Growth and wood properties of a 38-year-old Populus simonii × P.nigra plantation established with different densities in semi-arid areas of northeastern China

To characterize the effects of plantation densities on the growth characteristics(diameter at breast level,tree height and volume) and the common wood properties,38-year-old Populus simonii 9 P.nigra clones planted with four levels of spacing(2 m × 2 m,3 m × 3 m,4 m × 4 m,and 5 m × 5 m) in a semi-arid area in northeastern China were examined.The results of ANOVA showed significant differences(P0.01) for all the investigated growth traits and wood properties under different plantation densities,except for the chemical composition of wood.The repeatability and phenotypic variations of all the traits varied from 0.34 to 0.99 and from 13.45 to 59.65%,respectively.Except for wood density,which was significantly negatively correlated with the growth traits,a positive correlation was observed between the growth traits and all the other wood mechanical properties.However,most of the correlations between the growth traits and the chemical composition of the wood were not significant.The path analysis for the wood mechanical characteristics and the growth in the prediction of volume were significant and ranged from 0.18 to 0.72 for wood density and diameter at breast height,respectively,while those for the chemical composition of wood ranged from 0.001 to 0.336,which showed a low impact on the volume.The highest stand volume(610 m~3) per hectare was observed with the 2 m × 2 m spacing,which consequently provided a high total price and income,while a high individual volume growth per tree was observed with the 5 m × 5 m spacing.The results suggested that for the poplar trees younger than 40 years in a semi-arid area in China,2 m × 2 m spacing is suitable for obtaining a high volume per hectare,while 5 m × 5 m spacing is best for obtaining a high individual volume per tree.     

Growth and wood properties of a 38-year-old Populus simonii 3 P.nigra plantation established with different densities in semi-arid areas of northeastern China

To characterize the effects of plantation densities on the growth characteristics(diameter at breast level,tree height and volume)and the common wood properties,38-year-old Populus simonii 9 P.nigra clones planted with four levels of spacing(2 m 92 m,3 m 93 m,4 m 94 m,and 5 m 95 m)in a semi-arid area in northeastern China were examined.The results of ANOVA showed significant differences(P\0.01)for all the investigated growth traits and wood properties under different plantation densities,except for the chemical composition of wood.The repeatability and phenotypic variations of all the traits varied from 0.34 to 0.99 and from 13.45 to 59.65%,respectively.Except for wood density,which was significantly negatively correlated with the growth traits,a positive correlation was observed between the growth traits and all the other wood mechanical properties.However,most of the correlations between the growth traits and the chemical composition of the wood were not significant.The path analysis for the wood mechanical characteristics and the growth in the prediction of volume were significant and ranged from 0.18 to 0.72 for wood density and diameter at breast height,respectively,while those for the chemical composition of wood ranged from 0.001 to 0.336,which showed a low impact on the volume.The highest stand volume(610 m3)per hectare was observed with the 2 m 92 m spacing,which consequently provided a high total price and income,while a high individual volume growth per tree was observed with the 5 m 95 m spacing.The results suggested that for the poplar trees younger than 40 years in a semi-arid area in China,2 m 92 m spacing is suitable for obtaining a high volume per hectare,while 5 m 95 m spacing is best for obtaining a high individual volume per tree.     

Effects of Planting Density on Growth of New Clones in Populus tomentosa

Effects of seven planting densities on the growth and tree form of nine 5-year-old new clones in Populus tomentosa were studied. The plantations, arranged with completely random block design, were located in Wuzhi County, Henan Province.Results indicated that effects of planting density on the diameter at breast height (DBH), individual volume and growing stock increment of all new clones in P. tomentosa were significant at the 1% level of probability, effects of planting density on the tree height increment of new clones B2 and B31 and on the live branches height (LBH) increment of new clones B5 and B30 were significant at the 5% level of probability, while the interaction between planting density and clone was not significant at the 5% level of probability. It was concluded that the degree of differences among new clones within the same planting density was different with different planting densities and traits. For short rotation industrial timber, clones B 1, B3, B4, B5, B7, B9, B31 were suitable with the density of 1 000-2 500 trees per hectare, while for bigger diameter timber, clones B1, B3, B4, B7, B9, B31 could be used with the planting density of 660-833 trees per hectare. Clonal repeatability was also different in different planting densities.     

Growth variations and stability analyses of seven poplar clones at three sites in northeast China

Growth characteristics have complex inheritance patterns and genotype(G) by environment(E) interaction make predicting tree response to environmental changes difficult.In this study,the growth of seven poplar clones at three different sites was taken as the research focus,and heights and basal diameters were investigated in the second growing season.An ANOVA showed that all main effects,site,clone number and their interactions were highly significant in the overall F-tests.The coefficients of variation and repeatability of different traits ranged from 15.5 to 43.9%and from 0.549 to 0.912,respectively.AMMI(Additive Main Effects and Multiplicative Interaction) analysis results showed that genotype,environment and G × E interaction were significantly highly correlated.The stability analysis indicated that different clones showed different growth traits on different sites,which suggests that elite clones should be selected separately for different sites.Based on the growth traits,under a 10% selection rate,three clones were selected for different sites and the genetic gains of growth traits ranged from 4.7 to 11.2%.The three selected clones could be used to establish plantations in the future in different sites.     

An impacts of logging operations on understory plants for the broadleaved／Korean pine mixed forest on Changbai Mountain, China

Natural regeneration of tree species is important to the sustainability of native forest ecosystems in the temperate zone of northeast China. This study compared the densities and heights of seedlings and the diversities of shrubs and herbs on three sites of logging operations: log-skidding trails (LST), logging gaps (LG) and log landing sites (LLS). Sites undisturbed by logging gaps operations were sampied as control. The species, counts and height of tree seedlings and the species, counts, height and percentage coverage of shrubs and herbs were recorded in the field. The highest density and greatest height of regeneration trees were observed at LG and LST. The effects of LST on the densities of broadleaved trees were greater than those of coniferous trees. The difference in seedling density between LLS and control was significant (p=0.05). There was no significant difference in average seedling height for all the tree species between the disturbed sites and control. There were more shrub and herb species at the disturbed sites than at control. The diversity of understory plants at LG was the highest among all the sites. LST and LLS were different in shrub diversity, so were LLS and control. Both LG and LLS were different from control in herb diversity. Active measures need to be taken on the operation sites to protect the coniferous trees and the diversities of understory plants for sustaining the structure and composition of the broadleaved-Korean pine mixed forest on Changbai Mountain of China.Since different operation sites have different effects on different tree species, site-dependent actions must be taken to assure the regeneration of ecologically important tree species.     

Optimizing continuous cover management of boreal forest when timber prices and tree growth are stochastic

Background: Decisions on forest management are made under risk and uncertainty because the stand development cannot be predicted exactly and future timber prices are unknown. Deterministic calculations may lead to biased advice on optimal forest management. The study optimized continuous cover management of boreal forest in a situation where tree growth, regeneration, and timber prices include uncertainty.Methods: Both anticipatory and adaptive optimization approaches were used. The adaptive approach optimized the reservation price function instead of fixed cutting years. The future prices of different timber assortments were described by cross-correlated auto-regressive models. The high variation around ingrowth model was simulated using a model that describes the cross- and autocorrelations of the regeneration results of different species and years. Tree growth was predicted with individual tree models, the predictions of which were adjusted on the basis of a climate-induced growth trend, which was stochastic. Residuals of the deterministic diameter growth model were also simulated. They consisted of random tree factors and cross- and autocorrelated temporal terms.Results: Of the analyzed factors, timber price caused most uncertainty in the calculation of the net present value of a certain management schedule. Ingrowth and climate trend were less significant sources of risk and uncertainty than tree growth. Stochastic anticipatory optimization led to more diverse post-cutting stand structures than obtained in deterministic optimization. Cutting interval was shorter when risk and uncertainty were included in the analyses.Conclusions: Adaptive optimization and management led to 6%–14% higher net present values than obtained in management that was based on anticipatory optimization. Increasing risk aversion of the forest landowner led to earlier cuttings in a mature stand. The effect of risk attitude on optimization results was small.     

Effects of thinning on microsites and natural regeneration in a Larix olgensis plantation in mountainous regions of eastern Liaoning Province, China

In order to understand the effects of thinning on microsite conditions and natural regeneration in the larch plantation, thinning experiment was conducted in a 40-year-old Larix olgensis plantation in Qingyuan County in eastern Liaoning Province, China in 2003-2004 Five thinning treatments （0%, 10.2%, 19.8%, 29.7% and 40.3% thinned） were designed on the same site. After thinning, canopy openness and the microsite conditions such as photosynthetic photon flux density （PPFD）, soil moisture content, and soil temperature were measured in one growing season. Meanwhile, the investigation of natural regeneration was conducted at the end of the growing season. The results showed that the canopy openness increased with the increase of thinning intensities. PPFD and soil temperature and soil moisture content in different soil layers were positively relative with canopy openness after thinning. The richness of regenerating tree species did not significantly increase （p=0.30） after one growing season since thinning, but the regeneration density and frequency of tree species increased significantly （p〈0.05）. In addition, the number of regenerating tree species increased, and the increment was correlated with the characteristics of iudividual tree species. The increasing percentage of regenerating seedlings of the shade-intolerant tree species was more than that of shade-tolerant tree species. Among the investigated regeneration species, the biggest response of seedling emergency to the canopy openness was Phellodendron amurense. This paper confirmed the following conclusions： after thinning, the variety of regenerating tree species was correlative with the characteristics of regenerating tree species, and the distribution of unthinned trees and the site conditions in the investigated larch plantation were the additional factors influencing, the regeneration.     

Effects of leaf litter extraction fluid from dominant forest tree species on functional characteristics of soil microbial communities

The effects of extraction fluids from the leaf litter from different dominant tree species on the functional characteristics of the soil microbial community were studied to understand how changes in soil quality and synergism between plants and soil contribute to the process of forest succession. Leaf litter from dominant tree species at different stages of succession were collected and extracted with sterile deionized water. After treating the soil of abandoned land with the different extraction fluids,we analyzed changes in carbon utilization of the soil microbial community in Biolog Eco Plates, then considered these results with those of our previous study on forest vegetation succession in the Malan forest. The leaf litter enhanced the metabolic capacity and functional diversity of the soil microbes, especially in the following combinations:the leaf litter of Quercus liaotungensis–Pinus tabulaeformis, P. tabulaeformis–Betula platyphylla, Q. liaotungensis and P. tabulaeformiss. Second, when litter from onespecies evaluated, the species enhanced metabolism and diversity in the order of their successional relationship: B.Platyphylla \ P. tabulaeformis \ Q. liaotungensis. After soils were treated with different leaf litters at 25 C for7 days, the sorting pattern of the PCA values, based on the similarity of carbon source utilization by the soil microbes,corresponded to the successional pattern on the basis of the similarity of community composition of forest plants.Thus, changes in soil properties caused by leaf litter from different dominant trees probably play a unique role in the successional pattern of a forest community. We thus propose a successional mechanism that underlies the natural succession process within the Malan forest region. When the dominant forest species of the climax successional stage develops during the early successional stages, its forest litter probably alters soil properties such that the soil becomes unsuitable for the gradual growth and regeneration of the original dominant tree species but promotes the growth and establishment of later-invasive plants. In this way, the originally dominant species is replaced by the newly dominant tree species during forest succession.     

Tree survival and maximum density of planted forests–Observations from South African spacing studies

Background:Among the most important aspects of risk and hazard studies relating to forest ecosystems are maximum forest density and density-dependent tree survival.Methods:Long-term observations about the maximum density of unthinned Pinus patula and P.elliottii field plots based on the Correlated Curve Trend(CCT)spacing studies which were established almost 8 decades ago by O’Connor(Forest Research with Special Reference to Planting Distances and Thinning,1935)in South Africa.Three specific approaches were introduced for analysing maximum density and tree survival,namely the‘limiting line’,Nilson’s sparsity and tree survival with the Weibull function.Results:The main results are:a)Maximum densities differ greatly among the two species grown on the same site and within the same species grown on different sites;it is possible to relate these differences to site index in both species.b)The relationship between the quadratic mean diameter and the minimum average spacing of surviving trees(known as Nilson’s Sparsity)appears to be surprisingly similar in both species.c)An analysis of tree survival in response to different initial planting espacements shows that the Weibull survival function parameters can be estimated if the initial planting density is known.This result is presented for each of the eight large experiments used in this study.Conclusions:This study contributes to a better understanding of tree survival and maximum density which are the key factors required for estimating risk and uncertainty.The risk of tree mortality is not constant,but varies with tree species,planting density,tree age and growing site.For estimating that risk,therefore,continuous long-term observation on different sites and with varying planting densities,as provided by the unthinned CCT series,are essential.     

广义的Chapman-Richards函数及其在树木和林分生长中的应用

The generalized Chapman-Richards model was derived from the Chapman-Richards function in which parameters η,κ and m were unconstrained.Based on the structure of solutions and biological interpretations,the model could be classified into eight cases(three categories)at all and among them only 4 kinds of cases are suitable in forestry that represent four typical growth patterns of trees and stands.For each of 4 equations,the model properties and biological interpretations for parameters were discussed in detail.The generalized chapman-Richards model was capable of describing a wide range of growth curves that was asymptotic or nonasymptotic,with or without inflection point.In order to illustrate the versatility of the model,it was fitted to a group of data sets conceming the DBH growth of cryptomeria plantations with 4 initial densities and the DBH and height growth of natural Korean pine tree.Comparing the generalized Chapman-Richards function and the Sohnute model,it was found that the parameters and expressions of the two modets were interchangeable in theory,and the fitting results were explicitly identical in empirical applications.     

Differences in Growth and Physiological Characteristics in Different Growth Vigor Clones of Populus deltoids

To investigate differences in physiological characteristics of growth and physiological basis of high growth vigor in the first generation of Populus deltoides which are from different growth vigor clones,here we chose two groups of seedlings with different growth vigor:high（A） and low（B）.Indexes of phenotype and physiology were successively measured to study the growth,photosynthesis and nutrient absorption.There were significant or very significant differences in dry mass of root,stem, leaf and the total biomass between A and B.Dry matter of roots had the smallest proportion in different components,and the largest proportion was stem in A,while the leaf had the largest proportion in B.Changes in growth and physiological characteristics showed a certain regularity during June to September.All clones grew the most rapidly and physiological characteristics varied the most significantly in July.Correlation analysis showed that seedling height and ground diameter were both significantly correlated to leaf area,night respiration rate,NH₄^- uptake rate and the total photosynthetic rate（R>0.826,P<0.05）,suggesting that the seedling growth was mainly affected by their own total photosynthetic capacity,nutrient absorption and night respiration consumption.In general,A was superior to B in all these factors,which construct physiological basis of the high growth vigor.     

Early evaluation of growth traits of Larix kaempferi clones

Early selection is an important method to shorten the breeding cycle for tree species, which may differ in the time for early selection.To evaluate the early selected time for Larix kaempferi, tree height and diameter at breast height of 57 L.kaempferi clones were measured over many different growth years.The results indicated that, except for age × clone interaction for diameter at breast height(P = 0.741), there were significant differences among all variation sources(P 0.01).The coefficient of phenotypic variation ranged from 14.89 to 35.65%for height and from 19.17 to 23.86% for diameter at breast height in different growth years.The repeatability of height and of diameter at breast height among clones was high,ranging from 0.6181 to 0.8531(height) and from 0.8443 to0.8497(diameter at breast height), in different growth years.There were significant positive correlations between all pairs of growth traits except between height in the 2 nd growth year and height in the 30 th growth year; and between height in the 2 nd growth year × diameter at breast height in the 30 th growth year.With a comprehensive evaluation method and a selection ratio of 10%, L65,L1, L62, L9, L15, and L78 were selected as excellent clones in the 30 th growth year.Their average values of height and diameter at breast height were 9.81 and 16.57%higher than the overall average, representing genetic gains of 6.46 and 13.99%, respectively.This study provides a theoretical foundation for the genetic improvement of L.kaempferi.     

Cellulase in <Emphasis Type="Italic">Anoplophora glabripennis</Emphasis> adults fed on original host tree species and non-original host trees

Cellulase activities of Anoplophora glabripennis (Motsch.) adults from two host plants (Populus simonii × P.pyramidliscr cv.Opera Hsu.and Salix matsudana Koidz) fed on three different host tree species (Acer negundo Linn.,S.matsudana Koidz and P.simonii × P.pyramidliscr cv.Opera Hsu.) were investigated.Enzyme activities of endoglucanase and β-glucosidase in the intestines of the insects were measured.The results show that there are no statistically significant differences in the enzyme activities of endoglu...     

Growth performance of Avicennia officinalis L. and the effect of spacing on growth and yield of trees planted in the Western coastal belt of Bangladesh

A trial of Avicennia officinalis L. with five different spacings was conducted in the newly accreted lands along the western coastline(Patuakhali district) of Bangladesh since 1993 to assess growth performance and the effect of spacing on tree growth. Data on tree density, height, diameter, bole height, crown diameter were recorded and analyzed when the stand was 19 years old. Mean height ranged from 12.89-13.52 m and diameter at breast height(dbh) from 26.57-32.16 cm in plots of different spacings. The mean annual height increment ranged from 0.67-0.71 m, mean annual diameter increment from 1.40-1.69 cm and wood volume from 6.02-10.04 m3·ha-1·a-1 in different treatments. Significantly greater diameter(32.16 cm) and wood volume(10.04 m3?ha-1?a-1) were obtained with wider(2.13 m × 2.13 m) spacing than with closer spacings. But tree growth was unaffected by other spacings. Growth data were also recorded from other A. officinalis plantations raised by Forest Department(FD) on different islands in Patuakhali and Bhola districts of Bangladesh. At these sites, mean annual height increment ranged from 0.33-0.62 m, mean annual diameter increment from 0.72-1.37 cm and wood volume from 1.55-5.73 m3?ha-1?a-1. The growth performance of A. officinalis indicated that the newly accreted lands along the western shoreline may be suitable for raising Avicennia plantations for the enrichment of coastal vegetation.     

Variation analysis of growth traits of four poplar clones under different water and fertilizer management

To determine appropriate quantities of water and fertilizer required for early growth of hybrid poplar cuttings,we recorded the growth traits of four clones grown under four factors(irrigation and nitrogen,phosphorus,and potassium fertilizers),each with four levels,using an orthogonal experimental design.A logistic model was used to estimate growth in height.The growth curves for tree height were sigmoid,and the model R^2 values were greater than 0.9,which indicated that the fit was highly significant.ANOVA results for tree height and basal diameter indicated that all sources of variance showed significant differences(p<0.001).The average tree height and basal diameter for all the four clones under the different treatments ranged from 155.39 to 235.04 cm,and from 13.71 to 17.42 mm,respectively.A highly positive correlation between the extreme k value and tree height was observed,suggesting that the k value was an accurate estimation of tree height.For model parameters,the earliest average time point for the onset of the rapid growth period of poplar clones was 131 d,and the highest average increment in tree height during the rapid growth period was 138.78 cm.The highest average tree height for all clones under each factor was 219,210.51,200,and 201 cm when treated with either 1200 mL of water applied every third day,3 g of nitrogen,0 g of phosphorus,or 0 g of potassium,respectively.The most suitable treatment for the early growth of hybrid poplar cuttings,as suggested by the developed logistic model,was 1200 mL of water applied every third day and three applications of 1 g nitrogen(in the form of CH4N2O).     

Competition effects in an afrotemperate forest

Background： Information about competition responses is mainly available for monospecific stands or mixed stands with a small number of species. Studies on complex multi-species and highly structured forest ecosystems are scarce. Accordingly, the objective of this study was to quantify competition effects and analyse competition responses in a species-diverse afrotemperate forest in South Africa, based on an observational study with mapped tree positions and long-term diameter increment records. Methods： The sensitivity to competition was analysed for individual species and involved the calculation of the slope of the linear relation between the value of a competition index （CI） and diameter growth as a measure of sensitivity. In a next step different competition indices were combined and tree diameters were grouped in three classes as surrogates for canopy status and ontogenetic stage. Results： Five competition indices were found to be effective in showing sensitivity to competition for a number of canopy and sub-canopy species. Significant linear regressions were fitted for 18 of a total of 25 species. Species reactions varied significantly in their sensitivity to the different CIs. The indices were classified as belonging to two groups, those that responded more to local crowding and those that are more sensitive to overtopping, which revealed species-specific sensitivities to both factors. The analysis based on diameter classes revealed that species clearly changed their sensitivity to crowding or overtopping depending on diameter. Canopy and sub-canopy species showed distinct differences in their reactions. Conclusions： The application of multiple CIs brought novel insights relating to the dynamics of afrotemperate forests. The response patterns to different competition indices that focus on crowding and overtopping are varied and tree diameter dependent, indicating that oversimplified assumptions are not warranted in the interpretation of Cl- growth relations.     

Feeding performance of <Emphasis Type="Italic">Clostera fulgurita</Emphasis> on three clones of <Emphasis Type="Italic">Populus deltoides</Emphasis>

Poplar leaf defoliator, Clostera fulgurita (Walker) larvae were reared on three Populus deltoides clones (PL1, PL5 and PL7) in the laboratory. The nutritional indices were computed for working out the relationship between food consumption and growth rate of 3rd, 4th and 5th instar larvae on three clones. The result showed that the consumption index (CI), approximate digestibility (AD), growth rate (GR), relative growth rate (RGR) and efficiency of conversion of ingested food (ECI) decreased with the increase in the age of the larvae. Efficiency of conversion of digested food (ECD) increased with increase in age of the larvae. GR and RGR varied significantly, indicating that larval development was enhanced on PL1 as compared to PL5 & PL7. The values of AD, ECI and ECD were not affected by the different clones. Feeding and growth indices could be useful to define a defoliation prediction model.     

Absorption and Accumulation of Heavy Metal from Soil by Leaves of Populus x euramericana cv.‘Neva’Plantation

The absorption and enrichment of heavy metal elements by leaves of Populus×euramericana cv.’Neva’ were analyzed through content assessing of heavy metal elements in soils of three forest lands at Fangshan District in the southern suburb of Beijing. These forest lands with P.×euramericana cv. ’Neva’plantation were around with the various sources of pollution such as cement mill,stone mill, sewage and garbage.Some of heavy metal elements such as Cd,Pb,Cu,and Zn were found in the soil samples and leaves of P.×euramericana cv.’Neva’ grown on the three forest lands which were investigated.The results of investigation showed that the soils of three forest lands were polluted with Pb, Cd,Cu and Zn in varying degrees.The contents of Pb,Cu and Zn in soils were significantly different among the three forest lands,whereas the average content of Cd(0.077 6 mg·kg^-1) was less but that of Pb,Cu,and Zn(37.61,26.25 and 90.3 mg·kg^-1 ) were more than the average background value of Beijing.The contents of Pb,Cd,Cu and Zn in leaves of P.×euramericana cv.’Neva’ were different among three forestlands.With the changes of heavy metal contents in soil samples,there was no regularity on the changes of different heavy metal contents in leaves of P.×euramericana cv.’Neva’ grown on different forest land.P.×euramericana cv.’Neva’ can absorb and accumulate Pb,Cd,Cu and Zn in soil but showed different capacities of absorption and accumulation with the order of Cd>Zn>Cu>Pb.Especially,its absorption and accumulation capacity for Cd was strong with maximum enrichment factor higher than 16 and showed high accumulation on low background,whereas its enrichment capacities for Pb and Cu were relatively poorer with average enrichment factor of less than 1.At different forest lands,there existed great difference on absorption capacity of P.×euramericana cv.’Neva’ with the same heavy metal.     

Effects of precommercial thinning on growth parameters in Pinus nigra Arn. subsp. pallasiana(Lamb.) Holmboe stand

We investigated the effects of precommercial thinning(PCT) applied at different levels on the growth parameters of natural Anatolian black pine stand. The experimental site was located in the province of Isparta in southern Turkey. PCT was set up using a randomized complete block design with three replicates and three treatments(control, 2–2.5 m × 2–2.5 m and 3–3.5 m ×3–3.5 m spacing). The experimental plots were established in March 2014. At the end of the growing seasons for three years(2014–2016), growth parameters such as diameter, height and crown radius were measured. PCT was found to be significantly effective on diameter, height,individual tree basal area, and crown radius increment at the end of the third year(p 0.05). While diameter,individual tree basal area and crown radius increment increased with increasing PCT intensity, height increment was higher in control than PCT. Although the PCT treatments applied with 3–3.5 m spacing affected individual tree development positively, we need long-term results on wood quality and yield. According to the short-term results, it is thought that it is better to lower the standcloseness gradually, so, it may be advisable to apply PCT by 2–2.5 × 2–2.5 m spacing.     

Responses of intra-annual runoff to forest recovery patterns in subtropical China

Forest recovery plays a critical role in regulating eco-hydrological processes in forested watersheds.However,characteristics of the intra-annual runoff variation associated with different forest recovery patterns remain poorly understood.In this study,three forest change periods were identified,the baseline period(1961-1985),reforestation period(1986-2000) and fruit tree planting period(2001-2016).We selected the magnitude of seasonal runoff(wet and dry seasons) and distribution characteristics,i.e.,non-uniformity coefficient(C_v),complete accommodation coefficient(C_r),concentration ratio(C_n),concentration period(C_d),absolute variation ratio(ΔR) and relative variation ratio(C_(max)).The pair-wise approach evaluated the intra-annual runoff variation characteristics between forest change periods.Results indicate that reforestation decreased wet season runoff and increased dry season runoff.In contrast,fruit tree planting increased wet season runoff and had no significant effect on dry season runoff.For intra-annual runoff distribution characteristics,reforestation significantly reduced the C_v,C_r,C_n and C_(max).Distribution of the intra-annual runoff in the fruit tree planting period was not significantly different from the baseline.We concluded that reforestation reduced the occurance of extreme water conditions in wet and dry seasons and effectively increased the stability of the intra-annual runoff.In contrast,fruit tree planting increased instability and fluctuation of the intra-annual runoff after reforestation.The characteristics of the intra-annual runoff to fruit tree planting was similar to those of the baseline.Therefore,adopting fruit tree planting practices to regulate intra-annual runoff characteristics may not be a practical approach,and impacts of different reforestation practices should be ascertained in our study region.The implications of this study should guide regional land-water management,and this study adds to the understanding of the impacts gained in forest cover on hydrology.