Showing papers in "Journal of Forestry Research in 2020"

Protective and defensive roles of non-glandular trichomes against multiple stresses: structure–function coordination

Abstract: As superficial structures, non-glandular trichomes, protect plant organs against multiple biotic and abiotic stresses. The protective and defensive roles of these epidermal appendages are crucial to developing organs and can be attributed to the excellent combination of suitable structural traits and chemical reinforcement in the form of phenolic compounds, primarily flavonoids. Both the formation of trichomes and the accumulation of phenolics are interrelated at the molecular level. During the early stages of development, non-glandular trichomes show strong morphological similarities to glandular ones such as the balloon-like apical cells with numerous phenolics. At later developmental stages, and during secondary wall thickening, phenolics are transferred to the cell walls of the trichomes. Due to the diffuse deposition of phenolics in the cell walls, trichomes provide protection against UV-B radiation by behaving as optical filters, screening out wavelengths that could damage sensitive tissues. Protection from strong visible radiation is also afforded by increased surface light reflectance. Moreover, the mixtures of trichome phenolics represent a superficial chemical barrier that provides protection against biotic stress factors such as herbivores and pathogens. Although the cells of some trichomes die at maturity, they can modulate their quantitative and qualitative characteristics during development, depending on the prevailing conditions of the external biotic or abiotic environment. In fact, the structure and chemical constituents of trichomes may change due to the particular light regime, herbivore damage, wounding, water stress, salinity and the presence of heavy metals. Hence, trichomes represent dynamic protective structures that may greatly affect the outcome of many plant–environment interactions.

Past, present and future of industrial plantation forestry and implication on future timber harvesting technology.

Abstract: Plantation forests are established, and expanding, to satisfy increasing global demand for timber products. Shifting societal values, such as safety, productivity, environmental, quality and social are influencing the plantation forestry sector. This is primarily driven through an ever increasing world population, which in turn influences the way nations view the value systems by which they live. More people require more resources—also forest products. Also, the availability of information is influencing the pace of technological development. These changes could result in a difference in the management of plantations that could affect the forest engineering systems of the future. This review aimed to summarize the current status of plantation forests; summarize future developments and possible scenarios in forest plantation management for the various products; and assess whether these developments in a plantation environment could affect the harvesting systems used. Factors influencing the form of plantations include the type and nature of the plantation owner; the change in demand for different and new forest products; climate change factors, including the use of biomass for energy, carbon sequestration and trading; ecosystem services and other products and services; and sustainability certification of forest management. The impact and influence of these factors were summarised into a series of key drivers that will influence the technology used in harvesting machines, as well as the choice of harvesting machines, systems and methods. These drivers were the effect of variations in tree size, the expansion of plantation areas onto more difficult terrain, diversity in plantation design, increased attention towards site impacts and the increased use of biomass for energy. Specific information is provided regarding how the harvesting systems could be affected.

Ecology, growth and management of black locust (Robinia pseudoacacia L.), a non-native species integrated into European forests

Abstract: Black locust (Robinia pseudoacacia L.), a species native to the eastern North America, was introduced to Europe probably in 1601 and currently extends over 2.3 × 106 ha. It has become naturalized in all sub-Mediterranean and temperate regions rivaling Populus spp. as the second most planted broadleaved tree species worldwide after Eucalyptus spp. This wide-spreading planting is because black locust is an important multipurpose species, producing wood, fodder, and a source of honey as well as bio-oil and biomass. It is also important for carbon sequestration, soil stabilization and re-vegetation of landfills, mining areas and wastelands, in biotherapy and landscaping. In Europe, black locust is drought tolerant so grows in areas with annual precipitation as low as 500–550 mm. It tolerates dry, nutrient poor soils but grows best on deep, nutrient-rich, well-drained soils. It is a fast-growing tree and the height, diameter and volume growth peak before the age of 20. It mostly regenerates vegetatively by root suckers under a simple coppice system, which is considered the most cost-effective management system. It also regenerates, but less frequently, by stool sprouts. Its early silviculture in production forests includes release cutting to promote root suckers rather than stool shoots, and cleaning-respacing to remove low-quality stems, reduce the number of shoots per stool, and adjust spacing between root suckers. In addition, early, moderate and frequent thinning as well as limited pruning are carried out focusing on crop trees. The species is regarded as invasive in several European countries and its range here is expected to expand under predicted climate changes.

Physico-chemical characteristics and heavy metal concentrations of copper mine wastes in Zambia: implications for pollution risk and restoration

Abstract: Soil characterization is a vital activity to develop appropriate and effective restoration protocols for mine wastelands while insights into the total content of heavy metals in the soil is an important step in estimating the hazards that the metals may pose to the vital roles of soil in the ecosystem. This study addressed the following research questions: (1) To what extent do the physico-chemical characteristics vary between mine waste sediments and the nearby forest soil? (2) Are the concentrations of heavy metals high enough to be considered as toxic? and (3) Are heavy metals present in mine waste sediments potential sources of pollution? We hypothesized that the physico-chemical characteristics of mine waste sediments are less favorably for plant establishment and growth while the concentrations of heavy metals are very high, thus restricting the success of revegetation of mine waste lands. Mine waste sediments were sampled following a diagonal transect across tailings dams, overburden dump sites and the local forest soil from the top layer (0–20 cm) using a closed auger. Samples were analyzed for arsenic, barium, lead, cadmium, cobalt, copper, chromium, nickel, vanadium, and zinc as well as for soil physico-chemical properties. The mine waste sediments were dominated by silt whilst the forest soil by sand particles, with significantly high bulk density in the former. Both the forest soil and overburden sediments were acidic than the alkaline tailings dam sediment. Total organic carbon and nitrogen contents were significantly low in mine wasteland substrates but the concentration of Ca and Mg were significantly higher in tailings dam substrate than the forest soil. The concentrations of available P, K and Na were similar across sites. The mean concentrations of heavy metals were significantly (p Co > Ba > Ni > As > Zn > Pb > Cr > V > Cd, and that on the overburdens was Cu > Co > Ba > Ni > Zn > Cr > Pb > V > As > Cd. The pollution load index (PLI) was nearly twice higher for the tailings dam (8.97) than the overburden (5.84). The findings show that the copper mine wastes (the tailings dams and overburden waste rock sites) are highly contaminated by heavy metals; which, in turn, might pose serious hazards to human health and agricultural productivity. In addition, poor macro-nutrient availability, substrate compaction and soil acidity (particularly on overburden sites) coupled with toxic level of heavy metals would be the main challenges for successful phytostabilization of copper mine wastelands.

Effects of climate and forest age on the ecosystem carbon exchange of afforestation

Abstract: Afforestation is believed to be an effective practice to reduce global warming by sequestering large amounts of carbon in plant biomass and soil. However, the factors that determine the rate of carbon sequestration with afforestation are still poorly understood. We analyzed ecosystem carbon exchange after afforestation based on eddy covariance measurements with the aim to identify factors responsible for the rate of carbon exchange following afforestation. The results indicated that afforestation in the tropical/subtropical and temperate climate zones had greater capacities for carbon sequestration than those in boreal zones. Net ecosystem production (NEP), gross primary production (GPP) and ecosystem respiration (RE) varied greatly with age groups over time. Specifically, NEP was initially less than zero in the < 10 year group and then increased to its peak in the 10–20 year group. Afforestation of varied previous land use types and planting of diverse tree species did not result in different carbon fluxes. The general linear model showed that climate zone and age of afforestation were the dominant factors influencing carbon sequestration. These factors jointly controlled 51%, 61% and 63% of the variation in NEP, GPP and RE, respectively. Compared to the strong regulation of climate on GPP and RE, NEP showed greater sensitivity to the age of afforestation. These results increase our understanding of the variation in ecosystem carbon exchange of afforestation and suggest that afforestation in subtropical and temperate areas after 20 years would yield greater carbon sink benefits than would afforestation of boreal regions.

Comparative analysis of multi-criteria probabilistic FR and AHP models for forest fire risk (FFR) mapping in Melghat Tiger Reserve (MTR) forest

Abstract: A comparative study of Frequency Ratio (FR) and Analytic Hierarchy Process (AHP) models are performed for forest fire risk (FFR) mapping in Melghat Tiger Reserve forest, central India. Identification of FFR depends on various hydrometeorological parameters (altitude, slope, aspect, topographic position index, normalized differential vegetation index, rainfall, air temperature, land surface temperature, wind speed, distance to settlements, and distance by road are integrated using a GIS platform. The results from FR and AHP show similar trends. The FR model was significantly higher accurate (overall accuracy of 81.3%, kappa statistic 0.78) than the AHP model (overall accuracy 79.3%, kappa statistic 0.75). The FR model total forest fire risk areas were classified into five classes: very low (7.1%), low (22.2%), moderate (32.3%), high (26.9%), and very high (11.5%). The AHP fire risk classes were very low (6.7%), low (21.7%), moderate (34.0%), high (26.7%), and very high (10.9%). Sensitivity analyses were performed for AHP and FR models. The results of the two different models are compared and justified concerning the forest fire sample points (Forest Survey of India) and burn images (2010–2016). These results help in designing more effective fire management plans to improve the allocation of resources across a landscape framework.

Epidemiological derivation of flux-based critical levels for visible ozone injury in European forests

Abstract: The European MOTTLES project set-up a new-generation network for ozone (O3) monitoring in 17 plots in France, Italy and Romania. These monitoring stations allowed: (1) estimating the accumulated exposure AOT40 and stomatal O3 fluxes (PODY) with an hourly threshold of uptake (Y) to represent the detoxification capacity of trees (POD1, with Y = 1 nmol O3 m−2 s−1 per leaf area); and (2) collecting data of forest-response indicators, i.e. crown defoliation and visible foliar O3-like injury over the time period 2017–2019. The soil water content was the most important parameter affecting crown defoliation and was a key factor affecting the severity of visible foliar O3-like injury on the dominant tree species in a plot. The soil water content is thus an essential parameter in the PODY estimation, particularly for water-limited environments. An assessment based on stomatal flux-based standard and on real plant symptoms is more appropriated than the exposure-based method for protecting vegetation. From flux-effect relationships, we derived flux-based critical levels (CLef) for forest protection against visible foliar O3-like injury. We recommend CLef of 5 and 12 mmol m−2 POD1 for broadleaved species and conifers, respectively. Before using PODY as legislative standard in Europe, we recommend using the CLec for ≥ 25% of crown defoliation in a plot: 17,000 and 19,000 nmol mol−1 h AOT40 for conifers and broadleaved species, respectively.

Spatial variability of soil organic carbon and total nitrogen in the hilly red soil region of Southern China

Abstract: To obtain accurate spatial distribution maps of soil organic carbon (SOC) and total nitrogen (TN) in the Hetian Town in Fujian Province, China, soil samples from three depths (0–20, 20–40, and 40–60 cm) at 59 sampling sites were sampled by using traditional analysis and geostatistical approach. The SOC and TN ranged from 2.26 to 47.54 g kg−1, and from 0.28 to 2.71 g kg−1, respectively. The coefficient of variation for SOC and TN was moderate at 49.02–55.87% for all depths. According to the nugget-to-sill ratio values, a moderate spatial dependence of SOC content and a strong spatial dependence of TN content were found in different soil depths, demonstrating that SOC content was affected by both extrinsic and intrinsic factors while TN content was mainly influenced by intrinsic factors. Indices of cross-validation, such as mean error, mean standardized error, were close to zero, indicating that ordinary kriging interpolation is a reliable method to predict the spatial distribution of SOC and TN in different soil depths. Interpolation using ordinary kriging indicated the spatial pattern of SOC and TN were characterized by higher in the periphery and lower in the middle. To improve the accuracy of spatial interpolation for soil properties, it is necessary and important to incorporate a probabilistic and machine learning methods in the future study.

Decline and dieback of cork oak (Quercus suber L.) forests in the Mediterranean basin: a case study of Kroumirie, Northwest Tunisia

Abstract: Assessing the vulnerability of forest ecosystems in the climate change context is a challenging task as the mechanisms that determine this vulnerability cannot be directly observed. Based on the ecological interrelationships between forests and climate, the present review focused on providing current information about vulnerability assessments of cork oak (Quercus suber L.) forests in the Mediterranean basin, especially, in the Kroumirie region (northwest Tunisia), currently under historic extreme drought conditions. From comparing recent findings in this region, we synthesized data on cork oak decline and mortality collected during the historic drought years 1988–1995 period. Climate change impacts cork forest decline, with special interest shown in elevated temperatures and drought; cork oak forest regeneration, and the adaptation of the Kroumirie forest to climate change, are reviewed herein. The studied region has been influenced largely by frequent prolonged drought periods, especially from 1988 to 1995. Droughts were found to consistently have a more detrimental impact on the growth and mortality rates of cork oak populations. Cork oak mortality was recorded for up to 63,622 trees. In the future, more research studies and observational data will be needed, which could represent an important key to understand ecosystem processes, and to facilitate the development of better models that project climate change impacts and vulnerability. The study is useful for researchers and forestry decision makers to develop the appropriate strategies to restore and protect ecosystems, and to help anticipate potential future droughts and climate change.

The role of graveyards in species conservation and beta diversity: a vegetation appraisal of sacred habitats from Bannu, Pakistan

Abstract: Graveyards or sacred groves are often places of natural vegetation protected by spiritual believers because of their sacred beliefs and indigenous culture. A study of graveyards was conducted to determine their role in species conservation, community formation, and associated indicators and species composition using multivariate statistical approaches. It was hypothesized that variations in the age of graveyards would give rise to diverse plant communities under the impact of various edaphic and climatic factors. Quantitative ecological techniques were applied to determine various phytosociological attributes. All the data were put in MS Excel for analysis in PCORD and CANOCO softwares for cluster analysis (CA), two-way cluster analysis (TWCA), indicator species analysis and canonical correspondence analysis. CA and TWCA through Sorenson distance measurements identified five major graveyard plant communities: (1) Ficus–Bougainvillea–Chenopodium; (2) Acacia–Datura–Convolvulus; (3) Ziziphus–Vitex–Abutilon; (4) Acacia–Lantana–Salsola; and (5) Melia–Rhazya–Peganum. Species such as Capparis decidua, Herniaria hirsuta, Salvadora oliedes and Populus euphratica were only present inside graveyards rather than outside and advocate the role of graveyards in species conservation. The impact of different environmental and climatic variables plus the age of the graveyards were also assessed for comparison of plant communities and their respective indicator species. The results indicate that higher chlorine concentration, age of graveyards, low soil electrical conductivity, lower anthropogenic activities, higher nitrogen, calcium and magnesium concentrations in the soil, and sandy soils were the strong environmental variables playing a significant role in the formation of graveyard plant communities, their associated indicators and species distribution patterns. These results could further be utilized to evaluate the role of edaphic and climatic factors, indicator species and conservation management practices at a greater scale.

Do increasing respiratory costs explain the decline with age of forest growth rate

Abstract: Once forests have achieved a full canopy, their growth rate declines progressively with age. This work used a global data set with estimates from a wide range of forest types, aged 20‒795 years, of their annual photosynthetic production (gross primary production, GPP) and subsequent above- plus below-ground biomass production (net primary production, NPP). Both GPP and NPP increased with increasing mean annual temperature and precipitation. GPP was then unrelated to forest age whilst NPP declined progressively with increasing age. These results implied that autotrophic respiration increases with age. It has been proposed that GPP should decline in response to increasing water stress in leaves as water is raised to greater heights as trees grow taller with age. However, trees may make substantial plastic adjustment in morphology and anatomy of newly developing leaves, xylem and fine roots to compensate for this stress and maintain GPP with age. This work reviews the possibilities that NPP declines with age as respiratory costs increase progressively in, any or all of, the construction and maintenance of more complex tissues, the maintenance of increasing amounts of live tissue within the sapwood of stems and coarse roots, the conversion of sapwood to heartwood, the increasing distance of phloem transport, increased turnover rates of fine roots, cost of supporting very tall trees that are unable to compensate fully for increased water stress in their canopies or maintaining alive competitively unsuccessful small trees.

Variation in glomalin in soil profiles and its association with climatic conditions, shelterbelt characteristics, and soil properties in poplar shelterbelts of Northeast China

Abstract: Glomalin-related soil protein (GRSP) sequesters large amounts of carbon and plays important roles in maintaining terrestrial soil ecosystem functions and ecological restoration; however, little is known about GRSP variation in 1-m soil profiles and its association with stand characteristics, soil properties, and climatic conditions, hindering GRSP-related degraded soil improvement and GRSP evaluation. In this study, we sampled soils from 1-m profiles from poplar (Populus spp.) shelterbelts in Northeast China. GRSP contents were 1.8–2.0 times higher in the upper 40 cm soil layers than at 40–100 cm. GRSP-related soil organic carbon (SOC) sequestration in deeper soil layers was ~ 1.2 times higher than in surface layers. The amounts of GRSP-related nutrients were similar throughout the soil profile. A redundancy analysis showed that in both surface and deeper layers, soil properties (pH, electrical conductivity, water, SOC, and soil nutrients) explained the majority of the GRSP variation (59.5–84.2%); the second-most-important factor in GRSP regulation was climatic conditions (temperature, precipitation, and altitude), while specific shelterbelt characteristics had negligible effects (< 5%). Soil depth and climate indirectly affected GRSP features via soil properties, as manifested by structural equation model analysis. Our findings demonstrate that GRSP is important for carbon storage in deep soils, regardless of shelterbelt characteristics. Future glomalin assessments should consider these vertical patterns and possible regulating mechanisms that are related to soil properties and climatic changes.

At what carbon price forest cutting should stop

Abstract: The carbon sink of boreal forests can be increased by paying forest landowners for carbon sequestration and taxing carbon releases. The aim of the study was to analyze the effect of carbon pricing on optimal forest management when forests are managed for maximal discounted benefits from timber production and carbon payments. A 0.5% random sample of all private forest stands of Finland was used in the analyses (48,842 stands). Calculations were performed for a 100-year time horizon. It was assumed that the carbon balance (difference between sequestrated carbon and released carbon) in the forest (trees and soil) or the carbon balance of forestry (trees, soil and wood-based products) was subsidized (positive balance) or taxed (negative balance) by 0, 50, 100 or 150 € t−1, corresponding to CO2 prices of 0, 13.6, 27.3 or 40.9 € t−1, respectively. The results showed that paying forest landowners 150 € t−1 of carbon sequestrated in forests would lead to the cessation of all cuttings everywhere in Finland for at least 100 years. In the northern part of the country, a carbon price of 100 € t−1 would be enough to make the no-cutting management economically optimal. A low carbon price had the highest relative impact (value of increased sequestration divided by the cost of carbon payments). The benefit/cost ratio of carbon subsidies was higher in the northern part of boreal zone than in the southern parts. Subsidizing within-forest carbon sequestration by 50 € t−1 would increase the carbon sequestration of Finnish forestry by 50%, ranging from 36% (south Finland) to 116% (north Finland). A payment of 100 € t−1 or more would increase carbon sequestration by 70%, which is nearly the maximum possible increase that can be obtained by carbon subsidies.

Effects of sodium nitroprusside on callus browning of Ficus religiosa: an important medicinal plant

Abstract: Tissue browning is a major problem in tissue culturing of woody plants, especially for Ficus religiosa which occurs by the accumulation and oxidation of phenolic compounds. This study aimed to determine the effect of different concentrations of sodium nitroprusside on the appearance of callus browning from leaf explants. The results indicate that callus browning was significantly reduced by supplementation of sodium nitroprusside to the MS medium and supplemented with 2.26 μM of 2,4-dichlorophenoxyacetic acid and 0.22 μM of 6-benzyl amino purine. The accumulation of hydrogen peroxide and phenolic compounds in the callus tissues decreased at the 50 μM concentration of sodium nitroprusside. Although catalase and peroxidase activities decreased at the 50 μM concentration, the activity of superoxide dismutase and polyphenol oxidases, as well as proline content, increased exponentially. Sodium nitroprusside could be useful for the formation of non-embryogenic callus with high levels of metabolic activity for the production and isolation of secondary metabolites.

BP neural networks and random forest models to detect damage by Dendrolimus punctatus Walker

Abstract: The construction of a pest detection algorithm is an important step to couple “ground-space” characteristics, which is also the basis for rapid and accurate monitoring and detection of pest damage. In four experimental areas in Sanming City, Jiangle County, Sha County and Yanping District in Fujian Province, sample data on pest damage in 182 sets of Dendrolimus punctatus were collected. The data were randomly divided into a training set and testing set, and five duplicate tests and one eliminating-indicator test were done. Based on the characterization analysis of the host for D. punctatus damage, seven characteristic indicators of ground and remote sensing including leaf area index, standard error of leaf area index (SEL) of pine forest, normalized difference vegetation index (NDVI), wetness from tasseled cap transformation (WET), green band (B2), red band (B3), near-infrared band (B4) of remote sensing image are obtained to construct BP neural networks and random forest models of pest levels. The detection results of these two algorithms were comprehensively compared from the aspects of detection precision, kappa coefficient, receiver operating characteristic curve, and a paired t test. The results showed that the seven indicators all were responsive to pest damage, and NDVI was relatively weak; the average pest damage detection precision of six tests by BP neural networks was 77.29%, the kappa coefficient was 0.6869 and after the RF algorithm, the respective values were 79.30% and 0.7151, showing that the latter is more optimized, but there was no significant difference (p > 0.05); the detection precision, kappa coefficient and AUC of the RF algorithm was higher than the BP neural networks for three pest levels (no damage, moderate damage and severe damage). The detection precision and AUC of BP neural networks were a little higher for mild damage, but the difference was not significant (p > 0.05) except for the kappa coefficient for the no damage level (p < 0.05). An “over-fitting” phenomenon tends to occur in BP neural networks, while RF method is more robust, providing a detection effect that is better than the BP neural networks. Thus, the application of the random forest algorithm for pest damage and multilevel dispersed variables is thus feasible and suggests that attention to the proportionality of sample data from various categories is needed when collecting data.

Assessment of early survival and growth of planted Scots pine (Pinus sylvestris) seedlings under extreme continental climate conditions of northern Mongolia

Abstract: Environmental factors play vital roles in successful plantation and cultivation of tree seedlings. This study focuses on problems associated with reforestation under extreme continental climatic conditions. The objectives were to assess relative seedling performance (survival and growth) with respect to plantation age, and to analyze the influence of specific climatic factors during the early stages of Scots pine (Pinus sylvestris L.) plantations. The study was carried out in reforested areas of the Tujyin Nars region of northern Mongolia on six Scots pine plantations ranging from 5 to 10 years. In each of the six plantations, five 900 m2 permanent sample plots were established and survival rates and growth performance measured annually over 7 years. Results show high variation in survival among the plantations (p < 0.001, F = 29.7). Seedling survival in the first year corresponded directly to the number of dry days in May. However, survival rate appeared to stabilize after the second year. The insignificant variation of height categories throughout the observation period indicated low competition among individuals. Two linear mixed-effect models show that height and radial growth were best explained by relative air humidity, which we consider to be a reliable indicator of site-specific water availability. Insufficient amounts and uneven distribution of rainfall pose a major threat during the first year of plantation establishment. Humidity and water availability are decisive factors for a successful seedling plantation. This highlights the impact of drought on forest plantations in northern Mongolia and the importance of developing climate resilient reforestation strategies.

Forest cover change and its driving forces in Fagita Lekoma District, Ethiopia

Abstract: This study investigated forest cover change and the driving forces behind it in Fagita Lekoma District of Ethiopia that resulted in increased forest cover, which might be uncommon outside this case study area. The LULC change analysis was made from 2003 to 2017 based on Landsat images. Socioeconomic analysis was carried out to identify the major driving forces that resulted in LULC change. A questionnaire survey, focused group discussion, key informant interviews and field observation were employed to analyze the link between LULC change and the driving forces. The 15-year period (2003–2017) image analysis revealed that the coverage of forest lands, built-up areas and grassland has increased by 256%, 100% and 96%, respectively, at the expense of cultivated lands and wetlands. The increased forest cover is due to the woodlots expansion of Acacia decurrens Willd, which are designed for sustainable livelihoods and a land revitalization strategy in the study area. Rapid population growth, an increasing demand for charcoal and subsequent market opportunities, preferred qualities of A. decurrens or black wattle to halt land degradation as well as to improve land productivity, have been identified as the major driving forces of forest cover change. Chi squared analysis revealed that: a comparative cash income from the sale of A. decurrens; a dependency on natural forests; the distance from the district administrative center; the size of the active labor force, and the area of land owned have significantly affected the cover change. The major forest cover change is due to the expansion of A. decurrens plantations that have socioeconomic and environmental implications to improve rural livelihoods and revitalize the land. Thus, the positive experiences identified in this study should be scaled-up and applied in other similar settings.

Influencing in vitro clonal propagation of Chonemorpha fragrans (moon) Alston by culture media strength, plant growth regulators, carbon source and photo periodic incubation

Abstract: Chonemorpha fragrans is an endangered medicinal woody climber, regarded among alternative plant sources of camptothecin Camptothecin is a monoterpene indole anti-cancer alkaloid with annual trade value of over three billion US dollars in the recent, and is used in the production of its analog drugs approved for the chemotherapy of cancer of varied types Effects of plant growth regulators, culture media strength and photoperiodic duration on the micropropagation efficiency of C fragrans from nodal segment explants were studied on Murashige and Skoog (MS) medium amended with Thidiazuron (TDZ), Benzylaminopurine (BAP) or Kinetin (Kin) Thidiazuron was more efficient over BAP and Kin when half basal MS medium was used over full or quarter strength Results of carbon source experiment showed sucrose as the most effective over glucose, fructose, and maltose in the clonal production Studies on the photoperiodic incubation duration showed 12 h as the best light period and sub or supra-optimal resulted in the production of abnormal and albino micro shoots Experimental results on the evaluation of physiological, biochemical parameters showed the role of pigment molecules and antioxidant systems in the production of albino micro shoots

Ecophysiological acclimatization to cyclic water stress in Eucalyptus

Abstract: Drought is considered the main environmental factor limiting productivity in eucalyptus plantations in Brazil. However, recent studies have reported that exposure to water deficit conditions enables plants to respond to subsequent stresses. Thus, this study investigates the ecophysiological acclimatization of eucalyptus clones submitted to recurrent water deficit cycles. Eucalyptus seedlings were submitted to three recurrent water deficit cycles and anatomical, morphological and physiological changes were analyzed. The results were: (1) Eucalyptus seedlings responded to water deficits by directing carbohydrates to root and stem growth; (2) Size and number of stomata were reduced; (3) Stomatal conductance decreased which allowed the plants to reduce water losses through transpiration, increasing instantaneous water use efficiency; (4) The relationship between gas exchanges and available water contents allowed the seedlings to uptake the retained soil water at higher tensions; and, (5) Physiological recovery from subsequent water deficits became faster. As a result of these changes, the eucalyptus seedlings recovered from the same degree of water stress more rapidly.

Floristic analysis and dominance pattern of sal (Shorea robusta) forests in Ranchi, Jharkhand, eastern India

Abstract: The present study describes the floristic composition and dominance pattern of sal forests in Ranchi, Jharkhand, eastern India. Vegetation was studied in 47 belt transects (50 × 100 m) that had 137 plant species (110 identified and 27 unidentified) belonging to 51 families. The family Fabaceae with 17 species (8 spp. belonging to subfamily Faboideae, 6 spp. to Caesalpinioideae and 3 spp. to Mimosoidieae) contributed the most to diversity, followed by Rubiaceae (8 spp.) and Euphorbiaceae (6 spp.). Tree density in sal was inversely related to species richness. Total tree density (≥ 10 cm GBH) in the studied forests was 397 individuals ha−1, with a basal cover of 262.50 m2 ha−1. Important plants of conservation concern are Pterocarpus marsupium Roxb, Andrographis paniculata (Burm.f.) Wall, Sterculiaurens Roxb., Tinospora cordifolia (Willd.) Miers, and Asparagus densiflorus (Kunth) Jessop. Phanerophytes had the highest percentage (71%, with percentage deviation from normal life form of + 25) followed by therophyte (15%, with percentage deviation + 2). Observed percentage deviation from normal life form was much lower (with + 2 percentage deviation) in both chamaephytes (8%) and therophytes (15%), suggesting that the studied sal forests are favorable for supporting various plants species. The forest management strategies should focus on the increasing demands for different timber and non-timber forest products to conserve the plant diversity of these natural forests.

Aboveground biomass allometric equations and distribution of carbon stocks of the African oak (Afzelia africana Sm.) in Burkina Faso

Abstract: The significant role of tropical forest ecosystems in the global carbon budget has increased the need for accurate estimates of tropical forest biomass. The lack of large-scale biomass allometric equations hampers the understanding of the spatial distribution of tree biomass and carbon stocks and their influencing factors in West Africa. This study aimed to develop allometric equations to estimate aboveground biomass of African oak (Afzelia africana Sm.) in Burkina Faso and to analyze factors affecting the variability of tree biomass and carbon storage. Sixty individual trees were destructively sampled in four protected areas along two climatic zones. In each climatic zone, log–log models were tested and fitted to each aboveground biomass component and to the total aboveground biomass. Carbon content in tree aboveground components was evaluated using the ash method. All validated equations showed good fit and performance with high explained variance. Allometric equations differed between the Sudano-sahelian zone and the Sudanian zone, except for leaf biomass equations. Both biomass allocation and carbon content varied significantly between tree components but not between climatic zones. Carbon content in tree components followed the patterns of biomass allocation with branches accounting for the highest proportion. In the two climatic zones, carbon contents were 50.18–52.62% for leaves, 54.78–54.94% for stems and 54.96–55.99% for branches. Dry biomass ranged from 509.05 to 765.56 kg tree−1 at site level and from 620.21 to 624.48 kg tree−1 along climatic zones. Carbon content varied from 53.90% in the Sudano-sahelian zone to 54.39% in the Sudanian zone. This study indicated that climate does not influence aboveground biomass production and carbon sequestration of Afzelia africana along the Sudano-sahelian and the Sudanian climatic zones of Burkina Faso. Future studies on climate–growth relationships should contribute to better understanding climate effects on biomass production and carbon storage.

Identification of chemical compounds in agarwood-producing species Aquilaria malaccensis and Gyrinops versteegii

Abstract: Agarwood is a non-timber forest product found in tropical rain forests. It is a black and fragrant resin valued for the perfume industry and demand continues to increase. However, the Indonesian agarwood-producing species, Aquilaria malaccensis and Gyrinops versteegii do not automatically produce such quality resin. Bio-induction technology or inoculation using Fusarium solani is usually applied to these species to trigger resin production. This research aims to identify agarwood compounds formed in seedlings and trees of A. malaccensis and G. versteegii after these species were inoculated with the fungus F. solani. The chemical compounds were identified by comparing the patterns of mass spectra fragmentation in the sample and in previous studies. Five groups of agarwood compounds were identified: (1) sesquiterpen group—cis-jasmone and aromadendrenepoxide; (2) chromones group—8-methoxy-2-(2-phenylethyl)chromen-4-one and newly-discovered chromone derivative, 7-(benzyloxy)-5-hydroxy-2-methylchromone found only in G. versteegii; (3) aromatic group—benzylacetone, guaiacol, p-ethylguaiacol, phenol, syringaldehyde, vanilin, furfuryl alcohol, and furfural; (4) fatty acid group—palmitic acid, oleic acid, and lauric acid; and, (5) triterpen group—squalene.

Composition of forests and vegetation in the Kailash Sacred Landscape, Nepal

Abstract: A total of 141 quadrats were sampled using stratified random sampling to study forest, environment and human interactions along an elevation gradient 1800 to 3665 m at the remote Kailash Sacred Landscape, Nepal. Eight forest types were identified, including Laurel-Oak to Rhododendron to Blue pine, comprising 191 species including 60 useful from 166 genera and 87 families. The environmental variables elevation, slope, and temperature were significant (p < 0.001) in determining the composition and distribution of forest types. Records of large numbers of useful plants along with diverse forest and vegetation types suggest a strong association between the culture of local villages and nature conservation. Due to changes in climate, socio-culture and land-use, forest degradation is expected to accelerate, thus forcing government and indigenous community forest management measures to acknowledge human, cultural and environmental variables for sustainable forest management.

Fine-scale habitat differentiation shapes the composition, structure and aboveground biomass but not species richness of a tropical Atlantic forest

Abstract: Evaluating the influences of fine-scale habitat heterogeneity on the composition, diversity, structure and functioning of forests is critical to understand how tropical forests will respond to climate change and devise forest management strategies that will enhance biodiversity conservation and aboveground biomass stock. Here, we hypothesized that topographic and soil factors determine fine-scale habitat differentiation, which in turn shape community composition, species richness, structure and aboveground biomass at the local scale in tropical forests. To test this hypothesis, we selected two areas (each 100 × 100 m) with contrasting fine-scale topographic conditions where all trees, palms and lianas with a diameter at breast height ≥ 10 cm were tagged and identified to species. In each selected area, 100 subplots of 10 × 10 m were established. We mainly found that higher topographic variability caused higher habitat differentiation with changes in species composition and community structure, but did not change species richness. Our habitat-scale analyses indicated that, in the less heterogeneous area, the distribution of species was more uniform along a fine-scale topographical gradient with no variation in convexity, which induced changes in structure and aboveground biomass, but not in species richness. The nonsignificant relationship between species richness and aboveground biomass may be attributable to species redundancy or functional dominance. This study suggests that environmental filtering is a fundamental process for shaping community assembly and forest functioning along a local topographical gradient in tropical forests.

Seasonal dynamics of soil microbial biomass C and N of Keteleeria fortunei var. cyclolepis forests with different ages

Abstract: Soil microbial biomass is an important indicator to measure the dynamic changes of soil carbon pool. It is of great significance to understand the dynamics of soil microbial biomass in plantation for rational management and cultivation of plantation. In order to explore the temporal dynamics and influencing factors of soil microbial biomass of Keteleeria fortunei var. cyclolepis at different stand ages, the plantation of different ages (young forest, 5 years; middle-aged forest, 22 years; mature forest, 40 years) at the Guangxi Daguishan forest station of China were studied to examine the seasonal variation of their microbial biomass carbon (MBC) and microbial biomass nitrogen (MBN) by chloroform fumigation extraction method. It was found that among the forests of different age, MBC and MBN differed significantly in the 0–10 cm soil layer, and MBN differed significantly in the 10–20 cm soil layer, but there was no significant difference in MBC for the 10–20 cm soil layer or in either MBC or MBN for the 20–40 cm soil layer. With increasing maturity of the forest, MBC gradually decreased in the 0–10 cm soil layer and increased firstly and then decreased in the 10–20 cm and 20–40 cm soil layers, and MBN increased firstly and then decreased in all three soil layers. As the soil depth increased, both MBC and MBN gradually decreased for all three forests. The MBC and MBN basically had the same seasonal variation in all three soil layers of all three forests, i.e., high in the summer and low in the winter. Correlation analysis showed that MBC was significantly positively correlated with soil organic matter, total nitrogen, and soil moisture, whereas MBN was significantly positively correlated with soil total nitrogen. It showed that soil moisture content was the main factor determining the variation of soil microbial biomass by Redundancy analysis. The results showed that the soil properties changed continuously as the young forest grew into the middle-aged forest, which increased soil microbial biomass and enriched the soil nutrients. However, the soil microbial biomass declined as the middle-age forest continued to grow, and the soil nutrients were reduced in the mature forest.

Effects of historic wildfire and prescribed fire on site occupancy of bats in Shenandoah National Park, Virginia, USA

Abstract: Given the likelihood of regional extirpation of several once-common bat species in eastern North America from white-nose syndrome, it is critical that the impacts of forest management activities, such as prescribed fire, are known in order to minimize potentially additive negative effects on bat populations. Historic wildfires may offer a suitable surrogate to assess long-term burn impacts on bats for planning, implementing and assessing burn programs. To examine the effects of historic fire on bats, we sampled bat activities at 24 transect locations in burned and unburned forest stands in the central Appalachian Mountains of Shenandoah National Park (SNP), Virginia, USA. There was limited evidence of positive fire effects over time on hoary bats (Lasiurus cinereus Beauvois) and big brown bats (Eptesicus fuscus Beauvois) occupancy. Overall, there were few or mostly equivocal relationships of bat occupancy relative to burn conditions or time since fire in SNP across species using a false-positive occupancy approach. Our results suggest that fire does not strongly affect bat site occupancy short- or long-term in the central Appalachians.

Large-scale permafrost degradation as a primary factor in Larix sibirica forest dieback in the Khentii massif, northern Mongolia

Abstract: The objective of this study is to investigate the potential causes of widespread Larix sibirica Ledeb. mortality observed in the Khentii massif of northern Mongolia. The ratio of deadwood to living trees in affected stands in the Goricho region, the southernmost study site situated close to the Gobi Desert, was as high as 3.6:1. Moisture fluctuations monitored over 2 years using electrical impedance spectrometry revealed that the Goricho study site had higher soil moisture levels than the two less affected sites Barun Bayan and Dzun Bayan. High soil moisture was recorded in an area characterized by highly skeletal soils, ones with more than 35% by volume of rock fragments, and comparatively shallow soil horizons, from valley to mountains. The layer of permafrost influencing hydrogeological processes is much deeper in the Goricho region compared to the undisturbed study sites. Redundancy analysis confirmed a significant number of dead L. sibirica on sites with developed soils. Live forest stands, however damaged, grow in this region on well-drained scree slopes or on rocky bastions. The mass mortality observed for L. sibirica may be directly linked to accelerated permafrost thaw in the area bordered by the Tuul and the Terelj Rivers. Our assumption is that L. sibirica root system necrosis occurred as a result of long-term waterlogging of developed soils with high spatial heterogeneity, normally able to absorb high quantities of groundwater. The areas unaffected were scree fields and rocky bastions characterized by adequate drainage. All of our findings support the primary stages of large-scale permafrost thaw, i.e., correlating increases in soil moisture with increasing permafrost active layer thickness.

Fire alters the availability of soil nutrients and accelerates growth of Eucalyptus grandis in Zambia

Abstract: Fire has been used to prepare land during tree plantation establishment for many years but uncertainty about how ecosystems respond to prescribed burning makes it difficult to predict the effects of fire on soil nutrients. The aim of this study was to determine the effect of burning accumulated forest residues (slash) on soil chemical properties and how trees respond. We analyzed 40 burned and unburned sites and compared growth of Eucalyptus grandis W. Hill ex Maiden between sites. Soil pH increased by 39% after fire, suggesting reduced soil acidity and increased liming. Total nitrogen increased by 100%; other nutrients (Ca2+, Mg2+ and K+) also increased. Increase in nutrients had a significant effect on the growth of E. grandis; larger and taller trees were associated more with burned than unburned sites. This study provides evidence that burning accumulated slash during land preparation prior to plantation establishment alters soil nutrient status and enhances the growth of E. grandis.

Fuel characteristics, loads and consumption in Scots pine forests of central Siberia

Abstract: Forest fuel investigations in central and southern Siberian taiga of Scots pine forest stands dominated by lichen and feather moss ground vegetation cover revealed that total aboveground biomass varied from 13.1 to 21.0 kg/m2. Stand biomass was higher in plots in the southern taiga, while ground fuel loads were higher in the central taiga. We developed equations for fuel biomass (both aerial and ground) that could be applicable to similar pine forest sites of Central Siberia. Fuel loading variability found among plots is related to the impact and recovery time since the last wildfire and the mosaic distribution of living vegetation. Fuel consumption due to surface fires of low to high-intensities ranged from 0.95 to 3.08 kg/m2, that is, 18–74% from prefire values. The total amount of fuels available to burn in case of fire was up to 4.5–6.5 kg/m2. Moisture content of fuels (litter, lichen, feather moss) was related to weather conditions characterized by the Russian Fire Danger Index (PV-1) and FWI code of the Canadian Forest Fire Weather Index System. The data obtained provide a strong foundation for understanding and modeling fire behavior, emissions, and fire effects on ecosystem processes and carbon stocks and could be used to improve existing global and regional models that incorporate biomass and fuel characteristics.

Larix olgensis growth–climate response between lower and upper elevation limits: an intensive study along the eastern slope of the Changbai Mountains, northeastern China

Abstract: Larix olgensis is a dominant tree species in the forest ecosystems of the Changbai Mountains of northeast China. To assess the growth response of this species to global climate change, we developed three tree-ring width and biomass chronologies across a range of elevations in the subalpine forests on the eastern slope of the Changbai Mountains. We used dendroclimatic analyses to study key factors limiting radial growth in L. olgensis and its variation with elevation. The statistical characteristics of chronologies suggested that elevation is a determinant of tree growth patterns in the study area. Response function analysis of chronologies with climate factors indicated that climate–growth relationships changed with increasing elevation: tree growth at high elevation was strongly limited by June temperatures of the previous year, and as elevation decreases, the importance of temperature decreased; tree radial growth at mid-elevation was mainly controlled by precipitation towards the end of the growing season of the current year. Biomass chronologies reflected a stronger climatic signal than tree-ring width chronologies. Spatial correlation with gridded climate data revealed that our chronologies contained a strong regional temperature signal for northeast China. Trees growing below timberline appeared to be more sensitive to climate, thus optimal sites for examining growth trends as a function of climate variation are considered to be just below timberline. Our study objective was to provide information for more accurate prediction of the growth response of L. olgensis to future climate change on the eastern slope of the Changbai Mountains, and to provide information for future climate reconstructions using this tree species in humid and semi humid regions.