Should we respect the historical reference as basis for the objective of forest restoration? A case study from Northeastern China

Under climate change, the adoption of historical reference as the objective of forest restoration is being questioned. In this study, the spatially explicit forest landscape model LANDIS was utilized to analyze how the forest landscape in the upper Hun River area of Liaoning province in northeast China would be affected under current climate trends and future climate change; and to explore whether the historical reference should be the objective of restoration efforts. The results showed that (1) the area percentage (AP) of Quercusmongolica under climate change is always higher than that under the current climate regime, while the AP of Pinuskoraiensis is lower than that under current climate; and (2) the competitive ability of Q. mongolica and Populus davidiana increases, while that of other species decreases under climate change. As interspecies competition shifts under climate change, the historical reference appears in appropriate to serve as the objective of forest restoration. In addition, although Q. mongolica would likely benefit from a warmer and drier climate, use of this species for forest restoration under climate change still requires further research.     

Can farmer-to-farmer communication boost the dissemination of agroforestry innovations? A case study from Sulawesi,Indonesia

Research agencies generate a vast number of agroforestry innovations, many of which have significant potential to increase productivity and to improve livelihoods. However, the dissemination of information related to these innovations and their adoption rate remains low throughout Indonesia, particularly in areas with a low level of infrastructure development, such as in Sulawesi, Indonesia. In areas such as these, interpersonal communication between farmers (farmer-to-farmer interpersonal communication) is a significant means by which farmers obtain information related to agroforestry innovations that they may utilize to improve the productivity of their plots. Given the significance of this channel of communication, further investigation is merited to assess how it might be leveraged to improve the dissemination of information related to agroforestry innovations and how it can complement the use of other communication channels. Thus, this study was conducted to identify how farmer-to-farmer interpersonal communication is used and the extent to which it is a preferred means by which information related to agroforestry innovations is disseminated in Sulawesi, Indonesia. Data was collected through semi-structured interviews involving 144 farmers (40 % female) from 12 villages in the provinces of South Sulawesi and Southeast Sulawesi, Indonesia. Results show distinct differences in terms of farmers’ preferences for the various types of disseminators of information related to agroforestry innovations between provinces and genders. It was found that farmers play a significant role as reliable disseminators of information related to agroforestry innovations to a greater extent in areas where farmer’s access to government extension agents is limited and where language barriers act as a constraint to the dissemination of information by these agents. Farmer-to-farmer communication is not the only communication channel for the dissemination of the information, but it is preferred by farmers who only speak local languages. Thus, to enhance the dissemination rate of agroforestry innovations, farmer-to-farmer communication channels should be utilized to complement the use of other channels. In areas where farmer-to-farmer communication channels are preferred, deliberate measures to improve expert farmers’ and opinion leaders’ access to information related to agricultural and agroforestry innovations will facilitate the effective dissemination of this information amongst a greater number of farmers.     

Are composts from shredded leafy branches of fast-growing forest species suitable as nursery growing media in arid regions?

The morpho-physiological quality of seedlings is negatively affected by the wide scale use of forest soils as substrates in developing countries. With the objective of finding long-term sustainable supply of growing media, compost was produced from shredded branches of three fast growing species (Acacia cyanophylla (AA), Acacia cyclops (AS) and Eucalyptus gomphocephala (EG). The composting process covered three different periods over the course of a year. Pile temperatures were monitored daily and the composts were routinely sampled and analyzed for 19 chemical variables. Although composting is feasible year-round in arid climates, compost produced in the humid cool conditions of autumn, winter and early spring reaches the maturation phase more quickly than compost produced under hot, dry summer conditions. It also requires less turning and water. The evolution of the composting process and quality of the final product can be assessed using three chemical variables (C/N, pH, EC). Seed germination rates in the three types of compost were similar to that in a peat:vermiculite substrate and vigorous high quality seedlings were produced in the two acacia composts. However, compost-grown seedlings had significantly smaller shoots and root systems than those produced in peat substrate. Principal components analyses showed that the quality of a compost-based substrate is reproducible and that its final chemical composition can be predicted from its raw organic materials. The EG composts had higher pH than the acacia composts, whereas the AA and EG composts were higher in mineral salts than the AS.     

Afforestation with ‘multipurpose trees’ in ‘media lunas’, a case study from the Tarija basin,Bolivia

Human-induced soil erosion has already affected all of the potential farming land in the Tarija basin/South Bolivia. It is described as an afforestation method involving media lunas and multipurpose trees, whose implementation is associated with a high degree of mobilization of the target group.On sites where a sufficient number of media lunas have been established, surface runoff is drastically reduced. They diminish the risk of failure of newly planted trees during frequently occurring dry phases, and promote their growth by preventing excessively large fluctuations in the soil-water balance and increasing soil moisture in general. Mostly indigenous multipurpose trees (Acacia and Prosopis) serve to stabilize erosion-prone sites on a long-term basis, and become invaluable because they provide a source of firewood, improve the soil, and yield protein-rich livestock forage during dry season. Media lunas provide more favorable conditions for natural vegetation.     

Are plot data effective for landscape prediction? A simulation study of tree species response to climate warming under varying environmental heterogeneity

Introduction   

Extrapolating plot data to broader spatial scales depends largely on environmental heterogeneity.     

Do restoration fellings in protected forests increase the risk of bark beetle damages in adjacent forests? A case study from Fennoscandian boreal forest

Gap fellings are used to promote multi-cohort structures and to restore other natural forest structures and processes in protected areas that have been altered by anthropogenic activities. Gaps and felled trees may also provide breeding material for species that in high numbers can cause significant tree mortality, growth reduction and consequent economic losses in surrounding production forests. In this study, the effect of restoration gap fellings on feeding intensity of Tomicus spp. (pine shoot beetles) was evaluated by counting fallen pine shoots at different distances from gaps in a protected area in eastern Finland. Gap fellings had a clear effect on the feeding intensity of the beetles. The average density of fallen shoots m⁻² was 17 within a 10-m distance from gaps but decreased rapidly to around 4 at the distance of 50 m and beyond. The distance decay in shoot feeding is described well by the negative exponential models. Our results suggest that gap fellings have only a localized effect on shoot feeding by Tomicus in the forests surrounding the restoration gaps. In practical restoration, a buffer zone of 100–200 m around the gap fellings, as implemented here, is enough to minimize economically significant growth reduction in surrounding production forests. As shown in this study, restoration of natural forest structures and dynamics to protect biodiversity is not necessarily in conflict with forest hygiene objectives in production forests.     

Is it necessary to change the number of samples for different forest types when evaluating plant species richness? A case study in a forested landscape in central Japan

We demonstrate a method for evaluating the appropriate number of samples required to estimate plant species richness in different forest types within a forested landscape. In each of 36 plots (0.1 ha each) from 5 forest types (deciduous broad-leaved secondary forest and 4 categories of coniferous plantation classified according to stand age) in central Japan, 40 quadrats of 1 × 1 m were set in a regular pattern; the total number of quadrats in each forest type ranged from 200 to 400. In each plot, the number of observed species in 40 quadrats ranged from 60 to 80% of the number of species estimated by the rarefaction method for each forest type. Sampling 30 quadrats detected approximately 90% of the observed species in each plot that were detected using 40 quadrats. In specific functional groups (i.e., tall trees and weed species), the ratios of both tall trees and weed species to all species were at equilibrium for 30 or more quadrats. For fewer than 30 quadrats these ratios were highly variable. No significant differences were found among forest types in the ratio of the observed number of species in each plot to the estimated number of species calculated using the rarefaction method, and in sampling efficiency estimated by use of non-parametric estimators. We concluded that the number of samples does not need to be changed according to forest type or plantation stand age in the studied landscape, and that the method used to evaluate the number of samples could be useful.     

Forest edge length estimation – a case study using the Swedish National Forest Inventory (NFI)

Forest edges may affect the organisms in a forest fragment by changing biotic and abiotic conditions, and they have important effects on biodiversity. This characteristic of forest landscape is usually assessed using remotely sensed data. When doing so, forest edge length is estimated using either polygon delineation (manually or automatically) or sampling methods. This study attempts to estimate the total forest edge length (at regional level) using three estimation techniques: mapped plot, line intersects sampling, and buffer zone. Another aim is to compare the precision of the results using these techniques with field data from the Swedish National Forest Inventory (NFI). The Swedish NFI data allows reasonable precision (less than 10% SE) estimating total forest edge length. In most cases, line intersects sampling and mapped plot (at the subplot level) produce more precise estimates than buffer zone (at cluster level). All three techniques can be applied in monitoring programs aimed at measuring important biodiversity metrics from forest landscape patterns. It was also found that edge density was highest in the south of Sweden. Another future application worth investigating is the ability to determine how forest edge length metrics change over time.     

Does forest biomass harvesting for energy reduce fire hazard in the Mediterranean basin? a case study in the Caroig Massif (Eastern Spain)

The Mediterranean basin is a fire-prone area and is expected to continue being so according to projected climate and socioeconomic changes. Sustainable exploitation of forest biomass could have a positive effect on wildfire hazard mitigation. A modelling approach was used to compare how four different Scenarios for biomass collection for energy use affect fire behaviour and potential burnt area at landscape level under extreme meteorological conditions in a typical Mediterranean Massif. A case study of Pinus halepensis stands in Valencia (Eastern Spain) was conducted. The FARSITE simulator was used to evaluate the burnt area and fire behaviour parameters. Simulations predicted a significant increase in the burnt area and the values of most fire behaviour parameters in a Scenario of rural abandonment, relative to the current situation. Biomass management through thinning reduced canopy bulk density; however, no differences in the values of the main fire behaviour parameters were detected. Thinning and understory clearing, including biomass collection in large shrub fuel model areas, significantly reduces fire hazard. Forest biomass sustainable harvesting for energy is expected to reduce fire hazard if management includes intense modification of fuel models, comprising management of shrub biomass at the landscape level. Strong modification of forest fuel models requires intensive silvicultural treatments. Therefore, forest biomass collection for energy in the Mediterranean basin reduces fire hazard only if both tree and shrub strata are managed at landscape level.     

Can community forestry contribute to household income and sustainable forestry practices in rural area? A case study from Tshapey and Zariphensum in Bhutan

Community forestry is an emerging success model of state–community partnership for forest management and poverty reduction. Bhutan's initial experience of forest management by user group is promising, but merits further study on how community forests have experienced with harvesting and income generation consistent with national forest policy. This study quantifies whether community forestry contribute to household income with equitable products and income distribution and gender inclusive participation; and community forests are managed applying the principles of sustainable harvest without compromising regeneration and productivity. We applied a combination of social and ecological methods using household interview and forest sampling plots. Our findings revealed that community forestry contributes to household income through harvesting and marketing of large trees, and non-wood forest products where markets are accessible. Household income, however, vary widely between rich and poor households with former capitalizing on commercial and latter on subsistence products. Timber harvesting is consistent with the principles of sustainable harvest without altering species composition, regeneration and productivity. To narrow income inequality, pro-poor approach to community forestry needs to target poor households with income diversification activities and market accessibility. The promising results are context-driven and warrant consolidation from other community forests experiencing harvest in Bhutan.     

A New Record of the Genus Leptus Latrerille 1796 (Acari:Erythraeidae) from Japan

ＴｈｅｍｉｔｅｏｆｔｈｅｇｅｎｕｓＬｅｐｔｕｓｉｓｗｏｒｌｄ－ｗｉｄｅｄｉｓｔｒｉｂｕｔｅｄａｎｄｅｃｔｏｐａｒａｓｉｔｅｄｏｎｉｎｓｅｃｔｓａｎｄｏｎｓｐｉｄｅｒｓ．ＩｎＪａｐａｎ，ｎｉｎｅｓｐｅｃｉｅｓｏｆｔｈｉｓｇｅｎｕｓｈａｖｅｂｅｅｎｒｅｃ...     

Species selection for reforestations: what happens with historic local extinctions and habitat protection zones? A case study in the Cantabrian Range

Species selection for reforestations can be challenging in habitat protection zones, especially in human transformed landscapes, where nativeness of some species is not easily determined and yet is crucial for knowing whether a species can be used or not. We try to determine whether Pinus uncinata Ramond ex DC was present in the Cantabrian Range (Spain) and whether it could have disappeared recently due to anthropogenic causes. Plant morphology and needle anatomy were characterized in Pinus sylvestris L. and P. uncinata 2-year-old seedlings. An analysis of variance was used for selecting morphological markers capable of discriminating both species. These markers permit the comparison of seedlings coming from the highest zone of Puebla de Lillo relict pinewood (Cantabrian Range) with reference material from Castillo de Vinuesa (Iberian Range). This comparison was firstly made with two multivariate methods, a principal component analysis and a multivariate discriminant analysis. Subsequently, this was corroborated with the detection of a species-specific chloroplast DNA marker. The differences found between both species reflect the better adaptation of P. uncinata to typical highland environment. Several Puebla de Lillo seedlings had P. uncinata type morphology and haplotype, suggesting the presence of this species in the Cantabrian Range until recently. This discovery changes the current interpretation of the zone’s vegetation, enhancing the natural presence of highland open pinewoods. However, human activities (fire and livestock grazing) have driven them to extinction and have favoured the contemporary expansion of heathlands. Based on this P. uncinata case, we discuss how local extinctions can affect management and conservation policies negatively.     

Are small-scale overstory gaps effective in promoting the development of regenerating oaks (Quercus ithaburensis) in the forest understory?

We investigated the effect of small-scale overstory gaps on the ecophysiology and growth of Quercus ithaburensis saplings. The study aim was to characterize how changes in daily exposure to direct beam radiation affect photosynthetic performance in the short term and growth and biomass partitioning in the long term. Using individual net-houses, the following treatments were applied: (a) Unshaded (daily irradiance = 100 %), (b) shading net with no gap (Shade-daily irradiance = 6 %), (c) shading net with 1 h gap allowing direct beam radiation (11:00 am–12:00 pm, Shade+1-irradiance = 20 %), (d) shading net with 3 h gap (11:00 am–2:00 pm, Shade+3-irradiance = 44 %). The experiment was performed in an irrigated field. We measured growth, biomass allocation, leaf traits, daily courses of leaf gas exchange and water potential. Oak dry-weight increased while height to dry-weight ratio and specific leaf area decreased with increasing daily exposure to direct beam radiation. Leaf chlorophyll content was less affected. Higher net carbon assimilation rates (A), stomatal conductance (gs) and A/gs were associated with higher instantaneous photosynthetic photon flux density (PPFD) throughout the entire experimental PPFD range. However, during gap-hours, while exposed to saturating radiation levels of similar level (ca. 1,800 µmol photon m^?2 s^?1), A in the Shade+1 oaks was about half that of the Shade+3 oaks and nearly one-third that of the Unshaded oaks. Patterns of gs, intercellular CO₂ (Ci) and quantum efficiency of photosystem II pointed towards the possibility of a metabolic limitation. In conclusion, oaks benefited significantly from small scale overstory gaps though their capacity to utilize transient saturating radiation levels decreased with decreasing gap duration.     

Technical overview of nuclear microsatellites for Fagus sp., and their utility in F. sylvatica from the central Balkans (Serbia)

ABSTRACT

Selectively neutral nuclear microsatellites (SSRs) are available for Fagus sp., and have been used in F. sylvatica, an ecologically and economically most important European Fagus species. We provide a comprehensive technical overview of available Fagus sp. SSRs (185 loci), carry out meta-analysis of loci used in F. sylvatica (62 loci employed in 62 surveys), and validate a set of 16 loci in 45 individuals of this species from the central Balkans (Serbia). Erroneous usage of marker’s names/authors is rather frequent, and loci successfully used in a number of studies are characterized by other authors by high prevalence of null alleles and even multilocus amplification products. Frequent occurrence of null alleles at FS4-46, used in 26 surveys to date, most likely indicates a failure to record multiple alleles at this locus. Twelve loci are reliable/informative in F. sylvatica from the Balkans (5–18 alleles/locus, H_E ranging from 0.523 to 0.850), while four loci are characterized by high prevalence of null alleles (sfc0161 and sfc1063) and multilocus amplification products (FS4-46 and Fagsyl_007038). Our findings are important for future population genetics and studies on adaptation of F. sylvatica to its environment, because the latter rely on both selectively neutral and adaptive markers under selection.     

Does exceeding the critical loads for nitrogen alter nitrate leaching,the nutrient status of trees and their crown condition at Swiss Long-term Forest Ecosystem Research (LWF) sites?

Nitrogen (N) deposition exceeds the critical loads for this element in most parts of Switzerland apart from the Alps. At 17 sites (8 broadleaved stands, 8 coniferous stands, and 1 mixed stand) of the Swiss Long-term Forest Ecosystem Research network, we are investigating whether N deposition is associated with the N status of the forest ecosystems. N deposition, assessed from throughfall measurements, was related to the following indicators: (1) nitrate leaching below the rooting zone (measured on a subset of 9 sites); (2) the N nutrition of the forest stand based on foliar analyses (16 sites); and (3) crown defoliation, a non specific indicator of tree vitality (all 17 sites). Nitrate leaching ranging from about 2 to 16 kg N ha⁻¹ a⁻¹ was observed at sites subjected to moderate to high total N deposition (>10 kg ha⁻¹ a⁻¹). The C/N ratio of the soil organic layer, or, when it was not present, of the upper 5 cm of the mineral soil, together with the pool of organic carbon in the soil, played a critical role, as previous studies have also found. In addition, the humus type may need to be considered as well. For instance, little nitrate leaching (<2 kg N ha⁻¹ a⁻¹) was recorded at the Novaggio site, which is subjected to high total N deposition (>30 kg ha⁻¹ a⁻¹) but characterized by a C/N ratio of 24, large organic C stocks, and a moder humus type. Foliar N concentrations correlated with N deposition in both broadleaved and coniferous stands. In half of the coniferous stands, foliar N concentrations were in the deficiency range. Crown defoliation tended to be negatively correlated with N concentrations in the needles. In the majority of the broadleaved stands, foliar N concentrations were in the optimum nutritional range or, on one beech plot with high total N deposition (>25 kg ha⁻¹ a⁻¹), above the optimum values. There was no correlation between the crown defoliation of broadleaved trees and foliar concentrations.     

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.     

Dating branch growth units in a tropical tree using morphological and anatomical markers: the case of Parkia velutina Benoist (Mimoso?deae)

Context

In tropical areas, studies based on the retrospective analysis of tree development have focused principally on growth ring research. The interpretation of primary growth markers is overlooked although it opens perspectives to provide long time-series on tree-crown development.

Aims

This study focused on Parkia velutina, an emergent tree of neotropical rain forests. Our objectives were (1) to characterize the phenological cycle of this species, and (2) to identify temporally interpretable morphological and anatomical markers.

Methods

We collected dominant branches in 14 adult trees and identified growth markers that limit longitudinal and radial increments. We coupled this approach with a 2-year phenological survey of 20 trees.

Results

Leaf shedding, growth unit elongation and growth ring formation define the phenological cycle. At tree scale, this cycle is synchronous and affects all axes. At population scale, trees can be desynchronized. This cycle is annual despite some slight variability. Successive growth units and growth rings are easily identifiable.

Conclusion

Dating a branch by counting the number of growth units or growth rings is possible in many years with a reasonable error. Nevertheless, estimating their precise month of formation in order to study climatic influences remains difficult.