Effects of selection cutting on the forest structure and species diversity of evergreen broa-leaved forest in northern Fujian, southern China

The short-term effects of selection cutting of different intensities on the forest structure and species diversity of evergreen broad-leaved forest in northern Fujian Province were investigated and analyzed. The results showed that selection cutting of low and medium intensities caused little variation in the forest structure. After cutting, the dominant species retained their leading status in the community. However, the community structure changed significantly following selection cutting of high and extra-high intensities; the status of the dominant species of the community declined dramatically. Some tree species began to disappear from the sampling plots. Except for extra-high intensity cutting, the diversity of tree species did not change significantly for the other three cutting intensities. However, the evenness of the stands was very different among the four kinds of cutting plots. For low and medium intensity selection cutting, the evenness declined slightly. For extra-high intensity selection cutting, the evenness increased to some extent, which might be due to a more even distribution of tree species after cutting. Cutting operations resulted in some adverse reactions to development of arborous species diversity of evergreen broad-leaved forest, particularly serious damage to the forest canopy. But the rational selection cuttings, which may benefit the restoration and maintenance of species diversity over a long period and may come about from the variations in environmental factors such as sunlight, temperature and humidity.     

Decadal (2003–2013) changes in liana diversity,abundance and aboveground biomass in four inland tropical dry evergreen forest sites of peninsular India

In 2013, we re-inventoried all lianas(C1 cm diameter measured at 1.3 m from the rooting point) in four1-ha permanent plots distributed one each in four sites of inland tropical dry evergreen forest on the Coromandel Coast(Pudukottai district) of peninsular India, established in 2003. Among the four sites, Shanmuganathapuram(SP)and Araiyapatti(AP) were much disturbed and the other two sites(Karisakkadu—KR and Maramadakki—MM)were moderately disturbed. We inventoried a total of 3425 lianas representing 37 species of 33 genera and 22 families.Over a decade(2003–2013) liana species richness increased at two sites(MM and SP) and no changes occurred at the other two sites. Liana abundance increased by 210, 211, 164 and 162 individuals at sites AP, KR, MM and SP, respectively, and basal area increased(from 1.09 to1.76 m2 at AP, 0.67 to 0.86 m2 at KR, 1.68 to 2.06 m2 at MM, and from 0.44 to 1.06 m2 at SP). Over a 10-year period, three species(Abrus precatorius, Canavalia virosa,and Cocculus hirsutus) were lost and five species(Gloriosa superba, Ampelocissus tomentosa, Capparis sepiaria,Aganosma cymosa and Tiliacora acuminata) were newly added. Total aboveground biomass increased by 18.5, 0.74,3.6 and 9.5 Mg ha-1, respectively, at sites AP, KR, MM and SP.     

Effects of habitat type, vegetation structure, and proximity to forests on bird species richness in a forest–agricultural landscape of West Java, Indonesia

To halt biodiversity loss in the humid tropics of developing countries, it is crucial to understand the roles and effects of human-modified landscapes with fragmented forest remnants in maintaining biodiversity while fulfilling the demands of local communities and reducing poverty. To implement appropriate landscape planning for conserving biodiversity and ecosystem functioning, appropriate information is required about parameters of habitat suitability among various anthropogenic habitats with a range of distances to forests and vegetation characteristics, but such information is limited. We examined differences in avian communities between a remnant forest and four types of man-made forest (two mature plantations and two agroforests) in a forest–agricultural landscape of West Java, and we analyzed the effects of both local and landscape factors on various types of species richness in this landscape. The results from non-metric multidimensional scaling revealed avifauna in the two types of agroforest was clustered separately from that in the remnant forest, mainly because drastic declines in the abundance of forest specialists (including IUCN red-listed species) and their replacement with open-habitat generalists. The mixed-tree agroforests were colonized by 30 % of forest specialists and forest-edge species found in the remnant forest, and maintained the highest richness of species endemic to Indonesia among man-made forests, implying that some forest specialists and endemics might have adapted to ancient landscape heterogeneity. High proportion of insectivorous birds was found in the remnant forest (more than 50 %) and drastically decline in man-made forests, although the species richness of insectivores did not decline significantly in broad-leaved plantations. We concluded that protection of remnant forests should be prioritized to conserve forest bird diversity. However, as different environmental factors affected the richness values of different ecological groups, appropriate landscape design and habitat management could improve functional diversity in forest–agricultural landscapes in the tropics.     

Effect of forest thinning on hydrologic nitrate exports from a Nsaturated plantation

Although several studies have assessed the effects of thinning on water quality,including nitrogen(N)exports,few have examined N-saturated plantations.This study assessed the short-term effect of thinning on N exports from a N-saturated plantation forest in northern Kyushu,western Japan,that was thinned(43%of basal area)during January-March 2012.Water levels at the gauging station were continually measured,and streamwater baseflow and stormflow samples were collected before(2011)and after(2013)forest thinning.Annual precipitation before(2469 mm)and after(2418 mm)forest thinning differed little,and annual water discharge after thinning(1641 mm)was similar to that before thinning(1609 mm).However,direct flow during stormflow periods was higher after thinning(260 mm)than before(153 mm).The concentrations of major ions in stream water did not differ before and after thinning.As a result,the high annual dissolved inorganic N(DIN)exports differed little before(35.8 kg N ha^-1 a^-1)and after(36.5 kg N ha^-1 a^-1)forest thinning.DIN exports during stormflow periods were slightly higher after(12.2 kg N ha^-1 a^-1)than before thinning(10.5 kg N ha^-1 a^-1)and were proportional to the increased direct flow after thinning(561 mm after vs.470 mm before thinning).We concluded that thinning does not affect annual N exports from the N-saturated plantation forest,but it can increase the proportion of N exported during stormflow periods in proportion to increased water volume of direct flow after thinning.     

Analysis of temporal changes in land cover and landscape metrics of a managed forest in the west Black Sea region of northern Turkey: 1970–2010

Forest structure changes continuously by natural and anthropogenic effects. Because the level of goods and services provided by forest ecosystems are related to this structure, some attributes have to be controlled while they are being managed. In this paper we describe the long-term temporal changes in land area and landscape metrics related to different land uses of a managed forest in Turkey. The study was carried out for the Daday Forest Planning Unit located in the west Black Sea region of northern Turkey. The total area is 16,813 ha and besides wood production, it is managed for erosion control, public health, aesthetics, and recreation. Stand type maps that were constructed in 1970, 1989, 1999, and 2010 were used in this analysis. Transition matrixes that illustrate area changes among cover types and temporal changes on some landscape metrics were obtained using Geographic Information Systems. Stands were separated into small patches, and thus the number of patches increased nearly two-fold between 1970 and 2010. The total forest edge increased and through the associated fragmentation, the amount of core forest area decreased at the landscape scale. Landscape metrics were applied to digitized versions of historical maps to assess how forest area changed. Human use of the land has changed, forest management practices have evolved, and these along with natural forest growth have contributed to interesting changes in landscape character.     

Effect of forest structure and health on the relative surface temperature captured by airborne thermal imagery – Case study in Norway Spruce-dominated stands in Southern Finland

The effect of forest structure and health on the relative surface temperature captured by airborne thermal imagery was investigated in Norway Spruce-dominated stands in Southern Finland. Airborne thermal imagery, airborne scanning light detection and ranging (LiDAR) data and 92 field-measured sample plots were acquired at the area of interest. The surface temperature correlated most negatively with the logarithm of stem volume, Lorey’s height and the logarithm of basal area at a resolution of 254?m² (9?m radius). LiDAR-derived metrics: the standard deviations of the canopy heights, canopy height (upper percentiles and maximum height) and canopy cover percentage were most strongly negatively correlated with the surface temperature. Although forest structure has an effect on the detected surface temperature, higher temperatures were detected in severely defoliated canopies and the difference was statistically significant. We also found that the surface temperature differences between the segmented canopy and the entire plot were greater in the defoliated plots, indicating that thermal images may also provide some additional information for classifying forests health status. Based on our results, the effects of forest structure on the surface temperature captured by airborne thermal imagery should be taken into account when developing forest health mapping applications using thermal imagery.     

Disturbance history,species diversity,and structural complexity of a temperate deciduous forest

Stand structural complexity enhancement is an increasingly popular management objective,especially on public lands.Complex stand structures are hypothesized to support a relatively high degree of native forest diversity and be more resistant and resilient to disturbances.Complex structures are characterized by the presence of deadwood and heterogeneity of tree-size classes and tree architecture.Relatively little is known about how discrete disturbance events affect structural complexity and compositional diversity in Quercus-dominated stands at fine spatial scales(i.e.neighborhoods).We established 200.05 ha fixed-radius plots on the Sipsey Wilderness of William B.Bankhead National Forest in northern Alabama to quantify woody plant species composition and structure.Trees were mapped on each plot to quantify overstory structural complexity and compositional diversity.We extracted two cores from all canopy Quercus spp.C 5 cm diameter at breast height to quantify age,recruitment pulses,and reconstruct canopy disturbance history.Shannon species diversity in the sampled area was 1.75 for trees,2.08 for saplings,and 1.69 for seedlings.Quercus alba had the greatest basal area,and Ostrya virginiana had the highest density.The stand exhibited a reverse J-shaped distribution with a q-factor of 1.72.The oldest Quercus dated to 1795,and the largest recruitment pulse occurred in the 1870s.The mean return interval for intermediateseverity disturbance was 38 years.Although we documented no relationships between disturbance frequency and compositional diversity at the neighborhood scale(0.05 ha),less frequent disturbance was associated with higher structural complexity(r^2=0.258,p=0.026)at the neighborhood scale.We suggest that localized disturbance increases species diversity and structural complexity,but these processes are manifest at the stand level and not at the neighborhood scale.We conclude that the spatial variability(i.e.size,shape,orientation,microsite conditions)is likely more influential on diversity and complexity than the temporal variation(frequency)of these processes at the neighborhood scale.     

Error propagation in stock-difference and gain–loss estimates of a forest biomass carbon balance

According to the United Nations International Panel on Climate Change good practice guidance, an annual forest biomass carbon balance (AFCB) can be estimated by either the stock-difference (SD) or the gain–loss (GL) method. An AFCB should be accompanied by an analysis and estimation of uncertainty (EU). EUs are to be practicable and supported by sound statistical methods. Sampling and model errors both contribute to an EU. As sample size increases, the sampling error decreases but not the error due to errors in model parameters. Uncertainty in GL AFCB estimates is dominated by model-parameter errors. This study details the delta technique for obtaining an EU with the SD and the GL method applicable to the carbon in aboveground forest biomass. We employ a Brownian bridge process to annualize the uncertainty in SD AFCBs. A blend of actual and simulated data from three successive inventories are used to demonstrate the application of the delta technique to SD- and GL-derived AFCBs during the years covered by the three inventories (SD) and rescaled national wood volume harvest statistics (GL). Examples are limited to carbon in live trees with a stem diameter of 7 cm or greater. We confirm that a large contribution to the uncertainty in an AFCB comes from models used to estimate biomass. Application of the delta technique to summary statistics can significantly underestimate uncertainty as some sources of uncertainty cannot be quantified from the available information. We discuss limitations and problems with the Monte Carlo technique for quantifying uncertainty in an AFCB.     

Analysis of forest structural complexity using airborne LiDAR data and aerial photography in a mixed conifer–broadleaf forest in northern Japan

Determining forest structural complexity,i.e.,a measure of the number of different attributes of a forest and the relative abundance of each attribute,is important for forest management and conservation.In this study,we examined the structural complexity of mixed conifer–broadleaf forests by integrating multiple forest structural attributes derived from airborne Li DAR data and aerial photography.We sampled 76 plots from an unmanaged mixed conifer–broadleaf forest reserve in northern Japan.Plot-level metrics were computed for all plots using both field and remote sensing data to assess their ability to capture the vertical and horizontal variations of forest structure.A multivariate set of forest structural attributes that included three Li DAR metrics(95 th percentile canopy height,canopy density and surface area ratio) and one image metric(proportion of broadleaf cover),was used to classify forest structure into structural complexity classes.Our results revealed significant correlation between field and remote sensing metrics,indicating that these two sets of measurements captured similar patterns of structure in mixed conifer–broadleaf forests.Further,cluster analysis identified six forest structural complexity classes includingtwo low-complexity classes and four high-complexity classes that were distributed in different elevation ranges.In this study,we could reliably analyze the structural complexity of mixed conifer–broadleaf forests using a simple and easy to calculate set of forest structural attributes derived from airborne Li DAR data and high-resolution aerial photography.This study provides a good example of the use of airborne Li DAR data sets for wider purposes in forest ecology as well as in forest management.     

Climate change impacts on stand structure and competitive interactions in a southern Swedish spruce–beech forest

It is believed that European beech (Fagus sylvatica L.) will increase its competitive ability at its northern range margin in Scandinavia due to climate change. In mixed old-growth forests of beech and Norway spruce (Picea abies (L.) Karst.) at Siggaboda nature reserve (southern Sweden), stand structure characteristics were sequentially recorded in the years 2004, 2005 and 2007 as well as growth in stem diameter using tree-coring analyses. Using these measurements, we studied the effects on stand dynamics of an extreme storm event (2005 “Gudrun” hurricane), drought and heat (mid-summer 2006, spring 2007) and subsequent bark beetle attacks on spruce (growing season 2007), overlaid with warming tendencies. The storm, which caused disastrous damage in many stands nearby, had comparatively little impact on the structure of the spruce–beech stand. All together, only 32 trees (19 spruces, 10 beeches, 3 other species) per hectare were thrown or broken mainly in the leeward direction (NE) or impacted by secondary damage by uprooted neighbour trees; this represents 7% of the total tree number and 11% of the growing stock. Diameter and height structure did not change significantly. However, the 2006 drought and the 2007 attack of biotic agents changed the stand structure and composition strongly due to the death of about 19% of the dominating older spruce trees that accounted for 35% of total stand volume. This resulted in a considerable increase in beech’s contribution to stem number (4% increase) and wood volume of the living stand (7% increase). A comparison of diameter growth of beech and spruce during the periods 1894–1949 and 1950–2005 showed a distinct decrease in growth superiority of spruce during the last 50 years. These results support the idea of a northward migration of European beech as a nemoral tree species in Sweden, due to a higher tolerance to the abiotic and biotic threats accompanying climate change and an increased competitive ability compared to boreal tree species Norway spruce.     

Comparison of structural diversity of tree-crop associations in Peripheral and Buffer zones of Gachabari Sal forest area, Bangladesh

The original version of this article unfortunately contained three mistakes.
（1） The spelling of the [A. Nishad＇] name was incorrect. The corrected spelling is given below.     

Review of study on mineralization, saturation and cycle of Nitrogen in forest ecosystems

Nitrogen is one of the most important elements that can limit plant growth in forest ecosystems. Studies of nitrogen mineralization, nitrogen saturation and nitrogen cycle in forest ecosystems is very necessary for understanding the productivity of stand, nutrient cycle and turnover of nitrogen of forest ecosystems. Based on comparison and analysis of domestic and international academic references related to studies on nitrogen mineralization, nitrogen saturation and nitrogen cycle in recent 10 years, the current situation and development of the study on these aspects, and the problems existed in current researches were reviewed. At last, some advices were given for future researches.     

Genetic and historical studies on the origin of Norway spruce in Białowieża Primeval Forest in Poland

Białowieża Primeval Forest lies within the boreal part of the Norway spruce range, which, according to pollen data, was formed by a refugium located in the Russian Upland. However, recent genetic studies have indicated that spruce from the Eastern Carpathian refugium also occurs in Białowieża Forest. In order to investigate whether the Norway spruce from the Eastern Carpathian refugium migrated naturally into the boreal part of the Norway spruce range, we assessed the refugial origin of 234 of the oldest Norway spruce individuals from Białowieża Forest using mitochondrial marker mt15-D02. Out of the trees that we studied, 64.8% carried mitotype 1, which is specific to the Carpathian refugium, while 35.2% had mitotype 3, specific to the Russian refugium. Our genetic analysis, combined with historical data on forest management in this part of Europe, argues for a natural contribution of spruce from the Eastern Carpathian refugium during postglacial recolonization of Białowieża Primeval Forest.     

Rural household and forest: an evaluation of household’s dependency on community forest in Nepal

The aim of this paper is to analyze the level of dependency of rural households on forests, based on the economic status of the households and the property regimes of forests. The analysis of household-level dependency suggests that large numbers of rural households are benefiting regularly from their community forests. Out of three forest property regimes examined, community forests were found to be the most prominent sources for supplying forest products to local households. Analysis of the degree of forest-products dependency and the economic status of households shows that the low economic status households rely more on the community forest than the economically better-off households. In addition, a ² analysis indicates that the economic status of households affects the degree of forest-product collection activities. The results show three types of property regime with respect to forest management in Chitwan. Each regime holds its own ownership rights, which control the harvesting of forest products and provides incentives to the local households.     

Does the effect of forest roads extend a few meters or more into the adjacent forest? A study on understory plant diversity in managed oak stands

Roads are recognised as having different ecological roles such as barrier, corridor or habitat, but the spatial extent of road effects on plant communities in forests remains unclear. We studied the effect of forest road distance on plant understory diversity at 20 sites in young and adult oak stands in a French lowland forest with a long history of management and road construction. All vascular and bryophyte species were collected at five distances ranging from the road verge to 100 m into the adjacent forest stand. We analysed species composition, individual species response, a priori life-history traits response – life form, habitat preference and dispersal mode – and environmental indicator values in relation to road distance and stand age. Plant composition strongly differed between road verge and forest interior habitats. The main road effect extended less than 5 m into the forest stand. A third habitat was detected at the forest-road edge resulting from the road effect on light and soil conditions, and from edge-specific topography. Non-forest species were almost absent from the forest interior. In contrast, many bryophytes and several vascular plants kept away from the road. We identified a posteriori six species groups that better explained the variability of plant response profiles than a priori life-history traits. Plant response to road distance was also dependent on stand age: some species colonised from the road into the forest interior in young stands following regeneration cutting, while other species displayed the reverse pattern in adult stands once canopy closed above the forest road. Even if the depth of forest road effect measured in lowland managed stands was narrow, building of a new forest road has non-negligible effects on plant population dynamics. Forest managers should take into account the impacts of roads on biodiversity, since the expected intensification of silviculture in response to global changes is set to accentuate the effect of forest roads. We recommend further study on the role of dispersal by vehicles (i.e. agestochory) in road effects.     

Fuel loads,snag abundance,and snag recruitment in an unmanaged Jeffrey pine–mixed conifer forest in Northwestern Mexico

Management of downed woody fuels and snags (standing dead trees) is receiving increasing attention because of their ecosystem values and effects on potential fire behavior. Research has correlated the abundance of many wildlife species with snags and downed woody material but very little information exists of the abundance and arrangement of these forest structures, particularly in unmanaged forests. Conifer forests in northwestern Mexico have not experienced systematic fire suppression or harvesting making them unique in western North America. In 1998, average snag density in Jeffrey pine–mixed conifer forests in the Sierra San Pedro Martir (SSPM) National Park was 3.95 snags/ha but 35% of inventoried plots had no snags. In 2002, average snag density significantly increased to 5.10 snags/ha after a multiple-year drought. Average surface and ground fuel loads were 15.8 and 8.7 t/ha, respectively. High variability characterized all snag and fuel attributes measured in this forest. This high amount of variation is probably the result of the relatively intact frequent surface fire regime and because no harvesting has occurred in the sampled area. The patchy distribution of snags observed argues against the application of uniform targets for snag retention across similar forested landscapes. An improvement in management guidelines would be to manage for snag density and large fuels over moderate spatial scales (hundreds of hectares) instead of on a per hectare basis. Forest fragmentation and diverse ownerships in many western United States forests complicates this recommendation. Conservation of the forests in the SSPM is critical because it is the last landscape-scale, old-growth mixed conifer forest in western North America with a relatively intact frequent fire regime.     

Managing forest complexity through application of disturbance–recovery knowledge in development of silvicultural systems and ecological rehabilitation in natural forest systems in Africa

How can we accommodate the diversity in tree species and sizes in mixed-species/size/age stands in the sustainable management of natural forests and woodlands in Africa for diverse timber and non-timber forest products and services, and during rehabilitation of degraded forests? The evergreen moist tropical to warm-temperate forests, from the equator to 34°S, generally function through relative shade tolerance. The tropical, strongly seasonal, drier deciduous woodlands generally function through adaptation to fire and/or grazing/browsing. Silvicultural systems, when implemented, are often not aligned with the ecological characteristics of the particular forest systems or the specific targeted species. This paper presents the concept of using the basic disturbance–recovery processes, with recovery development via stand development stages, as the basis for the development of silvicultural systems suitable for maintenance of forest complexity. Grain analysis and stem diameter distributions, analysed from resource inventories, are used to determine the specific shade- or fire-tolerance characteristics of key economical and ecological tree species. The gained knowledge of the ecosystem and species characteristics (including modes of regeneration, i.e. from seed or vegetative regrowth) and processes is used to simulate the ecological disturbance–recovery processes through the development of mixed silvicultural systems, such as a single-tree selection system, a group felling system and a coppice management system in the same forest. Very similar concepts are used to develop rehabilitation strategies to recover the processes towards regrowth stands of diverse species and structure: through stands of introduced plantations and invader tree species; and through early regrowth stages in deciduous woodlands and evergreen forests, after fire, slash-and-burn traditional agriculture, charcoal production or open-cast mining.     

Gap evapotranspiration and drainage fluxes in a managed and a virgin dinaric silver fir–beech forest in Slovenia: a modelling study

The monthly water balance in gaps in a managed Dinaric silver fir–beech forest and a virgin forest remnant located in SE Slovenia was modelled using a capacity water balance model for two growing seasons. Two gaps of different size (ca. 0.07 and 0.15 ha) were selected in each forest and plots for soil moisture monitoring were established in each gap (2–4) and in the surrounding forest (2–3). We report on the modelled actual evapotranspiration (AET) and potential evapotranspiration (PET) and drainage fluxes (DF) from the rooting zone at the plots. Precipitation over the 2001 growing season (May–October) was considerably drier than average and that for 2002 growing season was wetter than average. Modelled AET for the 2001 growing season varied between 88% and 96% of PET for the managed forest plots and between 90% and 100% for the virgin forest plots. The values for the gap plots varied between 87% and 100% at the managed forest site and between 92% and 96% for the gaps in the virgin forest site. Monthly AET values declined to 57–59% of PET at plots in the centre of the gaps in the managed forest site and to 63–74% in the gaps in the virgin forest site (July), indicating that the highest drought stress occurs in gap centres. For 2002 growing season, AET for all plots was 100% of PET. Modelled DF values in 2001 were 13–35% of rainfall for plots in the gap centres and 12–16% for plots in the forest at the managed forest site. On an average, gap DF values were 20% (154 mm) higher than the forest plot values. DF values in 2002 were similar for all plots at the managed forest site, 31–33% of rainfall. At the virgin forest site, 2001 growing season, DF values varied between 12% and 30% of rainfall at the forest plots and between 12% and 32% at the gap plots. In 2002, DF values for all plots in the virgin forest site varied between 24% and 38% of growing season rainfall. The varying development of vegetation and forest in the gaps of the virgin forest remnant resulted in more variable evapotranspiration and DF during the drought year 2001, with values not as clearly related to distance from the gap centre as in the managed forest site.