Comparison of stand structure and growth between artificial and natural forests of Pinus sylvestiris var, mongolica on sandy land

Mongolian pine (Pinus sylvestiris Linnaeus var. mongolica Litvinov) as a valuable conifer tree species has been broadly introduced to the sandy land areas in “Three North” regions (North, northwest and northeast of China), but many prob-lems occurred in the earliest Mongolian pine plantations in 7hanggutai, 7hangwu County, Liaoning Province (ZZL). In order to clarify the reason, comprehensive investigations were carried out on differences in structure characteristics, growth processes and ecological factors between artificial stands (the first plantation established in ZZL in 1950s) and natural stands (the origin forests of the tree species in Honghuaerji, Inner Mongolia) on sandy land. The results showed that variation of diameter-class distributions in artificial stands and natural stands could be described by Weibull and Normal distribution models, respectively.Chapman-Richards growth model was employed to reconstruct the growth process of Mongolian pine based on the data from field investigation and stem analysis. The ages of maximum of relative growth rate and average growth rate of DBH, height, and volume of planted trees were 11,22 years, 8, 15 years and 35, 59 years earlier than those of natural stand trees, respectively. In respect of the incremental acceleration of volume, the artificial and natural stands reached their maximum values at 14 years and 33 years respectively. The quantitative maturity ages of artificial stands and natural stands were 43 years and 102 years respectively. It was concluded that the life span of the Mongolian pine trees in natural stands was about 60 years longer than those in artificial stands. The differences mentioned above between artificial and natural Mongolian pine forests on sandy land were partially attributed to the drastic variations of ecological conditions such as latitude, temperature, precipitation, evaporation and height above sea level. Human beings‘‘ disturbances and higher density in plantation forest may be ascribed as additional reasons. Those results may be potentially useful for the management and afforestation of Mongolian pine plantations on sandy land in arid and semi-arid areas.     

Do mature pine plantations resemble deciduous natural forests regarding understory plant diversity and canopy structure in historically modified landscapes?

We compared the structure of the arboreal layer and the diversity and species composition of the understory vegetation of three types of mature forest communities: oak (Quercus pyrenaica) and beech (Fagus sylvatica) forests and Scots pine (Pinus sylvestris) plantations. Our main aim was to determine whether differences in these variables existed and were due to the identity of the dominant tree species. We selected four stands or replicates per forest type located geographically close and with relatively similar conditions. We found no differences in the arboreal structure of oak and beech forests, which were characterised by great variability in tree size, while in case of plantations, this variability was lower at both the intra-stand (estimated by the coefficient of variation) and inter-stand (i.e. the four replicates harboured trees of similar sizes) scales. However, the highest variability in the canopy layer of natural forests was not consistently linked to greater understory species richness. Indeed, the lowest plant species richness was found in beech forests, while oak forests harboured the highest value at either the sampling unit (per m²) or stand scales. The greatest negative correlation between plant diversity and the environmental variables measured was found for litter depth, which was the highest in beech forests. The results obtained by the CCA indicated that the four replicates of each forest type clustered together, due to the presence of characteristic species. We concluded that pine plantations did not approach the environmental conditions of native forests, as plantations were characterised by singular understory species composition and low arboreal layer variability, compared to natural woodlands.     

How does economic research contribute to the management of forest ecosystem services?

Key message

More and more environmental and resource economists are taking a particular interest in research on forest ecosystem services (FES), especially in a context of climate change. Spatial and temporal issues are crucial to economic analyses and for the design of conservation policies. Interdisciplinary research involving ecological and economic disciplines is a prerequisite for the more effective management of forest ecosystems.

Context

Economists define non-market ecosystem services (ES) as public or common goods due to their characteristics of non-rivalry in terms of consumption and/or non-excludability. Just because they do not have a price does not mean that ES have no economic value because their social benefits are undoubtedly considerable. These features, associated with the market demand for timber and a poor climate risk assessment, may lead to the under-provision of non-market forest ES and the over-harvesting of timber.

Aims

In this article, we review research questions that are central to the enhancement of FES provision. Beyond the economic modelling of the joint provision of FES, we focus on issues related to the design of public policies to guide forest management. The objective is to provide crucial insights concerning the importance of a spatial and sustainable provision of FES.

Results

First, we provide an economic interpretation of the FES concept and a review of economic models of forest management. Second, we explain how spatial and temporal dimensions of FES can have major implications on their supply and demand. Both dimensions explain why FESs have to be taken into account in production decisions and public policies (including the design of payment for environmental services (PESs)).

Conclusion

A better understanding of FES provision and public policies to be enhanced is not possible without accounting for spatial and temporal dimensions. This helps to analyse the impact of intervention on FES and the cost-effectiveness of economic instruments, implying a coordinated effort to bring together ecological and economic data and models.

     

How does silviculture affect storm damage in forests of south-western Germany? Results from empirical modeling based on long-term observations

Storms represent the most important disturbance factor in forests of Central Europe. Using data from long-term growth and yield experiments in Baden-Wuerttemberg (south-western Germany), which permit separation of storm damage from other causes of mortality for individual trees, we investigated the influence of soil, site, forest stand, and tree parameters on storm damage, especially focusing on the influence of silvicultural interventions. For this purpose, a four-step modeling approach was applied in order to extract the main risk factors for (1) the general stand-level occurrence of storm damage, (2) the occurrence of total stand damage, and (3) partial storm damage within stands. The estimated stand-level probability of storm damage obtained in step 3 was then offset in order to describe the damage potential for the individual trees within each partially damaged stand (4). Generalized linear mixed models were applied. Our results indicate that tree species and stand height are the most important storm risk factors, also for characterizing the long-term storm risk. Additionally, data on past timber removals and selective thinnings appear more important for explaining storm damage predisposition than for example stand density, soil and site conditions or topographic variables. When quantified with a weighting method (summarizing the relative weight of single predictors or groups of predictors), removals could explain up to 20% of storm risk. The stepwise modeling approach proved an important methodological feature of the analysis, since it enabled consideration of the large number of observations without damage (“zero inflation”) in a statistically correct way. These results form a reliable basis for quantifying forest management’s direct impact on the risk of storm damage.     

How does light availability affect the aboveground biomass allocation and leaf morphology of saplings in temperate mixed deciduous forests?

New Forests - Light is the most important physical variable that affects patterns of biomass allocation. A quantitative understanding of biomass allocation patterns is crucial to quantifying...     

The effects of partial cutting on stand structure and growth of western hemlock–Sitka spruce stands in southeast Alaska

The effects of partial cutting on species composition, new and residual-tree cohorts, tree size distribution, and tree growth was evaluated on 73 plots in 18 stands throughout southeast Alaska. These partially cut stands were harvested 12–96 years ago, when 16–96% of the former stand basal area was removed.Partial cutting maintained stand structures similar to uncut old-growth stands, and the cutting had no significant effects on tree species composition. The establishment of new-tree cohorts was positively related to the proportion of basal-area cut. The current stand basal area, tree species composition, and stand growth were significantly related to trees left after harvest (p<0.001). Trees that were 20–80 cm dbh at the time of cutting had the greatest tree-diameter and basal-area growth and contributed the most to stand growth. Diameter growth of Sitka spruce and western hemlock was similar, and the proportion of stand basal-area growth between species was consistent for different cutting intensities.Concerns about changing tree species composition, lack of spruce regeneration, and greatly reduced stand growth and vigor with partial cuts were largely unsubstantiated. Silvicultural systems based on partial cutting can provide rapidly growing trees for timber production while maintaining complex stand structures with mixtures of spruce and hemlock trees similar to old-growth stands.     

Spatial variation of local stand structure in an Abies forest, 45 years after a large disturbance by the Isewan typhoon

Heterogeneity of forest stand structure often results from repeated small disturbances, but structural variation also arises in a stand that has regenerated after a single large stand-replacing disturbance. We explored the structural variation within a subalpine Abies forest in Japan that regenerated after a large typhoon in 1959. In 2004, four 50 × 50 m plots were established at two sites in the regenerated forest. To characterize local stand structure within each plot, we determined the stem density, stand basal area, mean diameter at breast height (DBH), and coefficient of variation (CV) of DBH in 10 × 10 m subplots. We analyzed the spatial distribution pattern of the trees in each subplot using the L(t) function and categorized the distributions as clumped or non-clumped. The analysis revealed marked variation among subplots in the stand’s structural characteristics. Although the spatial distribution patterns of the trees in all plots were clumped, 11 of 50 subplots at one site and 39 of 50 subplots at the other site were non-clumped. Subplots with a clumped distribution pattern generally had a smaller basal area, smaller mean DBH, and greater CV of DBH than subplots with the same density but a non-clumped pattern. These results illustrated the spatial heterogeneity of forest structure that can arise in Abies forest that has experienced a large disturbance, probably because of the different densities and distribution of saplings surviving the disturbance and the different forest growth dynamics that result.     

Correction to: How does light availability affect the aboveground biomass allocation and leaf morphology of saplings in temperate mixed deciduous forests?

New Forests - The original version of this article was inadvertently published without the acknowledgements section.     

Does variable stand structure associated with multi-cohort forests support diversity of ground beetle(Coleoptera,Carabidae) communities in the central Nearctic boreal forest?

Multi-cohort management(MCM) that retains a range of stand structures(age and size class) has been proposed to emulate natural disturbance and improve management in the Nearctic boreal forest.Although MCM forests contain both single-and multi-aged stands of mixed tree sizes,little is known about how variable stand structure affects associated fauna and biodiversity.Here,we examine the relationship between ground beetle(Coleoptera,Carabidae) communities and stand characteristics across a range of forest structure(=cohort classes).Given that MCM classes are defined by the distribution of their tree–stem diameters,we ask whether parameters associated with these distributions(Weibull) could explain observed variation in carabid communities,and if so,how this compares to traditional habitat variables such as stand age,foliage complexity or volume of downed woody debris.We sampled carabids using weekly pitfall collections and compared these with structural habitat variables across a range of cohort classes(stand structure and age since disturbance) in 18 sites of upland mixed boreal forests from central Canada.Results showed that richness and diversity of carabid communities were similar among cohort classes.Weibull parameters from the diameter distribution of all stems were the strongest predictors of variation in carabid communities among sites,but vertical foliage complexity,understory thickness,and percentage of deciduous composition were also significant.The abundance of several carabid forest specialists was strongly correlated with tree canopy height,the presence of large trees,and high vertical foliage complexity.Our results demonstrate that variable forest structure,as expected under MCM,may be useful in retaining the natural range of ground beetle species across the central Nearctic boreal forest.     

Tree and stand structure of the non-native Pinus contorta in relation to native Pinus sylvestris and Picea abies in young managed forests in boreal Sweden

Managed forest stands are typically younger and structurally less diverse than natural forests. Introduction of non-native tree species might increase the structural changes to managed forest stands, but detailed analyses of tree- and stand-structures of native and non-native managed forests are often lacking. Improved knowledge of non-native forest structure could help clarify their multiple values (e.g. habitat for native biodiversity, bioenergy opportunities). We studied the structural differences between the introduced, non-native Pinus contorta and the native Pinus sylvestris and Picea abies over young forest stand ages (13–34 years old) in managed forests in northern Sweden. We found that P. contorta stands had greater mean basal areas, tree heights, diameters at breast height, and surface area of living branches than the two native species in young stands. The surface area of dead attached branches was also greater in P. contorta than P. abies. Although this indicates greater habitat availability for branch-living organisms, it also contributes to the overall more shaded conditions in stands of P. contorta. Only one older 87 years old P. contorta stand was available, and future studies will tell how structural differences between P. contorta and native tree species develop over the full forestry cycle.     

Is generalisation of uneven-aged management in mountain forests the key to improve biodiversity conservation within forest landscape mosaics?

Context

Uneven-aged management systems based on selection silviculture have become popular in European mountain forests and progressively replace other silvicultural practices. In time, this trend could lead to a homogenisation of the forest mosaic with consequences on structural indices recognised as beneficial to forest biodiversity.

Aims

This study was conducted to investigate the potential effects of a generalisation of the selection silvicultural system on structural diversity in the forest landscape with consequences for forest biodiversity conservation.

Methods

We compared four structural indices (tree species richness, diameter heterogeneity, deadwood volume and basal area of mature trees) in five different stand types typical of the northern French Alps, using forest plot data in the Vercors mountain range. Through virtual landscape simulations, we then calculated predicted mean proportions of stand types under two different conservation strategies: (i) maximising mean index values at the landscape level and (ii) maximising the number of plots in the landscape with index values above given thresholds.

Results

Multi-staged forests did not maximise all indices, the best solution being to combine the five stand types in uneven proportions to improve biodiversity conservation.

Conclusion

The expansion of selection silviculture in European heterogeneous forest landscapes could enhance biodiversity conservation if other stand types with complementary structural characteristics are maintained.     

A giant tree stand in the West Carpathians—An exception or a relic of formerly widespread mountain European forests?

In Europe, remnants of formerly widespread natural mixed forests are rare. We analyzed an exceptionally tall tree stand with a very high wood volume in Hron?okovský grúň reserve, covering 55.2 ha in Slovenské Rudohorie Mountains in central Slovakia (48°43′N and 19°35′E) between 730 and 1050 m a.s.l. We compared our data to other natural stands to see if the growing stock and tree height were higher in Hron?okovský grúň.     

Hydrology-oriented (adaptive) silviculture in a semiarid pine plantation: How much can be modified the water cycle through forest management?

Hydrology-oriented silviculture might adapt Mediterranean forests to climatic changes, although its implementation demands a better understanding and quantification on the water fluxes. The influence of thinning intensity (high, medium, low and a control) and its effect on the mid-term (thinned plots in 1998 and 2008) on the water cycle (transpiration, soil water and interception) and growth [basal area increment (BAI)] were investigated in 55-year-old Aleppo pine trees. Thinning enhanced a lower dependence of growth on climate fluctuations. The high-intensity treatment showed significant increases in the mean annual BAI (from 4.1 to 17.3 cm²) that was maintained in the mid-term. Thinning intensity progressively increased the sap flow velocity (v _s) in all cases with respect to the control. In the mid-term, an increased functionality of the inner sapwood was also observed. Mean daily tree water use ranged from 5 (control) to 18 (high intensity) l tree^?1. However, when expressed on an area basis, daily transpiration ranged from 0.18 (medium) to 0.30 mm (control), meaning that in spite of the higher transpiration rates in the remaining trees, stand transpiration was reduced with thinning. Deep infiltration of water was also enhanced with thinning (about 30 % of rainfall) and did not compete with transpiration, as both presented opposite seasonal patterns. The changes in the stand water relationships after 10 years were well explained by the forest cover metric. The blue to green water ratio changed from 0.15 in the control to 0.72 in the high-intensity treatment, with the remaining treatments in the 0.34–0.48 range.     

Strategies on natural forest protection of collective forest area in minority nationality community in China─A case of the forest resource management in datu village

IntroductionForestisakindofmulti-function'resourcethatcanbesustaininglyutiIized,butsomeprobIems,suchasinsufficiencyoftimberyieId,soiIerosion,cIimateim-baIanceinpartdistrictetc.,oftenarousedbecauseofincorrectuseandmanagementofnaturalresources.InordertodevelopthefOrestry,IotsoffOrestrypoIi-cieshavebeenissuedandcarriedout.V8rioustypesofforestresourcesmanagementhavebeenaroused,especialIycollectiveforestareasinsouthChina.However,whydiff6rentefficiencies,good,badandworse,eventoresultinthedecrea…     

The effects of fire on the regeneration of a Quercus douglasii stand in Quail Ridge Reserve, Berryessa Valley (California)

Wildfire is an important element in the dynamics of the blue oak (Quercus douglasii) stand. We evaluated the effect of fire in the regeneration of a stand in Quail Ridge. This protected area is located on a peninsula formed by the flooding of Berryessa Valley (California) which has helped it maintain many elements of the native flora. Major vegetation types are blue oak woodland and forest (Q. douglasii, Fagaceae), chamise chaparral (Adenostoma fasciculatum, Rosaceae), and grasslands. In the blue oak stand, 14 plots were randomly located: seven in the burned area and seven outside of the burned areas (control). The effect of fire on sexual regeneration, asexual regeneration, mortality and species composition was analyzed. The fire caused changes in canopy cover, soil cover and litter cover. Asexual regeneration was significantly favored by the fire, but the effect on sexual regeneration was not significant. Fire caused a significant reduction in the basal area of Q. wislizeni and Arctostaphylos manzanita and a reduction in the density of Heteromeles arbutifolia. We concluded that fire does not have a significant effect on the sexual regeneration of Q. douglasii or Q. wislizeni. Fire does stimulate asexual regeneration in both species of oaks, but grazing reduces the regenerative effect of fire. Fire increases regeneration of Arctostaphylos manzanita and Heteromeles arbutifolia by stimulating asexual and sexual regeneration. The occupancies of these chaparral species are further enhanced by their lower palatability compared to both species of oaks.     

How well does a log decay-class system capture the ecology of decomposition? - A case-study from Tasmanian Eucalyptus obliqua forest

The use of decay-class systems in characterising the state of decomposition of a forest’s complement of rotting logs is widespread. While most systems are based on an assessment of logs’ external characteristics, there is an implicit assumption that doing so captures important information on the underlying processes of internal decomposition. However, the validity of this remains largely untested. We explored the relationship between decay-class and internal state of decomposition in logs of Eucalyptus obliqua in the lowland wet eucalypt forests of Southern Tasmania, Australia. We examined rotten-wood samples from a large population of logs across a wide range of diameters. From this we determined that smaller-diameter (<60 cm: regrowth-sized) logs differ from larger-diameter (>60 cm: mature-sized) logs in their pathways of internal decomposition. Decomposition in regrowth-sized logs is characterised by greater activity of surface rots, with white rot-types predominating. Decomposition in mature-sized logs is more concentrated in the interior of the log, with brown rot-types tending to dominate. These differences probably both reflect and help shape the communities of organisms inhabiting logs of different origins. Despite these differences, regrowth and mature-sized logs show the same general progression of internal decomposition across the five decay-classes, to the extent that each class represents logs that have lost a predictable proportion of their original mass. We conclude that a decay-class system that is restricted to a single dimension, such as the five-class system used for E. obliqua, will be quite able to capture the main trajectory of biomass loss, but will not be able to characterise the complexity of the ecological processes giving rise to this loss. Studies that employ single-dimension decay classes, and which aggregate decay-class data across logs, can be given added ecological meaning by first partitioning logs into diameter-classes that reflect the underlying differences in the maturity of the trees giving rise to the logs. For E. obliqua logs, a cut-off diameter of 60 cm offers an appropriate distinction between regrowth-aged and mature-aged trees.     

How does perception at multiple levels influence collective action in the commons? The case of Mikania micrantha in Chitwan,Nepal

Collective action has played a vital role in managing common pool resources in numerous global contexts. This article explores the factors affecting collective action related to the removal of the mile-a-minute weed (Mikania micrantha, referred to as Mikania), an invasive plant, in community forests in the buffer zone region around Chitwan National Park in Chitwan, Nepal. Few studies have combined larger sample size quantitative data with greater generalizability and nuanced, qualitative data to explore what factors influence collective action or focused on how perception of the issue at multiple levels affects outcomes. This research employs household and community forest management survey data from 21 community forests in and near the buffer zone of Chitwan National Park in Nepal. Our multilevel econometric analyses, including an analysis examining geographic space using eigenvectors, investigate what influences local people's participation in Mikania removal and we contextualize the findings with case-study interview data. Our results indicate that reliance on community forest resources, perception of the issue, and neighborhood sizes influence are influential factors in their participation in Mikania removal. The implications of these findings are discussed in the context of increasing the effectiveness of Mikania removal efforts and influencing collective action in relation to other global human-environment issues.     

Is forest certification delivering on First Nation issues? The effectiveness of the FSC standard in advancing First Nations' rights in the boreal forests of Ontario and Quebec,Canada

Forest certification has become a key driver in efforts towards sustainable forest management. Certification processes include commitments to respect the rights of Aboriginal peoples. However, there has been little investigation into the relationship between certification and Aboriginal rights. This paper examines the effectiveness of certification in addressing a range of First Nation concerns, taking the example of FSC's National Boreal Standard, applied in the provinces of Quebec and Ontario, Canada. This is done through documentary analysis of audit reports for all public land certificates in this region, with particular attention paid to ‘conditions’ (required changes) issued as part of the audit process. Results indicate that 86% of FSC certifications led to at least one condition relating to First Nations' rights, but that most were deemed minor. The two most common issues flagged by conditions were: agreement for the management plan and the evaluation and protection of First Nations' resources and sites. Analysis of subsequent reports revealed that all conditions were resolved within the allotted time period. A qualitative analysis of conditions revealed a tendency for auditors to accept partial conformance when evaluating compliance. We conclude that FSC certification is pushing forest managers to make progress on a wide variety of fronts, but through a lens of ‘continual improvement’ rather than strict conformance with the standard.