Pinus radiata(D.Don)dominates New Zealand's forestry industry,constituting 91%of plantations,and is among the world's most important plantation species.Given the socio-economic and environmental importance of ...Pinus radiata(D.Don)dominates New Zealand's forestry industry,constituting 91%of plantations,and is among the world's most important plantation species.Given the socio-economic and environmental importance of this species,it is important to have accurate and precise projections over time to make efficient decisions for forest management and greenfield investments in afforestation projects,especially for permanent carbon forests.Future projections of any natural resource systems rely on modeling;however,the acceleration of climate change makes future projections of yield less certain.These challenges also impact national expectations of the contribution planted forests will provide to address climate change and meet international commitments under the Paris Agreement.Using a large national-scale set of contemporary ground-measured data(2013–2023),this study investigates the performance of two growth models developed over 30 years ago that are widely used by NZ plantation growers:1)the Pumice Plateau Model 1988(PPM88)and 2)the 300-index(including a model variant of regional drift).Model simulations were made using the FORECASTER modeling suite with geographic boundaries to adjust for drift in space and time.Basal area(BA,m^(2)⋅ha^(-1))and volume(m^(3)⋅ha^(-1))were simulated,and standard errors and goodness-of-fit metrics calculated up to a typical rotation age of 30 years.Model residuals were then separated and analysed for the main plantation growing regions.The models overpredicted observed growth by between 6.8%and 16.2%,but model predictions and errors varied significantly between regions.The results of this study provided clear evidence of divergence between the outputs of both models and the measured data.Finally,this study suggests future measures to address challenges posed by these discrepancies that will provide better information for forest management and investment decisions in a changing climate.展开更多
The Andean montane forests provide a wide range of ecosystem services like water supply, carbon sequestration, and biodiversity preservation. Restoration of these forests is critical due to their degraded state and th...The Andean montane forests provide a wide range of ecosystem services like water supply, carbon sequestration, and biodiversity preservation. Restoration of these forests is critical due to their degraded state and the need to recover, maintain and enhance the ecosystem services they provide. However, we lack understanding of aboveground biomass (AGB) accumulation in restored Andean montane forests. AGB is a key indicator of ecosystem productivity and provides essential data on vegetation carbon stocks, permitting the assess successfulness of restoration efforts. In 2010 the initiative Más Bosques para Medellín was formulated in Medellín City, tropical Andes, Colombia, aiming to restore the forests located in the surrounding rural areas of the city, with interest in preserving the ecosystems services like water supply. The project established 548 ha of mixed plantations with native species. After 13 years, our study aims to developed in situ allometric equations and to evaluate AGB accumulation to assess restoration performance. We measured, harvested, and weighted 144 individuals from these arrangements to fit a general equation for the project and six specific equations for each one of the six most frequent species. The AGB had a positive correlation with diameter at breast height (D), total height (H) and specific wood density (WD). The best general equation uses D and WD as predictors (R^(2) = 0.928). The specific species equations certainly responded to the functional traits of each species. Using the latest inventory of permanent plots of the project we estimated a mean AGB accumulation of 41.91 ± 30.34 Mg ha^(–1) and a total accumulation of 22,996.05 Mg of AGB for the 548 ha. We compared these results with studies developed for natural forest in the region and other land covers. We found contrast behaviors in the AGB accumulation across our study zones. The developed equations have broad applicability across the Andes region, offering valuable insights for similar restoration initiatives. Furthermore, will facilitate the assessment of current restoration efforts and inform scientifically based decisions for future mixed plantation practices.展开更多
Phosphorus(P)is crucial for plant growth.However,its low availability in subtropical soils necessitates that trees rely on microorganisms for effective P acquisition.The introduction of broadleaf trees has been shown ...Phosphorus(P)is crucial for plant growth.However,its low availability in subtropical soils necessitates that trees rely on microorganisms for effective P acquisition.The introduction of broadleaf trees has been shown to facilitate P acquisition in coniferous plantations by altering the rhizosphere fungal communities.Despite this,functional shifts in these communities and the expression of root phosphorus cycling genes(PCGs)remain inadequately understood.This study investigated coniferous Pinus massoniana and Cunninghamia lanceolata plantations interplanted with broadleaf species associated with arbuscular mycorrhizal(AM)or ectomycorrhizal(ECM)fungi.Rhizosphere soil and fine roots from the conifers were analyzed to examine soil bioavailable P fractions,root mycorrhizal colonization,rhizosphere fungal community composition,enzyme function predictions,and root PCGs expression.We found that citric-P in rhizospheric soil of P.massoniana increased with the introduction of Quercus gilva(an ECM-associated tree species),whereas Bray-P content in the rhizosphere of C.lanceolata decreased upon the introduction of either Q.gilva or Phoebe zhennan(an ECM-associated tree species).Moreover,the relative abundance of saprophytic fungi(e.g.,Mortierella)increased following the introduction of broadleaf trees.Specifically,the introduction of Q.gilva was associated with elevated levels of organic P mineralization genes(e.g.,phoA)and enzymes(e.g.,phytases and acid phosphatase(ACP))in conifers.In contrast,the introduction of P.zhennan increased the expression of inorganic P solubilization genes(such as qppC in P.massoniana roots and ppa in C.lanceolata roots).Key contributors to P absorption in conifer roots included Cenococcum,Rhizopogon,and Glomus.This study advances our understanding of P cycling in coniferous rhizospheres and the dynamics of coexisting mycorrhizal tree systems,yielding valuable insights into sustainable management of plantation ecosystems.展开更多
[Objective]The aim was to study on the characteristics of soil organic carbon and nitrogen in rubber （Hevea brasiliensis Muell-Arg） plantations at different age stages in the western region of Hainan Island,so as to...[Objective]The aim was to study on the characteristics of soil organic carbon and nitrogen in rubber （Hevea brasiliensis Muell-Arg） plantations at different age stages in the western region of Hainan Island,so as to evaluate the ecological benefits of rubber plantations and provide basic data for studying the effect of tropical land utilization/cover change on the global carbon and nitrogen cycle. [Method]The situs was in Danzhou city,western region of Hainan Island,and the samples were four kinds of rubber plantations soil at different ages and one kind of control check （pepper,Piper nigrum L.） soil. In this research,four quadrats were set up in each sample,and the size of each was 20 cm×20 cm. Four specimens were gathered from four layers of 0-15,15-30,30-45,45-60,and the average of them was the last analysis result of each sample. Soil density was measured by cutting ring method,soil containing and hygroscopic water was detected by oven drying method,soil organic carbon （SOC） was measured by low temperature heated outside potassium dichromate oxidation-colorimetry method,and soil total nitrogen （STN） was detected by semimicro Kjeldahl method. [Result]SOC contents of different layers in rubber plantations soil at different age stages （including the CK pepper soil,the same as below） varied little,and the content of SOC in surface layer （0-15 cm） was higher,while the underlayer （45-60 cm） was lower than the average value; there was significant difference in SOC content among different kinds of soil,and the content was of 6.03-7.78 g/kg,tapping young trees （7 years） CK pepper mature age trees （30 years） prophase of young trees （2 years） tapping trees （16 years）; there was no significant difference in SOC storage among different kinds of soil,and the storage was of 61.33-74.29 t/hm2,mature age trees （30 years） tapping young trees （7 years） prophase of young trees （2 years） CK pepper tapping trees （16 years）; there was significant difference in STN content among rubber plantations soil at different age stages,the content was of 410.86-664.14 mg/kg2,CK pepper tapping young trees （7 years） prophase of young trees （2 years） mature age trees （30 years） tapping trees （16 years）,and STN content of tapping trees （16 years） soil was extremely lowest; there was significant difference in C/N ratio among different kinds of soil,the ratio was of 10.94-14.47,and the ratio of tapping trees （16 years） mature age trees （30 years） tapping young trees （7 years） CK pepper prophase of young trees （2 years）. [Conclusion]There wasn＇t unhealthy effect of rubber trees planted in tropical area on the content and storage of SOC,the content of STN and the ratio of C/N. there was no significant difference between rubber plantations and CK pepper soil,and the effects of rubber plantation on soil carbon-nitrogen was similar to that of other tropical crops （such as pepper）.展开更多
The influence of formula fertilization optimization on dry rubber yield and economic benefits of the rubber plantation in Hainan Longjiang Farm were studied by using ＂contrast＂ design method of fertilizer field expe...The influence of formula fertilization optimization on dry rubber yield and economic benefits of the rubber plantation in Hainan Longjiang Farm were studied by using ＂contrast＂ design method of fertilizer field experiments. The results showed that the actual production rate reached 4.61% and the net production rate of dry rubber reached 3.97% by application of optimized fertilization formula. Analysis of variance showed that the average dry rubber yield in optimization of formula fertil- ization area was significantly higher than that of conventional area. The results also indicated that the optimization of formula fertilization had obvious economic benefits, and each rubber tree reduced cost and increased 9.95 yuan on average after the test.展开更多
[Objectives]The soil permeability and its influencing factors in typical plantations were studied to provide a scientific basis for tending and managing plantations in the Haikou forest area of Kunming City.[Methods]W...[Objectives]The soil permeability and its influencing factors in typical plantations were studied to provide a scientific basis for tending and managing plantations in the Haikou forest area of Kunming City.[Methods]With three kinds of typical forest stands,i.e.,over-mature Pinus armandii Franch.,mid-mature Eucalyptus robusta Smith,and over-mature E.robusta Smith in this region as the research objects,soil infiltration changes and the effects on soil water retention in different stands,soil layers,and gap conditions under different moisture conditions were analyzed.[Results]①Under all three moisture conditions,the over-mature P.armandii forest demonstrated higher overall infiltration rates than the other two forest stands,which showed relatively similar infiltration rates.In all three stands,the soil infiltration rate decreased as the depth of the soil increased.Significant fluctuations in soil infiltration rate were observed during the initial 0-5 min,followed by gradual stabilization or regular fluctuations after 5 min.The infiltration process generally reached saturation after approximately 20 min.②The average infiltration rate was identified as the key factor affecting soil infiltration.Comprehensive evaluation of soil permeability revealed that the over-mature P.armandii forest exhibited optimal soil permeability.③Various soil physical and chemical properties significantly affected different indexes of soil permeability under varying conditions,with soil organic carbon content and water repellency demonstrating particularly notable effects on infiltration under different conditions.[Conclusions]Soil infiltration rates gradually decreased with the deepening of the soil layer.Principal component analysis(PCA)showed that the soil permeability of the over-mature P.armandii forest was stronger than that of the other two stands under the three moisture conditions,especially in non-gap positions.All soil indexes affected soil permeability,and soil organic carbon and water repellency were the key factors affecting soil permeability.展开更多
Mixed-species plantations generally exhibit higher ecosystem multifunctionality than monospecific plantations.However,it is unclear how tree species functional composition influences species mixture effects on ecosyst...Mixed-species plantations generally exhibit higher ecosystem multifunctionality than monospecific plantations.However,it is unclear how tree species functional composition influences species mixture effects on ecosystem multifunctionality.We selected 171 monospecific and mixed-species plantations from nine regions across subtropical China,and quantified 13 key ecosystem functional properties to investigate how species mixture effects on ecosystem multifunctionality are modulated by functional diversity and identity.We found that ecosystem multifunctionality was significantly higher(p<0.05)in mixed tree plantations than in monospecific plantations except the mixed-conifer species plantations.Across all regions,ecosystem multifunctionality was significantly higher(p<0.05)in mixed conifer-broadleaf plantations than in monospecific plantations of the corresponding species,but not different between mixed and monospecific coniferous plantations.The magnitude of species mixture effects on ecosystem multifunctionality varied greatly with tree species compositions.Taking Cunninghamia lanceolata Lamb.as an example,the effects varied from a range of 2.0%–9.6%when mixed with a conifer species to 36%–87%when mixed with a broadleaf species.The functional diversity was the dominate driver shaping ecosystem multifunctionality,while functional identity,as expressed by community-weighted mean of specific leaf area,also had a positive effect on ecosystem multifunctionality through the increased below-ground nitrogen and phosphorus stocks regulated by specific leaf area of the mixing tree species.Our study highlights the important role of functional diversity in shaping ecosystem multifunctionality across region-wide environmental conditions.Mixed conifer-broadleaf tree plantations with distinct functional traits benefit the enhancement of ecosystem multifunctionality,and the magnitude of species mixture effects is modulated by the functional identity of tree species composition;those relationships deserve a special consideration in multifunctional management context of subtropical plantations.展开更多
An investigation on soil organic carbon, total N and P, NO3-N, available P, microbial biomass C, N and P, basal respiration and metabolic quotients （qCO2） was conducted to compare differences in soil microbial prope...An investigation on soil organic carbon, total N and P, NO3-N, available P, microbial biomass C, N and P, basal respiration and metabolic quotients （qCO2） was conducted to compare differences in soil microbial properties and nutrients between 15-year-old pure Chinese fir （Cunninghamia lanceolata） and two mixed Chinese fir plantations （mixed plantations with Alnus crernastogyne, mixed plantations with Kalopanax septemlobus） at Huitong Experimental Station of Forest Ecology （26°45′N latitude and 109°30′E longitude）, Chinese Academy of Sciences in May, 2005. Results showed that the concentrations of soil organic carbon, total N, NO3^--N, total P and available P in mixed plantations were higher than that in pure plantation. Soil microbial biomass N in two mixed plantations was averagely higher 69% and 61% than that in pure plantation at the 0-10 cm and 10-20 cm soil depth, respectively. Soil microbial biomass C, P and basal respiration in mixed plantations were higher 11%, 14% and 4% at the 0-10 cm soil depth and 6%, 3% and 3% at the 10-20 cm soil depth compared with pure plantation. However, soil microbial C： N ratio and qCO2 were averagely lower 34% and 4% in mixed plantations than pure plantation. Additionally, there was a closer relation between soil microbial biomass and soil nutrients than between basal respiration, microbial C： N ratio and qCO2 and soil nutrients. In conclusion, introduction of broad-leaved tree species into pure coniferous plantation improved soil microbial properties and soil fertility, and can be helpful to restore degraded forest soil.展开更多
Mango is a commercial crop on Hainan Island,China,that is cultivated to develop the tropical rural economy.The development of accurate and up-to-date maps of the spatial distribution of mango plantations is necessary ...Mango is a commercial crop on Hainan Island,China,that is cultivated to develop the tropical rural economy.The development of accurate and up-to-date maps of the spatial distribution of mango plantations is necessary for agricultural monitoring and decision management by the local government.Pixel-based and object-oriented image analysis methods for mapping mango plantations were compared using two machine learning algorithms(support vector machine(SVM)and Random Forest(RF))based on Chinese high-resolution Gaofen-1(GF-1)imagery in parts of Hainan Island.To assess the importance of different features on classification accuracy,a combined layer of four original bands,32 gray-level co-occurrence(GLCM)texture indices,and 10 vegetation indices were used as input features.Then five different sets of variables(5,10,20,and 30 input variables and all 46 variables)were classified with the two machine learning algorithms at object-based level.Results of the feature optimization suggested that homogeneity and variance were very important variables for distinguishing mango plantations patches.The object-based classifiers could significantly improve overall accuracy between 2–7%when compared to pixel-based classifiers.When there were 5 and 10 input variables,SVM showed higher classification accuracy than RF,and when the input variables exceeded 20,RF showed better performances.After the accuracy achieved saturation points,there were only slightly classification accuracy improvements along with the numbers of feature increases for both of SVM and RF classifiers.The results indicated that GF-1 imagery can be successfully applied to mango plantation mapping in tropical regions,which would provide a useful framework for accurate tropical agriculture land management.展开更多
A study was conducted to determine the characters of soil structure in different water and soil conservation forests in Keshan County,northwest of Heilongjiang Province,China.The soil bulk density,the ratio of non-cap...A study was conducted to determine the characters of soil structure in different water and soil conservation forests in Keshan County,northwest of Heilongjiang Province,China.The soil bulk density,the ratio of non-capillary porosity and capillary porosity（NCP/CP）,and the generalized soil structure index（GSSI） were measured for Fraxinus mandshurica,Larix gmelini,Pinus sylvestris var.mongolica,and Picea koraiensis plantations as well as the abandoned land（as control） adjacent to the forests in typical black soil region.Results show that at soil depth of 0–30cm,the soil bulk density of F.mandshurica forest and L.gmelini forest was lower than that of P.sylvestris var.mongolica forest and P.koraiensis forest,with the relative decrease of 8.04%–11.01%.The soil bulk density of L.gmelini forest was significantly different from that of the P.sylvestris var.mongolica forest and P.koraiensis forest.The NCP/CP values of the four types of plantations were all higher（59.75%–128.82% relatively） than that of abandoned land（p〈0.05）,indicating that the soil aeration and permeability under forest were enhanced,especially under L.gmelini forest.GSSI values of the four types of forests were also relatively higher（2.98%–4.36%） than abandoned land（p〈0.05）,indicating that those soil and water conservation forests,especially the F.mandshurica forest and P.koraiensis forest,can promote soil condition to approximate ideal soil structure.The result of this study can provide theoretical basis for scientifically evaluating the effects of vegetation restoration on soil quality in typical black soil region.展开更多
To explore the influence of meteorological variables on the growth of Korean pine(Pinus koraiensis Sieb.et Zucc.) plantations and provide a scientific reference for the production and management of Korean pine,three a...To explore the influence of meteorological variables on the growth of Korean pine(Pinus koraiensis Sieb.et Zucc.) plantations and provide a scientific reference for the production and management of Korean pine,three approaches to interpolate meteorological variables during the growing season(i.e.,May-September) were compared in Heilongjiang Province,China.Optimized meteorological variable interpolation results were then combined with stand and individual tree variables,based on data from 56 sample plots and 2886 sample trees from Korean pine plantations in two regions of the province to develop an individualtree diameter growth model(Model I) and an individualtree diameter growth model with meteorological variables(Model Ⅱ) using a stepwise regression method.Moreover,an individual-tree diameter growth model with regional effects(Model Ⅲ) was developed using dummy variables in the regression,and the significance of introducing these dummy variables was verified with an F-test statistical analysis.The models were validated using an independent data set,and the predictive performance of the three models was assessed via the adjusted coefficient of determination(R_(a)^(2)) and root mean square error(RMSE).The results suggest that the growth increment in tree diameter of Korean pine plantations was significantly correlated with the natural logarithm of initial diameter(ln D),stand basal area(BAS),logarithmic deformation of the stand density index(ln SDI),ratio of basal area of trees larger than the subject tree to their initial diameter at breast height(DBH)(BAL/D),and the maximum growingseason precipitation(Pgmax).The individual-tree diameter growth models of Korean pine plantations developed in this study will provide a good basis for estimating and predicting growth increments of Korean pine forests over larger areas.展开更多
China’s growing economy and changes in policies that encourage afforestation, particularly in the industrial sector, have led vast areas in south China to be planted with eucalyptus. These large areas of eucalyptus p...China’s growing economy and changes in policies that encourage afforestation, particularly in the industrial sector, have led vast areas in south China to be planted with eucalyptus. These large areas of eucalyptus plantings have elicited environmental concerns for two primary reasons. First there is a concern related to the water demand of eucalyptus, in which it is feared these large areas of eucalyptus will deplete aquifers and create shortages in water supplies. The second concern is in regard to the reduction in biodiversity across large landscapes, leading to further ecological demises. This paper proposes two ideas to possibly mitigate some of the biodiversity concerns. The first is the interplanting of alder-leaf birch (Betula alnoides), a native but dwindling species in south China, to enhance biodiversity and encourage it’s reestablishment across the landscape. The second is to encourage retention harvests of alder-leaf birch planted within eucalyptus plantations to enhance not only biological diversity but also structural diversity across the landscape. Alder-leaf birch has demonstrated great potential in producing high quality timber and wood for use in furniture manufacturing.展开更多
Preventing and suppressing forest fires is one of the main tasks of forestry agencies to reduce resource loss and requires a thorough understanding of the importance of factors affecting their occurrence.This study wa...Preventing and suppressing forest fires is one of the main tasks of forestry agencies to reduce resource loss and requires a thorough understanding of the importance of factors affecting their occurrence.This study was carried out in forest plantations on Maoer Mountain in order to develop models for predicting the moisture content of dead fine fuel using meteorological and soil variables.Models by Nelson(Can J For Res 14:597-600,1984)and Van Wagner and Pickett(Can For Service 33,1985)describing the equilibrium moisture content as a function of relative humidity and temperature were evaluated.A random forest and generalized additive models were built to select the most important meteorological variables affecting fuel moisture content.Nelson’s(Can J For Res 14:597-600,1984)model was accurate for Pinus koraiensis,Pinus sylvestris,Larix gmelinii and mixed Larix gmelinii—Ulmus propinqua fuels.The random forest model showed that temperature and relative humidity were the most important factors affecting fuel moisture content.The generalized additive regression model showed that temperature,relative humidity and rain were the main drivers affecting fuel moisture content.In addition to the combined effects of temperature,rainfall and relative humidity,solar radiation or wind speed were also significant on some sites.In P.koraiensis and P.sylvestris plantations,where soil parameters were measured,rain,soil moisture and temperature were the main factors of fuel moisture content.The accuracies of the random forest model and generalized additive model were similar,however,the random forest model was more accurate but underestimated the effect of rain on fuel moisture.展开更多
Successive cultivation of Chinese fir(Cunninghamia lanceolata) would markedly affect the distribution and accumulation of soil inorganic phosphorus(Pi).However,how different chronosequence phases of Chinese fir planta...Successive cultivation of Chinese fir(Cunninghamia lanceolata) would markedly affect the distribution and accumulation of soil inorganic phosphorus(Pi).However,how different chronosequence phases of Chinese fir plantations exerting influences on the quality and quantity of soil Pi fractions in aggregate-scale remain poorly understood. This study researched the dynamic changes of aggregate-related Pi fractions encompassing occluded-P(O-P), aluminum-bound P(Al-P), iron-bound P(Fe-P), and calcium-bound P(Ca-P) in topsoil(0-20 cm) from different stand aged(9-, 17-, and 26-yr) Chinese fir plantations and one nearby abandoned land(CK) in Rongshui County,Guangxi, China. In this study, soil aggregates were classified into micro-aggregates(< 0.25 mm), small macro-aggregates(1-0.25 mm), medium macroaggregates(2-1 mm), and large macro-aggregates(> 2 mm) by one wet-sieving process. As the primary aggregate fractions correlated with better soil aggregate stability, the large macro-aggregates took the highest proportion in all aggregate sizes regardless of various stand ages of Chinese fir plantations. Besides, the 17-yr plantations of Chinese fir displayed the highest stability of aggregates structure. Compared with CK, all four soil Pi fractions from three different stand ages of Chinese fir plantations generally showed increasing trends.Irrespective of chronosequence phases, Al-P was mainly carried by small macro-aggregates. O-P showed the opposite tendency to Al-P, which had the lowest content in small macro-aggregates. Fe-P and Ca-P showed an even distribution in all aggregates.The contribution rates and stocks of each Pi fraction exhibited close relevance to the content of soil aggregates. As revealed from the results, planting of Chinese fir before 17-yr was beneficial to prompt the formation of large macro-aggregates and the level of soil P. But after 17-yr, successive monoculture planting of Chinese fir would reduce the stability of soil aggregates and render the losses of soil P. The dynamics of soil total phosphorous(TP) and Pi fractions contents were highly related to the stand ages of Chinese fir plantations, but less related to the distribution of soil aggregate sizes. As the major carriers for soil P stocks, the large macro-aggregates played a vital role in the cycles and reserves of soil P.展开更多
We quantified deviations in regional forest biomass from simple extrapolation of plot data by the biomass expansion factor method（BEF） versus estimates obtained from a local biomass model,based on large-scale empiri...We quantified deviations in regional forest biomass from simple extrapolation of plot data by the biomass expansion factor method（BEF） versus estimates obtained from a local biomass model,based on large-scale empirical field inventory sampling data.The sources and relative contributions of deviations between the two models were analyzed by the boosted regression trees method.Relative to the local model,BEF overestimated accumulative biomass by 22.12%.The predominant sources of the total deviation （70.94%） were stand-structure variables.Stand age and diameter at breast height are the major factors.Compared with biotic variables,abiotic variables had a smaller overall contribution （29.06%）,with elevation and soil depth being the most important among the examined abiotic factors.Large deviations in regional forest biomass and carbon stock estimates are likely to be obtained with BEF relative to estimates based on local data.To minimize deviations,stand age and elevation should be included in regional forest-biomass estimation.展开更多
Tropical forests provide several ecosystem services and functions and support approximately two-thirds of the world’s biodiversity but are seriously threatened by deforestation.Approaches to counteract this menace ha...Tropical forests provide several ecosystem services and functions and support approximately two-thirds of the world’s biodiversity but are seriously threatened by deforestation.Approaches to counteract this menace have revolved around aff orestation with several or a single tree species.We thus investigated how plantation forests with either a single or several tree species infl uenced arthropod taxonomic and community composition using pitfall traps to sample selected groups of epigeal arthropods(Araneae,Coleoptera,Orthoptera and Hymenoptera)and with environmental variables assessed simultaneously.Our results revealed 54 taxonomic groups with signifi cantly higher taxonomic richness,activity density,and diversity in the mixed stands than in the monoculture stands.The significant differences in community composition were mainly driven by families including Lycosidae,Formicidae,Staphylinidae,Scotylidae,Hydrophilidae,Gryllidae and Scarabaeidae and were explained by distinct habitat characteristics(canopy openness,litter depth,deadwood volume,and tree height).While the diverse tree communities and heterogeneous vegetation structure off ered food and habitat resources for diverse arthropod groups,the allelopathic nature coupled with homogenous stand characteristics of the Tectona grandis stands in the monoculture suppressed the growth of understorey vegetation that could otherwise serve as food and habitat resources for arthropods,which might have led to limited activities and diversity of arthropods in the monoculture plantation stands.The fi ndings thus highlight the need to promote mixed tree plantations in degraded tropical areas,especially when restoring biodiversity is the prime management focus.展开更多
Currently, transforming the mode of forest management and developing multiple forest management practices are actively encouraged in China. As one forest management type, ginseng cultivation under larch plantations ha...Currently, transforming the mode of forest management and developing multiple forest management practices are actively encouraged in China. As one forest management type, ginseng cultivation under larch plantations has been developed significantly in the east of Liaoning Province. However, research on the influence of the ecological environment for this mode of production is still deficient. Based on this, our study compares the plant diversity and soil properties in the ginseng cultivation under larch plantations(LG) with larch plantations(LP) and natural secondary forests(SF). First, we randomly selected three plots for each of the three stand types which have similar stand characteristics; then, we carried out a plant diversity survey and soil sampling in each of the nine plots. The results show that no significant difference was found in plant diversity between LG and LP, but theevenness of herbs was significantly lower in LG than LP. No obvious changes in soil physical properties were found in LG, but a significant decrease in most of the soil nutrient content was presented in LG. Furthermore, we found a correlation between plant diversity(H') and soil properties in the three kinds of stand types, especially between herbaceous plant diversity and soil properties. We conclude that ginseng cultivation under larch plantations has no obvious effect on plant diversity, except the herbaceous evenness. Soil fertility can be depleted significantly in LG, but physical structures are not affected. Moreover, maintaining the diversity of herbaceous plants and controlling the density of ginseng cultivation in LG by farmers are important for the ecological environment. Based on this study and its good comprehensive benefits and with the support of policy, we think this forest management type should be promoted moderately in the region.展开更多
Background: Land-use change and forest management may alter soil organic matter(SOM) and nutrient dynamics,due in part to alterations in litter input and quality. Acacia was introduced in eucalypt plantations establis...Background: Land-use change and forest management may alter soil organic matter(SOM) and nutrient dynamics,due in part to alterations in litter input and quality. Acacia was introduced in eucalypt plantations established in the Congolese coastal plains to improve soil fertility and tree growth. Eucalypt trees were expected to benefit from N2 fixed by acacia. However, some indicators suggest a perturbation in SOM and P dynamics might affect the sustainability of the system in the medium and long term. In tropical environments, most of the nutrient processes are determined by the high rates of organic matter(OM) mineralization. Therefore, SOM stability might play a crucial role in regulating soil-plant processes. In spite of this, the relationship between SOM quality, C and other nutrient dynamics are not well understood. In the present study, OM quality and P forms in forest floor and soil were investigated to get more insight on the C and P dynamics useful to sustainable management of forest plantations.Methods: Thermal analysis(differential scanning calorimetry(DSC) and thermogravimetry(TGA)) and nuclear magnetic resonance(solid state13 C CPMASS and NMR and31 P-NMR) spectroscopy have been applied to partially decomposed forest floor and soils of pure acacia and eucalypt, and mixed-species acacia-eucalypt stands.Results: Thermal analysis and13 C NMR analysis revealed a more advanced stage of humification in forest floor of acacia-eucalypt stands, suggesting a greater microbial activity in its litter. SOM were related to the OM recalcitrance of the forest floor, indicating this higher microbial activity of the forest floor in this stand might be favouring the incorporation of C into the mineral soil.Conclusions: In relation with the fast mineralization in this environment, highly soluble orthophosphate was the dominant P form in both forest floor and soils. However, the mixed-species forest stands immobilized greater P in organic forms, preventing the P losses by leaching and contributing to sustain the P demand in the medium term.This shows that interactions between plants, microorganisms and soil can sustain the demand of this ecosystem.For this, the forest floor plays a key role in tightening the P cycle, minimizing the P losses.展开更多
The Great Spotted Woodpecker Dendrocopos major （L.）, one of the natural predators of Anoplophora glabripennis （Motsch.） （Coleoptera： Cerambycidae）, is resident to Wulate Qianqi County of the Inner Mongolia and ...The Great Spotted Woodpecker Dendrocopos major （L.）, one of the natural predators of Anoplophora glabripennis （Motsch.） （Coleoptera： Cerambycidae）, is resident to Wulate Qianqi County of the Inner Mongolia and widely found in shelter plantations. In August 2005 and 2006, 174 and 153 nest-cavities of Great Spotted Woodpeckers were found respectively in Wulate Qianqi County and 22 breeding nest-cavities were investigated in 2007. The results showed that mostly willow species were selected for nesting by the Great Spotted Woodpecker, but mature poplar trees also could be chosen. Nest cavities were often found with a protuberance above the cavity entrance or with a downward sloping gradient, or both. The selection of the height of the nest-cavity height was not significant. The vertical diameter of the nest-cavity entrance （VDE） and the horizontal diameter of the nest-cavity entrance （HDE） ranged from 5.0 to 5.8 cm. The results also indicated that the compass orientation of more than 60% of nest-cavities were towards the north, northeast and east. This study suggests a convergence of some nest-cavity characteristics of the Great Spotted Woodpecker in shelter plantations and will help us to make artificial nest for conserving the woodpecker and, as well, use the bird for controlling pests.展开更多
A cross-sectional survey of 489 male subjects in the age group 15 to 65 years engageddirectly or indirectly in mango cultivation along with 208 control subjects was carried out to find their socio-economic, environmen...A cross-sectional survey of 489 male subjects in the age group 15 to 65 years engageddirectly or indirectly in mango cultivation along with 208 control subjects was carried out to find their socio-economic, environmental and health conditions. The conditions like high illiteracy rate (49.5%), poverty (PCI less than Rs 100 per month, 52.2%), poor housing (mud houses, 66.7%) unsafe water supply (78.6%) were prevailing in the surveyed population. The high respiratory morbidity may be attributed to high prevalence of smoking andprolonged inhalation of organic dusts during farming operation associated with illiteracyand poor socio-economic status. Gastrointestinal disorders were related to poor hygienic conditions, smoking and consumption of contaminated water. The symptoms pertaining to CNS, skin and eyes were found to be associated with exposure to pesticides展开更多
基金funded by Scion's Strategic Science Investment Fund(SSIF)the Forest Growers Levy Trust(FGLT)through the Resilient Forests Programme(Task No.A89220)。
文摘Pinus radiata(D.Don)dominates New Zealand's forestry industry,constituting 91%of plantations,and is among the world's most important plantation species.Given the socio-economic and environmental importance of this species,it is important to have accurate and precise projections over time to make efficient decisions for forest management and greenfield investments in afforestation projects,especially for permanent carbon forests.Future projections of any natural resource systems rely on modeling;however,the acceleration of climate change makes future projections of yield less certain.These challenges also impact national expectations of the contribution planted forests will provide to address climate change and meet international commitments under the Paris Agreement.Using a large national-scale set of contemporary ground-measured data(2013–2023),this study investigates the performance of two growth models developed over 30 years ago that are widely used by NZ plantation growers:1)the Pumice Plateau Model 1988(PPM88)and 2)the 300-index(including a model variant of regional drift).Model simulations were made using the FORECASTER modeling suite with geographic boundaries to adjust for drift in space and time.Basal area(BA,m^(2)⋅ha^(-1))and volume(m^(3)⋅ha^(-1))were simulated,and standard errors and goodness-of-fit metrics calculated up to a typical rotation age of 30 years.Model residuals were then separated and analysed for the main plantation growing regions.The models overpredicted observed growth by between 6.8%and 16.2%,but model predictions and errors varied significantly between regions.The results of this study provided clear evidence of divergence between the outputs of both models and the measured data.Finally,this study suggests future measures to address challenges posed by these discrepancies that will provide better information for forest management and investment decisions in a changing climate.
基金supported by resources of the Secretary of Environment of the Medellín district,through the agreement N°001-2023 between this entity,the Faculty of Agricultural Sciences of National University of Colombia at Medellín
文摘The Andean montane forests provide a wide range of ecosystem services like water supply, carbon sequestration, and biodiversity preservation. Restoration of these forests is critical due to their degraded state and the need to recover, maintain and enhance the ecosystem services they provide. However, we lack understanding of aboveground biomass (AGB) accumulation in restored Andean montane forests. AGB is a key indicator of ecosystem productivity and provides essential data on vegetation carbon stocks, permitting the assess successfulness of restoration efforts. In 2010 the initiative Más Bosques para Medellín was formulated in Medellín City, tropical Andes, Colombia, aiming to restore the forests located in the surrounding rural areas of the city, with interest in preserving the ecosystems services like water supply. The project established 548 ha of mixed plantations with native species. After 13 years, our study aims to developed in situ allometric equations and to evaluate AGB accumulation to assess restoration performance. We measured, harvested, and weighted 144 individuals from these arrangements to fit a general equation for the project and six specific equations for each one of the six most frequent species. The AGB had a positive correlation with diameter at breast height (D), total height (H) and specific wood density (WD). The best general equation uses D and WD as predictors (R^(2) = 0.928). The specific species equations certainly responded to the functional traits of each species. Using the latest inventory of permanent plots of the project we estimated a mean AGB accumulation of 41.91 ± 30.34 Mg ha^(–1) and a total accumulation of 22,996.05 Mg of AGB for the 548 ha. We compared these results with studies developed for natural forest in the region and other land covers. We found contrast behaviors in the AGB accumulation across our study zones. The developed equations have broad applicability across the Andes region, offering valuable insights for similar restoration initiatives. Furthermore, will facilitate the assessment of current restoration efforts and inform scientifically based decisions for future mixed plantation practices.
基金supported by the National Natural Science Foundation of China (No. 32271731)Research Project of Education Department of Hunan Province (Nos. 21A0164 and 22B0241)+7 种基金Furong Scholar (Young Scholar) of Education Department of Hunan Provincethe Changsha Outstanding Innovative Youth Training Program (No. kq2209018) to Chen NingThe National Natural Science Foundation of China (No. U21A20187)the China Postdoctoral Science Foundation (No. 2023M743973)the Hunan Provincial Natural Science Foundation of China (No. 2023JJ41033)the Changsha Municipal Natural Science Foundation (No. kq2208409)the Talent Research Initiation Fund of Central South University of Forestry and Technology (No. ZK2023YJ001) to Ting LiuThe Creative Research Groups of Provincial Natural Science Foundation of Hunan (No. 2024JJ1016) to Wende Yan
文摘Phosphorus(P)is crucial for plant growth.However,its low availability in subtropical soils necessitates that trees rely on microorganisms for effective P acquisition.The introduction of broadleaf trees has been shown to facilitate P acquisition in coniferous plantations by altering the rhizosphere fungal communities.Despite this,functional shifts in these communities and the expression of root phosphorus cycling genes(PCGs)remain inadequately understood.This study investigated coniferous Pinus massoniana and Cunninghamia lanceolata plantations interplanted with broadleaf species associated with arbuscular mycorrhizal(AM)or ectomycorrhizal(ECM)fungi.Rhizosphere soil and fine roots from the conifers were analyzed to examine soil bioavailable P fractions,root mycorrhizal colonization,rhizosphere fungal community composition,enzyme function predictions,and root PCGs expression.We found that citric-P in rhizospheric soil of P.massoniana increased with the introduction of Quercus gilva(an ECM-associated tree species),whereas Bray-P content in the rhizosphere of C.lanceolata decreased upon the introduction of either Q.gilva or Phoebe zhennan(an ECM-associated tree species).Moreover,the relative abundance of saprophytic fungi(e.g.,Mortierella)increased following the introduction of broadleaf trees.Specifically,the introduction of Q.gilva was associated with elevated levels of organic P mineralization genes(e.g.,phoA)and enzymes(e.g.,phytases and acid phosphatase(ACP))in conifers.In contrast,the introduction of P.zhennan increased the expression of inorganic P solubilization genes(such as qppC in P.massoniana roots and ppa in C.lanceolata roots).Key contributors to P absorption in conifer roots included Cenococcum,Rhizopogon,and Glomus.This study advances our understanding of P cycling in coniferous rhizospheres and the dynamics of coexisting mycorrhizal tree systems,yielding valuable insights into sustainable management of plantation ecosystems.
基金Supported by the Project of the Basic Research Operation Cost of State Level Research Institutes "Long-term Location Investigation of Basic Data for Rubber Production " ( XJSYWFZX-2008-14 and XJSYWFZX-2007-2)the Project Natural Sciences Fund of Hainan Province (807045)~~
文摘[Objective]The aim was to study on the characteristics of soil organic carbon and nitrogen in rubber （Hevea brasiliensis Muell-Arg） plantations at different age stages in the western region of Hainan Island,so as to evaluate the ecological benefits of rubber plantations and provide basic data for studying the effect of tropical land utilization/cover change on the global carbon and nitrogen cycle. [Method]The situs was in Danzhou city,western region of Hainan Island,and the samples were four kinds of rubber plantations soil at different ages and one kind of control check （pepper,Piper nigrum L.） soil. In this research,four quadrats were set up in each sample,and the size of each was 20 cm×20 cm. Four specimens were gathered from four layers of 0-15,15-30,30-45,45-60,and the average of them was the last analysis result of each sample. Soil density was measured by cutting ring method,soil containing and hygroscopic water was detected by oven drying method,soil organic carbon （SOC） was measured by low temperature heated outside potassium dichromate oxidation-colorimetry method,and soil total nitrogen （STN） was detected by semimicro Kjeldahl method. [Result]SOC contents of different layers in rubber plantations soil at different age stages （including the CK pepper soil,the same as below） varied little,and the content of SOC in surface layer （0-15 cm） was higher,while the underlayer （45-60 cm） was lower than the average value; there was significant difference in SOC content among different kinds of soil,and the content was of 6.03-7.78 g/kg,tapping young trees （7 years） CK pepper mature age trees （30 years） prophase of young trees （2 years） tapping trees （16 years）; there was no significant difference in SOC storage among different kinds of soil,and the storage was of 61.33-74.29 t/hm2,mature age trees （30 years） tapping young trees （7 years） prophase of young trees （2 years） CK pepper tapping trees （16 years）; there was significant difference in STN content among rubber plantations soil at different age stages,the content was of 410.86-664.14 mg/kg2,CK pepper tapping young trees （7 years） prophase of young trees （2 years） mature age trees （30 years） tapping trees （16 years）,and STN content of tapping trees （16 years） soil was extremely lowest; there was significant difference in C/N ratio among different kinds of soil,the ratio was of 10.94-14.47,and the ratio of tapping trees （16 years） mature age trees （30 years） tapping young trees （7 years） CK pepper prophase of young trees （2 years）. [Conclusion]There wasn＇t unhealthy effect of rubber trees planted in tropical area on the content and storage of SOC,the content of STN and the ratio of C/N. there was no significant difference between rubber plantations and CK pepper soil,and the effects of rubber plantation on soil carbon-nitrogen was similar to that of other tropical crops （such as pepper）.
基金Supported by Key Science and Technology Project of Hainan Land Reclamation Bureau([2009]57)~~
文摘The influence of formula fertilization optimization on dry rubber yield and economic benefits of the rubber plantation in Hainan Longjiang Farm were studied by using ＂contrast＂ design method of fertilizer field experiments. The results showed that the actual production rate reached 4.61% and the net production rate of dry rubber reached 3.97% by application of optimized fertilization formula. Analysis of variance showed that the average dry rubber yield in optimization of formula fertil- ization area was significantly higher than that of conventional area. The results also indicated that the optimization of formula fertilization had obvious economic benefits, and each rubber tree reduced cost and increased 9.95 yuan on average after the test.
文摘[Objectives]The soil permeability and its influencing factors in typical plantations were studied to provide a scientific basis for tending and managing plantations in the Haikou forest area of Kunming City.[Methods]With three kinds of typical forest stands,i.e.,over-mature Pinus armandii Franch.,mid-mature Eucalyptus robusta Smith,and over-mature E.robusta Smith in this region as the research objects,soil infiltration changes and the effects on soil water retention in different stands,soil layers,and gap conditions under different moisture conditions were analyzed.[Results]①Under all three moisture conditions,the over-mature P.armandii forest demonstrated higher overall infiltration rates than the other two forest stands,which showed relatively similar infiltration rates.In all three stands,the soil infiltration rate decreased as the depth of the soil increased.Significant fluctuations in soil infiltration rate were observed during the initial 0-5 min,followed by gradual stabilization or regular fluctuations after 5 min.The infiltration process generally reached saturation after approximately 20 min.②The average infiltration rate was identified as the key factor affecting soil infiltration.Comprehensive evaluation of soil permeability revealed that the over-mature P.armandii forest exhibited optimal soil permeability.③Various soil physical and chemical properties significantly affected different indexes of soil permeability under varying conditions,with soil organic carbon content and water repellency demonstrating particularly notable effects on infiltration under different conditions.[Conclusions]Soil infiltration rates gradually decreased with the deepening of the soil layer.Principal component analysis(PCA)showed that the soil permeability of the over-mature P.armandii forest was stronger than that of the other two stands under the three moisture conditions,especially in non-gap positions.All soil indexes affected soil permeability,and soil organic carbon and water repellency were the key factors affecting soil permeability.
基金funded by the National Natural Science Foundation of China (No. 31930078)the National Key Research and Development Program of China (No. 2021YFD2200405)
文摘Mixed-species plantations generally exhibit higher ecosystem multifunctionality than monospecific plantations.However,it is unclear how tree species functional composition influences species mixture effects on ecosystem multifunctionality.We selected 171 monospecific and mixed-species plantations from nine regions across subtropical China,and quantified 13 key ecosystem functional properties to investigate how species mixture effects on ecosystem multifunctionality are modulated by functional diversity and identity.We found that ecosystem multifunctionality was significantly higher(p<0.05)in mixed tree plantations than in monospecific plantations except the mixed-conifer species plantations.Across all regions,ecosystem multifunctionality was significantly higher(p<0.05)in mixed conifer-broadleaf plantations than in monospecific plantations of the corresponding species,but not different between mixed and monospecific coniferous plantations.The magnitude of species mixture effects on ecosystem multifunctionality varied greatly with tree species compositions.Taking Cunninghamia lanceolata Lamb.as an example,the effects varied from a range of 2.0%–9.6%when mixed with a conifer species to 36%–87%when mixed with a broadleaf species.The functional diversity was the dominate driver shaping ecosystem multifunctionality,while functional identity,as expressed by community-weighted mean of specific leaf area,also had a positive effect on ecosystem multifunctionality through the increased below-ground nitrogen and phosphorus stocks regulated by specific leaf area of the mixing tree species.Our study highlights the important role of functional diversity in shaping ecosystem multifunctionality across region-wide environmental conditions.Mixed conifer-broadleaf tree plantations with distinct functional traits benefit the enhancement of ecosystem multifunctionality,and the magnitude of species mixture effects is modulated by the functional identity of tree species composition;those relationships deserve a special consideration in multifunctional management context of subtropical plantations.
基金This study was supported by Chinese Academy of Science Program (KZCX2-YW-405)the Knowledge Innovation Program of the Chinese Academy of Sciences
文摘An investigation on soil organic carbon, total N and P, NO3-N, available P, microbial biomass C, N and P, basal respiration and metabolic quotients （qCO2） was conducted to compare differences in soil microbial properties and nutrients between 15-year-old pure Chinese fir （Cunninghamia lanceolata） and two mixed Chinese fir plantations （mixed plantations with Alnus crernastogyne, mixed plantations with Kalopanax septemlobus） at Huitong Experimental Station of Forest Ecology （26°45′N latitude and 109°30′E longitude）, Chinese Academy of Sciences in May, 2005. Results showed that the concentrations of soil organic carbon, total N, NO3^--N, total P and available P in mixed plantations were higher than that in pure plantation. Soil microbial biomass N in two mixed plantations was averagely higher 69% and 61% than that in pure plantation at the 0-10 cm and 10-20 cm soil depth, respectively. Soil microbial biomass C, P and basal respiration in mixed plantations were higher 11%, 14% and 4% at the 0-10 cm soil depth and 6%, 3% and 3% at the 10-20 cm soil depth compared with pure plantation. However, soil microbial C： N ratio and qCO2 were averagely lower 34% and 4% in mixed plantations than pure plantation. Additionally, there was a closer relation between soil microbial biomass and soil nutrients than between basal respiration, microbial C： N ratio and qCO2 and soil nutrients. In conclusion, introduction of broad-leaved tree species into pure coniferous plantation improved soil microbial properties and soil fertility, and can be helpful to restore degraded forest soil.
基金This research was funded by the Opening Foundation Program of Land Use Key Laboratory of the Ministry of Natural Resources of China,the Hainan Provincial Key Laboratory of Practical Research on Tropical Crops Information Technology,China(RDZWKFJJ2019001)the Central Public-interest Scientific Institution Basal Research Fund for Chinese Academy of Tropical Agricultural Sciences(1630072020006,1630072017004 and 1630072019001)+2 种基金the Natural Science Foundation of Hainan,China(619MS100)the National Natural Science Foundation of China(31601211)the Demonstration and Pilot Projects for Comprehensive Rural Reform,China(XXSNZG19-02).
文摘Mango is a commercial crop on Hainan Island,China,that is cultivated to develop the tropical rural economy.The development of accurate and up-to-date maps of the spatial distribution of mango plantations is necessary for agricultural monitoring and decision management by the local government.Pixel-based and object-oriented image analysis methods for mapping mango plantations were compared using two machine learning algorithms(support vector machine(SVM)and Random Forest(RF))based on Chinese high-resolution Gaofen-1(GF-1)imagery in parts of Hainan Island.To assess the importance of different features on classification accuracy,a combined layer of four original bands,32 gray-level co-occurrence(GLCM)texture indices,and 10 vegetation indices were used as input features.Then five different sets of variables(5,10,20,and 30 input variables and all 46 variables)were classified with the two machine learning algorithms at object-based level.Results of the feature optimization suggested that homogeneity and variance were very important variables for distinguishing mango plantations patches.The object-based classifiers could significantly improve overall accuracy between 2–7%when compared to pixel-based classifiers.When there were 5 and 10 input variables,SVM showed higher classification accuracy than RF,and when the input variables exceeded 20,RF showed better performances.After the accuracy achieved saturation points,there were only slightly classification accuracy improvements along with the numbers of feature increases for both of SVM and RF classifiers.The results indicated that GF-1 imagery can be successfully applied to mango plantation mapping in tropical regions,which would provide a useful framework for accurate tropical agriculture land management.
基金supported by National Natural Science Foundation of China (No 30872068)the Science and Technology Key Scientific Project of Heilongjiang Province (GA06B302-3)Fund of Thesis for Post Graduated Student of NEFU(GRAM09)
文摘A study was conducted to determine the characters of soil structure in different water and soil conservation forests in Keshan County,northwest of Heilongjiang Province,China.The soil bulk density,the ratio of non-capillary porosity and capillary porosity（NCP/CP）,and the generalized soil structure index（GSSI） were measured for Fraxinus mandshurica,Larix gmelini,Pinus sylvestris var.mongolica,and Picea koraiensis plantations as well as the abandoned land（as control） adjacent to the forests in typical black soil region.Results show that at soil depth of 0–30cm,the soil bulk density of F.mandshurica forest and L.gmelini forest was lower than that of P.sylvestris var.mongolica forest and P.koraiensis forest,with the relative decrease of 8.04%–11.01%.The soil bulk density of L.gmelini forest was significantly different from that of the P.sylvestris var.mongolica forest and P.koraiensis forest.The NCP/CP values of the four types of plantations were all higher（59.75%–128.82% relatively） than that of abandoned land（p〈0.05）,indicating that the soil aeration and permeability under forest were enhanced,especially under L.gmelini forest.GSSI values of the four types of forests were also relatively higher（2.98%–4.36%） than abandoned land（p〈0.05）,indicating that those soil and water conservation forests,especially the F.mandshurica forest and P.koraiensis forest,can promote soil condition to approximate ideal soil structure.The result of this study can provide theoretical basis for scientifically evaluating the effects of vegetation restoration on soil quality in typical black soil region.
基金funded partly by the National Key Research and Development Program of China (Project No.2017YFD0600601-01-04)the Fundamental Research Funds for the Central Universities (2572019CP15)。
文摘To explore the influence of meteorological variables on the growth of Korean pine(Pinus koraiensis Sieb.et Zucc.) plantations and provide a scientific reference for the production and management of Korean pine,three approaches to interpolate meteorological variables during the growing season(i.e.,May-September) were compared in Heilongjiang Province,China.Optimized meteorological variable interpolation results were then combined with stand and individual tree variables,based on data from 56 sample plots and 2886 sample trees from Korean pine plantations in two regions of the province to develop an individualtree diameter growth model(Model I) and an individualtree diameter growth model with meteorological variables(Model Ⅱ) using a stepwise regression method.Moreover,an individual-tree diameter growth model with regional effects(Model Ⅲ) was developed using dummy variables in the regression,and the significance of introducing these dummy variables was verified with an F-test statistical analysis.The models were validated using an independent data set,and the predictive performance of the three models was assessed via the adjusted coefficient of determination(R_(a)^(2)) and root mean square error(RMSE).The results suggest that the growth increment in tree diameter of Korean pine plantations was significantly correlated with the natural logarithm of initial diameter(ln D),stand basal area(BAS),logarithmic deformation of the stand density index(ln SDI),ratio of basal area of trees larger than the subject tree to their initial diameter at breast height(DBH)(BAL/D),and the maximum growingseason precipitation(Pgmax).The individual-tree diameter growth models of Korean pine plantations developed in this study will provide a good basis for estimating and predicting growth increments of Korean pine forests over larger areas.
文摘China’s growing economy and changes in policies that encourage afforestation, particularly in the industrial sector, have led vast areas in south China to be planted with eucalyptus. These large areas of eucalyptus plantings have elicited environmental concerns for two primary reasons. First there is a concern related to the water demand of eucalyptus, in which it is feared these large areas of eucalyptus will deplete aquifers and create shortages in water supplies. The second concern is in regard to the reduction in biodiversity across large landscapes, leading to further ecological demises. This paper proposes two ideas to possibly mitigate some of the biodiversity concerns. The first is the interplanting of alder-leaf birch (Betula alnoides), a native but dwindling species in south China, to enhance biodiversity and encourage it’s reestablishment across the landscape. The second is to encourage retention harvests of alder-leaf birch planted within eucalyptus plantations to enhance not only biological diversity but also structural diversity across the landscape. Alder-leaf birch has demonstrated great potential in producing high quality timber and wood for use in furniture manufacturing.
基金the National Key Research and Development Program of ChinaKey Projects for Strategic International Innovative Cooperation in Science and Technology(2018YFE0207800)+1 种基金Fundamental Research Funds for the Central Universities(2572019BA03)partly by the China Scholarship Council(CSC No.2016DFH417)。
文摘Preventing and suppressing forest fires is one of the main tasks of forestry agencies to reduce resource loss and requires a thorough understanding of the importance of factors affecting their occurrence.This study was carried out in forest plantations on Maoer Mountain in order to develop models for predicting the moisture content of dead fine fuel using meteorological and soil variables.Models by Nelson(Can J For Res 14:597-600,1984)and Van Wagner and Pickett(Can For Service 33,1985)describing the equilibrium moisture content as a function of relative humidity and temperature were evaluated.A random forest and generalized additive models were built to select the most important meteorological variables affecting fuel moisture content.Nelson’s(Can J For Res 14:597-600,1984)model was accurate for Pinus koraiensis,Pinus sylvestris,Larix gmelinii and mixed Larix gmelinii—Ulmus propinqua fuels.The random forest model showed that temperature and relative humidity were the most important factors affecting fuel moisture content.The generalized additive regression model showed that temperature,relative humidity and rain were the main drivers affecting fuel moisture content.In addition to the combined effects of temperature,rainfall and relative humidity,solar radiation or wind speed were also significant on some sites.In P.koraiensis and P.sylvestris plantations,where soil parameters were measured,rain,soil moisture and temperature were the main factors of fuel moisture content.The accuracies of the random forest model and generalized additive model were similar,however,the random forest model was more accurate but underestimated the effect of rain on fuel moisture.
基金supported by the Guangxi Special Fund Project for Innovation Driven Development (AA 17204087-8)the Innovation Project of Guangxi Graduate Education (YCSW2020022)。
文摘Successive cultivation of Chinese fir(Cunninghamia lanceolata) would markedly affect the distribution and accumulation of soil inorganic phosphorus(Pi).However,how different chronosequence phases of Chinese fir plantations exerting influences on the quality and quantity of soil Pi fractions in aggregate-scale remain poorly understood. This study researched the dynamic changes of aggregate-related Pi fractions encompassing occluded-P(O-P), aluminum-bound P(Al-P), iron-bound P(Fe-P), and calcium-bound P(Ca-P) in topsoil(0-20 cm) from different stand aged(9-, 17-, and 26-yr) Chinese fir plantations and one nearby abandoned land(CK) in Rongshui County,Guangxi, China. In this study, soil aggregates were classified into micro-aggregates(< 0.25 mm), small macro-aggregates(1-0.25 mm), medium macroaggregates(2-1 mm), and large macro-aggregates(> 2 mm) by one wet-sieving process. As the primary aggregate fractions correlated with better soil aggregate stability, the large macro-aggregates took the highest proportion in all aggregate sizes regardless of various stand ages of Chinese fir plantations. Besides, the 17-yr plantations of Chinese fir displayed the highest stability of aggregates structure. Compared with CK, all four soil Pi fractions from three different stand ages of Chinese fir plantations generally showed increasing trends.Irrespective of chronosequence phases, Al-P was mainly carried by small macro-aggregates. O-P showed the opposite tendency to Al-P, which had the lowest content in small macro-aggregates. Fe-P and Ca-P showed an even distribution in all aggregates.The contribution rates and stocks of each Pi fraction exhibited close relevance to the content of soil aggregates. As revealed from the results, planting of Chinese fir before 17-yr was beneficial to prompt the formation of large macro-aggregates and the level of soil P. But after 17-yr, successive monoculture planting of Chinese fir would reduce the stability of soil aggregates and render the losses of soil P. The dynamics of soil total phosphorous(TP) and Pi fractions contents were highly related to the stand ages of Chinese fir plantations, but less related to the distribution of soil aggregate sizes. As the major carriers for soil P stocks, the large macro-aggregates played a vital role in the cycles and reserves of soil P.
基金supported by the Major Research Development Program of China(2016YFC0502704)National Science Foundation of China(31670645,31470578 and 31200363)+4 种基金National Forestry Public Welfare Foundation of China(201304205)Fujian Provincial Department of S&T Project(2013YZ0001-1,2015Y0083,2016Y0083,2016T3037 and 2016T3032)Key Laboratory of Urban Environment and Health of CAS(KLUEH-C-201701)Youth Innovation Promotion Association CAS(2014267)Key Program of the Chinese Academy of Sciences(KFZDSW-324)
文摘We quantified deviations in regional forest biomass from simple extrapolation of plot data by the biomass expansion factor method（BEF） versus estimates obtained from a local biomass model,based on large-scale empirical field inventory sampling data.The sources and relative contributions of deviations between the two models were analyzed by the boosted regression trees method.Relative to the local model,BEF overestimated accumulative biomass by 22.12%.The predominant sources of the total deviation （70.94%） were stand-structure variables.Stand age and diameter at breast height are the major factors.Compared with biotic variables,abiotic variables had a smaller overall contribution （29.06%）,with elevation and soil depth being the most important among the examined abiotic factors.Large deviations in regional forest biomass and carbon stock estimates are likely to be obtained with BEF relative to estimates based on local data.To minimize deviations,stand age and elevation should be included in regional forest-biomass estimation.
文摘Tropical forests provide several ecosystem services and functions and support approximately two-thirds of the world’s biodiversity but are seriously threatened by deforestation.Approaches to counteract this menace have revolved around aff orestation with several or a single tree species.We thus investigated how plantation forests with either a single or several tree species infl uenced arthropod taxonomic and community composition using pitfall traps to sample selected groups of epigeal arthropods(Araneae,Coleoptera,Orthoptera and Hymenoptera)and with environmental variables assessed simultaneously.Our results revealed 54 taxonomic groups with signifi cantly higher taxonomic richness,activity density,and diversity in the mixed stands than in the monoculture stands.The significant differences in community composition were mainly driven by families including Lycosidae,Formicidae,Staphylinidae,Scotylidae,Hydrophilidae,Gryllidae and Scarabaeidae and were explained by distinct habitat characteristics(canopy openness,litter depth,deadwood volume,and tree height).While the diverse tree communities and heterogeneous vegetation structure off ered food and habitat resources for diverse arthropod groups,the allelopathic nature coupled with homogenous stand characteristics of the Tectona grandis stands in the monoculture suppressed the growth of understorey vegetation that could otherwise serve as food and habitat resources for arthropods,which might have led to limited activities and diversity of arthropods in the monoculture plantation stands.The fi ndings thus highlight the need to promote mixed tree plantations in degraded tropical areas,especially when restoring biodiversity is the prime management focus.
基金financially supported by the research on soft science of forestry(2014-R05)consulting project of the Chinese Academy of Engineering(2013-XZ-22)
文摘Currently, transforming the mode of forest management and developing multiple forest management practices are actively encouraged in China. As one forest management type, ginseng cultivation under larch plantations has been developed significantly in the east of Liaoning Province. However, research on the influence of the ecological environment for this mode of production is still deficient. Based on this, our study compares the plant diversity and soil properties in the ginseng cultivation under larch plantations(LG) with larch plantations(LP) and natural secondary forests(SF). First, we randomly selected three plots for each of the three stand types which have similar stand characteristics; then, we carried out a plant diversity survey and soil sampling in each of the nine plots. The results show that no significant difference was found in plant diversity between LG and LP, but theevenness of herbs was significantly lower in LG than LP. No obvious changes in soil physical properties were found in LG, but a significant decrease in most of the soil nutrient content was presented in LG. Furthermore, we found a correlation between plant diversity(H') and soil properties in the three kinds of stand types, especially between herbaceous plant diversity and soil properties. We conclude that ginseng cultivation under larch plantations has no obvious effect on plant diversity, except the herbaceous evenness. Soil fertility can be depleted significantly in LG, but physical structures are not affected. Moreover, maintaining the diversity of herbaceous plants and controlling the density of ginseng cultivation in LG by farmers are important for the ecological environment. Based on this study and its good comprehensive benefits and with the support of policy, we think this forest management type should be promoted moderately in the region.
基金supported by a TWAS-ENEA Research Training Fellowship Programme in Italy。
文摘Background: Land-use change and forest management may alter soil organic matter(SOM) and nutrient dynamics,due in part to alterations in litter input and quality. Acacia was introduced in eucalypt plantations established in the Congolese coastal plains to improve soil fertility and tree growth. Eucalypt trees were expected to benefit from N2 fixed by acacia. However, some indicators suggest a perturbation in SOM and P dynamics might affect the sustainability of the system in the medium and long term. In tropical environments, most of the nutrient processes are determined by the high rates of organic matter(OM) mineralization. Therefore, SOM stability might play a crucial role in regulating soil-plant processes. In spite of this, the relationship between SOM quality, C and other nutrient dynamics are not well understood. In the present study, OM quality and P forms in forest floor and soil were investigated to get more insight on the C and P dynamics useful to sustainable management of forest plantations.Methods: Thermal analysis(differential scanning calorimetry(DSC) and thermogravimetry(TGA)) and nuclear magnetic resonance(solid state13 C CPMASS and NMR and31 P-NMR) spectroscopy have been applied to partially decomposed forest floor and soils of pure acacia and eucalypt, and mixed-species acacia-eucalypt stands.Results: Thermal analysis and13 C NMR analysis revealed a more advanced stage of humification in forest floor of acacia-eucalypt stands, suggesting a greater microbial activity in its litter. SOM were related to the OM recalcitrance of the forest floor, indicating this higher microbial activity of the forest floor in this stand might be favouring the incorporation of C into the mineral soil.Conclusions: In relation with the fast mineralization in this environment, highly soluble orthophosphate was the dominant P form in both forest floor and soils. However, the mixed-species forest stands immobilized greater P in organic forms, preventing the P losses by leaching and contributing to sustain the P demand in the medium term.This shows that interactions between plants, microorganisms and soil can sustain the demand of this ecosystem.For this, the forest floor plays a key role in tightening the P cycle, minimizing the P losses.
文摘The Great Spotted Woodpecker Dendrocopos major （L.）, one of the natural predators of Anoplophora glabripennis （Motsch.） （Coleoptera： Cerambycidae）, is resident to Wulate Qianqi County of the Inner Mongolia and widely found in shelter plantations. In August 2005 and 2006, 174 and 153 nest-cavities of Great Spotted Woodpeckers were found respectively in Wulate Qianqi County and 22 breeding nest-cavities were investigated in 2007. The results showed that mostly willow species were selected for nesting by the Great Spotted Woodpecker, but mature poplar trees also could be chosen. Nest cavities were often found with a protuberance above the cavity entrance or with a downward sloping gradient, or both. The selection of the height of the nest-cavity height was not significant. The vertical diameter of the nest-cavity entrance （VDE） and the horizontal diameter of the nest-cavity entrance （HDE） ranged from 5.0 to 5.8 cm. The results also indicated that the compass orientation of more than 60% of nest-cavities were towards the north, northeast and east. This study suggests a convergence of some nest-cavity characteristics of the Great Spotted Woodpecker in shelter plantations and will help us to make artificial nest for conserving the woodpecker and, as well, use the bird for controlling pests.
文摘A cross-sectional survey of 489 male subjects in the age group 15 to 65 years engageddirectly or indirectly in mango cultivation along with 208 control subjects was carried out to find their socio-economic, environmental and health conditions. The conditions like high illiteracy rate (49.5%), poverty (PCI less than Rs 100 per month, 52.2%), poor housing (mud houses, 66.7%) unsafe water supply (78.6%) were prevailing in the surveyed population. The high respiratory morbidity may be attributed to high prevalence of smoking andprolonged inhalation of organic dusts during farming operation associated with illiteracyand poor socio-economic status. Gastrointestinal disorders were related to poor hygienic conditions, smoking and consumption of contaminated water. The symptoms pertaining to CNS, skin and eyes were found to be associated with exposure to pesticides
