) and Sasa status (Dead or Live). Gap‐Dead sites had the highest light levels and the greatest fluctuation in soil temperatures. The death of Sasa alone facilitated the emergence (Acer japonicum, Fagus crenata, Fraxinus lanuginosa, and Tilia japonica) and survival (Acanthopanax sciadophylloides, F. crenata, F. lanuginosa, Kalopanax pictus, and Sorbus commixta) of species with a seedling bank strategy. Cercidiphyllum japonicum grew at all sites at a higher density than other species, but survived well only in Gap‐Dead sites. This behaviour was associated with a seed rain strategy. The additive effects of Sasa death and canopy gap formation promoted seedling emergence of pioneer tree species (Betula maximowicziana, Lindera umbellata, and Magnolia obovata), probably through break of dormancy by the large temperature fluctuation. In addition, the scarcity of advance regeneration in canopy gaps due to Sasa cover facilitates the regeneration of pioneer species. The dominance and dieback cycle of Sasa contributes to species diversity in this forest. 相似文献
4.
Abstract. The effects of soil surface disturbance and light level on seedling emergence were examined by creating experimental conditions differing in soil surface treatment and light level in a temperate deciduous broadleaved secondary forest in central Japan. The results of MANOVA showed that soil surface disturbance exerted a favourable influence upon the seedling emergence of many species. Effect of soil disturbance on total density and number of emerged species was greater than that of a high light level. The interaction between soil surface disturbance and light level revealed significant positive effects for seedling emergence, especially for small‐seeded species. The relationship between the percentage of emerged seedlings and seed weight was significantly negative in the soil‐surface disturbed and high light level condition, suggesting that minute‐seeded species largely depend on both factors for seedling emergence. Both soil surface disturbance and high light level had a positive effect on the number of emerged species, suggesting that these factors contributed to species richness at the stage of seedling emergence. 相似文献
5.
Abstract. We investigated the effect of topography‐related environmental factors (i.e., ground‐surface stability and soil moisture) on seedling establishment of 8 deciduous tree species. A field experiment was carried out using canopy species, which were classified into 3 groups based on the spatial distribution of adult trees (ridge, slope and valley). Demographic parameters were compared among species during the early stage of seedling establishment among 3 topographic positions in combination with gap and canopy conditions. The percentage of emerging seedlings tended to be lower on the ridge irrespective of the adult topographical distribution patterns. There was no clear trend in seedling emergence among the species groups classified by their spatial distribution. Seedling survival during 2 growing seasons was significantly different among species, topographic positions and light conditions. On the ridge, seedlings of the species dominating ridge tops had greater survival than those of other species, probably due to differences in demand for soil moisture. On the slope, frequent physical damage caused by surface material movement was observed and some species showed greater adaptability to the disturbed slope habitat. Survival of all seedlings was highest in the valley plots. Light conditions were the critical factor for seedling survival in some species. The results of this study suggest that topography creates diverse habitats for the establishment of tree seedlings. In addition to soil moisture, surface material movement may be a significant factor affecting seedling establishment. 相似文献
6.
Fumito Koike 《植被学杂志》2001,12(3):327-336
Abstract. The dominance of a given tree or shrub species in a particular forest community may be determined by many ecological traits of the target species, as well as those of the surrounding species as its potential competitors. The present study was conducted to evaluate the possibility of predicting community status (species composition and dominance) on the basis of traits of local flora using statistical methods, and to visualize the mathematical function which determines species dominance. A general linear model and logistic regression were used for the statistical analysis. Dependent variables were designated as dominance and presence/absence of species in climax forest, with independent variables as vegetative and reproductive traits. Subalpine, cool‐temperate, warm‐temperate and subtropical climax rain forests in East Asia were studied. Quantitative prediction of climax community status could readily be made based on easily measured traits of local flora. Species composition and 74.6% of the total variance of species dominance were predicted based on two traits; maximum height and shade tolerance. Through application of this method, the capacity of an alien species to invade a climax forest community could possibly be predicted prior to introduction of the alien species. 相似文献
7.
Abstract. Early old‐field succession provides a model system for examining vegetation response to disturbance frequency and intensity within a manageable time scale. Disturbance frequency and intensity can interact with colonization and competition to influence relative abundance of earlier and later successional species and determine, respectively, how often and how far succession can be reset. We tested the joint effects of disturbance frequency and intensity on vegetation response (species richness, abundance, canopy structure) during the first six years of succession by clipping the dominant species (D) or all species (T) in spring and fall of each year (S), once per year in summer (Y1), each two years in summer (Y2), or each four years in summer (Y4). Vegetation response reflected disturbance effects on expansion of a later monospecific dominant perennial herb, Solidago altissima, and persistence of the early, richer flora of annuals. A more abundant and taller top Solidago canopy developed on plots clipped each 2 yr or less frequently. Plots clipped yearly or seasonally were richer, but had less abundant, shorter, and differently stratified canopy. Disturbance mediated the relative abundance of early and later successional species; however, frequency and intensity effects were not completely congruent. Persistence of a richer early successional flora increased through the most frequent disturbance (S), and was magnified by disturbance intensity. Disturbance as extreme as clipping all vegetation twice yearly did not cause a drop in species richness, but maintained the early successional community over the first six years of succession. We conclude that clipping disturbance influenced the rate of succession, but the early community could rebound through the range of disturbance frequency and intensity tested. 相似文献
8.
Robbie Goris Vincent Kint Kristof Haneca Guy Geudens Hans Beeckman Kris Verheyen 《应用植被学》2007,10(2):219-228
Question: What are the age structure and growth trends in a 160‐year old not‐managed Pinus sylvestris plantation with spontaneous development of Quercus robur and can recruitment of Q. robur be related to the radial growth pattern of the P. sylvestris overstorey? Location: Mattemburgh forest reserve, The Netherlands. Methods: Throughout the forest, we sampled 103 oaks and 102 pines with an increment corer. Tree ring widths were measured and cross‐dated to produce mean ring width series. With these data we determined tree ages, investigated growth trends and identified growth releases and suppressions. Results: Q. robur is uneven‐aged: some individuals recruited around 1925, but most reached coring height in the 1940s. The latter recruitment period related to a transition from stressed to released growth of the overstorey pines, growth releases of the oldest Q. robur and occurrence of P. sylvestris regeneration. No further recruitment has taken place since 1950. Conclusions: This study demonstrates that an old pine plantation can develop spontaneously into well‐structured pine forest with an understorey of oak and pine. However, understorey recruitment in these forest types is not a continuous process and in this case a single allogenic canopy disturbance triggered its establishment. 相似文献
9.
Abstract. Distribution of tree seedlings, forest architecture, light conditions, ground vegetation and humus conditions were studied in a 45 m × 100 m area including multiple gaps in an old-growth beech forest. Gaps were created after some beech trees had been felled in severe storms in February 1990. A group of adult ash trees is found near the study site. The data were analyzed by Correspondence Analysis. Young seedlings (< 4 yr), of both Fraxinus (a sun species) and Fagus (a shade species), were most abundant under the crown of beech trees in semi-shade conditions, and where beech litter did not accumulate. Differences in the dissemination of Fraxinus and Fagus explained differences in the establishment of the two species. In contrast, older seedlings of beech established before the storms were more numerous in the gaps, suggesting a change in the ecological requirements of beech seedlings in the course of time. 相似文献
10.
Abstract. The sequences of macrofossils in 17 cores from two Tasmanian valley Sphagnum peatlands reveal a wide variety of successional pathways. The most common sequence is from restiad mires to Sphagnum mires to heath. While it is impossible to conclusively separate allogenic and autogenic influences, it seems likely that the rapid rate of change recorded in the upper levels of the cores may, in part, reflect recent climatic change. Most other changes recorded in the core are likely to be predominantly autogenic. 相似文献
11.
Chang-Fu Hsieh Zueng-Sang Chen Yueh-Mei Hsu Kuoh-Chieng Yang Tsung-Hsin Hsieh 《植被学杂志》1998,9(2):201-212
Abstract. Evergreen broad-leaved forest was studied in a transect on the northwestern slope of Mount Lopei in order to reveal altitudinal zonation in structure and floristic composition and the decisive environmental factors. 20 plots of 20 m × 20 m at altitudes from 540 m to 1320 m were analysed. 144 woody species were found. The results of a DCA ordination clearly pointed to a single dominant altitudinal gradient. Nevertheless, wind-exposure associated topography was found to account for additional variation for a given altitudinal range. Along the altitudinal gradient, four dominance-based forest types were recognized. Tree density, species diversity and evenness of the four types differed significantly but total basal area and tree volume were not significantly different. The 95 % turnover range for woody species as measured by the Community Coefficient was calculated as 1030 m, and the 50 % turnover range as 238 m. For the understorey, the change in species composition with altitude was less obvious. Species population structures of 57 sufficiently abundant species revealed four characteristic patterns, but most species showed a good fit to the negatively exponential or power function distribution and thus appeared to have good reproduction and regular recruitment. Both ANOVA and Redundancy Analysis (RDA) showed that significant differences among forest types were found for most soil variables. Organic C, exchangeable Na and K tended to increase with altitude, while pH and available N showed a reverse trend. There was little evidence that the differences in soil pH and available N were responsible for the variation in forest growth. 相似文献
12.
Aristides Moustakas Matthias Guenther Kerstin Wiegand Karl‐Heinz Mueller David Ward Katrin M. Meyer Florian Jeltsch 《植被学杂志》2006,17(4):473-480
Question: Is there a relationship between size and death in the long‐lived, deep‐rooted tree, Acacia erioloba, in a semi‐arid savanna? What is the size‐class distribution of A. erioloba mortality? Does the mortality distribution differ from total tree size distribution? Does A. erioloba mortality distribution match the mortality distributions recorded thus far in other environments? Location: Dronfield Ranch, near Kimberley, Kalahari, South Africa. Methods: A combination of aerial photographs and a satellite image covering 61 year was used to provide long‐term spatial data on mortality. We used aerial photographs of the study area from 1940, 1964, 1984, 1993 and a satellite image from 2001 to follow three plots covering 510 ha. We were able to identify and individually follow ca. 3000 individual trees from 1940 till 2001. Results: The total number of trees increased over time. No relationship between total number of trees and mean tree size was detected. There were no trends over time in total number of deaths per plot or in size distributions of dead trees. Kolmogorov‐Smirnov tests showed no differences in size class distributions for living trees through time. The size distribution of dead trees was significantly different from the size distribution of all trees present on the plots. Overall, the number of dead trees was low in small size classes, reached a peak value when canopy area was 20 ‐ 30 m2, and declined in larger size‐classes. Mortality as a ratio of dead vs. total trees peaked at intermediate canopy sizes too. Conclusion: A. erioloba mortality was size‐dependent, peaking at intermediate sizes. The mortality distribution differs from all other tree mortality distributions recorded thus far. We suggest that a possible mechanism for this unusual mortality distribution is intraspecific competition for water in this semi‐arid environment. 相似文献
13.
Eugeniusz Bernadzki Leszek Bolibok Bogdan Brzeziecki Jacek Z&#x;jaczkowski Henryk ybura 《植被学杂志》1998,9(2):229-238
Abstract. This paper presents results of a long-term study on natural forest dynamics in the Bia?owieza National Park (BNP), northeastern Poland. Five permanent sample areas were used, each consisting of a transect of varying width (40 - 60 m) and length (200 - 1380 m). The total sample area is 14.9 ha. The study covers the period 1936–1992. During this period measurements were made on five occasions at approximately 10-yr intervals. On each measurement date all trees with DBH > 5 cm were identified and their spatial location, diameter, crown condition and position in the canopy determined. During the study period the stands underwent noticeable changes, mainly in terms of tree species composition. The major change was a quantitative increase of the late-successional species: Tilia cordata and Carpinus betulus, also to a lesser degree Fraxinus excelsior and, in the last period, of the early successional Alnus glutinosa. Declining species included both early- and late-succession species. Among the latter group, Picea abies ranked first. This species lost much of its importance during the last few decades. P. abies was followed by Pinus sylvestris which is an important component of the climax vegetation under the conditions prevailing in Bialowieza, at least on more oligotrophic sites. Still, this species has not been able to regenerate during the whole study period. Some other late-succession species, Acer platanoides and Quercus robur, were also amongst the declining species. Although the basal area of Q. robur increased, its population was getting older and the process of natural regeneration was markedly impeded. All typical pioneer, short-lived species: Betula pendula and B. pubescens, Salix caprea and Populus tremula also decreased, which was probably caused by a lack of major disturbances during the study period. In general, the results obtained for the semi-natural conditions of Bialowieza during the 56-yr observation period suggest a rather high compositional instability of the forest stands there. A more precise identification of the role of particular factors in the observed stand dynamics is difficult because of the paucity of appropriate historical and environmental data which refer directly to the study plots; moreover, the data are generally incompatible and of different resolution. 相似文献
14.
Abstract. We focused on community boundaries in a sub‐alpine forest landscape in the Shiretoko Peninsula, northern Japan. Gradient‐directed transects were conducted on the northwestern slope (ranging 500–600 m a.s.l.) of Mount On'nebetsu (1331 m), where complex topography was formed by past landslides. Pioneer Picea glehnii made up a mosaic of pure stands related to landslides. Structural and compositional changes from P. glehnii pure stands to P. glehnii and Abies sachalinensis mixed stands were characterized by ca. 20 m transitional zones over the landscape. Stand density of the species changed across boundaries. A. sachalinensis preferred less undulated slopes with deep soil and P. glehnii preferred undulated rocky sites. Positive spatial associations between overstorey‐understorey P. glehnii were found at undulated core parts of P. glehnii pure stands. Short‐lived A. sachalinensis grew faster to the smaller maximum size than long‐lived P. glehnii. Undulated topography controlled the increase of A. sachalinensis and provided regeneration sites for P. glehnii, which prevented the general trend of canopy replacement from P. glehnii to late‐successional A. sachalinensis. However, the locations of current boundaries were not accordant with the topographic changes in the meso‐scale landscape. Initial P. glehnii pure stands would extend to larger areas if current patterns reflect vegetation recovery since the last landslide. P. glehnii pure stands with accurate boundaries were not maintained by topographic complexity, but were dynamically arranged by the one‐sided canopy replacements from P. glehnii to A. sachalinensis at less undulated slopes in the sub‐alpine forest landscape. 相似文献
15.
Abstract. 14 old, unlogged, Picea-dominated stands in the moist cool Sub-Boreal Spruce biogeoclimatic subzone of central British Columbia, Canada, were sampled to describe canopy heterogeneity, regeneration patterns and tree population age structures. These stands are composed of Picea engelmannii × glauca hybrids, Abies lasiocarpa and lesser amounts of Pinus contorta and Populus tremuloides, and had survived 124–343 yr since the last stand-destroying wildfire. Canopy cover was patchy and highly variable (ranging from 30.5 % to 86.4 %) but was not significantly related to stand age. Vertical canopy structure was less variable, reflecting the shade-tolerance and live crown ratios (length of live canopy expressed relative to tree height) of component species: 18.8 % for Populus, 20.2 % for Pinus, 46.7 % for Picea and 51.4 % for Abies. Individual stands varied considerably in their population structures and in their stand development trajectories, yet some patterns are evident. Survivors of the initial post-disturbance cohort of trees took 51 to 118 yr (mean = 80, s.d. = 20) to establish. Some stands had all tree species present during stand initiation, while other stands indicated early successional roles for Populus and Pinus, or a late successional role for Abies. Abies recruitment, while often slow in the beginning, occurs uniformly throughout the history of most stands, reflecting the high shade-tolerance of this species. Picea is often recruited in high densities early in stand development, and then (after long periods of exclusion) may be displaced by Abies in some stands but maintains itself in others. Minor, single-tree disturbances (due to bark beetles, root rot, and windthrow) were important in accelerating the reinitiation of Picea in the understory. Results thus suggest that stands from this region can be self-perpetuating in the absence of fire. Yet, post-fire tree populations still clearly dominate these spruce-fir forests, for only the oldest stand had greater basal area in the replacement cohort than in the initial cohort. 相似文献
16.
Abstract. Methods for coupling two data sets (species composition and environmental variables for example) are well known and often used in ecology. All these methods require that variables of the two data sets have been recorded at the same sample stations. But if the two data sets arise from different sample schemes, sample locations can be different. In this case, scientists usually transform one data set to conform with the other one that is chosen as a reference. This inevitably leads to some loss of information. We propose a new ordination method, named spatial‐RLQ analysis, for coupling two data sets with different spatial sample techniques. Spatial‐RLQ analysis is an extension of co‐inertia analysis and is based on neighbourhood graph theory and classical RLQ analysis. This analysis finds linear combinations of variables of the two data sets which maximize the spatial cross‐covariance. This provides a co‐ordination of the two data sets according to their spatial relationships. A vegetation study concerning the forest of Chizé (western France) is presented to illustrate the method. 相似文献
17.
Abstract. Structural and compositional changes were analysed over the course of 400+ yr of post‐fire succession in the sub‐boreal forests of west‐central British Columbia. Using a chronosequence of 57 stands ranging from 11 to 438 yr in age, we examined changes in forest structure and composition with complementary PCA and DCA ordination techniques. To determine stand ages and timing of tree recruitment, approximately 1800 trees were aged. Most early successional forests were dominated by Pinus contorta, which established rapidly following fire. Abies lasiocarpa and Picea glauca × engel‐mannii were also able to establish quickly, but continued to establish throughout the sere. Few Pinus contorta survived beyond 200 yr, resulting in major changes in forest structure. In some stands P. contorta never established, which led to considerable variation among stands less than 200 yr old. The oldest forests converged on dominance by Abies lasiocarpa. Vascular plant diversity decreased during succession whereas canopy structure became more complex as gap dynamics developed. Although these sub‐boreal forests contain few tree species, successional changes were pronounced, with structure changing more than composition across the chronosequence. 相似文献
18.
Population structure and spatial patterns for trees in a temperate old-growth evergreen broad-leaved forest in Japan 总被引：9，自引：0，他引：9
The population structure and spatial pattern of major tree species in a warm-temperate old-growth evergreen broad-leaved forest in the Tatera Forest Reserve of Japan were investigated. All stems 5 cm in diameter at breast height (DBH) were mapped on a 4 ha plot and analyses were made of population structure and the spatial distribution and spatial association of stems in different vertical layers for nine species. This was done in the context of scale dependency. The plot was located on a very gentle slope and 17.1% of its canopy layer was in gaps. It contained 45 woody plant species and 4570 living stems with a basal area of 63.9 m2 ha–1. Castanopsis cuspidata var. sieboldii, the most dominant species for the basal area, had the maximum DBH among the species present, fewer smaller stems and a lower coefficient of statistical skewness of the DBH distribution. The second most dominant species, Dystilium racemosum, had the highest stem density (410 ha–1), more abundant smaller stems and a relatively higher coefficient of skewness. Most stems in different vertical layers showed a weakly aggregated distribution with loose colonies as basic units. Gap dependency for the occurrence of stems under the canopy layer was weak. Maximum slope degree of the plot also weakly affected the occurrence of stems. Spatial associations varied among intra- and interspecific cohorts in the different layers and spatial scales examined, and positive associations among cohorts were found more frequently as the scales examined became larger. This tendency suggests that key factors forming observed spatial associations might vary with the spatial scales. 相似文献
19.
Abstract. Recently established forests are commonly characterized by an impoverished understorey. Restoration is mostly based on spontaneous secondary succession, but little is known about the time period needed to achieve a community species pool with species composition equal to that of ancient forests. Vegetation in transects of 197 plots in 13 recent forest stands contiguous to the Meerdaalwoud ancient forest complex was surveyed. The recent forest stands ranged in age from 36 to 132 yr. The community species pool was described with an ecological, functional and phytosociological approach and based on groups derived from a CCA. Differences in community species pool between age classes of recent forest stands were analysed. During establishment of a new forest competitive species, forest edge species and species with high Ellenberg values for light and nitrogen and a more persistent seed bank will dominate the understorey. After 90 yr of succession the cover by these species decreases and reaches equal values to ancient forest after ca. 105 yr. A large number of forest species will be able to colonize the forest in less than 90 yr. Some typical forest species, however, have very low colonization rates and still have low cover in recent forest more than 105 yr old, so that complete restoration of the understorey requires a time period of over a century. Anthropogenic introduction of forest plant species may reduce the time required for ancient forest vegetation equality. 相似文献
20.
Abstract. The post-fire regeneration of a 45-yr-old Pinus halepensis (Aleppo pine) forest, burned in July 1989, has been studied on Mount Párnis, Attiki, Greece. Four experimental plots at various slopes and exposures were established at altitudes of 400 - 450 m, and monitored for 3 yr at 3-month intervals. Early regeneration took place abundantly, through both resprouting and seed germination of mostly hard-seeded herbs and shrubs; the floristic richness was high with 80 taxa. Pine seedling emergence took place during the winter of the first post-fire year. The mean pine seedling density by the end of the recruitment period (March 1990) was 5–6 seedlings/m2. This density decreased slightly during late spring and considerably during summer. During the second post-fire year only a relatively slight decline was observed; thereafter the density was stabilized to 1 - 2 seedlings/m2. Mortality follows a negative exponential curve that levels off at ca. 20 %. Height distributions throughout the three post-fire years were all positively skewed as a result of the presence of few very tall saplings. A considerable fraction (20 %) of very short (5–15 cm) saplings were still alive 39 months after the fire; these may constitute the sapling bank. Based on the analysis of height distribution curves, it is concluded that the taller seedlings survived significantly better than the shorter ones. 相似文献