| Montane mixed evergreen and deciduous broadleaved forests is endemic forest vegetation type of China. Southwest Hubei Province lies in a transition zone from lower hilly regions of southeastern China to the southwestern Plateau of China. And mixed evergreen and deciduous broadleaved forests is main body of montane forests in Southwest Hubei. However, due to long-term extensive deforestation, resulted in the forests area reducing, function declining, ecological problem increasingly protruding. The past studies on mixed evergreen and deciduous broadleaved forests were fewer, and were mainly focused on classification and description of natural community, we still know little about process and mechanism of those degraded communities after anthropogenic disturbance. On the basis of field investigations, field trial data collection and analysis, restoration process of the degraded communities, which were formed by means of different restoration period, different cutting way and different restoration way, were studied systematically by using principles and methods of phytosociology, restoration ecology and silviculture in this paper. And then synthetical appraisement of restored degree in the restoration process of degraded communities were analyzed. Finally restoration technique strategy was put forward so as to solve the problems of theory and technology of restoration about mixed evergreen and deciduous broadleaved forests. It not only enriches study content of mixed evergreen and deciduous broadleaved forests, promotes development of vegetation and silviculture,but also provides scientific basis and technological guide for subtropics montane forests restoration. It is important for rapidly restoration of mixed evergreen and deciduous broadleaved forests in theories and practices. Through fives years study, the main conclusions were as follows:(1) Dynamics of community structure in the process of natural restoration were systematically studied. The analysis, which was for life form spectrum and leaf feature of community, showed that the community for 35 years natural restoration or 14 years selective cuttings forest can basically form phsiognomy features of montane mixed evergreen and deciduous broadleaved forests; The analysis, which was for species composition and importance value of community, showed that tree species numbers indicated a tendency by increasing firstly, and then decreasing with the community restoration. Shrub species was less in the early stage and was more in the mid-stage and late-stage. But shrub species, herb species was more in early growth stage, was less in the mid-stage and late-stage. Importance value of the deciduous tree species in the community decreased gradually, meanwhile that of evergreen tree species increased gradually. Species composition and importance value of communities formed by different cutting way and different restoration way occurred different change with anthropogenic disturbance way, intensity and frequency. In the communities of intensive disturbance (clear cutting and artificial restoration), both herb species proportion and importance value of the deciduous tree species were higher. In the community of moderate-light disturbance (selective cutting and artificially-promoted natural restoration), both proportion of tree, shrub species and importance value of the evergreen tree species were higher; The analysis, which was for height classes structure and diameter classes structure of community, showed that numbers of height class and diameter class all increased with the community restoration. And standing timber proportion decreased with the increase of height class and diameter class, and the tendency was more obvious in early growth stage in general. The differences of cutting way and restoration way can cause changes of community structure to some extent, and it was decided by compound effects of the disturbance and restoration. Height class structure and diameter class structure in the selective cutting forests were better than in the clear cutting forests, and it was close to contrast. The standing timber proportion of low height class structure and small diameter class structure in the Cryptomeria fortunei plantation were low and unstable in the structure, but those in the Cunninghamia lanceolata and Sassafras tsumu mixture plantation, artificially-promoted natural restoration forest and natural restoration forest showed basically that standing tree individuals quantities decreased with increasing of height classes and diameter classes, and the community structure approached rationality.(2) Dynamics of community species diversity in the process of natural restoration were systematically studied. The study results showed that the change trends of species diversity indexes in the tree-layer in the natural restoration process were: Frist increasing, to the biggest value in the middle period of 60 years, afterwards decreasing. Whereas undergrowth woody plant layer, presented that change trends of waved decreasing. Selective cuttings strengthened environmental heterogeneity, its species diversity indexes were obvious higher than clear cutting and contrast. In the communities of different restoration way, that of the Cryptomeria fortunei plantation was the highest which were significantly lower than the Cunninghamia lanceolata and Sassafras tsumu mixture plantation, artificially-promoted natural restoration forest and natural restoration forest as well. Species diversity in the restoration mid-stage and moderate disturbance community were the highest. The results supported Intermediate Disturbance Hypothesis.(3) Dynamics of main tree niche in the process of natural restoration were systematically measured. The general trends of niche breadth of dominant deciduous tree species decreased with the community restoration, while that of dominant evergreen tree species was on the contrary. Niche breadth of dominant deciduous tree species in clear cutting forests was the highest (8.375), significantly higher than selective cuttings (2.951) and contrast (2.561), and that of dominant evergreen tree species were the lowest (1.374), obviously lower than selective cuttings (7.515) and contrast (7.097). No significantly differences existed between selective cuttings and contrast. In the communities of different restoration way, niche breadth of Cryptomeria fortunei was the highest in the Cryptomeria fortunei plantation, that of Cunninghamia lanceolata and Sassafras tsumu were the highest in the Cunninghamia lanceolata and Sassafras tsumu mixture plantation, that of Sassafras tsumu was the highest in the artificially-promoted natural restoration forests, that of Carpinus fargesii was the highest in the natural restoration forests. Niche breadth of dominant deciduous tree species in the Cryptomeria fortunei plantation and the Cunninghamia lanceolata and Sassafras tsumu mixture plantation was obviously lower than that in the artificially-promoted natural restoration forests and the natural restoration forests. That of dominant evergreen tree species in the Cryptomeria fortunei plantation was the lowest, obviously lower than that of other restoration way communities. With community restoration, niche overlaps of dominant deciduous tree species had a wavelike decreasing trend, meanwhile that of dominant evergreen tree species had a wavelike increasing trend on the whole. Average of niche overlaps of all tree species in communities in the process of vegetation restoration presented mainly that change tendence of small range waved decreasing. In the communities of different cutting way, niche overlap of dominant deciduous tree species in the clear cutting forests was obviously higher than selective cuttings and contrast. On the contrary, that of dominant evergreen tree species showed a different change tendency. And niche overlaps of selective cuttings was close to that of contrast. Average of niche overlaps among all tree species in communities in the process of vegetation restoration followed the law of clear cuttings > selective cuttings > contrast, and niche overlaps in the clear cutting forests was obviously higher than selective cuttings and contrast. In the communities of different restoration way, niche overlaps of dominant deciduous tree species in the Cunninghamia lanceolata and Sassafras tsumu mixture plantation was the highest, obviously higher than that of other restoration way communities. Whereas that of dominant evergreen tree species in the Cryptomeria fortunei plantation and the Cunninghamia lanceolata and Sassafras tsumu mixture plantation was obviously lower than that in the artificially-promoted natural restoration forests and the natural restoration forests. Differences of niche overlaps among all tree species in communities of different restoration way, was not clear, it was from 0.280 to 0.394, which Cryptomeria fortunei plantation was the lowest, Cunninghamia lanceolata and Sassafras tsumu mixture plantation were the highest. The research results of niche overlaps showed that higher niche overlaps among the same or similar life form early-successional species meant similarity and competition of tree species utilization resource. Increasing of niche overlaps of late-successional species with other tree species represented horizontal spatial overlap but vertical spatial split. It was mutualistic symbiosis not competition, was a full use mechanism of limited envirnmental resources.(4) Dynamics of stand growth in the process of natural restoration were studied. Standing volume and biomass in the community all increased continuous with the community restoration. In the middle period of 60 year, the standing volume of deciduous broadleaved commercial tree species in the community was the highest, afterwards decreasing, could be conducted selective cutting utilization. In the communities of different cutting way, the standing volume and biomass in the community all emerged: clear cuttings< selective cuttings< contrast, selective cuttings was obvious higher than clear cuttings. In the communities of different restoration way, the standing volume and biomass all in the community emerged: Cryptomeria fortunei plantation>Cunninghamia lanceolata and Sassafras tsumu mixture plantation > artificially-promoted natural restoration forest > natural restoration forest. The reasonable positive human-disturbance can promote obviously stand growth..(5) Dynamics of tree natural regeneration in the process of natural restoration were analyzed. The results showed that tree species natural regeneration capacity emerged in general change trends of increasing with the community restoration. In the communities of different cutting way, natural regeneration capacity was: selective cuttings>contrast>clear cuttings. In the communities of different restoration way, natural regeneration capacity of Cunninghamia lanceolata and Sassafras tsumu mixture plantation, artificially-promoted natural restoration forests and natural restoration forests were obviously bettter than that of Cryptomeria fortunei plantation.(6) Morphological response and ecological adaptation of four kinds of regeneration tree species seedlings of Schima superba, Castanea henryi, Fagus Longiptiolata and Cycloblanopsis glauca were studied in envirnmental stress condition. From gap's edge to gap's centre,the growth of main morphological factors and biomass of Schima superba seedlings increased gradually, and it was founded that Schima superba seedlings was a kind of helioskiophyte; the seedlings growth of Castanea henryi and Fagus Longiptiolata in weak light condition were lower, and change range of Castanea henryi was higher than Fagus Longiptiolata, but growth of Cycloblanopsis glauca seedlings had little differce in three different light condition. Castanea henryi seedlings had a stronger morphological plasticity, then it was Fagus Longiptiolata seedlings, but Cycloblanopsis glauca seedlings was not obvious. Castanea henryi was a kind of photophilic intolerant tree species, Fagus Longiptiolata was a late-period shade tolerant tree species, Cycloblanopsis glauca was a good adaptive power shade tolerant tree species. The relation between ramet height, basal diameter and biomass follows W= a(D~2H)~b. Quality index of Schima superba seedlings at gap's centre was the highest, and obviously higher than gap's edge. That of seedlings of Castanea henryi, Fagus Longiptiolata and Cycloblanopsis glauca in the full light condition were all the highest, Seedlings of Castanea henryi and Fagus Longiptiolata all showed significant differences but Cycloblanopsis glauca seedlings did not show significant differences in three different light condition.(7) Dynamics of soil ecological process in the process of natural restoration were studied. Soil physicochemical characteristics basically developed toward positive soil system, and change of upper levels soil (0-20 cm) was ralatively obvious. The selective cuttings had a less influences on soil physicochemical characteristics, on the contrary, clear cuttings had a ralative influences on it. Soil fertility in the artificially-promoted natural restoration forests and the natural restoration forests were higher, but Soil fertility in the Cryptomeria fortunei plantation was lower.(8) 12 evaluation indicators including soil and vegetation were established, and integrated evaluation about different typical restored community was conducted by method of principal component analysis. The results were coincided with forest restoration status in the mulinzi mountain. It is practicable for principal component analysis were applied in integrated evaluation of ecological restoration for degraded mixed evergreen and deciduous broadleaved forests.(9) Effect factors and possibility of restoration about montane mixed evergreen and deciduous broadleaved forests in Southwest Hubei were analyzed, objective and way were defined as well as restoration technique strategy was put forward.
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