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1.
Stand structure was studied with special reference to growth and mortality patterns of sapling and understorey trees in a
coniferousPicea jezoensis andAbies sachalinensis forest in Taisetsuzan National Park, Hokkaido, northern Japan.Picea jezoensis was dominant in the basal area, whileA. sachalinensis was abundant in large numbers in the canopy. Estimated mortalities increased significantly with diameter at breast height
(DBH) for bothP. jezoensis andA. sachalinensis in the canopy, but the tendency was different between the two species.Picea jezoensis had a lower mortality rate thanA. sachalinensis, especially at small DBH classes. The spatial distribution of understorey individuals ofA. sachalinensis did not show any significant correlation with the spatial distribution of canopy gaps, but that ofP. jezoensis showed a significant correlation.Abies sachalinensis can grow higher thanP. jezoensis under suppressed conditions; whileP. jezoensis requires canopy gaps for steady height growth. This growth pattern leads to a different waiting height in the understorey
(≥2 m in height and 10 cm in diameter at breast height).Abies sachalinensis waited for an improvement in light conditions at higher strata (max. 7 m), whileP. jezoensis waited at lower strata (max. 3 m). The estimated mortality of understoreyA. sachalinensis increased with size, while that of understoreyP. jezoensis decreased. Therefore,P. jezoensis gives priority to survival whileA. sachalinensis gives priority to understorey growth. The difference in the ‘waiting pattern’ between the two species in the understorey
was considered a significant feature for the canopy recruitment process ofP. jezoensis andA. sachalinensis. 相似文献
2.
In 1981 and 1993, trees over 2 m high were measured and mapped to clarify stand dynamics in two permanent plots of 0.1 ha
in a secondary, cool temperate, mixed broadleaf/conifer forest after logging in the Tomakomai Experiment Forest, central Hokkaido,
northern Japan. The species could be placed in two groups according to the change in basal area and density, and annual height
growth:Quercus mongolica var.grosseserrata, Phellodendron amurense, Prunus sargentii andTilia japonica (Group I: GI) showed episodic regeneration and/or fast height growth;Acer mono, Acer palmatum var.matsumuae andSorbus alnifolia (Group II: GII) showed continuous regeneration and/or slow height growth. The age distribution of stems over 10 cm in d.b.h.
suggests synchronous regeneration of GI and GII species. Vertical stratification was promoted during the 12-year period by
the difference in annual height growth between the two species groups. Additional tree censuses in both remnant old-growth
stands and second-growth stands after large scale blowdowns demonstrated thatQ. mongolica var.grosseserrata is most dominant in stands varying in the stages of development. Disturbance history and successional trends in dominant
species implied that stand-devastating disturbances were responsible for the regeneration ofQ. mongolica var.grosseserrata in the study forest. 相似文献
3.
Picea glehnii seedlings whose ages ranged from 2 to 5 years and which were growing in aP. glehnii-Abies sachalinensis natural forest where the surface had been scarified 6 years before, were assessed for the occurrence and types of ectomycorrhizae. Based on the macro- and microscopic characteristics, 34 types of ectomycorrhizae were classified. The basidiomycetes were clearly dominant and it was common to observe more than one type of mycorrhiza occurring in the same root tip. The diversity of mycorrhizal types and the presence of at least one type of ectomycorrhiza in a single seedling, observed in this work, indicate a very dynamic system of mycorrhizal formation inP. glehnii seedlings, which allows them to survive and grow in a forest surface subjected to soil scarification. 相似文献
4.
Mycena picta, a rare species of Agaricales, is reported for the first time from Japan, based on specimens collected in Hokkaido. 相似文献
5.
Toshihiko Sato 《Ecological Research》1994,9(1):77-84
Stand structure and regeneration pattern were examined inAbies sachalinensis coastal forest in northern Hokkaido. In the forest a similar phenomenon to the wave regeneration in subalpine forests has
been found. Wave regeneration has been reported for montaneAbies forests in central Japan and North America. Differences and similarities between wave-type stands in this coastal forest
and wave-regenerated montane forests were clarified.
The shift of dead tree zone, stand structure and regeneration pattern in wave-type stands are the same as in subalpine wave-regenerated
forests. High density of individuals is considered to be an internal factor which causes stand-level dieback and also enables
the stands to persist in the severe environment in both forests.
A difference between wave-regenerated forests andA. sachalinensis wave-type stands is the number of dead tree zones, which is only one in wave-type stands. Changes of regeneration patterns
ofAbies sachalinensis with environmental gradient from seaward to inland were related to this difference. 相似文献
6.
Seedling and tree-establishment microhabitats of Tsuga diversifolia and Abies mariesii were examined on the herb- and dwarf bamboo-dominated forest floor on Mount Hayachine, a mountain under intermediate snow conditions in northern Honshu, Japan. The four microsite types were fallen logs, buttresses, rocks and ground. The ground substratum was further divided into four subtypes by dominant undergrowth species: Lycopodium, Pteridophyllum, Carex and dwarf bamboo. The establishment of T. diversifolia seedlings on the ground was scarce, and depended mostly on non-ground microsites (i.e. fallen logs, buttresses and rocks). The seedling establishment of A. mariesii was not dependent on specific substrata, although on the ground, establishment sites were limited to the Lycopodium subtype situated on convex sites. Among the microhabitats for seedling establishment, larger trees of A. mariesii rarely occurred on higher portions of the non-ground microsites. In contrast, T. diversifolia could grow up to the height of canopy-layer trees in such microsites. Thus, non-ground microsites seem to be unsuitable for tree establishment in A. mariesii, and are probably useful microhabitats for regenerating T. diversifolia to avoid competition with A. mariesii. We also compared seedling-establishment microhabitats for the two conifers between Mount Hayachine and two other mountain regions under different undergrowth conditions (moss-dominated and dense dwarf bamboo-dominated). Our findings suggested that seedling recruitment in non-ground microsites was primarily determined by undergrowth conditions; T. diversifolia preferred such microsites where the moss-covered area was low, and A. mariesii preferred where dwarf bamboo-covered area was high. 相似文献
7.
Kanji Namikawa 《Ecological Research》1996,11(1):23-33
In 1979 and 1991, trees over 2.0 m high were measured and mapped together with their crown projections to clarify stand dynamics and shifts in canopy dominants during this period, in a permanent plot of 0.525 ha in an old-growth, cool temperate mixed forest of Mt Moiwa, Central Hokkaido, northern Japan. During this period, an abundant recruitment of trees was observed after some canopy trees were felled by a typhoon in 1981 leaving gaps in the canopy. Vigorous recruitment was observed forTilia japonica, Acer mono andPrunus ssiori. These species had different regeneration sites in relation to canopy state. NeitherUlmus japonica norKalopanax pictus had any recruits during the 12 year period even in gaps. The equilibrium composition of tree species projected from transition probability analysis also implied the above shift of dominant species during the 12 year period in the plot and suggested that the present forest is not in an equilibrium state. 相似文献
8.
Thomas Giesecke 《Vegetation History and Archaeobotany》2005,14(2):133-147
Pollen analyses of sediment cores from two small lakes within the boreal forest in the central Scandes Mountains help to elucidate the Holocene forest dynamics of the region. Analyses of pore/pollen grain diameter ratios of Alnus grains indicate the early Holocene presence of Alnus glutinosa in the study area. The results are discussed in conjunction with available pollen records to evaluate the importance of thermophilous trees during the early Holocene and to deduce the regional spread of Picea abies. Corylus avellana, Alnus glutinosa and Ulmus glabra were probably common constituents of the early Holocene forest. Tilia cordata may have occurred there as a rare tree. Pollen stratigraphies from the region do not indicate the occurrence of Quercus robur. The regional spread of Picea abies can be separated into two phases: a mid-Holocene establishment or first expansion of small outpost populations and a late-Holocene population expansion. The mid-Holocene shift in vegetation composition may have been caused by changes in the westerly airflow. 相似文献
9.
Effects of Sika deer on the regeneration of aFagus crenata forest on Kinkazan Island,northern Japan 总被引:5,自引:0,他引:5
Kinkazan Island, a sanctuary island that has been conserved for over 100 years, is inhabited by a Sika deer population of
high density (60 km−2). AFagus crenata forest, a climax forest of this region, was composed of only large sized trees (30–60 cm diameter breast height) and lacked
young trees. However, many saplings were found inside a deer proof fence, indicating this forest had a potential to produce
seedlings. They were tentatively protected by shrubs ofLeucothoe grayana var.glabra, an upalatable ericaceous shrub, but did not exceed the shrub height. Heavy browsing by the deer suppressed recruitment of
saplings ofF. crenata. The forest will be reduced without population control of the deer. 相似文献
10.
Shri Kant Tripathi Akihiro Sumida Kiyomi Ono Hideaki Shibata Shigeru Uemura Koichi Takahashi Toshihiko Hara 《Ecological Research》2006,21(2):315-320
We investigated the changes in soil microbial biomass C (MBC), microbial biomass N (MBN) and N mineralization in Sasa kurilensis-present (SP) and S. kurilensis-removed (SR) stands in a Betula ermanii forest. The mean levels of MBC and MBN were significantly higher in the SR stand than in the SP, which may have positively influenced the N-mineralization rate as depicted by a significant positive correlation between these variables and the N-mineralization rate. N immobilization and subsequent N release along with decreased use of available soil N due to S. kurilensis removal may have ensured greater N availability in the SR stand. 相似文献
11.
Justin Gerlach 《Journal for Nature Conservation》2004,12(3):149-155
A 10 year study of forest communities on Silhouette island, Seychelles demonstrates stability of forest composition in most areas over this time-scale. Areas with heavy invasion by alien species were found to be regenerating, particularly with the rapid loss of Clidemia hirta. This is attributed to the abundance of well-adapted native plants allowing competitive exclusion to take place, throughout competition for light. It was noted that invasive plant species tend to be unstable on the rocky slopes covered by native high forest. A high rate of tree fall and limited seed dispersal may reduce the impact of the invasive tree Paraserianthes falcataria in the future. Other species such as Cinnamomum verum and Psidium cattleianum may persist as major invaders due to wider seed dispersal. 相似文献
12.
Canopy gap area/age distributions and growth mechanisms were examined in a virgin subalpine forest in the White Mountains, New Hampshire, USA. The gap area distribution was negative exponential in form. Whithin gap tree ages varied widely in response to stepwise gap expansion caused by windthrow of peripheral trees or death of standing mature Picea rubens at gap edges. As a consequence, the density of small gaps may have been underestimated and the density of large gaps overestimated. The estimates of canopy turnover time, 303 yr, and of patch birth rate on an area basis, 3.3×10-3 ha new patches/ha land area/yr, were not affected by the gap expansion phenomenon. However, any estimate of patch birth rate as numbers of new patches formed per year would have been too low. Because of increasingly widespread Picea death, the patch area/age distribution of this forest may not currently be in steady-state. 相似文献
13.
Picea glehnii seedlings are affected by damping-off fungi in nurseries. The aims of this study were (1) to isolate fungi grown in the seedling rhizosphere in forest soil of P. glehnii, (2) to select fungi that produce antifungal compounds against Pythium vexans, and (3) to examine whether or not selected fungi can protect seedlings from P. vexans. Penicillium frequentans from Picea glehnii seedling roots produced antibiotic penicillic acid. Penicillic acid did not cause significant phytotoxicity to the seedlings. Penicillium frequentans increased the average percentage of surviving seedlings when inoculated together with Pythium vexans, but the increase was not significant. Vigorous mycelial growth of P. frequentans around seedling roots seems to be one of the mechanisms for protection, but the amount of penicillic acid was too low to show antifungal activity in the seedling rhizosphere. 相似文献
14.
15.
The regeneration process in a mixed forest was investigated in Nopporo National Forest, Hokkaido. The analysis of age structure in an 80 m×80 m plot revealed that almost all of the species regenerated intermittently. In eleven gaps observed in the plot, the regeneration of a boreal conifer (Abies sachalinensis) was seldom observed. Temperate hardwoods, even climax species (Acer mono, Quercus mongolica var. grosseserrata, Tilia japonica), regenerated vigorously in the gaps. The age structure in ten additional plots scattered all over the forest showed that Abies tended to regenerate synchronously. From previous records, regeneration of Abies could be ascribed to catastrophic storms causing serious windfalls. On the other hand, regeneration of the temperate hardwoods was not synchronous but independent in different places within the forest. They could regenerate not only after those catastrophic storms but also after less severe disturbances which caused the death and fall of one or several trees. It is concluded that the coexistence of boreal coniferous species and temperate deciduous broad-leaved species in mixed forests may be maintained not only by the difference in habitat but also by the balance between the less frequent large disturbances, and the more frequent smaller ones. 相似文献
16.
Arbuscular mycorrhizas (AM) are the most widespread mycorrhiza in nature and form two morphologies, Arum- and Paris-type. The determining factors defining the two different morphologies are not well understood. In this study, the distribution of Arum- and Paris-type AM was determined in a mixed pine forest. A total of 35 plant species belonging to 20 families and 32 genera were identified and examined for AM colonization and morphological types. AM morphological types in 14 families were confirmed as follows: Arum-type in Rosaceae, Oleaceae, Lauraceae, Vitaceae and Compositae, Paris-type in Aquifoliaceae, Ulmaceae, Araliaceae, Theaceae, Magnoliaceae, Rubiaceae and Dioscoraceae, and both and/or intermediate types in Caprifoliaceae and Gramineae. Plant families whose AM morphological status was previously unknown were clarified as follows: Polygonaceae and Commelinaceae showed Arum-type morphology; Celastraceae, Menispermaceae and Elaeagnaceae had typical Paris-type morphology. The proportion of Arum-type to Paris-type species decreased in the following order: annuals > perennials > deciduous species > evergreen species, and pioneer group > early successional group > late successional group. Evergreen plants had a higher tendency to form Paris-type AM than annuals, perennials and deciduous plants. The results indicate that environmental changes, such as shade during plant succession, control the distribution of plant growth forms in mixed pine forest and may also play a part in the distribution of Arum- and Paris-type morphology. The identity of the plant seems to strongly influence AM morphology, though control by the fungal genome cannot be ruled out. 相似文献
17.
The spatial pattern and canopy-understory association of trees in a cool temperate,mixed forest in western Japan 总被引:4,自引:0,他引:4
Nobuhiro Akashi 《Ecological Research》1996,11(3):311-319
The spatial distribution pattern of trees and the association between canopy and understory individuals were examined with
reference to the distribution of tree crowns in a cool temperate, mixed forest in Ohdaigahara, western Japan. Line transect
and contact sampling methods were used to examine the pattern over various spatial scales. These methods are useful to detect
patterns over a large study area. The dominance ofChamaecyparis obtusa on steep slopes forming large patches suggested that the distribution of this species is a consequence of landslides. UnderstoryFagus crenata showed a clumped distribution, and the relative coverage of this species was larger in canopy gaps than under a closed canopy.
Understory individuals ofAbies homolepis showed a positive association with canopy trees ofF. crenata but a negative association with conspecific canopy individuals. These patterns suggested thatF. crenata regenerates in canopy gaps and is replaced byA. homolepis. The dynamics of these two species are consistent with the process of gap dynamics. The effects of both small- and large-scale
disturbance must be evaluated to understand the mechanisms of patch formation and the coexistence of forest tree species. 相似文献
18.
Populus euphratica Oliv. is a main tree species that forms natural riparian forests in arid and semi-arid areas from Morocco to the Ordos Plateau.
This study is designed to clarify the forest structure and dynamics of P. euphratica and to elucidate the ecological mechanisms sustaining riparian forests under unreliable environmental conditions. This study
was conducted in a P. euphratica forest of the Ejina Oasis in Inner Mongolia, China, which is a hyperarid area. According to their tree size distribution,
P. euphratica forests can be grouped into juvenile, mature, and overmatured stages. Almost all large P. euphratica showed dieback. The regeneration density on the forest floor shows a relation with the degree of height decrease due to dieback
damage, as evaluated using the ratio of actual height to the maximum height estimated from the D–H relation. Therefore, after the mature stage, individual trees continue to grow while controlling their canopy size to adjust
to changing environmental conditions in the overmatured stage. Our results suggest that P. euphratica growing under large fluctuations in groundwater levels exhibit a sophisticated regeneration system with canopy degradation. 相似文献
19.
Summary Pool sizes of ATP and ADP were analysed in freeze-stopped, lyophilised homogenates of needles from Norway spruce [Picea abies (L.) Karst.]. Control experiments in which possible changes in adenylate pools during sample acquisition were investigated did not reveal significant differences between needles taken from branches in situ or within a 30-min period after cutting off a branch. In addition, pool sizes of ADP and ATP were not affected by changes in light intensity (between 60 and 1500 E*-m-2*s-1), which inevitably occur when samples have to be taken from the upper region of older trees. Levels of ATP and ADP showed considerable seasonal changes (May through October) with the highest ratios of ATP/ADP in developing needles. In general, there was a tendency towards increased ratios of ATP/ADP with increasing needle age. This observation was corroborated by analyses of needles from spruce trees of different age and growing under different conditions. Needles from declining trees or from trees specifically fumigated with low concentrations of ozone and sulphur dioxide had significantly increased ratios of ATP/ADP compared to controls. The results are discussed with respect to physiological responses connected with natural senescence and induced ageing. 相似文献
20.
Cheng-Hao Li Bao-Guang Liu Tae-Dong Kim Heung-Kyu Moon Yong-Eui Choi 《Plant biotechnology reports》2008,2(4):259-265
Picea koraiensis, called Korean spruce, is an evergreen tree and found mostly in northeast Asia. In this study, plant regeneration via somatic
embryogenesis from open-pollinated immature zygotic embryos of nine genotypes of elite trees was established. Immature zygotic
embryos were cultured onto RJW medium modified from 505 medium with 21.48 μM NAA, 2.22 μM BA, and 2.32 μM KT. The average
frequency for all nine genotypes was 74.2%. Embryogenic calluses of the nine genotypes of elite trees were subcultured on
RJW basal medium containing 8.06 μM NAA, 1.11 μM BA, and 1.16 μM kinetin. The calluses of three lines, 3#, 9#, and 2#, were actively proliferated but others were not. Somatic embryogenesis was induced from the embryogenic callus in genotypes
of 3#, 9#, and 2# on RJW medium with ABA and 60 g l−1 sucrose. Cotyledonary somatic embryos were subjected to a drying process. The drying of embryos by uncapping the culture
bottle for 5 days on a clean bench resulted in a high frequency of germination of somatic embryos (87% in RJW medium). However,
plantlet conversion from germinated embryos was greatly reduced and the optimal medium for plant conversion was 1/2 WPM or
1/2 BMI medium. In conclusion, we have, for the first time, established a plant regeneration system via somatic embryogenesis
in the Korean spruce, which can be applied for rapid micropropagation of elite trees. 相似文献