Showing papers in "Journal of Forestry Research in 2014"

A review of the roles of forest canopy gaps

Abstract: Treefall gap, canopy opening caused by the death of one or more trees, is the dominant form of disturbance in many forest systems worldwide. Gaps play an important role in forest ecology helping to preserve bio- and pedo-diversity, influencing nutrient cycles, and maintaining the complex structure of the late-successional forests. Over the last 30 years, numerous reviews have been written describing gap dynamics. Here we synthesize current understanding on gap dynamics relating to tree regeneration with particular emphasis on gap characteristics considered critical to develop ecologically sustainable forest management systems and to conserve native biodiversity. Specifically, we addressed the question: how do gaps influence forest structure? From the literature reviewed, the size of gaps induces important changes in factors such as light intensity, soil humidity and soil biological properties that influence tree species regeneration and differ in gaps of different sizes. Shadetolerant species can colonize small gaps; shade-intolerant species need large gaps for successful regeneration. Additionally, gap dynamics differ between temperate, boreal, and tropical forests, showing the importance of climate differences in driving forest regeneration. This review summarizes information of use to forest managers who design cutting regimes that mimic natural disturbances and who must consider forest structure, forest climate, and the role of natural disturbance in their designs.

Effects of gaps on regeneration of woody plants: a meta-analysis

Abstract: Forest gaps, openings in the canopy caused by death of one or more trees, have a profound effect on forest regeneration and drive the forest growth cycle. It is therefore necessary to understand the effects of forest gaps on regeneration for modern forest management. In order to provide a quantitative assessment of the effects of forest gaps on regeneration of woody plants, we conducted this review of gap effects on woody plant regeneration on the basis of 527 observations from 42 individual papers, and reported the results of these data in a meta-analysis. Overall, densities of regenerated woody plants were significantly greater (359%) in forest gaps than on the closed-canopy forest floor. The regeneration density in gaps of plantation forests was significantly greater (P < 0.05) than that of natural forest because the regeneration in gaps of plantation forests was improved by both gap effects and experimental measures. Similarly, in comparison to natural gaps, regeneration was better enhanced in artificial gaps. Regeneration density exhibited a significantly positive correlation with gap size, but a negative correlation with gap age because the gap size decreased with increasing gap age. Shade tolerance of woody plants affected regeneration density in gaps and understory. Average regeneration density of shade-tolerant species exhibited a significantly positive response to gaps but densities remained lower in total than those of intermediate and shade-intolerant species. Gap effects on regeneration decreased in response to increasing temperature and precipitation because of the limiting effects of lower temperature and moisture on woody plant regeneration. In summary, forest gaps enhance woody plant regeneration, and the effects of gaps varied by forest type, gap characteristics, environmental factors and plant traits. The results of this meta-analysis are useful for better understanding the effects and roles of gaps on forest regeneration and forest management.

Non-timber forest products and household incomes in Bonga forest area, southwestern Ethiopia

Abstract: We identified the major non-timber forest products (NTFPs), their contributions to household incomes, and the determinants influencing engagement of households in using NTFPs in the Bonga forest area of Gimbo and Decha Districts of Kaffa Zone, southwest Ethiopia. Six Kebeles (the lowest administrative unit in Ethiopia) were sampled from two Districts and 150 households were randomly sampled using proportional-to-size techniques based on the number of farm households in each Kebele. Secondary data were collected from and focus group discussions were conducted with selected individuals. The farmers diversified livelihood activities such as crop and livestock production, collection of NTFPs and off-farm activities. NTFPs played a significant role in household incomes. The contribution from the major NTFPs (forest coffee, honey and spices) accounted for 47% of annual household income. The role of NTFPs was influenced by a number of factors. Variables including being native to the area (+), total land holding (+), possession of livestock (+) and access to extension (+) significantly affected forest coffee production. Age of household head (−), land holding (+) and distance of the market from the residence (−) significantly affected honey production. Size of landholding (+), distance to market (−) and distance of the forest from the residence (−) were significant variables determining the NTFP incomes derived by the households. Attention is needed in the design of policies and strategies for the well-being of households to the contribution of NTFPs to local incomes and the variables that affect the collection of NTFPs must be considered.

Soil quality index as a tool for Scots pine (Pinus sylvestris) monoculture conversion planning on afforested, reclaimed mine land

Abstract: In Central Europe, a large portion of post-mining sites were afforested with Scots pine, which is characterized by good adaptability and a tolerance for poor habitat at the beginning of forest ecosystem development. Conversion of monoculture on mine sites into more biodiverse mixed hardwood forests, especially on more fertile deposits, can be an emerging need in this part of Europe in next decades. The ability to classify the forests at these post-mining sites will facilitate proper species selection as well as the management and formation of the developed ecosystem’s stability. This work describes the guidelines that can be followed to assess reclaimed mine soil (RMS) quality, using the mine soil quality index (MSQI) and a classification of developed forest sites as a basis of tree-stand species selection and conversion of pine monocultures. The research was conducted on four post-mining facilities (lignite, hard coal, sulphur, and sand pit mining areas) on different RMS substrates dominant in Central Europe. Soil quality assessment takes into account the following features of the soil: texture soil nutrients (Ca, Mg, K, Na, P); acidity (pH KCl); and Corg-to-Nt ratio in the initial organic horizon. An analysis was conducted of classification systems using the MSQI validation correlation (at p =0.05) with vegetation features affected by succession: aboveground biomass of forest floor and ecological indicators of vascular plants (calculated on the basis of Ellenberg’s (2009) system). Eventually, in the analysed data set, the MSQI ranged from 0.270 for soils on quaternary sands to 0.720 for a mix of quaternary loamy sands with neogene clays. Potential forest habitat types and the role of the pine in the next generation of tree stands on different RMS parent rock substrate were proposed.

Fungal inoculation induces agarwood in young Aquilaria malaccensis trees in the nursery

Abstract: Fungi are often used to induce agarwood in Aquilaria trees. This study was conducted to evaluate the effect of several fungi on agarwood formation over time in young Aquilaria malaccensis (Lam.) trees. Typical changes in the length and light intensity of the resulting discoloration were observed after three and six month periods following inoculation. Wood samples were observed microscopically and classified into several light intensity groups. The discoloration length was measured longitudinally. The duration after inoculation affected the mean of discoloration length: the 6-month old sample (1.70 cm) had a wider discoloration zone when compared to the 3-month old sample (1.17 cm). When measuring the discoloration intensity, a positive relationship with time was perceived. Digital images, captured using a camera-equipped microscope, revealed that wood samples collected after six months appeared to be 1.8-times darker than after three months. We concluded that time, not the species of any of the tested fungi, had significant effect on discoloration length and intensity. Gas chromatography/mass spectrometry (GCMS) analysis of the 6-month old sample yielded some important agarwood compounds such as benzylacetone, anisylacetone, guaiene and palustrol. This demonstrates that the tested fungi have the ability to induce agarwood formation in nursery A. malaccensis trees.

Estimating Pinus palustris tree diameter and stem volume from tree height, crown area and stand-level parameters

Abstract: Accurate and efficient estimation of forest growth and live biomass is a critical element in assessing potential responses to forest management and environmental change. The objective of this study was to develop models to predict longleaf pine tree diameter at breast height (dbh) and merchantable stem volume (V) using data obtained from field measurements. We used longleaf pine tree data from 3,376 planted trees on 127 permanent plots located in the U.S. Gulf Coastal Plain region to fit equations to predict dbh and V as functions of tree height (H) and crown area (CA). Prediction of dbh as a function of H improved when CA was added as an additional independent variable. Similarly, predic- tions of V based on H improved when CA was included. Incorporation of additional stand variables such as age, site index, dominant height, and stand density were also evaluated but resulted in only small improve- ments in model performance. For model testing we used data from planted and naturally-regenerated trees located inside and outside the geographic area used for model fitting. Our results suggest that the models are a robust alternative for dbh and V estimations when H and

Wildland fires and moist deciduous forests of Chhattisgarh, India: divergent component assessment

Abstract: We studied moist deciduous forests of Chhattisgarh, India (1) to assess the effect of four levels of historic wildland fire frequency (high, medium, low, and no-fire) on regeneration of seedlings in fire affected areas during pre and post-fire seasons, (2) to evaluate vegetation structure and diversity by layer in the four fire frequency zones, (3) to evaluate the impact of fire frequency on the structure of economically important tree species of the region, and (4) to quantify fuel loads by fire frequency level. We classified fire-affected areas into high, medium, low, and no-fire frequency classes based on government records. Tree species were unevenly distributed across fire frequency categories. Shrub density was maximum in zones of high fire frequency and minimum in low-frequency and no-fire zones. Lower tree density after fires indicated that regeneration of seedlings was reduced by fire. The population structure in the high-frequency zone was comprised of seedlings of size class (A) and saplings of size class (B), represented by Diospyros melanoxylon, Dalbergia sissoo, Shorea robusta and Tectona grandis. Younger and older trees were more abundant for Tectona grandis and Dalbargia sissoo after fire, whereas intermediate-aged trees were more abundant prefire, indicating that the latter age-class was thinned by the catastrophic effect of fire. The major contributing components of fuel load included duff litter and small woody branches and twigs on the forest floor. Total fuel load on the forest floor ranged from 2.2 to 3.38 Mg/ha. The net change in fuel load was positive in high- and medium-frequency fire zones and negative under low- and no-fire zones. Repeated fires, however, slowly reduced stand stability. An ecological approach is needed for fire management to restore the no-fire spatial and temporal structure of moist deciduous forests, their species composition and fuel loads. The management approach should incorporate participatory forest management. Use of controlled fire, fire lines and mapping of fire prone areas are fundamental principles of fire hazard reduction in these areas.

Forest Road Detection Using LiDAR Data

Abstract: We developed a three-step classification approach for forest road extraction utilizing LiDAR data. The first step employed the IDW method to interpolate LiDAR point data (first and last pulses) to achieve DSM, DTM and DNTM layers (at 1 m resolution). For this interpolation RMSE was 0.19 m. In the second step, the Support Vector Machine (SVM) was employed to classify the LiDAR data into two classes, road and non-road. For this classification, SVM indicated the merged distance layer with intensity data and yielded better identification of the road position. Assessments of the obtained results showed 63% correctness, 75% completeness and 52% quality of classification. In the next step, road edges were defined in the LiDAR-extracted layers, enabling accurate digitizing of the centerline location. More than 95% of the LiDAR-derived road was digitized within 1.3 m to the field surveyed normal. The proposed approach can provide thorough and accurate road inventory data to support forest management.

Fuel properties and combustion characteristics of some promising bamboo species in India

Abstract: We investigated the fuel characteristics of five important bamboo species viz., Dendrocalamus strictus, D. brandisii, D. stocksii, Bambusa bambos and B. balcooa. The selected species cover more than 85% of the total growing stock of bamboo in India. Basic density varied from 0.48 to 0.78 g·cm−3 among the bamboo species studied. Ash content, volatile matter content and fixed carbon content ranged between 1.4%–3.0%, 77.2%–80.8% and 17.6%–21.1%, respectively. Variation in calorific value (18.7–19.6 MJ·kg−1) was marginal. Fuel value index varied widely (586–2120) among bamboo species. The highest calorific value (19.6 MJ·kg−1) and fuel value index (2120) were found in B. balcooa. Ash elemental analysis revealed that silica and potassium are the major ash forming minerals in bamboo biomass. Silica content ranged from 8.7% to 49.0%, while potassium ranged from 20.6% to 69.8%. We studied combustion characteristics under oxidizing atmosphere. Burning profiles of the samples were derived by applying the derivative thermogravimetric technique which is discussed in detail. The five bamboo species were different in their combustion behaviour, mainly due to differences in physical and chemical properties. We compare fuel properties, ash elemental analysis and combustion characteristics of bamboo biomass with wood biomass of Eucalyptus hybrid (Eucalyptus tereticornis × Eucalyptus camaldulensis).

Spatial variability of soil organic carbon in the forestlands of northeast China

Abstract: Soil organic carbon (SOC) is an effective indicator of soil fertility and productivity, and it varies spatially and temporally in relation to other soil properties. Spatial variability of SOC in the forestlands of northeast China was characterized using geostatistics. Soil samples at the depths of 0–20 cm, 20–40 cm and 40–60 cm were collected from sixty-three temporary plots to evaluate SOC concentration and density (SOCD) and other soil properties. We analyzed correlations between SOC and soil properties. Soil organic carbon concentrations were high. The total amount of C stored in soil (0–60 cm) was 16.23 kg·m−2 with the highest SOCD of 7.98 kgm−2 in topsoil. Soil properties in most cases differed by horizon, suggesting different processes and effects in each horizon. Soil organic carbon had positive relationships with total N, P and K as well as readily available K, but did not show a significant positive correlation with available P. Spatial factors including elevation, slope and aspect affected SOC distribution. Soil organic carbon at 0–60 cm had strong spatial autocorrelation with nugget/sill ratio of 5.7%, and moderate structured dependence was found at 0–20 cm, which indicated the existence of a highly developed spatial structure. Spatial distributions of SOC concentration and SOCD were estimated using regression-kriging, with higher prediction accuracy than ordinary kriging. The fractal dimension of SOC indicated the preferential pattern of SOC distribution, with the greatest spatial heterogeneity and strongest spatial dependence in the northeast-southwest direction.

Analysis of forest cover change at Khadimnagar National Park, Sylhet, Bangladesh, using Landsat TM and GIS data

Abstract: We mapped the forest cover of Khadimnagar National Park (KNP) of Sylhet Forest Division and estimated forest change over a period of 22 years (1988–2010) using Landsat TM images and other GIS data. Supervised classification and Normalized Difference Vegetation Index (NDVI) image classification approaches were applied to the images to produce three cover classes, viz. dense forest, medium dense forest, and bare land. The change map was produced by differencing classified imageries of 1988 and 2010 as before image and after image, respectively, in ERDAS IMAGINE. Error matrix and kappa statistics were used to assess the accuracy of the produced maps. Overall map accuracies resulting from supervised classification of 1988 and 2010 imageries were 84.6% (Kappa 0.75) and 87.5% (Kappa 0.80), respectively. Forest cover statistics resulting from supervised classification showed that dense forest and bare land declined from 526 ha (67%) to 417 ha (59%) and 105 ha (13%) to 8 ha (1%), respectively, whereas medium dense forest increased from 155 ha (20%) to 317 ha (40%). Forest cover change statistics derived from NDVI classification showed that dense forest declined from 525 ha (67%) to 421 ha (54%) while medium dense forest increased from 253 ha (32%) to 356 ha (45%). Both supervised and NDVI classification approaches showed similar trends of forest change, i.e. decrease of dense forest and increase of medium dense forest, which indicates dense forest has been converted to medium dense forest. Area of bare land was unchanged. Illicit felling, encroachment, and settlement near forests caused the dense forest decline while short and long rotation plantations raised in various years caused the increase in area of medium dense forest. Protective measures should be undertaken to check further degradation of forest at KNP.

Afforestation, restoration and regeneration — Not all trees are created equal

Abstract: Undulations in weather patterns have caused climate shifts of increased frequency and duration around the world. The need for additional research and model data on this pressing problem has resulted in a plethora of research groups examining a particular tree species or biome for negative effects of climate change. This review aims to (1) collect and merge recent research data on regeneration within old- and new-growth forests, (2) highlight and expand upon selected topics for additional discussion, and (3) report how shade tolerance, drought tolerance, and inherent plasticity affect tree growth and development. Although shade and drought tolerance have been well studied by a number of research groups, this review reveals that in-depth analysis of a single or a few species in a given area will not generate the data required to implement a successful regeneration plan. Studies using historical accounts of previous species composition, information regarding site seasonality, species competition, and individual responses to drought and shade are needed to (1) develop best management plans and (2) ensure future modeling experiments are focused on a greater variety of species using more innovative methods to evaluate climate change effects.

Floristic diversity and regeneration status of woody plants in Zengena Forest, a remnant montane forest patch in northwestern Ethiopia

Abstract: The study was conducted at Zengena forest, a fragmented remnant montane forest in northwestern Ethiopia, which surrounds Lake Zengena. The purpose was to assess the species composition, diversity and the regeneration status of woody plants. A total of 27 plots of 20 m × 20 m were sampled along the line transects laid down the altitudinal gradient from the edge of the forest encompassing the lake to the edge of the lake in eight aspects. In each plot, woody species were counted and the diameter at breast height and the height of trees and shrubs were measured. A total of 50 woody species belonging to 31 families were found, of which 17 (34%) were trees, 7 (14%) trees or shrubs, 23 (46%) shrubs and 3 (6%) lianas. The overall Shannon-Wiener diversity and evenness indices of woody species were 2.74 and 0.7, respectively. Clausena anisata had the highest relative density (23.5%), Rapanea rhododendroides the highest relative frequency (6.5%) and Prunus africana the highest relative dominance (45%) and importance value index (IVI, 51.6). The total basal area and density of woody plants were 22.3 m2·ha−1 and 2,202 individuals·ha−1, respectively. The population structure showed variations among woody plants and revealed varied regeneration patterns of different species. The importance value index and population structure revealed that some species are threatened and need prioritization for conservation measures. The results suggest that remnant forest patches in the highlands of northern Ethiopia host several woody plant species that are almost disappearing in other areas due to deforestation.

Optimizing any-aged management of mixed boreal forest under residual basal area constraints

Abstract: The current trend of forest management in many countries is reduced use of clear-felling and planting, and increased use of continuous cover management. In Finland, the new forest act of 2014 made all types of cuttings equally allowable on the condition that if the post-cutting residual stand basal area is too low, the stand must be regenerated within certain time frame. Forest landowner can freely choose between even- and uneven-aged management. This study developed a method for optimizing the timing and type of cuttings without the need to categorize the management system as either even-aged or uneven-aged. A management system that does not set any requirements on the sequence of post-cutting diameter distributions is called any-aged management. Planting or sowing was used when stand basal area fell below the required minimum basal area and the amount of advance regeneration was less than required in the regulations. When the cuttings of 200 stands managed earlier with even-aged silviculture were optimized with the developed system, final felling followed by artificial regeneration was selected for almost 50% of stands. Reduction of the minimum basal area limit greatly decreased the use of artificial regeneration but improved profitability, suggesting that the truly optimal management would be to use natural regeneration in financially mature stands. The optimal type of thinning was high thinning in 97–99 % of cases. It was calculated that the minimum basal area requirement reduced the mean net present value of the stands by 12–16 % when discount rate was 3–5 %.

Response of Pinus koraiensis seedling growth to different light conditions based on the assessment of photosynthesis in current and one-year-old needles

Abstract: As one of the three major five-leaved pines in the northern hemisphere, Pinus koraiensis is the most important dominant tree species in the natural mixed-broadleaved Korean pine forests. However, the regeneration of P. koraiensis under the canopy of secondary forest stands is poor because of the light limitation. This study was conducted to understand how P. koraiensis seedlings adapt to different light intensities and what would be the optimum light level for their establishment and growth. Three repetition plots with four light intensities (15%, 30%, 60% and 100% of the natural incident irradiances, achieved by suspending layers of black nylon net above and surrounding the plots) were set up under natural climate conditions in a montane region in eastern Liaoning Province, Northeast China. A total of 80 P. koraiensis seedlings with similar height and root collar diameter were transplanted into four plots. After one year of acclimation to the specific light conditions, the seasonal variations of the photosynthetic variables and needle traits of the current and one-year-old needles, and the growth parameters were observed under four light intensities. The results indicated that: (1) The seedling at 60% treatment exhibited the greatest growth, which agreed with the response of the light-saturated photosynthetic rates (A max) and the dark respiration rate (R d) in the current and one-year-old needles, i.e., R d at 60% treatment was significantly lower than that at 100% treatment, but A max did not differ between the seedlings at 100% and 60% treatments. (2) The P. koraiensis seedlings have a certain photosynthetic plasticity to adapt the light conditions by adjusting their needle traits and regulating the physiological processes, because A max, R d, light saturation point and compensation point, the needle mass area, needle nitrogen and chlorophyll contents were significantly (p<0.05) correlated with the light intensities. Especially, A max at 100% and 60% treatments was significantly higher (p<0.05) than that at 30% and 15% treatments for both current and one-year-old needles. (3) The needles of different ages played a commutative role during the growing season, i.e., the one-year-old needles played a major role for the photosynthesis in the early growing season; the current year needles did in the later growing season. This ensured the effective photosynthesis throughout the growing season. These findings suggest that P. koraiensis is the in-between heliophilous and shade-tolerant tree species at least for the seedlings up to 8 years.

Litterfall production and nutrient return in different-aged Chinese fir (Cunninghamia lanceolata) plantations in South China

Abstract: The amounts of litter produced and nutrients returned play a fundamental role in the productivity and biogeochemical and nutrient cycling of forest ecosystems. We monitored annual litterfall production, nutrient return, and monthly dynamics over a one-year period in Chinese fir plantations aged 10, 22, and 34 years. Our objective was to quantify litterfall and nutrient return over a complete harvest rotation of Chinese fir. Annual litterfall production increased with stand age and was recorded as (3,294.6 ± 360.4), (3,733.9 ± 211.2), and (4,876.1 ± 212.8) kg ha−1 a−1 in stands aged 10, 22 and 34 years, respectively. Total litter production was significantly greater in the stand aged 34 years than in the stand aged 10 years (p N (39.32–62.04 kg ha−1 a−1) > K (15.95–22.44 kg ha−1 a−1) > P (1.30–1.63 kg ha−1 a−1). C, N, K and P input to soil was significantly lower in the 10-year-old stand in comparison to the 22- and 34-year-old stands (p < 0.05). Litterfall production and nutrient return (C, N and K) followed similar patterns, and C and N input to soil was significantly related to litterfall production (needle, branch and total litterfall). C, N, P and K input to soil and total litterfall production were mainly driven by needle litterfall.

Effects of plant growth regulators, carbon sources and pH values on callus induction in Aquilaria malaccensis leaf explants and characteristics of the resultant calli

Abstract: The endangered tropical tree, Aquilaria malaccensis, produces agarwood for use in fragrance and medicines. Efforts are currently underway to produce valuable agarwood compoundsn tissue culture. The purpose of this study was to develop an optimal growth medium, specifically, the best hormone combination for callus suspension culture. Using nursery-grown A. malaccensis, sterilized leaf explants were first incubated on basic Murashige and Skoog (MS) gel medium containing 15g/L sucrose and at pH 5.7. Different auxin types including 1-naphthaleneacetic acid (NAA), 2,4-dichlorophenoxyacetic acid (2,4-D), and indole-3-butyric acid (IBA), were tested at various concentrations (0.55, 1.1 and 1.65 μM) using the basic medium. Leaf explants were incubated for 30 days in the dark. Callus induced by 1.1 μM NAA had the highest biomass dry weight (DW) of 17.3 mg; however the callus was of a compact type. This auxin concentration was then combined with either 6-benzylaminopurine (BAP) or kinetin at 0.55, 1.1, 2.2 or 3.3 μM to induce growth of friable callus. The 1.1μM NAA + 2.2μM BAP combination produced friable callus with the highest biomass (93.3mg DW). When testing the different carbon sources and pHs, sucrose at 15g/L and pH at 5.7 yielded highest biomasses at 87.7mg and 83mg DW, respectively. Microscopic observations revealed the arrangement of the friable cells as loosely packed with relatively large cells, while for the compact callus, the cells were small and densely packed. We concluded that MS medium containing 15 g/L sucrose, 1.1 μM NAA + 2.2 μM BAP hormone combination, and a pH of 5.7 was highly effective for inducing friable callus from leaf explants of A. malaccensis for the purpose of establishing cell suspension culture.

The spatial-temporal pattern and influencing factors of negative air ions in urban forests, Shanghai, China

Abstract: Negative air ions are natural components of the air we breathe. Forests are the main continuous natural source of negative air ions (NAI). The spatio-temporal patterns of negative air ions were explored in Shanghai, based on monthly monitoring in 15 parks from March 2009 to February 2010. In each park, sampling sites were selected in forests and open spaces. The annual variation in negative air ion concentrations (NAIC) showed peak values from June to October and minimum values from December to January. NAIC were highest in summer and autumn, intermediate in spring, and lowest in winter. During spring and summer, NAIC in open spaces were significantly higher in rural areas than those in suburban areas. However, there were no significant differences in NAIC at forest sites among seasons. For open spaces, total suspended particles (TSP) were the dominant determining factor of NAIC in summer, and air temperature and air humidity were the dominant determining factors of NAIC in spring, which were tightly correlated with Shanghai’s ongoing urbanization and its impacts on the environment. It is suggested that urbanization could induce variation in NAIC along the urban-rural gradient, but that may not change the temporal variation pattern. Furthermore, the effects of urbanization on NAIC were limited in non-vegetated or less-vegetated sites, such as open spaces, but not in well-vegetated areas, such as urban forests. Therefore, we suggest that urban greening, especially urban forest, has significant resistance to the effect of urbanization on NAIC.

Biochar-based bioenergy and its environmental impact in Northwestern Ontario Canada: A review

Abstract: Biochar is normally produced as a by-product of bioenergy. However, if biochar is produced as a co-product with bioenergy from sustainably managed forests and used for soil amendment, it could provide a carbon neutral or even carbon negative solution for current environmental degradation problems. In this paper, we present a comprehensive review of biochar production as a co-product of bioenergy and its implications. We focus on biochar production with reference to biomass availability and sustainability and on biochar utilization for its soil amendment and greenhouse gas emissions reduction properties. Past studies confirm that northwestern Ontario has a sustainable and sufficient supply of biomass feedstock that can be used to produce bioenergy, with biochar as a co-product that can replace fossil fuel consumption, increase soil productivity and sequester carbon in the long run. For the next step, we recommend that comprehensive life cycle assessment of biochar-based bioenergy production, from raw material collection to biochar application, with an extensive economic assessment is necessary for making this technology commercially viable in northwestern Ontario.

The coppice-with-standards silvicultural system as applied to Eucalyptus plantations — a review

Abstract: 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 multipurpose species. We discuss (1) short rotation Eucalyptus coppice management for energy and pulping and (2) Eucalyptus seedling management for solid wood products. We review the literature and discuss experiences 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 environment 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 applied 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.

Future of Abies pindrow in Swat district, northern Pakistan

Abstract: Swat district is a biodiversity hub of Pakistan. The plant species, especially trees, in the Swat District are exposed to extinction threat from global climate change. Maximum entropy (MaxEnt) modelling of species distribution, using HADCM3 A2a global climate change scenario, predicted a considerable change in the future distribution of Abies pindrow (Royle ex D.Don) Royle. AUC (area under the curve) values of 0.972 and 0.983 were significant for the present and future distribution models of the species, respectively. It is clear that bioclimatic variables such as the mean temperature of the warmest quarter (bio_10) and the annual temperature range (bio_7) contribute significantly to the model and thus affect the predicted distribution and density of the species. The future model predicts that by the year 2080 population density will have decreased significantly. The highest density of the species is recorded in the eastern and western borders of the Valley in the areas of Sulatanr and Mankial. The changes in density and distribution of the species can have considerable impact, not only on the tree species itself, but on the associated subflora as well.

Biodiversity and ecological assessments of Indian sacred groves

Abstract: Sacred groves are patches of forests preserved for their spiritual and religious significance. The practice gained relevance with the spread of agriculture that caused large-scale deforestation affecting biodiversity and watersheds. Sacred groves may lose their prominence nowadays, but are still relevant in Indian rural landscapes inhabited by traditional communities. The recent rise of interest in this tradition encouraged scientific study that despite its pan-Indian distribution, focused on India’s northeast, Western Ghats and east coast either for their global/importance or unique ecosystems. Most studies focused on flora, mainly angiosperms, and the faunal studies concentrated on vertebrates while lower life forms were grossly neglected. Studies on ecosystem functioning are few although observations are available. Most studies attributed watershed protection values to sacred groves but hardly highlighted hydrological process or water yield in comparison with other land use types. The grove studies require diversification from a stereotyped path and must move towards creating credible scientific foundations for conservation. Documentation should continue in unexplored areas but more work is needed on basic ecological functions and ecosystem dynamics to strengthen planning for scientifically sound sacred grove management.

Calorific values and ash contents of different parts of Masson pine trees in southern China

Abstract: Calorific value of plants is an important parameter for evaluating and indexing material cycles and energy conversion in forest ecosystems. Based on mensuration data of 150 sample sets, we analyzed the calorific value (CV) and ash content (AC) of different parts of Masson pine (Pinus massoniana) trees in southern China using hypothesis testing and regression analysis. CV and AC of different tree parts were almost significantly different (P branch > stem bark > root > stem wood, and AC ranked as foliage > stem bark > root > branch > stem wood. CV and AC of stem wood from the top, middle and lower sections of trees differed significantly. CV increased from the top to the lower sections of the trunk while AC decreased. Mean gross calorific value (GCV) and AFCV of aboveground parts were significantly higher than those of belowground parts (roots). The mean GCV, AFCV and AC of a whole tree of Masson pine were 21.54 kJ/g, 21.74 kJ/g and 0.90%, respectively. CV and AC of different tree parts were, to some extent, correlated with tree diameter, height and origin.

A preliminary evaluation of throughfall sampling techniques in a mature coniferous forest

Abstract: Rainfall, throughfall and stemflow were measured and canopy interception loss was derived for 14 rainfall events from June 22 to August 30, 2008 within a mature declining hybrid white spruce (Picea glauca (Moench) Voss × P. engelmannii Parry ex Engelm.)-subalpine fir (Abies lasiocarpa (Hook.) Nutt.)-lodgepole pine (Pinus contorta var. latifolia Dougl. ex Loud.) stand in south-central British Columbia, Canada. Stemflow was negligible during the study period, while, respectively, throughfall and canopy interception loss accounted for approximately 59.4% and 40.6% of the 50.1 mm of cumulative rainfall. Throughfall variability was assessed with three approaches involving roving and stationary wedge-type gauges, and stationary trough gauges. Throughfall exhibited large spatial variability with the coefficient of variability of study period throughfall sampled using 16 stationary trough gauges being 30.3%, while it was 38.0% and 28.7% for 32 stationary and 32 roving wedge gauges, respectively. Our analysis suggests that a roving gauge method is better than a stationary approach since the errors associated with event mean throughfalls are summed quadratically and a greater portion of the canopy area is sampled. Trough gauges were more efficient than wedge gauges; however, this efficiency was less than expected given their much larger sampling areas, suggesting that spatial autocorrelation lengths of throughfall may be longer than the trough systems. The spatial distribution of throughfall showed a high degree of temporal persistence throughout the study suggesting the existence of stable “wet” and “dry” inputs to the floors of these coniferous forests.

Estimating above-ground biomass by fusion of LiDAR and multispectral data in subtropical woody plant communities in topographically complex terrain in North-eastern Australia

Abstract: We investigated a strategy to improve predicting capacity of plot-scale above-ground biomass (AGB) by fusion of LiDAR and Landsat5 TM derived biophysical variables for subtropical rainforest and eucalypts dominated forest in topographically complex landscapes in North-eastern Australia. Investigation was carried out in two study areas separately and in combination. From each plot of both study areas, LiDAR derived structural parameters of vegetation and reflectance of all Landsat bands, vegetation indices were employed. The regression analysis was carried out separately for LiDAR and Landsat derived variables individually and in combination. Strong relationships were found with LiDAR alone for eucalypts dominated forest and combined sites compared to the accuracy of AGB estimates by Landsat data. Fusing LiDAR with Landsat5 TM derived variables increased overall performance for the eucalypt forest and combined sites data by describing extra variation (3% for eucalypt forest and 2% combined sites) of field estimated plot-scale above-ground biomass. In contrast, separate LiDAR and imagery data, and fusion of LiDAR and Landsat data performed poorly across structurally complex closed canopy subtropical rainforest. These findings reinforced that obtaining accurate estimates of above ground biomass using remotely sensed data is a function of the complexity of horizontal and vertical structural diversity of vegetation.

Evolution of forest cover in Portugal: A review of the 12th–20th centuries

Abstract: Portugal’s forests in the 12th century were dominated by the Fagaceae represented by Quercus and Castanea, and several pine species. From the 12th century onwards, forests underwent changes in their management starting with protection and ultimately leading to intense exploitation. The massive naval construction during the maritime expansion (mainly in the 15th–16th centuries) involved felling of approximately 5 million trees mainly Quercus suber, Pinus pinea and other Quercus species. Cumulative fuel-wood consumption of 959 Mm3 during 1300–1854 was attributed to demographic expansion while the deforestation rate during 1636–1854 accounted for a minimum of 72.6% and a maximum of 96% of total forest cover. The volume of timber used in railway sleepers from 1856 onwards might have reached 0.5 Mm3. The last quarter of the 20th century increased the forest cover of Portugal through the World Bank program of Eucalyptus globulus reforestation.

Changes induced by osmotic stress in the morphology, biochemistry, physiology, anatomy and stomatal parameters of almond species ( Prunus L. spp.) grown in vitro

Abstract: We investigated the influence of different levels of osmotic stress on growth and development in selected wild almond species (eight Prunus spp.) grown in vitro. The study, while endorsing the efficacy of in vitro screening of auxiliary buds of wild almond for osmotic stress tolerance, showed species variability in its response to osmotic stress. Osmotic stress reduced growth and development of all the species. How- ever, the putative tolerant Prunus spp. showed better performance than the putative susceptible genotypes. On average there was an 80% de- crease in shoot dry weight at -1.2 MPa. Reduction in shoot weight was more common in osmotic stress-susceptible species in the section labeled 'Euamygdalus'. The tolerant Prunus species produced smaller changes in biochemical responses than the sensitive cultivars for malondialdehyde content, catalase activity, relative permeability of protoplast membranes, and net photosynthetic rate. The tolerant species maintained cell integrity better than drought sensitive species. Wild almond species in the section labeled 'Spartioides' (Prunus arabica (Olivier) Neikle, Prunus glauca

Deforestation effects on biological and other important soil properties in an upland watershed of Bangladesh

Abstract: Deforestation occurs at an alarming rate in upland watersheds of Bangladesh and has many detrimental effects on the environment. This study reports the effects of deforestation on soil biological properties along with some important physicochemical parameters of a southern upland watershed in Bangladesh. Soils were sampled at 4 paired sites, each pair representing a deforested site and a forested site, and having similar topographical characteristics. Significantly fewer (p≤0.001) fungi and bacteria, and lower microbial respiration, active microbial biomass, metabolic and microbial quotients were found in soils of the deforested sites. Soil physical properties such as moisture content, water holding capacity, and chemical properties such as organic matter, total N, available P and EC were also lower in deforested soils. Bulk density and pH were significantly higher in deforested soils. Available Ca and Mg were inconsistent between the two land uses at all the paired sites. Reduced abundance and biomass of soil mesofauna were recorded in deforested soils. However, soil anecic species were more abundant in deforested soils than epigeic and endogeic species, which were more abundant in forested soils than on deforested sites.

The changing landscape of mangroves in Bangladesh compared to four other countries in tropical regions

Abstract: Loss of mangroves and consequent habitat fragmentation is a major concern throughout the world’s tropical countries. Conversion of mangrove habitat due to aquaculture, agriculture, urbanization and industrialization, ecotourism, overlapping bureaucracy and conflicting policies is occurring at a striking rate. This paper reviews the trends of mangrove area changes in Bangladesh and compares them with four other countries in tropical regions that have significant mangrove areas. The rate of mangrove loss from the 1980 to 2005 was calculated using the compound interest rate formula for its explicit biological implication. In Bangladesh, the area of mangroves was found to have increased due to its higher accretion rate. In India the rate of mangrove loss had fallen. The rate of mangrove loss in Malaysia in the 1990s (−0.008 ha·a−1) was higher than the 1980s (−0.004 ha·a−1). In Indonesia, the rate decreased, from the 1980s (−0.018 ha·a−1) to the 1990s (−0.010 ha·a−1). Finally in Myanmar the rate of mangrove loss gradually accelerated. Aquaculture was found to be the common cause of mangrove conversion in the regions. Loss of mangroves is now a prominent global issue, associated with the loss of biodiversity, deterioration of habitat integrity, climatic changes, the amount of carbon sequestration, and resulting sea-level rise. Therefore, a systematic evaluation of these environmental impacts is prerequisite to realize sustainable mangrove management.

Bio-amelioration of alkali soils through agroforestry systems in central Indo-Gangetic plains of India

Abstract: A long-term field study was initiated during 1995 at Central Soil Salinity Research Institute, Regional Research Station, Lucknow (26°47′58″ N and 80°46′24″ E) to analyze the effect of agroforestry systems on amelioration of alkali soils. Three agroforestry systems (pastoral, silvipastoral and silvicultural) were compared with the control where no agroforestry system was introduced. Tree-based silvicultural and silvipastoral systems were characterized by tree species Prosopis juliflora and Acacia nilotica along with grass species Leptochloa fusca, Panicum maximum, Trifolium alexandrium and Chloris gayana. Growth of ten-year-old Prosopis juliflora and Acacia nilotica planted in combination with grasses was significantly higher over the silviculture system with the same species. Tree biomass yields of P. juliflora (77.20 t·ha−1) and A. nilotica (63.20 t·ha−1) planted under silvipastoral system were significantly higher than the sole plantation of (64.50 t·ha−1 and 52.75 t·ha−1). Fodder yield under the pastoral system was significantly higher than the silvipastoral system during initial years but it was at par with that of silvipastoral systems after eight years of plantation. The microbial biomass carbon in the soils of silvipastoral systems was significantly higher than in soils under sole plantation of trees and control systems. The Prosopis-based silvipastoral system proved more effective in reducing soil pH, displacing Na+ from the exchange complex, increasing organic carbon and available N, P and K. Improvement in soil physical properties such as bulk density, porosity, soil moisture and infiltration rate was higher in the Prosopis-based silvipastoral system than in the silviculture system or control. On the basis of biomass production and improvement in soil health due to tree + grass systems, silvipastoral agroforestry system could be adopted for sustainable reclamation of highly alkali soils.