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
We review the management of Eucalyptus species under a coppice-with-standards （CWS） silvicultural system. CWS management results in product diversification, permitting production of small and large scale timber from...We review the management of Eucalyptus species under a coppice-with-standards （CWS） silvicultural system. CWS management results in product diversification, permitting production of small and large scale timber from the same stand. Eucalyptus species are suitable candidates for CWS management because： there are large worldwide plantation areas, sprouting capacity is high, and eucalypts are multipur- pose species. We discuss （1） short rotation Eucalyptus coppice manage- ment for energy and pulping and （2） Eucalyptus seedling management for solid wood products. We review the literature and discuss experi- ences with Eucalyptus managed under the CWS system. We also assess projects dealing with Eucalyptus coppice management, stand density regulation, pruning, and stand and wood quality. The growth environ- ment of the standard trees （heavy competition up to the first harvest, free growth afterwards） coupled with long rotations （〉20 years） results in high quality logs for solid wood products. Early pruning should be ap- plied to enhance wood quality. We propose a system for the silvicultural management of Eucalyptus under the CWS system, elaborating on the consequences of initial planting density, site productivity, and standard tree densities as well as timing of basic silvicultural applications.展开更多
This paper sets out to determine the link between socio-economic attributes of smallholders, silvicultural activity and the stand quality of Acacia mangium and Eucalyptus urophylla plantations in two unrelated commune...This paper sets out to determine the link between socio-economic attributes of smallholders, silvicultural activity and the stand quality of Acacia mangium and Eucalyptus urophylla plantations in two unrelated communes in Phu Tho province, Vietnam. The necessary data was collected by interviewing the smallholders and conducting inventory of the stands. The data was analyzed with descriptive statistics, Mann-Whitney tests and Spearman correlations. More silvicultural practices were conducted by A. mangium planters with larger areas. Most of the smallholders practiced the suggested silvicultural activities. Productivity was affected by pruning in medium quality sites. This research recommends that smallholders were supported with incentives for the plantation establishment, education for smallholders in silvicultural techniques, organization and development activities for the wider market.展开更多
Lichen woodlands (LW) located in the closed-crown boreal forest are not a successional stage moving towards a closed black spruce feathermoss stand (FM), but an alternative stable state, due to their previous forest h...Lichen woodlands (LW) located in the closed-crown boreal forest are not a successional stage moving towards a closed black spruce feathermoss stand (FM), but an alternative stable state, due to their previous forest history, and the occurrence of LWs located nearby closed-crown FM stands. Therefore, afforestation in those LWs through site preparation and plantation could shift back LW into FM stands. We implemented an experimental design with different combinations of silvicultural treatments in both site types (LW, FM). We monitored the evolution of plant diversity and the physiology of three bio-indicators (Picea mariana, Kalmia angustifolia, Rhododendron groenlandicum) in different microsites created by the silvicultural treatments. The return to the initial composition was noticed only two years after treatments, especially in the LW stands, thus indicating a higher level of early ecosystem resilience in LWs compared to FM stands. Mean species cover, especially in the FM stands, decreased the most in the skid trails created by logging, probably due to a lack of acclimation of bryophytes to open stand conditions. Conversely, ericaceous shrubs and lichens found in the LWs were already acclimated to open stand conditions, which give to LWs a restructuring advantage compared to FM plant communities after silvicultural treatments. Overall, FM and LW short-term resilience was similar, indicating equally efficient ecosystem reorganization in both stands. The comparable early resilience in managed LW and FM stands, in terms of plant biodiversity, contradicts the presumed fragility of LW stands, especially in this case where LWs are assumed to be an alternative stable state created by compound disturbances. Silvicultural treatments maintained the functional group diversity in LWs, a key element for ecosystem resilience. Therefore, this study support the idea that plantation following site preparation in LWs could be a valuable management strategy to reach several objectives, such as increasing forest carbon sinks.展开更多
In this research, some of site and silvicultural characteristics of Yew stand in northern forests of Iran was studied. For this purpose, compartment number 16 of district 4 Shir-ghalaye was selected. According to rese...In this research, some of site and silvicultural characteristics of Yew stand in northern forests of Iran was studied. For this purpose, compartment number 16 of district 4 Shir-ghalaye was selected. According to research purposes, stands with an area of 20 ha were chosen in center of the compartment and was separated from map. Due to restricted area of region and according to few number of Yew trees in the stand, the full-callipering method was conducted for measuring quantitative and qualitative characteristics. In the stand diameter at breast height （D.B.H.）, height and canopy diameter of all Yew trees were measured. The results showed that the diameter distribution curve and height distribution curve of Yew trees were similar to even-age forests curve. But according to average annual increment, mixture type of Yew trees in stand, diameter distribution of other species and low rate regeneration of Yew, it can be concluded that the studied Yew stand, is an uneven-age stand and because of low rate regeneration in previous years the number of young Yew trees were reduced and even-age forest curve was formed subsequently. The maximum height and diameter of Yew trees were recorded 26.8 m and 112 cm, respectively. Also, the number of trees per hectare and basal area per hectare of Yew trees were calculated 14.55 and 3.23 m2 respectively.展开更多
We simulated a shelterwood forest regeneration treatment by reducing basal area,and monitored the response of an avian community in oak–hickory forest on the southern Cumberland Plateau,northern Alabama,USA.We used f...We simulated a shelterwood forest regeneration treatment by reducing basal area,and monitored the response of an avian community in oak–hickory forest on the southern Cumberland Plateau,northern Alabama,USA.We used five treatments:control(no removal),clear-cut(100%removal),and 25,50,and 75%removal of basal area.Territory mapping was used to quantify bird community between mid-April and July of both 2002 and 2003.Microclimate variables were recorded at each plot.The residual basal area and canopy cover showed three distinct conditions after treatment:closed canopy,open forest,and clear-cut.The microclimate varied among treatments:air temperature was highest in clear-cut plots and lowest in control plots,whereas soil moisture had the opposite pattern.A total of 71 bird species were detected,with 36 of them defending territories.Territory density,species richness,and Shannon diversity index differed among the treatments;the relationship between these bird community indices and the level of basal area removal was quadratic,lowest in the clear-cut plots and highest in the intermediate levels.Although species richness was similar among the control,25,50,and 75%removal treatments,species composition varied.The richness difference among treatments became smaller in the second year post-treatment(2003)with an increase in bird density and richness occurring in the clear-cut plots.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
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
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
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
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
A better understanding and a more quantitative design of mixed-species stands will contribute to more integrative and goal-oriented research in mixed-species forests. Much recent work has indicated that the structure ...A better understanding and a more quantitative design of mixed-species stands will contribute to more integrative and goal-oriented research in mixed-species forests. Much recent work has indicated that the structure and growth of mixed species forests may fundamentally differ from monocultures. Here we suggest how to progress from the present accumulation of phenomenological findings to a design of mixed-species stands and advanced silvicultural prescriptions by means of modelling. First, the knowledge of mixing effects on the structure and growth at the stand, species, and individual tree level is reviewed, with a focus on those findings that are most essential for suitable modelling and silvicultural designs and the regulation of mixed stands as opposed to monocultures. Then, the key role of growth models, stand simulators, and scenario assessments for designing mixed species stands is discussed The next section illustrates that existing forest stand growth models require some fundamental modifications to become suitable for both monocultures and mixed-species stands. We then explore how silvicultural prescriptions derived from scenario runs would need to be both quantified and simplified for transfer to forest management and demonstrated in training plots. Finally, we address the main remaining knowledge gaps that could be remedied through empirical research.展开更多
It is widely accepted that global warming, which results from the increase of carbon dioxide(CO2) in the atmosphere, has a negative impact on human beings. Forests are the largest terrestrial ecosystem and play an imp...It is widely accepted that global warming, which results from the increase of carbon dioxide(CO2) in the atmosphere, has a negative impact on human beings. Forests are the largest terrestrial ecosystem and play an important role in carbon sequestration. Many studies have documented that a mixed-species forest can sequester more carbon than single species forests, depending on the site conditions. Therefore, uneven-aged mixed-species forest management has been receiving more and more attention. In 2008, an experiment with five silvicultural models for Pinus massoniana(Chinese red pine) plantation, i.e., four transformation treatments(A1-A4) and one control treatment(A5) was conducted in the Experimental Center of Tropical Forestry of Chinese Academy of Forestry in Pingxiang City, in southwestern Guangxi Zhuang Autonomous Region, southern China. The four transformation treatments(A1-A4) enriched Castanopsis hystrix, Manglietia glance, Erythrophleum fordii and Quercus griffithii with differed richness and composition after thinning(removed 70% of trees), while no silvicultural treatment was used in the control treatment A5. In this study, we compared the carbon sequestration capacity of these five silvicultural models based on periodic annual increment and growth rate. Our results indicated that all the transformation treatments performed significantly better in carbon sequestration than the control treatment. A significant difference was also observed amongst the transformation treatments. Moreover, the transformation treatment A1 with enrichment species Castanopsis hystrix(350 trees·ha^-1) and Manglietia glance(350 trees·ha^-1) was determined to be the optimal model for maximum carbon sequestration because of its high tree-level growth rate and high economic value of enriched plantings, which could be popularized in other places. Our results further confirmed that management using mixed-species forests is a better approach to combat climate change than using monoculture forests.展开更多
Any-aged forest management (AAF) is a means to reduce clear-felling without compromising profitability or timber production. The concept of AAF is to choose between clear-felling or thinning one harvest at a time base...Any-aged forest management (AAF) is a means to reduce clear-felling without compromising profitability or timber production. The concept of AAF is to choose between clear-felling or thinning one harvest at a time based on what is better at that time in terms of the management objectives for the forest. No permanent choice is made between rotation forest management (RFM) and continuous cover forestry (CCF). Optimized AAF is never less profitable than RFM or CCF because all cutting types of both RMF and CCF are also allowed in AAF. This study developed a new set of guidelines for managing boreal forest stands under AAF when the forest landowner maximizes economic profitability. The first part of the guidelines indicates whether the stand should be cut or left to grow. This advice is based on stand basal area, mean tree diameter, minimum allowable post-thinning basal area, site productivity, and discount rate. If the optimal decision is harvesting, the second instruction determines whether the harvest should be clear-felling or thinning. In the case of thinning, the remaining two steps determine the optimal harvest rate in different diameter classes. The guidelines were developed using two different modeling approaches, regression analysis, and optimization, and applied to two Finnish forest holdings, one representing the southern boreal zone and the other the northern parts of the boreal zone. The results show that AAF improves profitability compared to current Finnish management instructions for RFM. The use of clear-felling also decreased the lower the minimum acceptable post-thinning basal area of the stand.展开更多
Background:Forestry management modifies the diversity,structure,and functioning of intervened forests.Timber extraction reduces tree density and basal area,leading to changes in the communities of vascular epiphytes.T...Background:Forestry management modifies the diversity,structure,and functioning of intervened forests.Timber extraction reduces tree density and basal area,leading to changes in the communities of vascular epiphytes.The objective of this study was to evaluate the diversity and biomass of vascular epiphytes in Quercus trees remaining in two pine-oak forest stands that have been subjected to two stages of the Silvicultural Development Method(release cutting,and thinning)in comparison with an unharvested old-secondary forest in southern Mexico.For each treatment,richness of epiphytes present on 60 oak trees was recorded and their dry biomass estimated.We calculated the true diversity(Hill numbers)and beta diversity using the Jaccard coefficient of similarity,and generated rank abundance curves per taxonomic epiphyte group(bromeliads,orchids,ferns and others).For each treatment,the relationships between overall diversity and epiphyte biomass to the host trees basal area were analyzed using log linear models.Results:We recorded a total of 67 species of epiphytes species belonging to 10 families hosted by five species of oaks.The greatest species richness(^(0)D)was recorded in the old-secondary forest.Fewer common(^(1)D)and dominant(^(2)D)species were recorded in the release cutting than in the other treatments.Epiphyte diversity and biomass were both slightly related to host tree basal area.Composition of epiphytes was similar(60%)among treatments,although orchids,bromeliads,and other families were more diverse in the old-secondary forest.Most bromeliad species were shared across all treatments,although orchids presented the most exclusive species in the unharvested forest.The bromeliad Tillandsia seleriana provided the greatest contribution to biomass in all treatments,followed by the orchid Camaridium densum.Generalized linear models indicated that epiphyte diversity was significantly related to treatment,and epiphyte biomass to basal area of host trees.Conclusions:Although forest management affects diversity,composition,and abundance of vascular epiphytes,most of their diversity and biomass can be maintained despite timber harvesting.This requires sparing some mature oaks during logging,as they contribute to conservation,establishment,and development of epiphytic communities,and maintaining untreated areas as a source of propagules for these communities.展开更多
Forest management may have significant effects on forest connectivity and natural population sizes.Harvesting old-growth single trees may also change natural patterns of genetic variation and spatial genetic structure...Forest management may have significant effects on forest connectivity and natural population sizes.Harvesting old-growth single trees may also change natural patterns of genetic variation and spatial genetic structure.This study evaluated the impacts of forest management using a silvicultural system of seed trees on the genetic diversity and spatial genetic structure of Eremanthus erythropappus(DC.)MacLeish.A complete survey of 275 trees on four plots was undertaken out to compare the genetic variation of a managed stand with an unmanaged stand.We genotyped all adult and juvenile individuals 60 months after the management and compared the genetic diversity and the spatial genetic structure parameters.Genetic diversity was considered high because of an efficient gene flow between stands.There were no genetic differences between stands and no evidence of inbreeding.Genetic clustering identified a single population(K=1),indicating no genetic differentiation between managed and unmanaged stands.Adult and juvenile individuals of the unmanaged stand were more geographically structured than individuals from the managed one.There was a tendency of coancestry among juveniles at the first class of distance of the managed stand,suggesting a drift of genetic structure possibly caused by management.Understanding early responses to management on genetic diversity and stand structure is a first step to ensuring the effectiveness of conservation practices of tree species.The sustainability of forest management of E.erythropappus on genetic diversity,and more accurately,on spatial genetic structure needs evaluation over time to promote effective conservation of the population size and genetic variability.展开更多
Silvicultural practices applied in managed forest plantations may help counteract the effects of climate change by influencing soil surface CO_(2)efflux(Fs).Understanding the effects of silvicultural practices on Fs w...Silvicultural practices applied in managed forest plantations may help counteract the effects of climate change by influencing soil surface CO_(2)efflux(Fs).Understanding the effects of silvicultural practices on Fs will provide unbiased estimates of carbon fluxes and allow better silvicultural decisions for carbon sequestration.Therefore,we assessed how Fs differed seasonally across silvicultural practices(i.e.,stocking levels,clone,fertilization and weed control treatments)and evaluated the effects of soil temperature(Ts)and soil volumetric water content(θv)on Fs across these practices for a mid-rotation(14 year-old)Pinus radiata plantation in the Canterbury region of New Zealand.There were significant differences in Fs(p<0.05)over the four seasons,three levels of stocking,and five clones.The effects of fertilization and weed control applied 12 years previously on Fs were insignificant.Annual estimate of Fs(mean±1 standard deviation)from the study site was 22.7±7.1 t ha^(-1)a^(-1)in the form of CO_(2)(6.2±2.1 t ha^(-1)a^(-1)in the form of C).Fs values were consistently higher in plots with 1250 stems ha^(-1)compared to 2500 stems ha^(-1),which may be related to a strong soil resource limitation because of the close spacing in the latter plantation.Significant differences in Fs across clones suggest that variations in carbon partitioning might explain their growth performance.Silvicultural treatments influenced Fs response to soil temperature(p<0.05),resulting in models explaining 28-49%of the total variance in Fs.These findings provide insights into how silvicultural management decisions may impact Fs in mid-rotation radiata pine plantations,contributing towards developing more precise and unbiased plantation carbon budgets.展开更多
Background:Soil erosion is still identified as the main cause of land degradation worldwide,threatening soil functions and driving several research and policy efforts to reverse it.Trees are commonly associated to som...Background:Soil erosion is still identified as the main cause of land degradation worldwide,threatening soil functions and driving several research and policy efforts to reverse it.Trees are commonly associated to some of the most successful land-use systems to achieve soil protection goals,but the extent to which forest ecosystems reduce erosion risks can largely depend on management decisions and associated silvicultural practices.Optimization tools can assist foresters in solving the complex planning problem they face,concerning the demand for different,and often conflicting,ecosystem services.A resource capability model(RCM),based on a linear programming approach,was built and solved for a forest landscape management problem in Northwest Portugal,over a 90-years planning horizon,divided in 10-years periods.Results:Timber provision and soil erosion were found to be in trade-off.The management alternatives included in the model were proven to be sufficiently flexible to obtain the desired level of timber yield,both in volume and even distribution along the planning horizon,while ensuring lower levels of soil loss estimates(below 35 Mg·ha^(−1)·year^(−1)).However,under climate change conditions,compatible with an increasing greenhouse gases emission scenario,potential landscape soil erosion may be enhanced up to 46 Mg·ha^(−1)·year^(−1) in critical periods.Conclusions:Soil conservation concerns in landscape-level forest management planning can be addressed by LPbased optimization methods.Besides providing an optimal management solution at landscape level,this approach enables a comprehensive analysis of the RCM,possible trade-offs and potential changes towards uncertainties.展开更多
Background： Australia＇s energy future is at the crossroads and the role of renewable sources is in focus. Biomass from sustainably managed forests provide a significant opportunity for electricity and heat generatio...Background： Australia＇s energy future is at the crossroads and the role of renewable sources is in focus. Biomass from sustainably managed forests provide a significant opportunity for electricity and heat generation and production of liquid fuels. Australia has extensive native forests of which a significant proportion are on private land. However, there is limited knowledge on the potential capacity of this resource to contribute to the expansion of a biomass for bioenergy industry. In addition, there are concerns on how to reconcile biomass harvesting with environmental protection. Methods： We used regional ecosystem vegetation mapping for Queensland to stratify harvestable forests within the 1.8 m hectares of private native forests present in the Southeast Queensland bioregion in 2014. We used a dataset of 52,620 individual tree measurements from 541 forest inventory plots collected over the last 10 years. Tree biomass was estimated using current biomass allometric equations for Australia. Biomass potentially available from selective sawlog harvesting and silvicultural treatment across the bioregion was calculated and mapped. Results： Current sawlog harvesting extracts 41.4% of the standing tree biomass and a biomass for bioenergy harvest would retain on average 36% of felled tree biomass on site for the protection of environmental and fauna habitat values. The estimated area extent of harvestable private native forests in the bioregion in 2013 was 888,000 ha and estimated available biomass for bioenergy in living trees was 13.6 million tonnes （t）. The spotted gum （Corymbio citriodora subsp, variegata） forests were the most extensive, covering an area of 379,823 ha and with a biomass for bioenergy yield of 14.2 t-ha-1 （with approximately 11.2 t.ha-1 of the biomass harvested from silvicultural thinning and 3 t.ha-1 recovered from sawlog harvest residual）. Conclusions： Silvicultural treatment of private native forests in the Southeast Queensland bioregion, has the capacity to supply a large quantity of biomass for bioenergy. The availability of a biomass for bioenergy market, and integration of sawlog harvesting and silvicultural treatment operations, could provide land owners with additional commercial incentive to improve the management of private native forests. This could potentially promote restoration of degraded forests, ecological sustainability and continued provision of wood products.展开更多
Background: Forest management faces a climate induced shift in growth potential and increasing current and emerging new risks. Vulnerability analysis provides decision support based on projections of natural resources...Background: Forest management faces a climate induced shift in growth potential and increasing current and emerging new risks. Vulnerability analysis provides decision support based on projections of natural resources taking risks and uncertainties into account. In this paper we(1) characterize differences in forest dynamics under three management scenarios,(2) analyse the effects of the three scenarios on two risk factors, windthrow and drought stress, and(3) quantify the effects and the amount of uncertainty arising from climate projections on height increment and drought stress.Methods: In four regions in northern Germany, we apply three contrasting management scenarios and project forest development under climate change until 2070. Three climate runs(minimum, median, maximum) based on the emission scenario RCP 8.5 control the site-sensitive forest growth functions. The minimum and maximum climate run define the range of prospective climate development.Results: The projections of different management regimes until 2070 show the diverging medium-term effects of thinnings and harvests and long-term effects of species conversion on a regional scale. Examples of windthrow vulnerability and drought stress reveal how adaptation measures depend on the applied management path and the decision-maker’s risk attitude. Uncertainty analysis shows the increasing variability of drought risk projections with time. The effect of climate projections on height growth are quantified and uncertainty analysis reveals that height growth of young trees is dominated by the age-trend whereas the climate signal in height increment of older trees is decisive.Conclusions: Drought risk is a serious issue in the eastern regions independent of the applied silvicultural scenario,but adaptation measures are limited as the proportion of the most drought tolerant species Scots pine is already high. Windthrow risk is no serious overall threat in any region, but adequate counter-measures such as species conversion, species mixture or reduction of target diameter can be taken. This simulation study of three silvicultural scenarios and three climate runs spans a decision space of potential forest development to be used for decision making. Which adaptation measures to counteract climate induced risks and uncertainty are to be taken is,however, a matter of individual risk attitude.展开更多
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.
基金suported by the Coordenacao de Aperfeicoamento de Pessoal de Nível Superior(CAPES),through the PSDE program,process number BEX:2939/12-6.
文摘We review the management of Eucalyptus species under a coppice-with-standards （CWS） silvicultural system. CWS management results in product diversification, permitting production of small and large scale timber from the same stand. Eucalyptus species are suitable candidates for CWS management because： there are large worldwide plantation areas, sprouting capacity is high, and eucalypts are multipur- pose species. We discuss （1） short rotation Eucalyptus coppice manage- ment for energy and pulping and （2） Eucalyptus seedling management for solid wood products. We review the literature and discuss experi- ences with Eucalyptus managed under the CWS system. We also assess projects dealing with Eucalyptus coppice management, stand density regulation, pruning, and stand and wood quality. The growth environ- ment of the standard trees （heavy competition up to the first harvest, free growth afterwards） coupled with long rotations （〉20 years） results in high quality logs for solid wood products. Early pruning should be ap- plied to enhance wood quality. We propose a system for the silvicultural management of Eucalyptus under the CWS system, elaborating on the consequences of initial planting density, site productivity, and standard tree densities as well as timing of basic silvicultural applications.
文摘This paper sets out to determine the link between socio-economic attributes of smallholders, silvicultural activity and the stand quality of Acacia mangium and Eucalyptus urophylla plantations in two unrelated communes in Phu Tho province, Vietnam. The necessary data was collected by interviewing the smallholders and conducting inventory of the stands. The data was analyzed with descriptive statistics, Mann-Whitney tests and Spearman correlations. More silvicultural practices were conducted by A. mangium planters with larger areas. Most of the smallholders practiced the suggested silvicultural activities. Productivity was affected by pruning in medium quality sites. This research recommends that smallholders were supported with incentives for the plantation establishment, education for smallholders in silvicultural techniques, organization and development activities for the wider market.
基金funded by a Fonds de Recherche pour la Nature et des Technologies du Gouvernement du Québec(FQRNT)grant to D.Lord,and the Carbone boréal project.
文摘Lichen woodlands (LW) located in the closed-crown boreal forest are not a successional stage moving towards a closed black spruce feathermoss stand (FM), but an alternative stable state, due to their previous forest history, and the occurrence of LWs located nearby closed-crown FM stands. Therefore, afforestation in those LWs through site preparation and plantation could shift back LW into FM stands. We implemented an experimental design with different combinations of silvicultural treatments in both site types (LW, FM). We monitored the evolution of plant diversity and the physiology of three bio-indicators (Picea mariana, Kalmia angustifolia, Rhododendron groenlandicum) in different microsites created by the silvicultural treatments. The return to the initial composition was noticed only two years after treatments, especially in the LW stands, thus indicating a higher level of early ecosystem resilience in LWs compared to FM stands. Mean species cover, especially in the FM stands, decreased the most in the skid trails created by logging, probably due to a lack of acclimation of bryophytes to open stand conditions. Conversely, ericaceous shrubs and lichens found in the LWs were already acclimated to open stand conditions, which give to LWs a restructuring advantage compared to FM plant communities after silvicultural treatments. Overall, FM and LW short-term resilience was similar, indicating equally efficient ecosystem reorganization in both stands. The comparable early resilience in managed LW and FM stands, in terms of plant biodiversity, contradicts the presumed fragility of LW stands, especially in this case where LWs are assumed to be an alternative stable state created by compound disturbances. Silvicultural treatments maintained the functional group diversity in LWs, a key element for ecosystem resilience. Therefore, this study support the idea that plantation following site preparation in LWs could be a valuable management strategy to reach several objectives, such as increasing forest carbon sinks.
文摘In this research, some of site and silvicultural characteristics of Yew stand in northern forests of Iran was studied. For this purpose, compartment number 16 of district 4 Shir-ghalaye was selected. According to research purposes, stands with an area of 20 ha were chosen in center of the compartment and was separated from map. Due to restricted area of region and according to few number of Yew trees in the stand, the full-callipering method was conducted for measuring quantitative and qualitative characteristics. In the stand diameter at breast height （D.B.H.）, height and canopy diameter of all Yew trees were measured. The results showed that the diameter distribution curve and height distribution curve of Yew trees were similar to even-age forests curve. But according to average annual increment, mixture type of Yew trees in stand, diameter distribution of other species and low rate regeneration of Yew, it can be concluded that the studied Yew stand, is an uneven-age stand and because of low rate regeneration in previous years the number of young Yew trees were reduced and even-age forest curve was formed subsequently. The maximum height and diameter of Yew trees were recorded 26.8 m and 112 cm, respectively. Also, the number of trees per hectare and basal area per hectare of Yew trees were calculated 14.55 and 3.23 m2 respectively.
文摘We simulated a shelterwood forest regeneration treatment by reducing basal area,and monitored the response of an avian community in oak–hickory forest on the southern Cumberland Plateau,northern Alabama,USA.We used five treatments:control(no removal),clear-cut(100%removal),and 25,50,and 75%removal of basal area.Territory mapping was used to quantify bird community between mid-April and July of both 2002 and 2003.Microclimate variables were recorded at each plot.The residual basal area and canopy cover showed three distinct conditions after treatment:closed canopy,open forest,and clear-cut.The microclimate varied among treatments:air temperature was highest in clear-cut plots and lowest in control plots,whereas soil moisture had the opposite pattern.A total of 71 bird species were detected,with 36 of them defending territories.Territory density,species richness,and Shannon diversity index differed among the treatments;the relationship between these bird community indices and the level of basal area removal was quadratic,lowest in the clear-cut plots and highest in the intermediate levels.Although species richness was similar among the control,25,50,and 75%removal treatments,species composition varied.The richness difference among treatments became smaller in the second year post-treatment(2003)with an increase in bird density and richness occurring in the clear-cut plots.
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.
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 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.
基金the European Union for funding of the project "Management of mixed-species stands.Options for a low-risk forest management (REFORM)"(# 2816ERA02S)the Bavarian State Ministry for Nutrition,Agriculture,and Forestry for permanent support of the project W 07" Long-term experimental plots for forest growth and yield research "(# 7831-22209-2013)+1 种基金the German Science Foundation for providing the funds for the projects PR 292/12-1" Tree and stand-level growth reactions on drought in mixed versus pure forests of Norway spruce and European beech"the National Institute of Food and Agriculture/Pennsylvania Agriculture Experiment Station project PEN 04516 for its support
文摘A better understanding and a more quantitative design of mixed-species stands will contribute to more integrative and goal-oriented research in mixed-species forests. Much recent work has indicated that the structure and growth of mixed species forests may fundamentally differ from monocultures. Here we suggest how to progress from the present accumulation of phenomenological findings to a design of mixed-species stands and advanced silvicultural prescriptions by means of modelling. First, the knowledge of mixing effects on the structure and growth at the stand, species, and individual tree level is reviewed, with a focus on those findings that are most essential for suitable modelling and silvicultural designs and the regulation of mixed stands as opposed to monocultures. Then, the key role of growth models, stand simulators, and scenario assessments for designing mixed species stands is discussed The next section illustrates that existing forest stand growth models require some fundamental modifications to become suitable for both monocultures and mixed-species stands. We then explore how silvicultural prescriptions derived from scenario runs would need to be both quantified and simplified for transfer to forest management and demonstrated in training plots. Finally, we address the main remaining knowledge gaps that could be remedied through empirical research.
基金the National Key R&D Program of China(2016YFD060020501).
文摘It is widely accepted that global warming, which results from the increase of carbon dioxide(CO2) in the atmosphere, has a negative impact on human beings. Forests are the largest terrestrial ecosystem and play an important role in carbon sequestration. Many studies have documented that a mixed-species forest can sequester more carbon than single species forests, depending on the site conditions. Therefore, uneven-aged mixed-species forest management has been receiving more and more attention. In 2008, an experiment with five silvicultural models for Pinus massoniana(Chinese red pine) plantation, i.e., four transformation treatments(A1-A4) and one control treatment(A5) was conducted in the Experimental Center of Tropical Forestry of Chinese Academy of Forestry in Pingxiang City, in southwestern Guangxi Zhuang Autonomous Region, southern China. The four transformation treatments(A1-A4) enriched Castanopsis hystrix, Manglietia glance, Erythrophleum fordii and Quercus griffithii with differed richness and composition after thinning(removed 70% of trees), while no silvicultural treatment was used in the control treatment A5. In this study, we compared the carbon sequestration capacity of these five silvicultural models based on periodic annual increment and growth rate. Our results indicated that all the transformation treatments performed significantly better in carbon sequestration than the control treatment. A significant difference was also observed amongst the transformation treatments. Moreover, the transformation treatment A1 with enrichment species Castanopsis hystrix(350 trees·ha^-1) and Manglietia glance(350 trees·ha^-1) was determined to be the optimal model for maximum carbon sequestration because of its high tree-level growth rate and high economic value of enriched plantings, which could be popularized in other places. Our results further confirmed that management using mixed-species forests is a better approach to combat climate change than using monoculture forests.
文摘Any-aged forest management (AAF) is a means to reduce clear-felling without compromising profitability or timber production. The concept of AAF is to choose between clear-felling or thinning one harvest at a time based on what is better at that time in terms of the management objectives for the forest. No permanent choice is made between rotation forest management (RFM) and continuous cover forestry (CCF). Optimized AAF is never less profitable than RFM or CCF because all cutting types of both RMF and CCF are also allowed in AAF. This study developed a new set of guidelines for managing boreal forest stands under AAF when the forest landowner maximizes economic profitability. The first part of the guidelines indicates whether the stand should be cut or left to grow. This advice is based on stand basal area, mean tree diameter, minimum allowable post-thinning basal area, site productivity, and discount rate. If the optimal decision is harvesting, the second instruction determines whether the harvest should be clear-felling or thinning. In the case of thinning, the remaining two steps determine the optimal harvest rate in different diameter classes. The guidelines were developed using two different modeling approaches, regression analysis, and optimization, and applied to two Finnish forest holdings, one representing the southern boreal zone and the other the northern parts of the boreal zone. The results show that AAF improves profitability compared to current Finnish management instructions for RFM. The use of clear-felling also decreased the lower the minimum acceptable post-thinning basal area of the stand.
基金This study received research funding from the Rufford Foundation(Grant No.25259-1)from federal funds allotted to ECOSUR(NRM).
文摘Background:Forestry management modifies the diversity,structure,and functioning of intervened forests.Timber extraction reduces tree density and basal area,leading to changes in the communities of vascular epiphytes.The objective of this study was to evaluate the diversity and biomass of vascular epiphytes in Quercus trees remaining in two pine-oak forest stands that have been subjected to two stages of the Silvicultural Development Method(release cutting,and thinning)in comparison with an unharvested old-secondary forest in southern Mexico.For each treatment,richness of epiphytes present on 60 oak trees was recorded and their dry biomass estimated.We calculated the true diversity(Hill numbers)and beta diversity using the Jaccard coefficient of similarity,and generated rank abundance curves per taxonomic epiphyte group(bromeliads,orchids,ferns and others).For each treatment,the relationships between overall diversity and epiphyte biomass to the host trees basal area were analyzed using log linear models.Results:We recorded a total of 67 species of epiphytes species belonging to 10 families hosted by five species of oaks.The greatest species richness(^(0)D)was recorded in the old-secondary forest.Fewer common(^(1)D)and dominant(^(2)D)species were recorded in the release cutting than in the other treatments.Epiphyte diversity and biomass were both slightly related to host tree basal area.Composition of epiphytes was similar(60%)among treatments,although orchids,bromeliads,and other families were more diverse in the old-secondary forest.Most bromeliad species were shared across all treatments,although orchids presented the most exclusive species in the unharvested forest.The bromeliad Tillandsia seleriana provided the greatest contribution to biomass in all treatments,followed by the orchid Camaridium densum.Generalized linear models indicated that epiphyte diversity was significantly related to treatment,and epiphyte biomass to basal area of host trees.Conclusions:Although forest management affects diversity,composition,and abundance of vascular epiphytes,most of their diversity and biomass can be maintained despite timber harvesting.This requires sparing some mature oaks during logging,as they contribute to conservation,establishment,and development of epiphytic communities,and maintaining untreated areas as a source of propagules for these communities.
基金supported by the Fundacao de Amparo a Pesquisa do Estado de Minas Gerais (FAPEMIG)[CRA APQ-02641-14]in part by the Coordenacao de Aperfeicoamento de Pessoal de Nivel Superior-Brasil(CAPES)-Finance Code 001。
文摘Forest management may have significant effects on forest connectivity and natural population sizes.Harvesting old-growth single trees may also change natural patterns of genetic variation and spatial genetic structure.This study evaluated the impacts of forest management using a silvicultural system of seed trees on the genetic diversity and spatial genetic structure of Eremanthus erythropappus(DC.)MacLeish.A complete survey of 275 trees on four plots was undertaken out to compare the genetic variation of a managed stand with an unmanaged stand.We genotyped all adult and juvenile individuals 60 months after the management and compared the genetic diversity and the spatial genetic structure parameters.Genetic diversity was considered high because of an efficient gene flow between stands.There were no genetic differences between stands and no evidence of inbreeding.Genetic clustering identified a single population(K=1),indicating no genetic differentiation between managed and unmanaged stands.Adult and juvenile individuals of the unmanaged stand were more geographically structured than individuals from the managed one.There was a tendency of coancestry among juveniles at the first class of distance of the managed stand,suggesting a drift of genetic structure possibly caused by management.Understanding early responses to management on genetic diversity and stand structure is a first step to ensuring the effectiveness of conservation practices of tree species.The sustainability of forest management of E.erythropappus on genetic diversity,and more accurately,on spatial genetic structure needs evaluation over time to promote effective conservation of the population size and genetic variability.
基金The work was supported by the NZ Ministry of Foreign Aff air and Trade(MFAT)’s NZAID Programme.
文摘Silvicultural practices applied in managed forest plantations may help counteract the effects of climate change by influencing soil surface CO_(2)efflux(Fs).Understanding the effects of silvicultural practices on Fs will provide unbiased estimates of carbon fluxes and allow better silvicultural decisions for carbon sequestration.Therefore,we assessed how Fs differed seasonally across silvicultural practices(i.e.,stocking levels,clone,fertilization and weed control treatments)and evaluated the effects of soil temperature(Ts)and soil volumetric water content(θv)on Fs across these practices for a mid-rotation(14 year-old)Pinus radiata plantation in the Canterbury region of New Zealand.There were significant differences in Fs(p<0.05)over the four seasons,three levels of stocking,and five clones.The effects of fertilization and weed control applied 12 years previously on Fs were insignificant.Annual estimate of Fs(mean±1 standard deviation)from the study site was 22.7±7.1 t ha^(-1)a^(-1)in the form of CO_(2)(6.2±2.1 t ha^(-1)a^(-1)in the form of C).Fs values were consistently higher in plots with 1250 stems ha^(-1)compared to 2500 stems ha^(-1),which may be related to a strong soil resource limitation because of the close spacing in the latter plantation.Significant differences in Fs across clones suggest that variations in carbon partitioning might explain their growth performance.Silvicultural treatments influenced Fs response to soil temperature(p<0.05),resulting in models explaining 28-49%of the total variance in Fs.These findings provide insights into how silvicultural management decisions may impact Fs in mid-rotation radiata pine plantations,contributing towards developing more precise and unbiased plantation carbon budgets.
基金funded by BIOECOSYS project“Forest ecosystem management decision-making methods:an integrated bioeconomic approach to sustainability”(LISBOA-01-0145-FEDER-030391,PTDC/ASP-SIL/30391/2017)MODFIRE project“A multiple criteria approach to integrate wildfire behaviour in forest management planning with the reference”(PCIF/MOS/0217/2017)+1 种基金NOBEL project“Novel business models to sustainably supply forest ecosystem services”,under the umbrella of ERA-NET cofund ForestValue(Horizon 2020 research and innovation programme grant agreement N°773324)funded by Fundacao para a Ciencia e a Tecnologia I.P.(FCT),Portugal within UID/AGR/00239/2020.
文摘Background:Soil erosion is still identified as the main cause of land degradation worldwide,threatening soil functions and driving several research and policy efforts to reverse it.Trees are commonly associated to some of the most successful land-use systems to achieve soil protection goals,but the extent to which forest ecosystems reduce erosion risks can largely depend on management decisions and associated silvicultural practices.Optimization tools can assist foresters in solving the complex planning problem they face,concerning the demand for different,and often conflicting,ecosystem services.A resource capability model(RCM),based on a linear programming approach,was built and solved for a forest landscape management problem in Northwest Portugal,over a 90-years planning horizon,divided in 10-years periods.Results:Timber provision and soil erosion were found to be in trade-off.The management alternatives included in the model were proven to be sufficiently flexible to obtain the desired level of timber yield,both in volume and even distribution along the planning horizon,while ensuring lower levels of soil loss estimates(below 35 Mg·ha^(−1)·year^(−1)).However,under climate change conditions,compatible with an increasing greenhouse gases emission scenario,potential landscape soil erosion may be enhanced up to 46 Mg·ha^(−1)·year^(−1) in critical periods.Conclusions:Soil conservation concerns in landscape-level forest management planning can be addressed by LPbased optimization methods.Besides providing an optimal management solution at landscape level,this approach enables a comprehensive analysis of the RCM,possible trade-offs and potential changes towards uncertainties.
基金supported by the Australian Biomass for Bioenergy Assessment(ABBA)Project,Queensland Government
文摘Background： Australia＇s energy future is at the crossroads and the role of renewable sources is in focus. Biomass from sustainably managed forests provide a significant opportunity for electricity and heat generation and production of liquid fuels. Australia has extensive native forests of which a significant proportion are on private land. However, there is limited knowledge on the potential capacity of this resource to contribute to the expansion of a biomass for bioenergy industry. In addition, there are concerns on how to reconcile biomass harvesting with environmental protection. Methods： We used regional ecosystem vegetation mapping for Queensland to stratify harvestable forests within the 1.8 m hectares of private native forests present in the Southeast Queensland bioregion in 2014. We used a dataset of 52,620 individual tree measurements from 541 forest inventory plots collected over the last 10 years. Tree biomass was estimated using current biomass allometric equations for Australia. Biomass potentially available from selective sawlog harvesting and silvicultural treatment across the bioregion was calculated and mapped. Results： Current sawlog harvesting extracts 41.4% of the standing tree biomass and a biomass for bioenergy harvest would retain on average 36% of felled tree biomass on site for the protection of environmental and fauna habitat values. The estimated area extent of harvestable private native forests in the bioregion in 2013 was 888,000 ha and estimated available biomass for bioenergy in living trees was 13.6 million tonnes （t）. The spotted gum （Corymbio citriodora subsp, variegata） forests were the most extensive, covering an area of 379,823 ha and with a biomass for bioenergy yield of 14.2 t-ha-1 （with approximately 11.2 t.ha-1 of the biomass harvested from silvicultural thinning and 3 t.ha-1 recovered from sawlog harvest residual）. Conclusions： Silvicultural treatment of private native forests in the Southeast Queensland bioregion, has the capacity to supply a large quantity of biomass for bioenergy. The availability of a biomass for bioenergy market, and integration of sawlog harvesting and silvicultural treatment operations, could provide land owners with additional commercial incentive to improve the management of private native forests. This could potentially promote restoration of degraded forests, ecological sustainability and continued provision of wood products.
基金funded by the German Federal Ministry of Education and Research under research grant 033L029H
文摘Background: Forest management faces a climate induced shift in growth potential and increasing current and emerging new risks. Vulnerability analysis provides decision support based on projections of natural resources taking risks and uncertainties into account. In this paper we(1) characterize differences in forest dynamics under three management scenarios,(2) analyse the effects of the three scenarios on two risk factors, windthrow and drought stress, and(3) quantify the effects and the amount of uncertainty arising from climate projections on height increment and drought stress.Methods: In four regions in northern Germany, we apply three contrasting management scenarios and project forest development under climate change until 2070. Three climate runs(minimum, median, maximum) based on the emission scenario RCP 8.5 control the site-sensitive forest growth functions. The minimum and maximum climate run define the range of prospective climate development.Results: The projections of different management regimes until 2070 show the diverging medium-term effects of thinnings and harvests and long-term effects of species conversion on a regional scale. Examples of windthrow vulnerability and drought stress reveal how adaptation measures depend on the applied management path and the decision-maker’s risk attitude. Uncertainty analysis shows the increasing variability of drought risk projections with time. The effect of climate projections on height growth are quantified and uncertainty analysis reveals that height growth of young trees is dominated by the age-trend whereas the climate signal in height increment of older trees is decisive.Conclusions: Drought risk is a serious issue in the eastern regions independent of the applied silvicultural scenario,but adaptation measures are limited as the proportion of the most drought tolerant species Scots pine is already high. Windthrow risk is no serious overall threat in any region, but adequate counter-measures such as species conversion, species mixture or reduction of target diameter can be taken. This simulation study of three silvicultural scenarios and three climate runs spans a decision space of potential forest development to be used for decision making. Which adaptation measures to counteract climate induced risks and uncertainty are to be taken is,however, a matter of individual risk attitude.
