This paper studied root biomass and underground carbon (C) and nitrogen (N) storage of a more than 200-year-old primitive Korean pine and broad-leaved forest and its two 20- and 80-year-old secondary Populus davidiana and Betula platyphylla forests in Changbai Mountain, northeast China. The results showed that with forest succession, the root biomass of 20-year-old, 80-year-old, and primitive forests was 2.437, 2.742, and 4.114 kg/m², respectively. The root C storage was 1.113, 1.323, and 2.023 kg/m², soil C storage was 11.911, 11.943, and 12.587 kg/m², and underground C storage was 13.024, 13.266, and 14.610 kg/m², respectively, while the root N storage was 0.035, 0.032, and 0.038 kg/m², soil N storage was 1.208, 1.222, and 0.915 kg/m², and underground N storage was 1.243, 1.254, and 0.955 kg/m², respectively, which indicated that along with forest succession, the forest underground became a potential carbon sink,  whereas underground N storage did not change obviously.

Regeneration of tree species associated with canopy gaps in broad-leaved Korean pine forests was investigated. Species diversity in gaps and under closed canopy was compared, the relationship between biodiversity and gap structure was analyzed. Results indicate that there were significant differences between tree species diversity in gaps and that under canopy (p<0.01). In terms of Shannon-Wiener index, evenness index, and abundance index, the biodiversity in gap community were higher than those under forest canopy in regeneration layer. In terms of Simpson s dominance index, the dominance of certain species in the regeneration layer increased from gaps to closed canopy (p<0.01). In contrast, trends of biodiversity changes of succession layer in gaps and under closed canopy were opposite. Tree species diversity of different layers reacted directly to the change of gap size class. For example, Shannon-Wiener index and abundance index is higher and Simpson s dominance index is the lowest in succession layer of medium-size gap (100 250 m²) in the broad-leaved Korean pine forest of Changbai Mountains. Shannon-Wiener index reached the highest in a size of ≥250 m² and <100 m², reached the lowest in a size of 200 250 m² in the regeneration layer. Simpson s dominance index reached its maximum when the gap size was between 200 and 250 m². Generally, species of different layers reacted differently to the changes of gap size classes. The gap size class with more seedlings did not correspond to size class containing more medium-size trees. Tree species diversity indices in the two layers behaved reciprocally during the development process of forest gaps.

This study investigated root biomass and productivity in dominant populations in western Sichuan, China. A total of 4 plots (Picea balfouriana plantation for 22 age in Maerkang, 9 trees, mean DBH of population for 10.4 cm and height for 10.5 m; Larix maxteriana plantation for 22 age in Wolong, 9 trees, mean DBH of population for 17.0 cm and height for 13.8 m; Abies fabri plantation for 35 age in Ebian, 18 trees, mean DBH of population for 14.1 cm and height for 11.9 m; Larix kaempferi plantation for 23 age in Miyaluo, 8 trees, mean DBH of population for 17.4 cm and height for 14.5 m; a 20 m?25 m plot located on each of the 4 types in western Sichuan, China) were randomly selected and excavated to a depth of 60 cm for each of the 4 plantation types. To estimate the root biomass of an individual tree using D²H, an exponential model was selected with the highest coefficient ranging from 0.94 to 0.99. The total root biomass per hm² varied among plantation population types following the order: L. kaempferi (37.832 t/hm²) > A. fabri (24.907 t/hm²) > L. maxteriana (18.320 t/hm²) > P. balfouriana (15.982 t/hm²). The biomass fractions of a given root size class compared to the total root biomass differed among plantation population types. For all 4 studied plantation types, the majority of the roots were distributed in the top 40 cm of soil, e.g., 97.88% for P. balfouriana population, 96.78% for L. maxteriana, 95.65% for A. fabri, and 99.72 for L. kaempferi population. The root biomass fractions distributed in the top 20 cm of soil were 77.13% for P. balfouriana, 77.13% for L. maxteriana, 65.02% for A. fabri and 80.66% for L. kaempferi, respectively. The root allocation in the 0 20, 20 40, and 40 60 cm soil layers gave ratios of 34:12:1 for P. balfouriana, 24:6:1 for L. maxteriana, 15:7:1 for A. fabri, and 64:4:1 for L. kaempferi populations. The root biomass density of dominant plantation population was 10.782 t/(hm²•m) for P. balfouriana, 8.230 t/(hm²•m) for L. maxteriana, 24.546 t/(hm²•m) for A. fabri, and 13.211 t/(hm²•m) for L. kaempferi population, respectively. The root biomass productivity was found to be 0.57 t/(hm²•year) for P. balfouriana, 0.83 t/(hm²•year) for L. maxteriana, 0.71 t/(hm²•year) for A. fabri and 1.64 t/(hm²•year) for L. kaempferi population, respectively.

This study is based on Quercus mongolica, Fraxinus mandshurica, Phellodendron amurense, Juglans mandshurica, Tilia amurensis, and Pinus koraiensis trees of the same age (12 years) and seedling origin under the same site conditions. The sap flow density, water consumption, and related environmental factors were also measured using thermal dissipation method and ICT-2000TE (Transpiration-Environment) automatic measuring system for tree transpiration and environmental factors. On clear days during the growing season, the sap flow density exhibited mono-peak diurnal patterns, mostly between 10:00 and 14:00, except for Phellodendron amurense, whose sap flow showed two peaks during the daytime three times. The photosynthetically active radiation (PAR) and vapour pressure deficit (VPD) were the major factors influencing diurnal changes in sap flow, which explained 60% 74% variations in sap flow density for all species except Phellodendron amurense. Maximum sap flow densities for F. mandshurica, Phellodendron amurense, Q. mongolica, J. mandshurica, T. amurensis, and Pinus koraiensis were 516.36, 234.00, 625.93, 945.83, 507.93, and 286.21 cm³/(cm²•h), in July, June, September, August, August, and July, respectively. Water consumption during the whole growing season for J. mandshurica, T. amurensis, F. mandshurica, Pinus koraiensis, Phellodendron amurense, and Q. mongolica was 3,840, 2,820, 2,710, 2,120, 1,470, and 1,390 kg/sapling, respectively.

In the semi-arid area of the Loess Plateau, Caragana korshinski, a leguminous shrub, is the dominant plant species widely used in vegetation rehabilitation programs. We collected soil samples in 8- and 18-year-old C. korshinski plantations to assess the effects of the shrub on the physical and chemical properties of the soil as well as enzyme activities. Soil samples were taken from two depths (0 20 and 20 40 cm) under the shrub canopy between shrubs. Results showed that shrub rehabilitation and development enhanced accumulation of organic C and total N. Carbon and nitrogen concentrations increased significantly with plantation age and had increased by 15.3 20.5-fold and 11.1 13.6-fold at 0 20 cm depth at the 18-year-old plantation compared with farmland soil. It was found that C. korshinski contributed significant enrichment of C and N contents under their canopies compared with farmland. The content of water stable aggregates in 18-year-old shrub land soil is higher than the 8-year-old shrub land, and the big aggregates (>5 mm) increased for the most part, by 67.4% and 59.0% in different layers, respectively. The contents of aggregates of over 0.25 mm in two shrub land soils in the upper layer (0 20 cm) increased by 4.6% and 14.1% compared with farmland. It indicates that C. korshinski afforestation can increase the content of aggregates. C. korshinski plantation can accelerate the increase of soil urea activity and invertase activity, respectively, especially in the upper layer.

Calculating aggregation index by the sample-plot data used to lead to computing error due to the existence of a boundary effect. Here, we suggest a method for adjusting boundary effect in the analysis of spatial patterns at different stages of development of the broad-leaved Korean pine forest. This method is good for the reasonable management and biological control of the forests. The total station was used to sample the relative coordinates data at four corners of the temporary sample plot and of each tree in the field. Based on the sampling data, a correct approach to the boundary effect on aggregation index was put forward to the spatial pattern analysis of the broad-leaved Korean pine forest in its different stages of development. The results showed that the forest trees grew in a clumped pattern in the stage dominated by the pioneer trees, and that the trees were distributed in a random pattern in the stage dominated by the companion trees or in the mature stage. The spatial pattern of the broad-leaved Korean pine forest changing from clumped to random distribution is influenced by biological characteristic, the adaptive strategy of tree species and the natural disturbance in its entire development.

A pair of primers were designed according to published literature on Populus trichocarpa gene (PTD), and PtAP3, an AP3 homologous gene from Populus tomentosa was isolated by PCR using genomic DNA of the male clone of P. tomentosa (L50) as a template. The result indicated that the sequence was 1,813 bp (BamH!`and Sac!` were introduced at the 5 2 and 3 2 end) including 7 extrons and 6 introns, coding 238 amino acids. It was found that there was 52%-82% homology to proteins from Lilium regale (AF503913), Petunia hybrida (AF230704), Gerbera hybrida (AJ009724), Rosa rugosa (AB055966), Malus domestica (AJ251116), and P. trichocarpa (AF057708) determined by blast analysis in the GenBank. There was a highly conserved MADS-box motif in the protein of PtAP3, so it was putatived to be a transcription factor. The result of Southern blot analysis indicated that there were double copies of PtAP3 or two members which had a high homology to each other in P. tomentosa (L50, male) genomic DNA, and there was single copy PtAP3 in P. tomentosa (5082, female) genomic DNA. Sense and antisense expression vectors of PtAP3 were constructed by PCR and restriction enzymes digestion identification, and transformed into tobacco (Nicotiana tabacum) by Agrobacterium GV3101 and LBA4404. Some transgenic tobacco plantlets were obtained by PCR identification. The results mentioned above have provided important data to understand the molecular mechanism of male flower development of P. tomentosa, and has contributed to the study on controlling flowering of P. tomentosa using genetic engineering.

We surveyed the forest litter amount at the Lianxiahe watershed in the Three Gorges Reservoir Area and analyzed some hydrological characteristics such as the maximum water-holding capacity and water absorption rate of litter in six types of forests, i.e. the Cupressus funebris forest, the coniferous mixed forest, the coniferous and broad-leaved mixed forest, the broad-leaved forest, the Pinus massoniana forest, the bush forest. Results showed that the litter amount follows the order of the coniferous and broad-leaved mixed forest > the pure C. funebris forest, the P. massoniana forest > the coniferous mixed forest > the broad-leaved forest > the bush forest. The maximal water holding capacity of the undecomposed litter is in the order of the C. funebris forest > the coniferous mixed forest > the bush forest > the coniferous and broad-leaved mixed forest > the broad-leaved forest > the P. massoniana forest. The maximal water-holding capacity of the half-decomposed litter is the P. massoniana forest > the coniferous and broad-leaved mixed forest > the C. funebris forest > the coniferous mixed forest > the broad-leaved forest > the bush forest. In this watershed, the water holding capacity of the litter in the C. funebris forest is the highest, followed by the coniferous mixed forest, coniferous and broad-leaved mixed forest, P. massoniana forest, broad-leaved forest and bush forest. When the soil is covered only by litter, both the maximal rainfall amount and intensity in different forest stands are different if there is no water infiltration and runoff from the ground surface.

Using quantification theory I, an analysis of the relation of soil water and qualitative factors, such as, slope degree, slope aspect, slope position, and soil in Wangjiagou watershed area has been done. The study aims to quantify the factors influencing soil water, the descending order of the factors being the slope aspect, soil, slope degree, and slope position, thereby scientifically facilitating division of afforestation site types and afforestation site products digitally on geographical information system (GIS).

This study investigated the dynamic modulus of elasticity (DMOE) of wood panels of Fraxinus mandshurica, Pinus koraiensis, and Juglans mandshurica using the natural frequency measurement system of fast Fourier transform (FFT). The results were compared with the static modulus of elasticity (E_S) tested by a mechanical test machine. The results show a significant correlation between E_S, transverse vibration DMOE (E_F), and longitudinal vibration DMOE (E_L). For all of these species, the correlation between E_S, E_F and E_L is more significant than the individual species, which indicated that the FFT method is universal. The correlations between E_s and sample s density (ρ) are significant, but the correlation coefficient of E_S and ρ is lower than those between E_F, E_L and E_S. The E_S of wood is more accurately tested by the analysis based on FFT measurement than by the estimation based on density.

Longitudinal sawn wood are usually selected as samples in the study of sound properties of a musical instrument board. But in real production, radial sawn timber are cut and are also widely used as vibration component. Therefore, it is very important to evaluate the vibration properties of the board in the round, especially for the sound radiation characteristic of radial sawn timber and its relationship to longitudinal sawn timber. However, for the national and international experts, researches on radial sawn timber and its role and function in sound emission have not yet been developed. This paper describes a study of seven important spruces that grow up in the Sichuan and Heilongjiang provinces of China, and one Picea sitchensis specimen from North America. Under the high bending vibration mode, resonance frequency and other parameters of longitudinal and radial wood were tested. Analysis result disclosed the relationship between longitudinal and radial wood vibration property. An important conclusion of wood for musical instruments with proper anisotropy, fine toughness, and weak shear of longitudinal and radial vibration was inducted.

The structures of the solid state products formed by the partial combustion of Korean pine wood treated with fire-retardant FRW were analyzed by microscopic FTIR. The volatile pyrolytic products of basswood (Tilia amurensis) specimens treated with FRW and its components guanylurea phosphate and boric acid were analyzed by GC-FTIR. The pyrolytic and charring process, the effects of fire-retardant, and the structural characteristics of the pyrolytic products were discussed. It was concluded that upon heating and by the catalysis of FRW and its decomposition products reactions of wood took place successively, namely the dehydration of polysaccharide, the elimination of acetic acid from hemicellulose, the degradation of polysaccharide, the degradation of lignin, the polymerization of the pyrolytic products of wood, reactions of oxygen-element-elimination of aliphatic polymers and the structural change of the latter to form aromatic structures, and charring. The pyrolysis process of wood was altered and the yield of volatile pyrolytic products was decreased by FRW treatment.

This paper studies the problem of high energy waste in the course of the wood fiber processing in the wood-based panel industry. In the light of the energy economy principle, the cutting theory on the micron and long-slice wood fiber was put forward. In this paper, by means of analyzing the power waste in traditional processing, a series of analytical measures, such as, cytology, super precision work theory and fiber processing, and so on were utilized in the micron wood fiber formation process, and the cutting conception of the micron and long-slice wood fiber was put forward. Accordingly, the study of the micron and long-slice wood fiber was put into the microstructure study. This paper scientifically explains the reasons why the traditional wood fiber processing consumes more energy and the fiber quality low. In an example, the cutting power on the micron and long-slice wood fiber was calculated, which was compared with the traditional cutting power. The result showed that the energy waste by machining at micron is much lower than by heat grind and the high quality and long-slice wood fiber was gained. Thus, a revolutionary step was taken in the paper-making and wood-based panel industry of China.

Differentiating from normal wood, pit membranes in wetwood of subalpine fir contain bacteria of water drop shape or orbicular shape, and flaky shape, as observed using Scanning Electronic Microscope. Not only are ray parenchyma cells in wetwood partially degraded but also margo strands in pit membranes are somewhat degraded by bacterial activities. Most of the bordered-pit membranes in normal wood are unaspirated in green conditions and the proportions of aspirated pits in earlywood and latewood account for only 6.8% and 13.4%, respectively. Nevertheless, most of the bordered-pit membranes in wetwood are aspirated in green conditions and the proportions of aspirated pits account for 77.7% and 72.1%, respectively. The problem of hard-to-dry for subalpine fir could be reasoned from the considerable amount of aspirated pit membranes in wetwood.

Chinese pine caterpillar (Dendrolimus tabulaeformis) larvae were fed with pine needles of different degrees of damage to evaluate the effects of pine needles on the growth and development of larvae. The results showed that the nutritional index of the larvae declines after feeding on the damaged pine needlings. The lowest amount of food ingested and voided feces, the lowest nutritional index, slowest development, lightest pupae and most mortality were found in those pine caterpillar larvae fed with pine needles which were 50% damaged. The damaged pine needles significantly affected the population dynamics of Chinese pine caterpillars. The nutritional indices of larvae fed with 25% and 75% damaged pine needles were similar. The nutritional index of the dark morphs was higher than that of the tinted morphs, however, their mortality was lower than that of the tinted morphs. This phenomenon was reversed at the later stage of development when the larvae were fed on 50% damaged pine needles.

In November 2003 and June 2004, the insect borers and their spatial distribution within Pinus massoniana were investigated in Zhoushan City, in East China s Zhejiang Province, where pine wood nematode (Bursaphelenchus xylophilus) are typically found. The niche width, proportional similarity of niche and the niche overlap of dominant species of dying trees were computed. Results show that five insect species infect and damage Pinus massoniana, which had been infected by pine wood nematodes, among which four are wood boring beetles and one termite. Species within host trees vary from winter to summer and all the species have their own niche width, proportional similarity of niche and the niche overlap. They can achieve competitive equilibrium and coexistence according to their biological characteristics and life habits.

From January 2001 to December 2004, the investigation on the species of insect pests and diseases in Torreya grandis Merrillii was conducted and integrated control technologies of the main insect pests and diseases were studied in Zhuji, Shaoxin, Shenzhou, Dongyang, and Jiande counties of Zhejiang Province. Via field survey, a system of regular observations, 55 species of insect pests belonging to 9 orders and 29 families, and 4 species of diseases were recorded. Among them, Lepteucosma torreyae and Macrolygus torreyae were found to be new species. The biological characteristics of the major insect pests and diseases, such as Rhyncaphytoptus abiesis, Helicobasidium compacum, Erwinia carotovora, Chlorella sp., Macrolygus torreyae, and Lepteucosma torreyae, were primarily recorded, and their outbreaks and epidemics were researched. The forecasting method for Lepteucosma torreyae was established. Based on strengthening cultivation and management, integrated control measures were put forward including physical, biologic and chemical methods. Medications with higher effect and lower toxicity were screened by comparing the effect of different pesticide treatments.