Pteroceltis tatarinowii is one of the native precious tree species of China and the bark is the main raw material for manufacturing Xuan paper. Based on the introduction of resource distribution and ecological charact...Pteroceltis tatarinowii is one of the native precious tree species of China and the bark is the main raw material for manufacturing Xuan paper. Based on the introduction of resource distribution and ecological characteristics of P. tatarinowii, this paper summarized current and advanced science and technology of the studies and management of this species in recent 20 years, which include the relationship between bark quality of P. tatarinowii and Xuan Paper, the key techniques related to improving seedling production and plantation productivity, and establishment of optimum silviculture patterns of P. tatarinowii. The development potential and further required study of P. tatarinowii plantations were also discussed and prospected. The paper will provide some bases for directive silviculture of P. tatarinowii plantation and sustainable development of Xuan Paper production.展开更多
Background Tree regeneration is a key component of resilience because it promotes post-disturbance recovery of forests.Northwestern Patagonia from Argentina is occupied by Nothofagus alpina(Na),N.obliqua(No),and N.dom...Background Tree regeneration is a key component of resilience because it promotes post-disturbance recovery of forests.Northwestern Patagonia from Argentina is occupied by Nothofagus alpina(Na),N.obliqua(No),and N.dombeyi(Nd)forests that grow along an intense precipitation gradient,managed throughout shelterwood silvicultural system by technicians of the Lanin Natural Reserve.The objective of this study was to evaluate the influence of seeding cuttings over the dynamics of Nothofagus mixed forests across landscape(precipitation gradient)based mainly on the composition and abundance of tree regeneration,permanent sampling plots and generalized linear mixed models.In particular,we analysed:(i)the structure of sexual and asexual regeneration during<10,10–20 and>20 years after harvest(the dynamics of managed forests),and(ii)the structure of sexual regeneration in primary and managed forests after>20 years of harvest(the effect of silviculture).Results Nd was the most abundant species in the regeneration of managed forests during all periods in both sites despite its lower contribution to the adult cohort.During the 10–20 years period after harvest,the humid site exhibited higher regeneration density than the mesic site(120,000 and 6000 ind ha^(-1),respectively),and it decreased afterwards.The number of established regeneration(>2 m height)was lower for Na in the mesic site and for No in the humid site(0 and 57 ind ha^(-1),respectively).However,in comparison to No,Na showed a higher number of sprouted stumps and sprouts per stump,and a higher sprout height in the mesic site.No exhibited higher sprout mortality in the humid site.Finally,the regeneration of primary forests showed lower density and height,and a more balanced composition than that of managed forests.Conclusions The silvicultural effects on the mixed forest regeneration dynamics was strongly influenced by the condition of sites.Therefore,management prescriptions should be adjusted in order to consider the environmental variation occurring through the entire landscape.An adaptive management that considers the pattern and process of sexual and asexual regeneration and disturbance will contribute to promote a greater resilience of mixed forest ecosystems.展开更多
Background: Continuous Cover Forestry(CCF) is a type of forest management that is based on ecological, environmental, and biological principles. Specific definitions of CCF greatly vary and the concept usually include...Background: Continuous Cover Forestry(CCF) is a type of forest management that is based on ecological, environmental, and biological principles. Specific definitions of CCF greatly vary and the concept usually includes a number of tenets or criteria. The most important tenet of CCF is the requirement to abandon the practice of largescale clearfelling in favour of selective thinning/harvesting and natural regeneration methods.Methods: CCF is commonly believed to have its main origin in an academic debate that was conducted through publications in a number of European and North American countries towards the end of the 19th and the beginning of the 20th century. Our findings are exclusively based on a literature review of the history of CCF and they revealed that the European origins of CCF go much further back to a form of farm forestry that started to be practised in Central Europe in the 17th century. Eventually, this type of farm forestry led to the formation of the single-tree selection system as we know it today. Another influential tradition line contributing to modern CCF is individual-based forest management, which breaks forest stands down into small neighbourhood-based units. The centres of these units are dominant frame trees which form the framework of a forest stand. Consequently, management is only carried out in the local neighbourhood of frame trees. Individual-based forest management also modified inflexible area-control approaches of plantation forest management in favour of the flexible sizecontrol method.Results and conclusions: We found evidence that the three aforementioned tradition lines are equally important and much interacted in shaping modern CCF. Since CCF is an international accomplishment, it is helpful to thoroughly study the drivers and causes of such concepts. Understanding the gradual evolution can give valuable clues for the introduction and adaptation of CCF in countries where the concept is new.展开更多
A growing recognition that uneven-aged silviculture can offer multiple benefits to forested ecosystems has encouraged some landowners in the southern region of the United States to convert even-aged pine stands into m...A growing recognition that uneven-aged silviculture can offer multiple benefits to forested ecosystems has encouraged some landowners in the southern region of the United States to convert even-aged pine stands into multi-aged stands.For shade-intolerant pines of the southern United States,however,few studies have examined residual tree growth following silvicultural treatments that convert even-aged stands to multi-aged stands.Understanding the growth response of residual trees to different kinds of stand conversion treatments is critical to stand development and sustainability,as trees must be recruited into larger size classes during the conversion process to develop the desired stand structure and maintain productivity.In this study,we utilized a replicated,long-term silvicultural experimental trial in the southeastern United States to assess the effects of two cutting treatments(dispersed"single tree cutting"that created small canopy gaps and the"patch cutting"that created 0.1-0.8ha patch openings)and an uncut control on the 14-year growth(~cutting cycle length)of residual longleaf pine(Pinus palustris Mill.)trees.We found that tree growth,measured as mean basal area increment(BAI),was significantly higher following patch cutting(mean BAI of 16.97cm^(2))compared to both the single tree cutting(13.33cm^(2))and the uncut control(12.68cm^(2))(p<0.001).In patch cutting,the size of the patch opening,the location of trees surrounding the patch opening,and the position of the tree canopy all had a significant effect on BAI.Trees surrounding patch openings of 0.4ha exhibited greater growth,with a mean BAI of 19.24cm^(2),compared to those surrounding 0.1 and 0.8ha patch openings,which had mean BAI values of 15.89 and 15.71cm^(2),respectively(p<0.001).The position of a tree around the patch opening also influenced tree growth,as residual trees more to the North,South,and East sides exhibited significantly higher mean BAI than trees on the West side of the patch openings(p<0.001).However,distance from the patch opening border did not significantly affect the mean BAI(p=0.522).In all treatments,dominant and co-dominant trees exhibited higher BAI than intermediate and overtopped trees,indicating that tree canopy position significantly influenced tree growth(p<0.001).Understanding how residual trees grow after these silvicultural treatments is crucial for thoroughly assessing their efficacy with longleaf pine.This study's findings will enhance our understanding of stand dynamics during stand conversion and help land managers anticipate the growth of longleaf pine into larger size categories after single tree and patch cuttings.展开更多
To understand the roles of charcoal and ectomycorrhizal fungi(ECMF)on tree growth,which relates to the rehabilitation of forest ecosystems after forest fires,two experiments were set up in this study,the first was to ...To understand the roles of charcoal and ectomycorrhizal fungi(ECMF)on tree growth,which relates to the rehabilitation of forest ecosystems after forest fires,two experiments were set up in this study,the first was to determine the correct amount of charcoal for Japanese larch(Larix kaempferi Sarg.)seedling growth by applying oak charcoal to basic soil medium at ratios of 1:1,1:2,1:4 and 1:8 by volume.The second experiment investigated the combined effects of four types of charcoal:derived from oak wood,husks of buckwheat,rice and activated charcoal of larch wood,and two types of ECMF:Pt(Pisolithus tinctorius Pers.)and Ec(Pt+Rhizopogon spp.+Laccaria spp.+Scleroderma spp.)on the growth of Japanese larch seedlings.Our results show that growth was significantly stressed by large amounts charcoal applications.There were significant variations among the four types of charcoal on growth.We concluded that the addition of charcoal was the critical factor that influenced larch growth and ECMF formation.Rice charcoal and Ec stimulates the growth and nitrogen uptake of Japanese larch seedlings,thus the most suitable fungus and charcoal for practices is Ec-rice charcoal(1:8 charcoal to basic soil).展开更多
Temperate rainforests have historically been considered highly vulnerable to disturbance.Climate change,which is expected to increase the intensity,frequency,and impacts of disturbance events,is consequently a signifi...Temperate rainforests have historically been considered highly vulnerable to disturbance.Climate change,which is expected to increase the intensity,frequency,and impacts of disturbance events,is consequently a significant threat to their long-term persistence.However,data describing the long-term response of temperate rainforests to disturbance is rare.In the cool temperate rainforests of northern New South Wales,Australia,Nothofagus moorei is considered especially vulnerable to climate change due to a decreasing number of mature individuals,limited remaining suitable habitat,and low rates of sexual regeneration.In this study,we used over 50 years of empirical data from silvicultural experiments with multiple thinning intensities to characterise the demographic responses(i.e.,growth,mortality,and recruitment)of cool temperate rainforest species,including N.moorei,to disturbance over time.Cool temperate rainforest species showed resilience to disturbance,predominantly through their widespread ability to basally coppice.Nothofagus moorei,in particular,demonstrated higher rates of successful sexual and vegetative recruitment and grew faster in response to higher intensities of disturbance,in comparison to very low rates of recruitment pre-disturbance.These results challenge successional models that position rainforests as disturbance-sensitive ecosystems and identify N.moorei as a species that requires large-scale disturbance to successfully regenerate.Management regimes that actively exclude disturbance from these forests risk the local loss of disturbance-dependent rainforest species such as N.moorei.展开更多
The current Tanzanian policy guidelines regarding ecological restoration encourage total protection (enclosure system) against grazing activities, fires and wood extraction to allow regeneration in state-based Miombo ...The current Tanzanian policy guidelines regarding ecological restoration encourage total protection (enclosure system) against grazing activities, fires and wood extraction to allow regeneration in state-based Miombo woodlands. However, there is little evidence on how such treatments would promote restoration. We fetched the pieces of evidence from studies that evaluated the impact of management treatments on the lightly degraded Miombo woodlands at Kitulangalo Forest Reserve in eastern Tanzania. Plot fencing and fire exclusion constrained woody species regeneration due to competition compared to unfenced plots. Adopting quota grazing policies and controlled burning systems can be the shortest and most eco-friendly pathways towards Miombo restoration. The results pointed out that stand disturbances and silvicultural practices can promote regeneration, which is crucial to promoting ecological restoration in Miombo woodlands.展开更多
The current trend of forest management in many countries is reduced use of clear-felling and planting, and increased use of continuous cover management. In Finland, the new forest act of 2014 made all types of cutting...The current trend of forest management in many countries is reduced use of clear-felling and planting, and increased use of continuous cover management. In Finland, the new forest act of 2014 made all types of cuttings equally allowable on the condition that if the post-cutting residual stand basal area is too low, the stand must be regenerated within certain time frame. Forest landowner can freely choose between even-and uneven-aged management. This study developed a method for opti-mizing the timing and type of cuttings without the need to categorize the management system as either even-aged or uneven-aged. A management system that does not set any requirements on the sequence of post-cutting diameter distributions is called any-aged management. Planting or sow-ing was used when stand basal area fell below the required minimum basal area and the amount of advance regeneration was less than required in the regulations. When the cuttings of 200 stands managed earlier with even-aged silviculture were optimized with the developed system, final felling followed by artificial regeneration was selected for almost 50%of stands. Reduction of the minimum basal area limit greatly decreased the use of artificial regeneration but improved profitability, suggesting that the truly optimal management would be to use natural regeneration in financially mature stands. The optimal type of thinning was high thinning in 97-99%of cases. It was calculated that the minimum basal area re-quirement reduced the mean net present value of the stands by 12-16%when discount rate was 3-5%.展开更多
The stand density index,one of the most important metrics for managing site occupancy,is generally calculated from empirical data by means of a coefficient derived from the“self-thinning rule”or stand density model....The stand density index,one of the most important metrics for managing site occupancy,is generally calculated from empirical data by means of a coefficient derived from the“self-thinning rule”or stand density model.I undertook an exploratory analysis of model fitting based on simulated data.I discuss the use of the logarithmic transformation(i.e.,linearisation)of the relationship between the total number of trees per hectare(N)and the quadratic mean diameter of the stand(QMD).I compare the classic method used by Reineke(J Agric Res 46:627–638,1933),i.e.,linear OLS model fitting after logarithmic transformation of data,with the“pure”powerlaw model,which represents the native mathematical structure of this relationship.I evaluated the results according to the correlation between N and QMD.Linear OLS and nonlinear fitting agreed in the estimation of coefficients only for highly correlated(between-1 and-0.85)or poorly correlated([-0.39)datasets.At average correlation values(i.e.,between-0.75 and-0.4),it is probable that for practical applications,the differences were relevant,especially concerning the key coefficient for Reineke’s stand density index calculation.This introduced a non-negligible bias in SDI calculation.The linearised log–log model always estimated a lower slope term than did the exponent of the nonlinear function except at the extremes of the correlation range.While the logarithmic transformation is mathematically correct and always equivalent to a nonlinear model in case of prediction of the dependent variable,the difference detected in my studies between the two methods(i.e.,coefficient estimation)was directly related to the correlation between N and QMD in each simulated/disturbed dataset.In general,given the power law as the“natural”structure of the N versus QMD relationship,the nonlinear model is preferred,with a logarithmic transformation used only in the case of violation of parametric assumptions(e.g.data distributed non-normally).展开更多
The walnut-fruit forests （Juglans regia L.） in southern Kyrgyzstan are considered to be biodiversity hotspots and of considerable economic and ecological importance to local populations. The fruiting ability and sta...The walnut-fruit forests （Juglans regia L.） in southern Kyrgyzstan are considered to be biodiversity hotspots and of considerable economic and ecological importance to local populations. The fruiting ability and stability of these forests are, however, decreasing because of infrequent silvicultural interventions and non-existent natural regeneration. Continuous inventories and walnut harvest measurements were carded out on 18 trial and control plots over the course of i3 year. Results showed that i） thinning had a positive influence on diameter at breast height （dbh） increase, ii） dbh growth and crown area increases are strongly and positively correlated, iii） large crowns enhanced the production of fruits, and iv） temperature conditions had a major influence on the production of fruits. The above-mentioned points are particularly relevant for young plantations but are also valid for relatively old plantations （〉 50 years）. We conclude that regular thinning substantially improves diameter growth, fruit production and ability of trees to withstand wind and snow damage in both young stands and in older walnut-fruit forests.展开更多
Unlike fire or insect outbreaks, for which a suppression program can be implemented, it is impossible to prevent a windstorm event or stop it while it is occurring. Reducing stand susceptibility to windstorms requires...Unlike fire or insect outbreaks, for which a suppression program can be implemented, it is impossible to prevent a windstorm event or stop it while it is occurring. Reducing stand susceptibility to windstorms requires a good understanding of the factors affecting this susceptibility. Distinct species- and size-related differences in stem windthrow susceptibility are difficult to obtain because it is impossible to distinguish their relative effects from those of wind intensity. Using a damage assessment database (60 20-metre radius plots) acquired after an exceptional wind storm in Western Quebec in 2007, we developed an approach in which proportions of windthrown sugar maple poles were used as bio-indicators of wind intensities affecting the plots. We distinguished between single and interactive effects of wind intensity, species, stem size, and local basal area on stem windthrow susceptibility. The best logistic regression model predicting stem windthrow included the wind intensity bio-indicator, species, basal area, and the species by diameter at breast height (DBH, 1.3 m) interaction. Stem windthrow probability generally increased with DBH and decreased with basal area. Species wind-firmness was ordered as: yellow birch > sugar maple = eastern hemlock = American beech > ironwood > basswood = other hardwoods = other softwoods. Our method remained an indirect method of measuring wind intensity and its real test would require a comparison with anemometer measurements during a windstorm. Despite its indirect nature, the method is both simple and ecologically sound. Hence, it opens the door to conducting similar windthrow studies in other ecosystems.展开更多
Black locust(Robinia pseudoacacia L.) was the first North-American tree species imported to Europe at the beginning of the seventeenth century. It is commonly planted worldwide because of its adaptability to environme...Black locust(Robinia pseudoacacia L.) was the first North-American tree species imported to Europe at the beginning of the seventeenth century. It is commonly planted worldwide because of its adaptability to environmental stresses, its valuable wood, easy propagation, frequent and abundant seed production, excellent coppicing,high seedling survival, and relatively high wood yield. In Europe, Romania and Hungary have the most highly-developed black locust growing techniques and experiences.As a result of increasing interest in black locust in many countries, this review aims to provide a comprehensive overview of state-of-the-art site requirements, propagation, improvement and management(including growth and yield as well as use in energy plantations).展开更多
The divergent gap characteristics and spatial patterns of canopy gaps created by natural or artificial disturbances can exert a dominant influence on forest structure and composition.However,little research has been c...The divergent gap characteristics and spatial patterns of canopy gaps created by natural or artificial disturbances can exert a dominant influence on forest structure and composition.However,little research has been conducted on the effects of ice storm damage on canopy gaps in subtropical mature forests of South China.In this study,one semi-natural site was dominated by a broad-leaf forest and two managed sites were representative of plantations with coniferous forests.Based on airborne laser scanning data and field evidence across sites,statistical analyses were used to examine gap characteristics following ice storms of moderate severity.Generalized Ripley’s K-function analysis was applied to test gap spatial patterns at a range of scales,and spatial point pattern analysis was used to quantitate the relative importance of specific influences on patterns of gap occurrence.The results revealed that the average gap size was 75.7 m^2 and that 12.2 gaps occurred per hectare.Most gaps were single-tree fall events.In addition to more gaps,the mean gap size was smaller and the shape was more complex in the semi-natural site than in two managed sites.Large differences in gap characteristics were observed among snapped,uprooted,snag,and artificial gap damage types.Gaps generally showed a clustered distribution at large scales(e.g.70 m),whereas spatial patterns varied with gap damage types at different sites.The occurrence of gaps was strongly related to slope and topographic position at the semi-natural site,whereas slope,stem density,and human accessibility(proximity to pathways)were the most important factors affecting gap occurrence at the managed sites.We suggest that gap-based silvicultural treatments and natural disturbances regimes conjoin,highlighting interactions with other factors such as microsite conditions,non-tree vegetation and more.展开更多
Managing mature Douglas-fir[Pseudotsuga menziesii(Mirb.)Franco]stands to emulate the structural complexity of natural old-growth forest requires identifying structural targets at the sub-stand level at which neighborh...Managing mature Douglas-fir[Pseudotsuga menziesii(Mirb.)Franco]stands to emulate the structural complexity of natural old-growth forest requires identifying structural targets at the sub-stand level at which neighborhood dynamics and patchy disturbance shape structure.We therefore sought to describe the archetypal shapes of predominant sub-stand diameter distribution types(DDTs)observed in natural tree neighborhoods in stands comprising a chronosequence(ca.120-450+yrs)encompassing mature,vertical diversification,and horizontal diversification development stages.The ten 1.0 ha stands are located in the southcentral Oregon Cascades,USA.Building on the known spatial position of each tree,natural tree neighborhoods were identified using the floating neighborhood approach based on spatial tessellation connecting neighboring trees at the first-(mean 61 m2)through fifth-(mean 2058 m2)order scales.Cluster analysis was then used to objectively identify the most predominant DDTs among the relative tree size distributions observed in the trans-scale neighborhoods within each stand.Repeated measures regression was used to classify each DDT to one of six observed archetypal shapes:negative exponential,unimodal,rotated sigmoid,bimodal,concave,or multi-modal.Only three of the 81 observed DDTs deviated by<10%from the stand average,while every stand had at least one DDT that deviated by>50%(maximum 83%).Within each stand,five to ten predominant DDTs were observed,which deviated from the stand average by 30-48%and were characterized by two to five different archetypal shapes.Consequently,in some stands the majority of tree neighborhoods were best characterized by a different shape from that assigned at the stand level.Deviation from the stand average increased from the youngest stand in the mature development stage through the middle stands in the vertical diversification stage to the oldest stands in the horizontal diversification stage.The complexity of DDT shapes tended to increase along the chronosequence(from negative exponential and uniform toward concave and multi-modal),with shape richness highest mid-sequence and evenness peaking in the oldest stands.The high diversity of sub-stand structural complexity reduces the utility of standlevel diameter distributions as old-growth restoration targets.However,the presence in early-sequence stands of sub-stand diameter distributions common to later-sequence stands may facilitate active management at the neighborhood level to promote future old-growth condition.Restoration of substand diameter structures would likely require combining spatial perspectives,such as by augmenting tree-level croptree management with diameter distribution targets for the resulting tree neighborhoods.展开更多
A study was conducted to determine the influences of initial planting densities, thinning intensities, exposures and slope sites on physical property （wood density） and mechanical properties such as modulus of elast...A study was conducted to determine the influences of initial planting densities, thinning intensities, exposures and slope sites on physical property （wood density） and mechanical properties such as modulus of elasticity （MOE）, bending strength, impact strength, compression strength along grain and hardness） of Pinus sylvestris var. mongolica plantation in Mao＇ershan Forest Farm, Northeast China. Results show that the different initial planting densities （1.5 m×1.0 m, 1.5 m×2.0 m and 1.5 m×2.5 m） had significant effects on wood density and MOE, and the highest mean wood density and indexes of mechanical properties occurred in the stand with an initial planting density of 1.5 m×1.0 m. The indexes of mechanical properties such as hardness of end, bending strength, MOE and compression strength along grain of wood increased after mild thinning, but decreased after violent thinning. The exposures （sunny slope and shady slope） had a significant effect on MOE, and the highest mean MOE occurred on sunny slope. The slope sites （upper site and lower site） had a significant effect on wood density and main mechanical properties, except hardness. The highest mean wood density and mechanical properties occurred at lower site.展开更多
Management of the Pointe-Noire Forest requires high-performance tools for simulating tree and stand growth and assessing the sustainability of plantations. Modelling the dynamics of even-aged and mono-species stands i...Management of the Pointe-Noire Forest requires high-performance tools for simulating tree and stand growth and assessing the sustainability of plantations. Modelling the dynamics of even-aged and mono-species stands is a very active research topic. The approaches adopted by researchers vary according to the objectives and species considered: dendrometrical, Eco physiological or architectural. Thanks to the particular nature of these plantations and the trial set-up, it will be possible to explore the various aspects of production, clearly separating the part linked to genetics (three clones tested) from the part linked to the environment (via fertilisation) and the part associated with competition between trees (via planting densities and thinning regimes). This study will make a major contribution to the applicability of the self-thinning line and the RDI (Reineke Density Index) (Reineke, 1933) to fast-growing plantations. This research work will contribute to two points: 1) product diversification, which is a way of coping with international variations in timber markets, and 2) understanding how ecosystems function in exceptionally poor conditions, which will then enable the environmental impacts of the various recommended silvicultural itineraries to be assessed. The results obtained show that competition between trees in a stand of eucalyptus at very high density (10,000 stems/ha) and in two environments of very contrasting fertility is different depending on the clone. The decision on the date of the first thinning with a view to silviculture for timber and energy wood, which aims to ensure sustained and sustainable production of eucalyptus wood in these soils, should be taken between 12 and 14 months. The competition band is strong between 14 and 17 months, when the RDI = 0.8 is double that observed at 12 months.展开更多
After the new taxation system was practiced, the burden of forestry taxation was increased generally. How to extricate oneself from a predicament, it needs to draft tax reduction by the government. The revenue of both...After the new taxation system was practiced, the burden of forestry taxation was increased generally. How to extricate oneself from a predicament, it needs to draft tax reduction by the government. The revenue of both forestry products and multiple management should be exempted from taxation, the timber products logs of forest industry shouldn’t be imposed added-value tax, 8 percent tax on special products of agriculture and forestry levied by enterprise acting for tax bureau should be is delayed to pratice, the fund of for silviculture shouldn’t be imposed duties as taxable service.展开更多
The present study introduces an exploratory data analysis based on structural indicators with the aim to assess the effect of silvicultural practices on tree stand structure. The study was carried out in three Italian...The present study introduces an exploratory data analysis based on structural indicators with the aim to assess the effect of silvicultural practices on tree stand structure. The study was carried out in three Italian beech forests of different ages with stand structures that originated from dissimilar regeneration and cultivation techniques(Cansiglio, northern Italy, Chiarano, central Italy,and Mongiana, southern Italy). Ten structural indicators were considered when investigating the latent multivariate relationship between stand structure attributes before and after thinning operations by using a multiway factor analysis(MFA). The MFA results identified the older stand at Cansiglio as more homogeneous for cultivation regimes,and more stable to practices when compared with the younger sites(Chiarano and Mongiana). Heterogeneous stands were sensitive to silvicultural practice thus suggesting their possible impact on forest attributes. The proposed approach proved to be an operational tool to evaluate comprehensively the response of forest structure to planned interventions.展开更多
The main objective of this study was to examine how different stand types influenced the tendency of visitors for varying recreational activities(i.e.,hiking,trekking,camping and hunting)from 1993 to 2018 in the surro...The main objective of this study was to examine how different stand types influenced the tendency of visitors for varying recreational activities(i.e.,hiking,trekking,camping and hunting)from 1993 to 2018 in the surrounding areas of Uluyayla Natural Recreation Site in Bart1n,northern Turkey.A total of 627 visitors were selected on a voluntary basis,and questioned in the form of questionnaire.Most of the participants were in the age of 21-40 years old,and they were mostly(62.4%)male.Most of the participants(82.7%)lived in cities,while 62.8%of them were tourists when visiting the site.In determining the preferences of the visitors regarding the stand types for different recreational activities,several images of each stand were shared with them,and they were asked which stand type they would prefer for a given recreation activity(i.e.,hiking,tracking,camping and hunting).A range of options from 1 to 5 in Likert's scale was used in evaluating the given responses.The degree of positive and negative effects was examined via trend analysis.It was found that stand type had influence on the preferences of visitors regarding the recreational activities.In general,unmanaged and moderately treated stands were more preferred by visitors for the recreational purposes,compared to the previously managed stands.On the other hand,visitors'preference for the activities were different during two periods(i.e.,1993-2005 and 2006-2018).For each recreational activity,there was an increasing trend from 1993 to 2018.There had been a continuous increase for hunting since 1996,and for trekking and camping after 1999.The increases between 1993-1996 and 1996-1999 were likely due to the increasing awareness of the society as a result of the training and consciousness raising activities for nature conservation.The demand on the recreational activities continuously increased in unmanaged and moderately treated stands,while no significant changes were examined in the previously managed stands.The study points out that forest planning and management should consider different needs of visitors for recreational infrastructure.展开更多
The Brazil nut tree（Bertholletia excelsa） is a frequent component of agroforestry systems in the Amazon because of its adaptation to nutrient-poor upland soils and multiple uses.We investigated the aboveground bioma...The Brazil nut tree（Bertholletia excelsa） is a frequent component of agroforestry systems in the Amazon because of its adaptation to nutrient-poor upland soils and multiple uses.We investigated the aboveground biomass production（kg dry weight）,nutrient uptake and requirements（N,P,Ca,Mg,K） of Brazil nut trees of different sizes grown under agroforestry conditions and fertilized at different levels.Eight of 70 experimental trees with different size were harvested and stem,branches and leaves were separated.Nutrient contents were determined for three trees of varying size.Average tree growth was fast,but variability was high,suggesting considerable potential for the improvement of this economically important species.The trees responded to increased levels of fertilizer and lime with significantly increased foliar nutrient contents and growth,probably because of the improved availability of Mg and Ca for which the species seems to have a relatively high demand.In contrast to Brazil nut trees grown in forest or dense plantations,the agroforestry trees invested a substantial part of their biomass and nutrients in large branches and developed spreading crowns.To improve stem form,reduce competition with associated crops for light and recycle nutrients,regular pruning of lower branches or planting arrangements that favor self-pruning are recommended.These measures would also increase the recycling of Ca and Mg,large quantities of which are contained in the branches.展开更多
文摘Pteroceltis tatarinowii is one of the native precious tree species of China and the bark is the main raw material for manufacturing Xuan paper. Based on the introduction of resource distribution and ecological characteristics of P. tatarinowii, this paper summarized current and advanced science and technology of the studies and management of this species in recent 20 years, which include the relationship between bark quality of P. tatarinowii and Xuan Paper, the key techniques related to improving seedling production and plantation productivity, and establishment of optimum silviculture patterns of P. tatarinowii. The development potential and further required study of P. tatarinowii plantations were also discussed and prospected. The paper will provide some bases for directive silviculture of P. tatarinowii plantation and sustainable development of Xuan Paper production.
基金funded by CONICET,FONCYT[PICT-2020-SERIEA-00931“Indicadores de manejo forestal sustentable:regeneración arbórea y diversidad biológica en el bosque mixto de Nothofagus alpina,N.obliqua y N.dombeyi en diferentes condiciones ambientales de sitio y micrositio”]the Universidad Nacional del Comahue[PI 04/S025“Resiliencia,disturbios y servicios ecosistémicos del Bosque Subantártico”]
文摘Background Tree regeneration is a key component of resilience because it promotes post-disturbance recovery of forests.Northwestern Patagonia from Argentina is occupied by Nothofagus alpina(Na),N.obliqua(No),and N.dombeyi(Nd)forests that grow along an intense precipitation gradient,managed throughout shelterwood silvicultural system by technicians of the Lanin Natural Reserve.The objective of this study was to evaluate the influence of seeding cuttings over the dynamics of Nothofagus mixed forests across landscape(precipitation gradient)based mainly on the composition and abundance of tree regeneration,permanent sampling plots and generalized linear mixed models.In particular,we analysed:(i)the structure of sexual and asexual regeneration during<10,10–20 and>20 years after harvest(the dynamics of managed forests),and(ii)the structure of sexual regeneration in primary and managed forests after>20 years of harvest(the effect of silviculture).Results Nd was the most abundant species in the regeneration of managed forests during all periods in both sites despite its lower contribution to the adult cohort.During the 10–20 years period after harvest,the humid site exhibited higher regeneration density than the mesic site(120,000 and 6000 ind ha^(-1),respectively),and it decreased afterwards.The number of established regeneration(>2 m height)was lower for Na in the mesic site and for No in the humid site(0 and 57 ind ha^(-1),respectively).However,in comparison to No,Na showed a higher number of sprouted stumps and sprouts per stump,and a higher sprout height in the mesic site.No exhibited higher sprout mortality in the humid site.Finally,the regeneration of primary forests showed lower density and height,and a more balanced composition than that of managed forests.Conclusions The silvicultural effects on the mixed forest regeneration dynamics was strongly influenced by the condition of sites.Therefore,management prescriptions should be adjusted in order to consider the environmental variation occurring through the entire landscape.An adaptive management that considers the pattern and process of sexual and asexual regeneration and disturbance will contribute to promote a greater resilience of mixed forest ecosystems.
基金supported by the Swedish Government Research Council for Sustainable Development(Formas)grant#2023-00994.
文摘Background: Continuous Cover Forestry(CCF) is a type of forest management that is based on ecological, environmental, and biological principles. Specific definitions of CCF greatly vary and the concept usually includes a number of tenets or criteria. The most important tenet of CCF is the requirement to abandon the practice of largescale clearfelling in favour of selective thinning/harvesting and natural regeneration methods.Methods: CCF is commonly believed to have its main origin in an academic debate that was conducted through publications in a number of European and North American countries towards the end of the 19th and the beginning of the 20th century. Our findings are exclusively based on a literature review of the history of CCF and they revealed that the European origins of CCF go much further back to a form of farm forestry that started to be practised in Central Europe in the 17th century. Eventually, this type of farm forestry led to the formation of the single-tree selection system as we know it today. Another influential tradition line contributing to modern CCF is individual-based forest management, which breaks forest stands down into small neighbourhood-based units. The centres of these units are dominant frame trees which form the framework of a forest stand. Consequently, management is only carried out in the local neighbourhood of frame trees. Individual-based forest management also modified inflexible area-control approaches of plantation forest management in favour of the flexible sizecontrol method.Results and conclusions: We found evidence that the three aforementioned tradition lines are equally important and much interacted in shaping modern CCF. Since CCF is an international accomplishment, it is helpful to thoroughly study the drivers and causes of such concepts. Understanding the gradual evolution can give valuable clues for the introduction and adaptation of CCF in countries where the concept is new.
基金The USDA NIFA McIntire Stennis project#1014653 and the University of Florida Institute of Food and Agricultural Sciences funded the research presented in this publication.
文摘A growing recognition that uneven-aged silviculture can offer multiple benefits to forested ecosystems has encouraged some landowners in the southern region of the United States to convert even-aged pine stands into multi-aged stands.For shade-intolerant pines of the southern United States,however,few studies have examined residual tree growth following silvicultural treatments that convert even-aged stands to multi-aged stands.Understanding the growth response of residual trees to different kinds of stand conversion treatments is critical to stand development and sustainability,as trees must be recruited into larger size classes during the conversion process to develop the desired stand structure and maintain productivity.In this study,we utilized a replicated,long-term silvicultural experimental trial in the southeastern United States to assess the effects of two cutting treatments(dispersed"single tree cutting"that created small canopy gaps and the"patch cutting"that created 0.1-0.8ha patch openings)and an uncut control on the 14-year growth(~cutting cycle length)of residual longleaf pine(Pinus palustris Mill.)trees.We found that tree growth,measured as mean basal area increment(BAI),was significantly higher following patch cutting(mean BAI of 16.97cm^(2))compared to both the single tree cutting(13.33cm^(2))and the uncut control(12.68cm^(2))(p<0.001).In patch cutting,the size of the patch opening,the location of trees surrounding the patch opening,and the position of the tree canopy all had a significant effect on BAI.Trees surrounding patch openings of 0.4ha exhibited greater growth,with a mean BAI of 19.24cm^(2),compared to those surrounding 0.1 and 0.8ha patch openings,which had mean BAI values of 15.89 and 15.71cm^(2),respectively(p<0.001).The position of a tree around the patch opening also influenced tree growth,as residual trees more to the North,South,and East sides exhibited significantly higher mean BAI than trees on the West side of the patch openings(p<0.001).However,distance from the patch opening border did not significantly affect the mean BAI(p=0.522).In all treatments,dominant and co-dominant trees exhibited higher BAI than intermediate and overtopped trees,indicating that tree canopy position significantly influenced tree growth(p<0.001).Understanding how residual trees grow after these silvicultural treatments is crucial for thoroughly assessing their efficacy with longleaf pine.This study's findings will enhance our understanding of stand dynamics during stand conversion and help land managers anticipate the growth of longleaf pine into larger size categories after single tree and patch cuttings.
基金supported by the National Key Research and Development Program of China(2022 YFF 1303201)the Japan Society for the Promotion of Science.
文摘To understand the roles of charcoal and ectomycorrhizal fungi(ECMF)on tree growth,which relates to the rehabilitation of forest ecosystems after forest fires,two experiments were set up in this study,the first was to determine the correct amount of charcoal for Japanese larch(Larix kaempferi Sarg.)seedling growth by applying oak charcoal to basic soil medium at ratios of 1:1,1:2,1:4 and 1:8 by volume.The second experiment investigated the combined effects of four types of charcoal:derived from oak wood,husks of buckwheat,rice and activated charcoal of larch wood,and two types of ECMF:Pt(Pisolithus tinctorius Pers.)and Ec(Pt+Rhizopogon spp.+Laccaria spp.+Scleroderma spp.)on the growth of Japanese larch seedlings.Our results show that growth was significantly stressed by large amounts charcoal applications.There were significant variations among the four types of charcoal on growth.We concluded that the addition of charcoal was the critical factor that influenced larch growth and ECMF formation.Rice charcoal and Ec stimulates the growth and nitrogen uptake of Japanese larch seedlings,thus the most suitable fungus and charcoal for practices is Ec-rice charcoal(1:8 charcoal to basic soil).
基金supported by the Bushfire and Natural Hazards Cooperative Research Centre and New South Wales National Parks and Wildlife Service.
文摘Temperate rainforests have historically been considered highly vulnerable to disturbance.Climate change,which is expected to increase the intensity,frequency,and impacts of disturbance events,is consequently a significant threat to their long-term persistence.However,data describing the long-term response of temperate rainforests to disturbance is rare.In the cool temperate rainforests of northern New South Wales,Australia,Nothofagus moorei is considered especially vulnerable to climate change due to a decreasing number of mature individuals,limited remaining suitable habitat,and low rates of sexual regeneration.In this study,we used over 50 years of empirical data from silvicultural experiments with multiple thinning intensities to characterise the demographic responses(i.e.,growth,mortality,and recruitment)of cool temperate rainforest species,including N.moorei,to disturbance over time.Cool temperate rainforest species showed resilience to disturbance,predominantly through their widespread ability to basally coppice.Nothofagus moorei,in particular,demonstrated higher rates of successful sexual and vegetative recruitment and grew faster in response to higher intensities of disturbance,in comparison to very low rates of recruitment pre-disturbance.These results challenge successional models that position rainforests as disturbance-sensitive ecosystems and identify N.moorei as a species that requires large-scale disturbance to successfully regenerate.Management regimes that actively exclude disturbance from these forests risk the local loss of disturbance-dependent rainforest species such as N.moorei.
文摘The current Tanzanian policy guidelines regarding ecological restoration encourage total protection (enclosure system) against grazing activities, fires and wood extraction to allow regeneration in state-based Miombo woodlands. However, there is little evidence on how such treatments would promote restoration. We fetched the pieces of evidence from studies that evaluated the impact of management treatments on the lightly degraded Miombo woodlands at Kitulangalo Forest Reserve in eastern Tanzania. Plot fencing and fire exclusion constrained woody species regeneration due to competition compared to unfenced plots. Adopting quota grazing policies and controlled burning systems can be the shortest and most eco-friendly pathways towards Miombo restoration. The results pointed out that stand disturbances and silvicultural practices can promote regeneration, which is crucial to promoting ecological restoration in Miombo woodlands.
文摘The current trend of forest management in many countries is reduced use of clear-felling and planting, and increased use of continuous cover management. In Finland, the new forest act of 2014 made all types of cuttings equally allowable on the condition that if the post-cutting residual stand basal area is too low, the stand must be regenerated within certain time frame. Forest landowner can freely choose between even-and uneven-aged management. This study developed a method for opti-mizing the timing and type of cuttings without the need to categorize the management system as either even-aged or uneven-aged. A management system that does not set any requirements on the sequence of post-cutting diameter distributions is called any-aged management. Planting or sow-ing was used when stand basal area fell below the required minimum basal area and the amount of advance regeneration was less than required in the regulations. When the cuttings of 200 stands managed earlier with even-aged silviculture were optimized with the developed system, final felling followed by artificial regeneration was selected for almost 50%of stands. Reduction of the minimum basal area limit greatly decreased the use of artificial regeneration but improved profitability, suggesting that the truly optimal management would be to use natural regeneration in financially mature stands. The optimal type of thinning was high thinning in 97-99%of cases. It was calculated that the minimum basal area re-quirement reduced the mean net present value of the stands by 12-16%when discount rate was 3-5%.
基金fully funded by the Italian National Rural Network project,in the framework of the European Network for Rural Development(ENRD)by EU,in the framework of the Horizon 2020 B4EST project ‘‘Adaptive BREEDING for productive,sustainable and resilient FORESTs under climate change’’,UE Grant Agreement 773383(http://b4est.eu/)
文摘The stand density index,one of the most important metrics for managing site occupancy,is generally calculated from empirical data by means of a coefficient derived from the“self-thinning rule”or stand density model.I undertook an exploratory analysis of model fitting based on simulated data.I discuss the use of the logarithmic transformation(i.e.,linearisation)of the relationship between the total number of trees per hectare(N)and the quadratic mean diameter of the stand(QMD).I compare the classic method used by Reineke(J Agric Res 46:627–638,1933),i.e.,linear OLS model fitting after logarithmic transformation of data,with the“pure”powerlaw model,which represents the native mathematical structure of this relationship.I evaluated the results according to the correlation between N and QMD.Linear OLS and nonlinear fitting agreed in the estimation of coefficients only for highly correlated(between-1 and-0.85)or poorly correlated([-0.39)datasets.At average correlation values(i.e.,between-0.75 and-0.4),it is probable that for practical applications,the differences were relevant,especially concerning the key coefficient for Reineke’s stand density index calculation.This introduced a non-negligible bias in SDI calculation.The linearised log–log model always estimated a lower slope term than did the exponent of the nonlinear function except at the extremes of the correlation range.While the logarithmic transformation is mathematically correct and always equivalent to a nonlinear model in case of prediction of the dependent variable,the difference detected in my studies between the two methods(i.e.,coefficient estimation)was directly related to the correlation between N and QMD in each simulated/disturbed dataset.In general,given the power law as the“natural”structure of the N versus QMD relationship,the nonlinear model is preferred,with a logarithmic transformation used only in the case of violation of parametric assumptions(e.g.data distributed non-normally).
基金the Swiss National Science Foundationthe Velux Foundation+1 种基金the Karl Popper Foundationthe Vontobel Foundation for their financial support
文摘The walnut-fruit forests （Juglans regia L.） in southern Kyrgyzstan are considered to be biodiversity hotspots and of considerable economic and ecological importance to local populations. The fruiting ability and stability of these forests are, however, decreasing because of infrequent silvicultural interventions and non-existent natural regeneration. Continuous inventories and walnut harvest measurements were carded out on 18 trial and control plots over the course of i3 year. Results showed that i） thinning had a positive influence on diameter at breast height （dbh） increase, ii） dbh growth and crown area increases are strongly and positively correlated, iii） large crowns enhanced the production of fruits, and iv） temperature conditions had a major influence on the production of fruits. The above-mentioned points are particularly relevant for young plantations but are also valid for relatively old plantations （〉 50 years）. We conclude that regular thinning substantially improves diameter growth, fruit production and ability of trees to withstand wind and snow damage in both young stands and in older walnut-fruit forests.
文摘Unlike fire or insect outbreaks, for which a suppression program can be implemented, it is impossible to prevent a windstorm event or stop it while it is occurring. Reducing stand susceptibility to windstorms requires a good understanding of the factors affecting this susceptibility. Distinct species- and size-related differences in stem windthrow susceptibility are difficult to obtain because it is impossible to distinguish their relative effects from those of wind intensity. Using a damage assessment database (60 20-metre radius plots) acquired after an exceptional wind storm in Western Quebec in 2007, we developed an approach in which proportions of windthrown sugar maple poles were used as bio-indicators of wind intensities affecting the plots. We distinguished between single and interactive effects of wind intensity, species, stem size, and local basal area on stem windthrow susceptibility. The best logistic regression model predicting stem windthrow included the wind intensity bio-indicator, species, basal area, and the species by diameter at breast height (DBH, 1.3 m) interaction. Stem windthrow probability generally increased with DBH and decreased with basal area. Species wind-firmness was ordered as: yellow birch > sugar maple = eastern hemlock = American beech > ironwood > basswood = other hardwoods = other softwoods. Our method remained an indirect method of measuring wind intensity and its real test would require a comparison with anemometer measurements during a windstorm. Despite its indirect nature, the method is both simple and ecologically sound. Hence, it opens the door to conducting similar windthrow studies in other ecosystems.
文摘Black locust(Robinia pseudoacacia L.) was the first North-American tree species imported to Europe at the beginning of the seventeenth century. It is commonly planted worldwide because of its adaptability to environmental stresses, its valuable wood, easy propagation, frequent and abundant seed production, excellent coppicing,high seedling survival, and relatively high wood yield. In Europe, Romania and Hungary have the most highly-developed black locust growing techniques and experiences.As a result of increasing interest in black locust in many countries, this review aims to provide a comprehensive overview of state-of-the-art site requirements, propagation, improvement and management(including growth and yield as well as use in energy plantations).
基金funded by the Science&Technology Innovation Platform and Talents Plan of Hunan Province in China(Grants No.2017TP1022)the Natural Science Foundation of Hunan Province in China(Grant No.2020JJ4938)。
文摘The divergent gap characteristics and spatial patterns of canopy gaps created by natural or artificial disturbances can exert a dominant influence on forest structure and composition.However,little research has been conducted on the effects of ice storm damage on canopy gaps in subtropical mature forests of South China.In this study,one semi-natural site was dominated by a broad-leaf forest and two managed sites were representative of plantations with coniferous forests.Based on airborne laser scanning data and field evidence across sites,statistical analyses were used to examine gap characteristics following ice storms of moderate severity.Generalized Ripley’s K-function analysis was applied to test gap spatial patterns at a range of scales,and spatial point pattern analysis was used to quantitate the relative importance of specific influences on patterns of gap occurrence.The results revealed that the average gap size was 75.7 m^2 and that 12.2 gaps occurred per hectare.Most gaps were single-tree fall events.In addition to more gaps,the mean gap size was smaller and the shape was more complex in the semi-natural site than in two managed sites.Large differences in gap characteristics were observed among snapped,uprooted,snag,and artificial gap damage types.Gaps generally showed a clustered distribution at large scales(e.g.70 m),whereas spatial patterns varied with gap damage types at different sites.The occurrence of gaps was strongly related to slope and topographic position at the semi-natural site,whereas slope,stem density,and human accessibility(proximity to pathways)were the most important factors affecting gap occurrence at the managed sites.We suggest that gap-based silvicultural treatments and natural disturbances regimes conjoin,highlighting interactions with other factors such as microsite conditions,non-tree vegetation and more.
基金funded by USDA National Institute of Food and Agriculture Hatch Appropriations[#PEN04639,Accession#1015105,EZ]。
文摘Managing mature Douglas-fir[Pseudotsuga menziesii(Mirb.)Franco]stands to emulate the structural complexity of natural old-growth forest requires identifying structural targets at the sub-stand level at which neighborhood dynamics and patchy disturbance shape structure.We therefore sought to describe the archetypal shapes of predominant sub-stand diameter distribution types(DDTs)observed in natural tree neighborhoods in stands comprising a chronosequence(ca.120-450+yrs)encompassing mature,vertical diversification,and horizontal diversification development stages.The ten 1.0 ha stands are located in the southcentral Oregon Cascades,USA.Building on the known spatial position of each tree,natural tree neighborhoods were identified using the floating neighborhood approach based on spatial tessellation connecting neighboring trees at the first-(mean 61 m2)through fifth-(mean 2058 m2)order scales.Cluster analysis was then used to objectively identify the most predominant DDTs among the relative tree size distributions observed in the trans-scale neighborhoods within each stand.Repeated measures regression was used to classify each DDT to one of six observed archetypal shapes:negative exponential,unimodal,rotated sigmoid,bimodal,concave,or multi-modal.Only three of the 81 observed DDTs deviated by<10%from the stand average,while every stand had at least one DDT that deviated by>50%(maximum 83%).Within each stand,five to ten predominant DDTs were observed,which deviated from the stand average by 30-48%and were characterized by two to five different archetypal shapes.Consequently,in some stands the majority of tree neighborhoods were best characterized by a different shape from that assigned at the stand level.Deviation from the stand average increased from the youngest stand in the mature development stage through the middle stands in the vertical diversification stage to the oldest stands in the horizontal diversification stage.The complexity of DDT shapes tended to increase along the chronosequence(from negative exponential and uniform toward concave and multi-modal),with shape richness highest mid-sequence and evenness peaking in the oldest stands.The high diversity of sub-stand structural complexity reduces the utility of standlevel diameter distributions as old-growth restoration targets.However,the presence in early-sequence stands of sub-stand diameter distributions common to later-sequence stands may facilitate active management at the neighborhood level to promote future old-growth condition.Restoration of substand diameter structures would likely require combining spatial perspectives,such as by augmenting tree-level croptree management with diameter distribution targets for the resulting tree neighborhoods.
基金This study was supported by National Natural Science Foundation of China (30471355) and the Key Technologies R&D Program of Heilongjiang Province (G99B5-3)
文摘A study was conducted to determine the influences of initial planting densities, thinning intensities, exposures and slope sites on physical property （wood density） and mechanical properties such as modulus of elasticity （MOE）, bending strength, impact strength, compression strength along grain and hardness） of Pinus sylvestris var. mongolica plantation in Mao＇ershan Forest Farm, Northeast China. Results show that the different initial planting densities （1.5 m×1.0 m, 1.5 m×2.0 m and 1.5 m×2.5 m） had significant effects on wood density and MOE, and the highest mean wood density and indexes of mechanical properties occurred in the stand with an initial planting density of 1.5 m×1.0 m. The indexes of mechanical properties such as hardness of end, bending strength, MOE and compression strength along grain of wood increased after mild thinning, but decreased after violent thinning. The exposures （sunny slope and shady slope） had a significant effect on MOE, and the highest mean MOE occurred on sunny slope. The slope sites （upper site and lower site） had a significant effect on wood density and main mechanical properties, except hardness. The highest mean wood density and mechanical properties occurred at lower site.
文摘Management of the Pointe-Noire Forest requires high-performance tools for simulating tree and stand growth and assessing the sustainability of plantations. Modelling the dynamics of even-aged and mono-species stands is a very active research topic. The approaches adopted by researchers vary according to the objectives and species considered: dendrometrical, Eco physiological or architectural. Thanks to the particular nature of these plantations and the trial set-up, it will be possible to explore the various aspects of production, clearly separating the part linked to genetics (three clones tested) from the part linked to the environment (via fertilisation) and the part associated with competition between trees (via planting densities and thinning regimes). This study will make a major contribution to the applicability of the self-thinning line and the RDI (Reineke Density Index) (Reineke, 1933) to fast-growing plantations. This research work will contribute to two points: 1) product diversification, which is a way of coping with international variations in timber markets, and 2) understanding how ecosystems function in exceptionally poor conditions, which will then enable the environmental impacts of the various recommended silvicultural itineraries to be assessed. The results obtained show that competition between trees in a stand of eucalyptus at very high density (10,000 stems/ha) and in two environments of very contrasting fertility is different depending on the clone. The decision on the date of the first thinning with a view to silviculture for timber and energy wood, which aims to ensure sustained and sustainable production of eucalyptus wood in these soils, should be taken between 12 and 14 months. The competition band is strong between 14 and 17 months, when the RDI = 0.8 is double that observed at 12 months.
文摘After the new taxation system was practiced, the burden of forestry taxation was increased generally. How to extricate oneself from a predicament, it needs to draft tax reduction by the government. The revenue of both forestry products and multiple management should be exempted from taxation, the timber products logs of forest industry shouldn’t be imposed added-value tax, 8 percent tax on special products of agriculture and forestry levied by enterprise acting for tax bureau should be is delayed to pratice, the fund of for silviculture shouldn’t be imposed duties as taxable service.
基金funded within the Project LIFE09 ENV/IT000078 ‘‘Managing Forests for multiple purpose:Carbon,Biodiversity and socio-economic wellbeing’’(ManForCBD)
文摘The present study introduces an exploratory data analysis based on structural indicators with the aim to assess the effect of silvicultural practices on tree stand structure. The study was carried out in three Italian beech forests of different ages with stand structures that originated from dissimilar regeneration and cultivation techniques(Cansiglio, northern Italy, Chiarano, central Italy,and Mongiana, southern Italy). Ten structural indicators were considered when investigating the latent multivariate relationship between stand structure attributes before and after thinning operations by using a multiway factor analysis(MFA). The MFA results identified the older stand at Cansiglio as more homogeneous for cultivation regimes,and more stable to practices when compared with the younger sites(Chiarano and Mongiana). Heterogeneous stands were sensitive to silvicultural practice thus suggesting their possible impact on forest attributes. The proposed approach proved to be an operational tool to evaluate comprehensively the response of forest structure to planned interventions.
文摘The main objective of this study was to examine how different stand types influenced the tendency of visitors for varying recreational activities(i.e.,hiking,trekking,camping and hunting)from 1993 to 2018 in the surrounding areas of Uluyayla Natural Recreation Site in Bart1n,northern Turkey.A total of 627 visitors were selected on a voluntary basis,and questioned in the form of questionnaire.Most of the participants were in the age of 21-40 years old,and they were mostly(62.4%)male.Most of the participants(82.7%)lived in cities,while 62.8%of them were tourists when visiting the site.In determining the preferences of the visitors regarding the stand types for different recreational activities,several images of each stand were shared with them,and they were asked which stand type they would prefer for a given recreation activity(i.e.,hiking,tracking,camping and hunting).A range of options from 1 to 5 in Likert's scale was used in evaluating the given responses.The degree of positive and negative effects was examined via trend analysis.It was found that stand type had influence on the preferences of visitors regarding the recreational activities.In general,unmanaged and moderately treated stands were more preferred by visitors for the recreational purposes,compared to the previously managed stands.On the other hand,visitors'preference for the activities were different during two periods(i.e.,1993-2005 and 2006-2018).For each recreational activity,there was an increasing trend from 1993 to 2018.There had been a continuous increase for hunting since 1996,and for trekking and camping after 1999.The increases between 1993-1996 and 1996-1999 were likely due to the increasing awareness of the society as a result of the training and consciousness raising activities for nature conservation.The demand on the recreational activities continuously increased in unmanaged and moderately treated stands,while no significant changes were examined in the previously managed stands.The study points out that forest planning and management should consider different needs of visitors for recreational infrastructure.
基金funded by the German Ministry of Education and Research(BMBF)the Brazilian Conselho National de Desenvolvimento Científico e Tecnológico(CNPq)
文摘The Brazil nut tree（Bertholletia excelsa） is a frequent component of agroforestry systems in the Amazon because of its adaptation to nutrient-poor upland soils and multiple uses.We investigated the aboveground biomass production（kg dry weight）,nutrient uptake and requirements（N,P,Ca,Mg,K） of Brazil nut trees of different sizes grown under agroforestry conditions and fertilized at different levels.Eight of 70 experimental trees with different size were harvested and stem,branches and leaves were separated.Nutrient contents were determined for three trees of varying size.Average tree growth was fast,but variability was high,suggesting considerable potential for the improvement of this economically important species.The trees responded to increased levels of fertilizer and lime with significantly increased foliar nutrient contents and growth,probably because of the improved availability of Mg and Ca for which the species seems to have a relatively high demand.In contrast to Brazil nut trees grown in forest or dense plantations,the agroforestry trees invested a substantial part of their biomass and nutrients in large branches and developed spreading crowns.To improve stem form,reduce competition with associated crops for light and recycle nutrients,regular pruning of lower branches or planting arrangements that favor self-pruning are recommended.These measures would also increase the recycling of Ca and Mg,large quantities of which are contained in the branches.
