Comparative study of leaf carbon gain in saplings ofThujopsis dolabrata var.hondai andQuercus mongolica var.grosseserrata in a cool-temperate deciduous forest

Seasonal courses of leaf CO₂ gas exchange in a growing season were examined in saplings ofThujopsis dolabrata var.hondai andQuercus mongolica var.grosseserrata in a cool temperate deciduous forest. Between the two tree species there were no large differences in the light compensation point of leaf photosynthesis, except for the season of new leaf expansion. However, light-saturated rates of net photosynthesis were obviously high inT. dolabrata var.hondai. EvergreenT. dolabrata var.hondai saplings had large photosynthetic production in two seasons, before the emergence of new foliage and after foliage fall of the overstory deciduous trees, because of the significantly high solar radiant energy penetrating under the forest canopy during the seasons. Saplings of deciduousQ. mongolica var.grosseserrata were heavily shaded throughout the growing season by foliage of the overstory trees, which resulted in a low daily surplus production. The annual surplus production of leaves in the growing season was estimated to be 2300 mmol CO₂ m⁻² inT. dolabrata var.hondai and −100 mmol CO₂ m⁻², slightly negative, inQ. mongolica var.grosseserrata. These results supported the high survivability ofT. dolabrata var.hondai saplings and the high mortality ofQ. mongolica var.grosseserrata in the deciduous forest.     

Effects of microenvironmental heterogeneity on the seed-to-seedling process and tree coexistence in a riparian forest

In a temperate riparian forest, the effects of substrate types, canopy gaps and conspecific seedfall density were investigated on the seed-to-seedling process for the five dominant species (Aesculus turbinata, Fagus crenata, Acer mono, Pterocarya rhoifolia and Cercidiphyllum japonicum). Densities of seedfall and subsequent seedling recruits were measured in the stand over a period of 6 years. A model assuming that local density of seedling recruits is proportional to seedfall density in the preceding year significantly explained a spatial variation in seedling recruits for all species. Several environmental factors were then added. Substrate composition had a positive effect on P. rhoifolia and C. japonicum. P. rhoifolia was favored by gravel substrate, which also explained the adult distribution of this species in this forest. C. japonicum appeared to be facilitated by a mineral-soil substrate. However, the distributions of this substrate and adults of C. japonicum did not follow each other closely. A. mono was negatively affected by gaps, and F. crenata was negatively affected by conspecific seedfall density. In contrast, A. turbinata was not significantly affected by any of the environmental factors tested. The microenvironmental heterogeneity in this forest explained species coexistence to a limited extent in the context of seed-to-seedling processes. Performances at later stages of the life-cycle and/or catastrophic disturbances (e.g. landslides) might have a stronger influence on species coexistence in this forest.     

Stand dynamics during a 12-year period in a second-growth stand in a cool temperature forest in northern Japan

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.     

The effects of Sasa and canopy gap formation on tree regeneration in an old beech forest

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.     

Contrasting litter effects on old field tree germination and emergence

Because the fate of seeds is critical to understanding the invasion of old fields by trees, and plant litter is an important component defining the old field microsite of dispersed seeds, I investigated the effects of litter type (Solidago spp./goldenrod,Quercus spp./oak, mixed) and litter amount (100–800 g/m²) on tree seed germination and seedling emergence. I found that at all densities bothSolidago andQuercus litter greatly reduced emergence of the small-seeded, bird-dispersed species,Juniperus virginiana andCornus florida. For one of the large-seeded, mammal-dispersed species,Carya tomentosa, high densitySolidago litter and high density mixed litter treatments reduced emergence. For the other large-seeded species,Quercus rubra, the high density mixed litter treatment and all levels ofSolidago litter reduced emergence.Quercus seedlings emerged twice as often as the other three species in control pots without litter.Carya emerged before the other species but the high density oak treatment delayed the expansion of its cotyledons. My results suggest that litter may contribute to the slow rate of tree invasion and the low probability of tree establishment in old fields. However, old field litter studies taken together point to the difficulty in drawing general conclusions about any net effect of litter on old field tree establishment.     

Response of Japanese beech (Fagus japonica Maxim.) sprouts to canopy gaps

The response of Japanese beech (Fagus japonica Maxim.) sprouts to canopy gaps in natural beech forest in central Japan was studied using two contrasted gaps in which tree-ring chronologies of regenerating stems were analyzed. The gaps were created by uprooting of a single Quercus mongolica var. grosseserrata stem (diameter: 50 cm; gap size: 40 m²; 23 years old) and by concurrent uprootings of four F. japonica stools (gap size: 180 m²; 30 years old). Japanese beech sprouts emerged before and after the gap formation and dominated stem populations in both gaps. In gaps, growth of F. japonica sprouts was equal or lower than growth of stems of seed origin, but most sprouts (F. japonica, Acer mono var. marmoratum) appeared a few years before emergence of seedlings. The small gap created by single stem fall was dominated by some beech sprouts from stools adjacent to the gap. The multiple gap was not closed by beech sprouts from stools surrounding the gap, but some dominant beech stems were resprouts from the uprooted beech stools. The existence of a sprout bank under the canopy may play an important role in the closing process of gaps in natural Japanese beech forest.     

Susceptibility to photoinhibition of three deciduous broadleaf tree species with different successional traits raised under various light regimes

The susceptibility to photoinhibition of tree species from three different successional stages were examined using chlorophyll fluorescence and gas exchange techniques. The three deciduous broadleaf tree species were Betula platyphylla var. japonica, pioneer and early successional, Quercus mongolica, intermediate shade‐tolerant and mid‐successional, and Acer mono, shade‐tolerant and late successional. Tree seedlings were raised under three light regimes: full sunlight (open), 10% full sun, and 5% full sun. Susceptibility to photoinhibition was assessed on the basis of the recovery kinetics of the ratio of vaviable to maximum fluorescence (F_v/F_m) of detached leaf discs exposed to about 2000 μmol m^?1 s^?1 photon flux density (PFD) for 2 h under controlled conditions (25 to 28 °C, fully hydrated). Differences in susceptibility to photodamage among species were not significant in the open and 10% full sun treatments. But in 5% full sun, B. platyphylla sustained a significantly greater photodamage than other species, probably associated with having the lowest photosynthetic capacity indicated by light‐saturated photosynthetic rate (B. platyphylla, 9·87, 5·85 and 2·82; Q. mongolica, 8·05, 6·28 and 4·41; A. mono, 7·93, 6·11 and 5·08 μmol CO₂ m^?1 s^?1for open, 10% and 5% full sun, respectively). To simulate a gap formation and assess its complex effects including high temperature and water stress in addition to strong light on the susceptibility to photoinhibition, we examined photoinhibition in the field by means of monitoring ΔF/F′_m on the first day of transfer to natural daylight. Compared with ΔF/F′_m in AM, the lower ΔF/F′_m in PM responding to lower PFD following high PFD around noon indicated that photoinhibition occurred in plants grown in 10 and 5% full sun. The diurnal changes of ΔF/F′_m showed that Q. mongolica grown in 5% full sun was less susceptible to photoinhibition than A. mono although they showed little differences both in photosynthetic capacity in intact leaves and susceptibility to photoinhibition based on leaf disc measurements. These results suggest that shade‐grown Q. mongolica had a higher tolerance for additional stresses such as high temperature and water stress in the field, possibly due to their lower plasticity in leaf anatomy to low light environment.     

Mixing Effects of Understory Plant Litter on Decomposition and Nutrient Release of Tree Litter in Two Plantations in Northeast China

Understory vegetation plays a crucial role in carbon and nutrient cycling in forest ecosystems; however, it is not clear how understory species affect tree litter decomposition and nutrient dynamics. In this study, we examined the impacts of understory litter on the decomposition and nutrient release of tree litter both in a pine (Pinus sylvestris var. mongolica) and a poplar (Populus × xiaozhuanica) plantation in Northeast China. Leaf litter of tree species, and senesced aboveground materials from two dominant understory species, Artemisia scoparia and Setaria viridis in the pine stand and Elymus villifer and A. sieversiana in the poplar stand, were collected. Mass loss and N and P fluxes of single-species litter and three-species mixtures in each of the two forests were quantified. Data from single-species litterbags were used to generate predicted mass loss and N and P fluxes for the mixed-species litterbags. In the mixture from the pine stand, the observed mass loss and N release did not differ from the predicted value, whereas the observed P release was greater than the predicted value. However, the presence of understory litter decelerated the mass loss and did not affect N and P releases from the pine litter. In the poplar stand, litter mixture presented a positive non-additive effect on litter mass loss and P release, but an addition effect on N release. The presence of understory species accelerated only N release of poplar litter. Moreover, the responses of mass loss and N and P releases of understory litter in the mixtures varied with species in both pine and poplar plantations. Our results suggest that the effects of understory species on tree litter decomposition vary with tree species, and also highlight the importance of understory species in litter decomposition and nutrient cycles in forest ecosystems.     

黄土高原樟子松和落叶松与其他树种枯落叶混合分解对土壤的影响

通过采集树木枯落叶与土壤进行室内混合分解培养试验,研究了黄土高原常见的樟子松和落叶松与其他树种枯落叶混合分解对土壤性质的影响及存在的相互作用,从而为不同树木种间关系的探索和该地区人工纯林的混交改造提供科学指导。结果表明:12种枯落叶单一分解均明显提高了土壤脲酶(54%—110%)、脱氢酶(85%—288%)和磷酸酶(81%—301%)活性以及有机质(29%—55%)和碱解N(12%—49%)含量,但对土壤速效P含量和CEC的影响存在较大差异。综合而言,樟子松分别与白桦、刺槐、白榆、柠条和落叶松枯落叶混合分解在对土壤性质的影响中存在相互促进作用,而分别与小叶杨、沙棘、紫穗槐、侧柏和辽东栎枯落叶混合分解在对土壤性质的影响中存在相互抑制作用;落叶松分别与刺槐、白桦、小叶杨和紫穗槐枯落叶混合分解在对土壤性质的影响中存在相互促进作用,而分别与柠条、侧柏、辽东栎、沙棘、油松和白榆枯落叶混合分解在对土壤性质的影响中存在相互抑制作用。     

Carbon allocation to defense, storage, and growth in seedlings of two temperate broad-leaved tree species

Optimal carbon allocation to growth, defense, or storage is a critical trait in determining the shade tolerance of tree species. Thus, examining interspecific differences in carbon allocation patterns is useful when evaluating niche partitioning in forest communities. We hypothesized that shade-tolerant species allocate more carbon to defense and storage and less to growth compared to shade-intolerant species. In gaps and forest understory, we measured relative growth rates (RGR), carbon-based defensive compounds (condensed tannin, total phenolics), and storage compounds (total non-structural carbohydrate; TNC) in seedlings of two tree species differing in shade tolerance. RGR was greater in the shade-intolerant species, Castanea crenata, than in the shade-tolerant species, Quercus mongolica var. grosseserrata, in gaps, but did not differ between the species in the forest understory. In contrast, concentrations of condensed tannin and total phenolics were greater in Quercus than in Castanea at both sites. TNC pool sizes did not differ between the species. Condensed tannin concentrations increased with increasing growth rate of structural biomass (GRstr) in Quercus but not in Castanea. TNC pool sizes increased with increasing GRstr in both species, but the rate of increase did not differ between the species. Accordingly, the amount of condensed tannin against TNC pool sizes was usually higher in Quercus than in Castanea. Hence, Quercus preferentially invested more carbon in defense than in storage. Such a large allocation of carbon to defense would be advantageous for a shade-tolerant species, allowing Quercus to persist in the forest understory where damage from herbivores and pathogens is costly. In contrast, the shade-intolerant Castanea preferentially invested more carbon in growth rather than defense (and similar amounts in storage as Quercus), ensuring establishment success in gaps, where severe competition occurs for light among neighboring plants. These contrasting carbon allocation patterns are closely associated with strategies for persistence in these species’ respective habitats.     

Litter decomposition of a pine plantation is affected by species evenness and soil nitrogen availability

Background and aims

Litter decomposition is a key process controlling flows of energy and nutrients in ecosystems. Altered biodiversity and nutrient availability may affect litter decomposition. However, little is known about the response of litter decomposition to co-occurring changes in species evenness and soil nutrient availability.

Methods

We used a microcosm experiment to evaluate the simultaneous effects of species evenness (two levels), identity of the dominant species (three species) and soil N availability (control and N addition) on litter decomposition in a Mongolian pine (Pinus sylvestris var. mongolica) plantation in Northeast China. Mongolian pine needles and senesced aboveground materials of two dominant understory species (Setaria viridis and Artemisia scoparia) were used for incubation.

Results

Litter evenness, dominant species identity and N addition significantly affected species interaction and litter decomposition. Higher level of species evenness increased the decomposition rate of litter mixtures and decreased the incidence of antagonistic effects. A. scoparia-dominated litter mixtures decomposed faster than P. sylvestris var. mongolica- and S. viridis-dominated litter mixtures. Notably, N addition increased decomposition rate of both single-species litters and litter mixtures, and meanwhile altered the incidence and direction of non-additive effects during decomposition of litter mixtures. The presence of understory species litters stimulated the decomposition rate of pine litters irrespective of N addition, whereas the presence of pine litters suppressed the mass loss of A. scoparia litters. Moreover, N addition weakened the promoting effects of understory species litters on decomposition of pine litters.

Conclusions

Pine litter retarded the decomposition of understory species litters whereas its own decomposition was accelerated in mixtures. Nitrogen addition and understory species evenness altered species interaction through species-specific responses in litter mixtures and thus affected litter decomposition in Mongolian pine forests, which could produce a potential influence on ecosystem C budget and nutrient cycling.     

Dwarf bamboos affect the regeneration of zoochorous trees by providing habitats to acorn-feeding rodents

The effects of dwarf bamboos (Sasa spp.) on the regeneration of trees in a natural hardwood forest were studied by analysing the spatial dispersion of seedlings and saplings of anemochores (Acer palmatum var. matsumurae, Fraxinus lanuginosa, and Carpinus laxiflora) and zoochores (Quercus mongolica var. grosseserrata and Q. serrata). Relative photosynthetic photon flux density at 10 cm above ground was significantly correlated with the coverage of dwarf bamboos (r=0.661, P<0.001). Seedlings were abundant and were randomly distributed in the anemochores, other than the shade-intolerant species C. laxiflora which was significantly more sparse in sites with dense Sasa than in sites where Sasa was rare. Distribution of saplings was also random in the shadetolerant anemochores A. palmatum var. matsumurae and F. lanuginosa but aggregated in sites with sparse Sasa in the shade-intolerant anemochore C. laxiflora. In contrast to the anemochores, seedlings of zoochores were very few and were distributed in sites with sparse Sasa. Saplings were also aggregated and negatively correlated with Sasa cover in the shade-intolerant species Q. serrata and the tolerant species Q. mongolica var. grosseserrata. The acorns put on the forest floor in a site with dense Sasa were quickly removed by small rodents such as Apodemus speciosus and A. argenteus. Trap census of rodents revealed that those mammals prefer the dense Sasa habitat to the sparse Sasa habitat. This suggests that the dwarf bamboos strongly affect the regeneration of zoochorous trees not only by shading the seedlings but also by providing habitats to acorn-feeding small mammals.     

Fire Tolerance and the Fire-related Sprouting Characteristics of Two Cool-temperate Broad-leaved Tree Species

This study was conducted in a secondary broad-leaved forestin northern Hokkaido, Japan, which burned on 20–21 April1998. The study plot, set up on 13 July 1998, contained Quercusmongolica var. grosseserrata and Betula platyphylla var. japonicatrees. The latter were more severely damaged by the fire. Size-dependentsurvivorship was observed in both species with larger treesbeing more likely to survive the fire. However, many largeBetulatrees were completely destroyed. Both species developed abundantroot collar sprouts immediately after the fire. The number ofsprouts ranged from 0 to 296 in Betula and from 0 to 34 in Quercus.Trees with no sprouts were not necessarily dead. The frequencydistribution of the sprouting pattern in Betula was bimodal.This was related to damage severity, with the most abundantsprouting manifest in the most severely damaged trees. Thispattern was not observed inQuercus . Stem diameter also appearedto influence the extent of sprouting in Betula, while in Quercusthere was no distinct correlation between basal area and thenumber of sprouts. In Betula, the relationship between the numberof sprouts and the damage severity suggests a trade-off in resourceallocation for sprouting vs. shoot flushing in the crown. Copyright2000 Annals of Botany Company Betula platyphylla var. japonica, fire, fire tolerance, Quercus mongolica var.grosseserrata , resource allocation, root collar sprouting, stem diameter size.     

Seed demography of three co-occurring Acer species in a Japanese temperate deciduous forest

Abstract. Seed demography of three co-occurring Acer species in an old-growth mixed deciduous forest in Japan was studied. Almost all of the seeds of A. mono germinated in the first spring, while those of A. palmatum var. amoenum showed a delay in germination of almost one year. A. rufinerve showed a rather opportunistic germination habit. Both A. palmatum var. amoenum and A. rufinerve form short-term persistent seed banks, but without input of newly dispersed seeds they may become extinct in about one year. The seed bank for these two species is not as significant as for a typical pioneer species, and the seedling bank is important for all three species. Only a small proportion of the dispersed propagules contained viable embryos, mainly due to pollination failure or abortion (A. mono and A. palmatum var. amoenum), and invertebrate predation (A. rufinerve). For all three species, larger seed crops had a higher percentage of viable seeds. Even for these relatively small, wind-dispersed seeds, the predation pressure was very high. A large part of the dispersed seeds was eaten by wood mice during the first winter (30–80 %). Estimation from the 5-yr average of seed dispersal and seedling emergence showed that only 7–16 % of the dispersed viable seeds succeeded in germinating.     

Removal of invasive shrubs alters light but not leaf litter inputs in a deciduous forest understory

The establishment and spread of non‐native, invasive shrubs in forests poses an important obstacle to natural resource conservation and management. This study assesses the impacts of the physical removal of a complex of woody invasive shrub species on deciduous forest understory resources. We compared leaf litter quantity and quality and understory light transmittance in five pairs of invaded and removal plots in an oak‐dominated suburban mature forest. Removal plots were cleared of all non‐native invasive shrubs. The invasive shrubs were abundant (143,456 stems/ha) and diverse, dominated by species in the genera Ligustrum, Viburnum, Lonicera, and Euonymus. Annual leaf litter biomass and carbon inputs of invaded plots were not different from removal plots due to low leaf litter biomass of invasive shrubs. Invasive shrub litter had higher nitrogen (N) concentrations than native species; however, low biomass of invasive litter led to low N inputs by litter of invasive species compared to native. Light transmittance at the forest floor and at 2 m was lower in invaded plots than in removal plots. We conclude that the removal of the abundant invasive shrubs from a native deciduous forest understory did not alter litter quantity or N inputs, one measure of litter quality, and increased forest understory light availability. More light in the forest understory could facilitate the restoration of forest understory dynamics.     

Phytosociological study on natural summer-green forests in Korea

Two phytosociological associations, Corylo-Quercetum mongolicae and Lespedezo-Quercetum serratae, were recognized as natural summer-green forests in the cool-temperate zone of Korea. They belong to the alliance, Rhododendro-Quercion mongolicae and Lespedezo-Quercion serratae, respectively. The former alliance occurs in northern areas of the cool-temperate zone and the latter develops in southern areas. Both alliances belong to the phytosociological ranking order, Acero-Quercetalia mongolicae. In contrast to Korean cool-temperate, summer-green forest associations, the Japanese ones, such asFagus crenata orQuercus mongolica var.grosseserrata associations, belong to the order, Saso-Fagetalia crenatae. Died 26 September 1986.     

A newOphiostoma species isolated from Japanese oak infested byPlatypus quercivorus

A newOphiostoma species was isolated from the sapwood ofQuercus mongolica var.grosseserrata and described asOphiostoma longicollum sp. nov. The species is characterized by a long perithecial neck with a gelatinous cap at the apex and a constricted base, orange-section-shaped ascospores that accumulate in a yellow-orange drop at the apex of the neck, and itsSporothrix anamorph. Contribution No. 137, Laboratory of Plant Pathology and Mycology, Institute of Agriculture and Forestry, University of Tsukuba.     

东北温带森林常见树种粗根分解过程及调控因子

粗根是森林生态系统中重要的碳库和养分库，对生态系统的碳和养分循环起着重要的作用。但目前人们对于影响粗根分解的主要因素以及粗根分解模式的研究较少。采用埋袋法对东北温带森林常见的10个树种（黄檗、胡桃楸、水曲柳、色木槭、红松、落叶松、白桦、春榆、紫缎、蒙古栎）的粗根（5-10 mm）进行了为期1年的分解实验研究，来探索粗根分解和养分释放的动态变化规律。研究结果表明：黄檗、胡桃楸、水曲柳、色木槭、红松、落叶松、白桦、春榆、紫缎、蒙古栎粗根年分解系数分别为0.826、0.897、0.477、0.341、0.358、0.264、0.244、0.593、0.458、0.227。由此可见，胡桃楸分解速率最快，蒙古栎分解速率最慢。在粗根分解过程中，不同调控因子对根系分解的影响不同。研究结果表明，粗根的分解速率与根系的初始C/N比例呈显著负相关（P<0.0001），与初始木质素含量呈负相关（P<0.0001），与初始非结构性碳水化合物（NSC）含量呈正相关（P<0.0001）。初始C/N、木质素含量与非结构性碳水化合物含量分别可以解释所研究的10个树种粗根分解速率的68%、20%与65%。研究结论对于预测粗根参与的碳循环与养分释放具有重要意义。     

不同树叶凋落物对人参土壤理化性质及微生物群落结构的影响

树种选择是林下山参护育成败的关键,研究树叶凋落物对人参土壤养分、微生物群落结构组成的影响,旨在为林下山参护育选择适宜林地及农田栽参土壤改良提供科学依据和理论指导。通过盆栽试验,研究添加5.0 g色木槭Acer mono.Maxim.var.mono(A)、赤松Pinus densiflora Sieb.et Zucc.(B)、胡桃楸Juglans mandshurica Maxim.(C)、紫椴Tilia amurensis Rupr.(D)、蒙古栎Quercus mongolica Fisch.ex Ledeb.(E)树叶凋落物到土壤中,种植人参(Panax ginseng C.A.meyer)后研究土壤理化性质以及微生物群落结构的变化。结果表明:添加不同树叶处理后人参土壤性质发生改变,土壤p H值显著高于对照土壤5.91(P0.05),土壤全氮、速效氮磷、微生物碳氮在所有树叶处理中显著增加(P0.05),而土壤容重、速效钾和C/N在添加树叶处理中降低。18个土壤样品基因组,经16S和ITS1测序分别得到6064和1900个OUTs。其中细菌涵盖了42门、117纲、170目、213科、225属,真菌涵盖了24门、98纲、196目、330科、435属。不同树叶处理人参土壤细菌和真菌地位发生改变,细菌Proteobacteria是树叶分解的关键微生物,添加树叶后其多样性显著高于对照(P0.05)。而细菌Bacteroidetes和真菌Basidiomycota可能是区别阔叶林和针叶林树种的关键微生物,针叶林中含量显著低于阔叶林(P0.05),而真菌Ascomycota是针叶林分解的关键微生物。进一步从不同分类水平上得到特定树叶凋落物的特异细菌和真菌。典型相关分析(CDA)表明细菌Bacteroidetes、Chloroflexi、Actinobacteria及真菌Basidiomycota、Zygomycota、Chytridiomycota及Ascomycota的位置及多样性的改变均与土壤因子SMBN、TN、AP、SOC、AK、C/N、p H有关。综上所述,添加不同树叶后不仅提高土壤微生物量碳氮、改善土壤理化性质,同时改变微生物群落结构组成,不同树叶处理土壤理化性质不同导致人参土壤微生物组成的差异,本结果对于林下参选地和农田栽参土壤微生物改良具有理论指导作用。