ARTICLE Download: 87| View: 217| Comments: 0 | doi:10.20944/preprints201905.0222.v1
Subject: Biology, Forestry Keywords: tree seed pathogens, alien invasive species, emerging forest disease, global trade, plant biosecurity, commercial seed, Pinus, Diplodia sapinea, Sydowia polyspora, Lasiodiplodia theobromae, mycobiome, FUNGuild
Online: 17 May 2019 (11:08:40 CEST)
The import and export of tree seed carries with it risks of inadvertent introduction of pests and pathogens to hitherto unaffected regions. Although trade in seed of specified trees is regulated, phytosanitary requirements for most tree species are minimal, even those related to the most important forest tree species in a given region. A better understanding of the microbiome associated with seed intended for commercial production or ornamental use, and their potential risk with the transport from the source origin of distributors, will help regulatory agencies implement measures to prevent new and emerging risks. In this study we used high throughput sequencing to show that highly diverse fungal communities were associated with seed of 14 different Pinus species obtained from seed banks (seed orchards) and retail sources (online distributors) in North America and Europe. Fungal diversity differed among the 23 seedlots tested. Community composition did not relate to the species of Pinus nor the country of origin. Assigned potential functions based on sequence identity using FUNGuild provided an overall understanding of the likely life strategies associated fungal OTUs. Of those sequences classified to a trophic level, 453 were plant pathogens, with the Dothideomycetes having the highest prevalence. The most common plant pathogens detected included Sydowia polyspora, Lasiodiplodia theobromae, Diplodia intermedia and Diplodia sapinea. The evidence presented here illustrates an urgent need for plant protection authorities, practitioners and the general public to recognize the potential risk of introducing harmful pathogens through innocent transport of seed.
Mon, 15 April 2019
ARTICLE Download: 25| View: 98| Comments: 0
Subject: Biology, Forestry Keywords: diversity; ecosystem functioning; stand growth; resistance; recovery; climate change; forests; Alps
Online: 15 April 2019 (10:57:38 CEST)
As climate change should lead to an increase in the vulnerability and the sensitivity of forests to extreme climatic events, quantifying and predicting their response to more severe droughts remains a key task for foresters. Furthermore, recent works have suggested that tree diversity may affect forest ecosystem functioning, including their response to extreme events. In this study we aimed at testing whether the growth response of forest stands to stressful climatic events varied between mixed and monospecific stands, under various environmental conditions. We focused on beech-fir forests (Fagus sylvatica [L.] and Abies alba [L.]) and beech-oak forests (Fagus sylvatica [L.] and Quercus pubescent [L.]) in the French Alps. We used a dendrochronological dataset sampled in forest plots organized by triplets (one mixture and two monospecific stands) distributed in six sites along a latitudinal gradient. We tested (1) whether stand diversity (two-species stands vs monospecific stands) modulates the stands’ response to drought events in terms of productivity, (2) whether species identity may drive the diversity effect on resistance and recovery, and (3) whether this can be explained by interspecific interactions. We found that (1) interspecific differences in response to extreme drought events (possibly due to interspecific differences in hydraulic characteristics) can induce a mixture effect on stand growth, although it appeared (2) to be strongly depending on species identity (positive effect only found for beech-fir mixed stands), while (3) there were no significant non-additive effects of diversity on stand resistance and recovery, except for some specific cases. Overall, our study shows that promoting selected mixed stands management may buffer extrem drought effect on stand productivity.
Thu, 21 March 2019
ARTICLE Download: 56| View: 227| Comments: 0
Subject: Biology, Forestry Keywords: Polish primitive horse, forest site type, herb layer, undergrowth layer, understory layer, biodiversity
Online: 21 March 2019 (10:04:14 CET)
The study was conducted in coniferous and deciduous old growth forests in two forest complexes located in: i) the fenced area of the Popielno Research Station of the Polish Academy of Sciences, with free-living Polish pony [Polish primitive horse (Equus ferus caballus)], and ii) open Maskulińskie Forest District managed (harvested) forest, without horses. The impact of forest animals on ground cover layer as well as on understory shrub layer and undergrowth, in i) area (horses and other forest animals) was compared with the results in ii) area (forest animals without horses). Very significant differences in the understory and undergrowth (above 0,5 m) layer vegetation communities structure between both areas and type of stands were found. The results suggest that the presence of the Polish horse substantially changed the species composition and increased the species diversity of the ground layer and shrub layer both on coniferous forest and in the deciduous forest habitats. The height of the shrub layer trees was lower by 30% in the area with the Polish horse.
Fri, 1 February 2019
ARTICLE Download: 91| View: 543| Comments: 0 | doi:10.20944/preprints201902.0012.v1
Subject: Biology, Forestry Keywords: Capital return; pulpwood-sawlog transition; diameter-limit cutting
Online: 1 February 2019 (10:30:55 CET)
We investigate financial feasibility of a few thinning schedules for spruce stands. Some example stands have previously experienced commercial low thinning, whereas others young stand cleaning only. High thinning is combined with quality thinning, and further growth of trees is estimated using a Norwegian growth model. High capital return rates are gained by diameter-limit cutting to the transition diameter between pulpwood and sawlogs. Repeated thinnings lead to reduction in the capitalization during several decades, the system approaching a stationary state. The transient forest stands investigated shown a significant excess capital return, in relation to the stationary state, and this excess return is due to transient tree size distribution. Correspondingly, capital return rate gained in rotation forestry is somewhat higher than that of stationary continuous-cover forestry, and the volumetric yield is much higher. The productive capacity of stands previously thinned from below apparently has been ruined by that treatment.
Mon, 21 January 2019
ARTICLE Download: 47| View: 309| Comments: 0 | doi:10.20944/preprints201901.0194.v1
Online: 21 January 2019 (07:28:01 CET)
We investigate wealth accumulation in forestry, assuming that revenues are re-invested. Three different optimization criteria are compared, two of which are based on cash flows, the third financially grounded. Direct optimization of wealth appreciation rate always yields best results. Procedures gained by maximizing internal rate of return are only slightly inferior. With external discounting interest rate, the maximization of net present value yields arbitrary results, with at worst devastating financial consequences.
Fri, 11 January 2019
COMMUNICATION Download: 55| View: 143| Comments: 0 | doi:10.20944/preprints201901.0105.v1
Online: 11 January 2019 (07:13:57 CET)
Research Highlights: The correlations between the analyzed physical properties of seeds and seed mass were determined. The results were analyzed to determine most effective seed separation devices for the evaluated fir species. Background and Objectives: Information about the variations and correlations between the physical properties of seeds is essential for designing and modeling seed processing operations such as seed separation. The aim of this study was to determine the range of variations in the basic physical properties of seeds of selected fir species, and to identify the correlations between these attributes for the needs of the seed sorting processes. Materials and Methods: Terminal velocity, thickness, width, length, the angle of external friction and mass were determined in the seeds of 11 fir species. The measured parameters were used to calculate the geometric mean diameter, three aspect ratios, sphericity index and the specific mass of each seed. Results: The average values of the basic physical properties of the analyzed seeds were determined in the following range: terminal velocity – from 4.8 to 7.1 m s-1, thickness – from 1.76 to 3.22 mm, width – from 3.29 to 5.57 mm, length – from 5.44 to 11.06 mm, angle of external friction – from 26 to 33°, and mass – from 7.9 to 48.3 mg. The seeds of Sierra white fir where most similar, whereas the seeds of balsam fir differed most considerably from the seeds of the remaining fir species. Conclusions: Fir seeds should be sorted primarily with the use of mesh sieves with longitudinal openings to obtain fractions with similar seed mass and to eliminate the need for dewinging.
Tue, 4 December 2018
REVIEW Download: 97| View: 177| Comments: 0 | doi:10.20944/preprints201812.0055.v1
Subject: Biology, Forestry Keywords: black timber bark beetle; biological invasion; Xyleborini; ambrosia beetle; spread; occurrence; ethanol; forest management
Online: 4 December 2018 (09:57:21 CET)
The black timber bark beetle Xylosandrus germanus (Blandford) is an invasive ambrosia beetle originating from Southeastern Asia that has become successfully established within Europe and North America. Herein, we provide a review of the spread and distribution of this pest of trees and timber across Europe before and after 2000, along with a review of its habitat preferences. Since the spread of X. germanus across Europe has accelerated rapidly post-2000, emphasis is placed on this period. X. germanus was first recorded in Germany in 1951 and since then in 21 European countries along with Russia. Ethanol-baited traps were deployed in oak, beech, and spruce forest ecosystems in the Western Carpathians, Central Europe, Slovakia, to characterize the distribution and habitat preference of this non-native ambrosia beetle. Captures of X. germanus within Slovakia have been rising rapidly since its first record in 2010, and now this species dominates captures of native ambrosia beetles. X. germanus has spread throughout the whole Slovakia from the south-southwest to the north-northeast over the period of 5–10 years and has also spread vertically into higher altitudes within this country. While living but weakened trees in Europe and North America are attacked by X. germanus, the greatest negative impact within Slovakia is attacks on recently felled logs of oak, beech and spruce trees providing high quality timber/lumber. We suggest that the recent rapid spread of X. germanus in Central Europe is being facilitated by environmental changes, specifically global warming, and the increasing frequency of timber trade. Recommendations for management of X. germanus in forest ecosystems are proposed and discussed, including early detection, monitoring, sanitary measures, etc.
Mon, 12 November 2018
ARTICLE Download: 88| View: 96| Comments: 0 | doi:10.20944/preprints201811.0282.v1
Subject: Biology, Forestry Keywords: adaptive forestry; dendroecology; diffuse–porous wood; drought years; vessel traits; wood anatomy
Online: 12 November 2018 (10:31:23 CET)
The distribution of Mexican Magnolia species´ occur under restricted climatic conditions. As many other tree species from the tropical montane cloud forests (TMCF), Magnolia species appear to be sensitive to drought. Through the use of dendrochronological techniques, this study aims to determine the climate influence on the vessel traits of M. vovidesii and M. schiedeana which are endangered tree species that are endemic to the Sierra Madre Oriental in eastern Mexico. Because most of the tree species in TMCFs are sensitive to climate fluctuations, it is necessary to investigate the differences in the climatic adaptability of the vessel architecture of these trees. This could allow us to further understand the potential peril of climate change on TMCFs. We compared vessel frequency, length and diameter in drought and non–drought years in two Mexican Magnolia species. We used tree–rings width and vessel traits to assess the drought effects on Magnolias’ diffuse–porous wood back to the year 1929. We obtained independent chronologies for M. vovidesii with a span of 75 years (1941–2016), while for M. schiedeana we obtained a span of 319 years (1697–2016). We found that temperature and precipitation are strongly associated with differences in tree–ring width (TRW) between drought and non–drought years. Our results showed anatomical differences in vessel trait response between these two Magnolia species to climatic variation. We suggest that our approach of combining dendroclimatic and anatomical techniques is a powerful tool to analyse anatomic wood plasticity to climatic variation in Magnolia species.
Tue, 6 November 2018
ARTICLE Download: 77| View: 113| Comments: 0 | doi:10.20944/preprints201811.0145.v1
Subject: Biology, Forestry Keywords: Highway Beautification; Transplant Shock; Transportation; Tree Health; Tree Establishment; Urban Forestry
Online: 6 November 2018 (14:22:48 CET)
Urban tree planting initiatives can experience high levels of mortality during establishment years. Mortality tied to the stresses of transplanting can be partially negated or exacerbated depending on the species selected, nursery materials used, site conditions present, and management practices employed. Past research has quantified post-planting survival, health, and growth. However, varying climates, species, land use types, and management practices warrant additional region-specific research. The purpose of this study is to assess the success of plantings along Florida highways and identify species, site, and management factors related to tree and palm health and establishment. Results show high annual establishment survival (98.5%) across 21 planting projects ranging from 9 to 58 months after installation, (n = 2711). For transplanted palms, the presence of on-site irrigation significantly improved establishment from 96.2% to 99.4%. No establishment differences were detected with regard to irrigation treatment for small-stature trees, shade trees, and conifers. Additionally, there were significant differences in tree health response among tree groups given species, management, and site factors.
Wed, 24 October 2018
ARTICLE Download: 72| View: 107| Comments: 0 | doi:10.20944/preprints201810.0568.v1
Subject: Biology, Forestry Keywords: ecological chemometrics; carbon cycle; nitrogen cycle; carbon and nitrogen distribution; plant leaf-litter-soil continuum
Online: 24 October 2018 (11:12:48 CEST)
We analyzed the plant-litter-soil continuum to investigate the carbon and nitrogen distribution and ecological stoichiometry of an evergreen broad-leaved forest at Dagangshan Mountain, Jiangxi. The results showed that the average C and N contents and C:N ratios in the leaves and fine roots among 6 different tree species were 401.87g/kg, 21.41g/kg, 19.27 and 348.64g/kg, 15.73g/kg, 23.97, respectively; the average C and N contents and C:N ratios were 323.06 g/kg, 12.76 g/kg, 25.58 respectively in leaf litter, and 16.40 g/kg, 1.09 g/kg, 16.27 respectively for soil. In contrast with the C content, the total N content of the fine roots and litter had a high coefficient of variation and a high spatial heterogeneity. We ranked the six different representative tree species according to total C and N content in leaves and fine roots. The results for each species were generally consistent with each other, showing a positive correlation relationship between total C and N content in the leaves and roots. Among them, S. discolor (Champ. ex Benth.) Muell. plants displayed high carbon and nitrogen storage capacities, and on the other hand, C. fargesii Franch., C. myrsinifolia (Blume) Oersted, A. fortunei (Hemsl.) Makino, and V. fordii (Hemsl.) Airy Shaw showed a high nitrogen transfer rate. Total soil N and C decreased with depth. Soil organic carbon (SOC), soil resistant organic carbon (ROC), total N, alkali nitrogen, NH4+-N and NO3--N contents were all also negative correlated with soil depth, but the contents of the NH4+-N and NO3--N did not change significantly; The spatial distribution of soil NO3--N was significantly heterogeneous. At 0-10 cm soil depth, SOC was positively correlated with alkaline nitrogen, and at 10-20 cm soil depth, SOC was significantly positively correlated with total N. In general, when soil carbon was abundant, nitrogen supply capacity was also high.
Tue, 23 October 2018
ARTICLE Download: 34| View: 109| Comments: 0 | doi:10.20944/preprints201810.0543.v1
Subject: Biology, Forestry Keywords: similarity relation neighborhoods, similarity relation decomposition, statistical analysis of within-set variability
Online: 23 October 2018 (16:12:37 CEST)
Maximally similar sets (MSS) are sets of elements that share a neighborhood in a high-dimensional space defined by symmetric, reflexive similarity relation. Each element of the universe is employed as the kernel of a neighborhood of a given size (number of members), and elements are added to the neighborhood in order of similarity to the current members of the set until the desired neighborhood size is achieved. The set of neighborhoods is then reduced to the set of unique maximally similar sets by eliminating all sets that are permutations of an existing set. Subsequently, the within-MSS variability of attributes associated with the elements is compared to random sets of the same size to estimate the probability of obtaining variability as low as observed. Individual attributes can be compared for effect size by the ratio of within-MSS variability to random set variability, correcting for statistical power as necessary. The analyses performed identify constraints, as opposed to determinants, in the triangular distribution of pair-wise element similarity. In the example given here, the variability in spring temperature, summer temperature, and growing degree days of forest vegetation samples shows the greatest constraint on forest composition of a large set of candidate environmental variables
Thu, 18 October 2018
ARTICLE Download: 186| View: 125| Comments: 0 | doi:10.20944/preprints201810.0426.v1
Subject: Biology, Forestry Keywords: acacia species; allometric equation; above ground biomass; carbon stock
Online: 18 October 2018 (15:58:15 CEST)
Allometric equations are used to estimate accurate biomass and carbon stock of forests. However, in Ethiopia only few allometric equations as compared to its floral diversity and species-specific allometric equations for Acacia species are still not developed in Ethiopia. The numbers of tree marked for sampling are Fifty-four (54) using preferential sampling. Diameter at breast height, wood density and tree height were collected as independent variables to predict species specific dry biomass of Acacia species. The new species-specific allometric models have been performed using linear regression analysis in the R software. The Above ground biomass (AGB) have been validated using quantitative statically using the pantropic model. Six candidate models have been developed for each species and four best models for each species of dry biomass was selected based on goodness-of-fit statistics and equation performance analysis of the candidate models. The best model for predicting above ground biomass for Acacia seyal is 0.20636*((DBH2)Hρ) 0.53167, for Acacia polyacantha is 7.26982((DBH)2Hρ)0.21750, for Acacia ethibcia is 29.01898*((DBH)2Hρ)0.21518 and for Acacia toritolis is 3.82427*((DBH)2Hρ)0.16748. The selected models are the best performing (P> 0.01) and higher adjusted R2 (>80%) and has lower Akaike’s Information Criteria (AIC) and residual standard error (RSE) values as comparing the rest of the model. The validation of new developed biomass model using Tukey test indicated that significant variation of mean biomass (P<0.05) between the new developed model and the generalized model. The statistics model performance analysis of Nash-Sutcliffe efficiency (NSE) value is approaching to one, indicating that the new developed model has better performance model as compared with generalized model. Moreover, the percent bias of the new developed models is close to zero which indicates that the site-specific biomass models have more accurate estimator and the generalized biomass models have overestimated biomass for the four Acacia species.
Mon, 15 October 2018
ARTICLE Download: 361| View: 100| Comments: 0 | doi:10.20944/preprints201810.0333.v1
Subject: Biology, Forestry Keywords: Insects, Forest, Fungi, ITS1, metagenomics, NGS, Oomycete, Phytopathogens, Phytophthora, vectors
Online: 15 October 2018 (18:52:27 CEST)
Understanding ecological interactions is a key in managing phytopathology. Although entomologists rely mostly on both traditional molecular methods and morphological characteristics to identify pests, next-generation sequencing is becoming the go-to avenue for scientists studying fungal and oomycete phytopathogens. These organisms sometimes infect plants together with insects. There are many relationships yet to be discovered and much to learn about how these organisms interact with one another. Considering the growing number of exotic insect introductions in Canada, a high-throughput strategy for screening those insects is already implemented by the Canadian Food Inspection Agency (CFIA). However, no plan is deployed to investigate the phytopathogenic fungal and oomycete species interacting with insects. Metagenomics analysis was performed on the preservation fluids from CFIA’s insect traps across Canada. Using the Ion Torrent PGM technology and fusion primers for multiplexing and indexing, community profiling was conducted on the different semiochemicals used in the insect traps and the various areas where these traps were placed. Internal transcribed spacer 1 (fungi and oomycetes) and adenosine triphosphate synthase subunit 9-nicotinamide adenine dinucleotide dehydrogenase subunit 9 spacer amplicons were generated. Although direct links between organisms could not be established, moderately phytopathogenic fungi (e.g., Leptographium spp. and Meria laricis) and oomycetes (mainly Peronospora spp. and Pythium spp.) unique to every type of semiochemical were discovered. The entomopathogenic yeast Candida michaelii was also detected. This project demonstrated our ability to screen for unwanted species faster and at a higher scale and throughput than traditional pathogen diagnostic techniques. Additionally, minimal modifications to this approach would allow it to be used in other phytopathology fields.
Thu, 20 September 2018
ARTICLE Download: 124| View: 149| Comments: 0 | doi:10.20944/preprints201809.0399.v1
Subject: Biology, Forestry Keywords: scots pine; plus-trees; xylem; lignification; physiological condition; hereditary conditionality; factor analysis; cluster analysis
Online: 20 September 2018 (05:34:23 CEST)
An important moment in the establishment of forestry seed orchards is the formation of their optimal composition, avoiding inbreeding depression in the outgoing seed material which occurs due to crossbreeding between closely related plus trees, the clones of which comprise the orchards. It is possible to minimize the negative effect of inbreeding by considering the hereditary aspect of the heterogeneous seed orchard material. The purpose of our work is to provide a comparative assessment of the formation and lignification of xylem in annual shoots of the plus trees of Scots pine. We investigated the formation and lignification of xylem in the annual shoots of the plus trees of Scots pine (Pinus sylvestris L.), found in natural forests in the Nizhny Novgorod region of the Russian Federation. Their vegetative progeny were cultivated in the clone archive stationed in the same region. Analyzing the one-type of the 1-year shoots, the time that the shoots were cut from the branches corresponded to the presence of plants in the characteristic phenological phases of seasonal development. A histochemical study of xylem was conducted, using the qualitative reactions of phloroglucinol to lignin. The power of xylem development was estimated by counting, in the radial direction, the cell rows from the core to the cambium in the microscope’s field of view. A significant differentiation of plus trees was revealed in a complex of signs characterizing the level of xylem development and the degree of xylem cell lignification in the tissues of annual shoots. Phenotypic differences in the physiological state of plus trees appeared given a leveled ecological background, indicating their genotypic determinism. This was confirmed by an analysis of variance. The share of the influence of differences between the proper plus trees was between 25.16% ± 8.91% and 53.98% ± 5.48% of the total phenotypic variance of the signs of the seasonal state of xylem. Factor analysis was used to reduce the number of considered indicators of xylem physiological state. The results allowed a cluster analysis to be carried out on the basis of the normalized values of the initial xylem features as well as the principal components derived from them. The association of plus trees was done on the basis of the similarity of the multidimensional estimates of xylem seasonal condition. The objects that were the most remote from the others were identified. This information provides a reasonable approach to the formation of an assortment of Scots pine seed orchards.
Wed, 19 September 2018
ARTICLE Download: 108| View: 89| Comments: 0 | doi:10.20944/preprints201809.0382.v1
Subject: Biology, Forestry Keywords: forest road surface; forest road damage; vibration measurements; vibration software
Online: 19 September 2018 (10:43:25 CEST)
Regarding number of vehicles, forest roads are characterized by low traffic intensity, but on the other hand great values of ground pressure between wheels of timber truck units and forest road surface occur, often with pressures values above 80 kN which additionally causes damage of the upper and lower forest road layer. There are currently several methods for assessing condition of a forest road surface which are mainly used for assessing state of public roads, but can be used in forestry as well. Assessing condition of forest road surface was done by measuring vibrations with a specially developed software for Android OS installed on a Huawei MediaPad 7 Lite. Software measured vibrations in all three axes, coordinates of device, speed of the vehicle and time. Aim of this research was to determine accuracy of collected data so that this method can be used for scientific and practical purposes. Research was carried out on the segment of a forest road during driving a vehicle equipped with a measuring device. Tests were performed in both driving direction of the forest road segment with different measuring frequencies, tyre inflation pressures and driving speeds. Values of vibrations were classified and translated on a map of forest road together with devices’ measured coordinates. Vibration values were compared with places of recorded forest road surface damages. Research results show no significant difference in vibration values between 1 Hz and 10 Hz of measurement frequencies. Based on the analysis of collected data and obtained results, it is clear that it is possible to assess the condition of a forest road surface by measuring vibrations. The greatest values of vibrations were recorded on the most damaged parts of the forest road. Vibrations do not depend on tyre inflation pressure, but ranges of vibrations are decreasing with decreasing driving speed. Accuracy of collected data depends on GPS signal quality, so it is recommended that each segment of forest road is recorded twice so that location of damages on forest road can be confirmed with certainty.
Wed, 12 September 2018
ARTICLE Download: 84| View: 111| Comments: 0 | doi:10.20944/preprints201809.0220.v1
Subject: Biology, Forestry Keywords: sequential chemical extraction; 31P-nuclear magnetic resonance spectroscopy (31P-NMR); phosphorus; coastal sand dune; Casuarina forests
Online: 12 September 2018 (12:35:31 CEST)
Continuous research into the availability of phosphorus (P) in forest soil is critical for sustainable management of forest ecosystems. In this study, we used sequential chemical extraction and 31P-nuclear magnetic resonance spectroscopy (31P-NMR) to evaluate the form and distribution of inorganic P (Pi) and organic P (Po) in Casuarina forest soils of a subtropical coastal sand dune at Houlong in Taiwan. The soil samples were collected from humic (+2-0 cm) and mineral layers (mineral-I: 0-10, mineral-II: 10-20 cm) at two topographic locations (upland and lowland) by elevation. Sequential chemical extraction revealed that the NaOH-Po fraction, as moderately recalcitrant P, was the dominant form in humic and mineral-I layers in both upland and lowland soils, whereas the cHCl-Pi fraction was the dominant form in the mineral-II layer. Resistant P content, including NaOH-Pi, HCl-Pi, cHCl-Pi, and cHCl-Po fractions, was higher in the upland than lowland in the corresponding layers; however, labile P content, NaHCO3-Po, showed the opposite pattern. Content of resistant Pi (NaOH-Pi, HCl-Pi, and cHCl-Pi) increased significantly with depth, but that of labile Pi (resin-Pi and NaHCO3-Pi) and recalcitrant Po (NaHCO3-Po, NaOH-Po, and cHCl-Po) decreased significantly with depth at both locations. 31P-NMR spectroscopy revealed inorganic orthophosphate and monoesters-P as the major forms in this area. The proportions of Pi and Po evaluated by sequential chemical extraction and 31P-NMR spectroscopy were basically consistent. The results indicated that the soils were in weathered conditions. Furthermore, the P distribution and forms significantly differed between the upland and lowland by variation in elevation and eolian aggradation effects in this coastal sand dune landscape.
Thu, 30 August 2018
ARTICLE Download: 68| View: 105| Comments: 0 | doi:10.20944/preprints201808.0515.v1
Subject: Biology, Forestry Keywords: balsam fir; white spruce; seedlings; partial cut; plantation; naturals stands; light; seed rain
Online: 30 August 2018 (05:36:10 CEST)
This study documents the conditions associated to white spruce and balsam fir regeneration after partial cutting. Measurements were collected 9 to 30 years after partial cutting in 12 natural fir stands and 5 white spruce plantations. We estimated seed input, measured light reaching the undergrowth, recorded seedlings (<150 cm) and their age on 6 different seedling establishment substrates: mineral soil, moss, rotten wood, litterfall, herbaceous and dead wood. Partial cutting generally favours the establishment and growth of seedlings. The number of fir and spruce seedlings is always greater in natural stands than in plantations, a trend likely associated with the reduced abundance of preferential establishment substrate in the latter. White spruce significantly prefers rotten wood while fir settles on all types of substrates that cover at least 10% of the forest floor. There is a strong relationship between light intensity and the median height of spruce seedlings, but this relationship is non-significant for fir. Seedlings of both species can survive at incident light intensities as low as 3%, but an intensity of 15% or more seems to offer the best growth conditions. The conditions for successful forest regeneration proposed in this study should be applied when the goal is to establish a new stand prior to clear cutting or to convert stand structure.
Wed, 22 August 2018
COMMUNICATION Download: 113| View: 168| Comments: 0 | doi:10.20944/preprints201808.0400.v1
Subject: Biology, Forestry Keywords: seeds; physical properties; range of variation; correlations; sorting
Online: 22 August 2018 (15:04:22 CEST)
Information about the variations and correlations between the physical properties of seeds is essential for designing and modeling seed processing operations. The aim of this study was to determine the variations in the basic physical properties of seeds of selected spruce species and to identify the correlations between these attributes for the needs of the seed sorting processes. Terminal velocity, thickness, width, length, mass and the angle of external friction were determined in the seeds of 11 spruce species. The measured parameters were used to calculate three aspect ratios, geometric mean diameter, sphericity index and specific mass of each seed. The average values of the basic physical properties of the analyzed seeds were determined in the following range: terminal velocity – 5.25 to 8.34 m s-1, thickness – 1.10 to 2.32 mm, width – 1.43 to 3.19 mm, length – 2.76 to 5.52 mm, the angle of external friction – 23.1 to 30.0°, and mass – 2.29 to 18.57 mg. The seeds of Jezo spruce and Meyer's spruce were most similar to the seeds of other spruce species, whereas oriental spruce seeds differed most considerably from the remaining seeds. Our findings indicate that spruce seeds should be sorted primarily with the use of mesh sieves with longitudinal openings to obtain fractions with similar seed mass and to promote even germination.
Sat, 18 August 2018
ARTICLE Download: 119| View: 179| Comments: 0 | doi:10.20944/preprints201808.0337.v1
Subject: Biology, Forestry Keywords: Southeastern rim of Tibetan plateau; dendrochronology; climate response; climate warming; subalpine conifer forests
Online: 18 August 2018 (12:08:03 CEST)
Climate change has a inevitable impacts on tree radial growth, particularly at mountain timeberlines. To understand climate effects on conifer radial growth in the central Hengduan Mountains and potential impacts of future climate change on conifer forest, we studied growth responses to climate variables in Abies georgei, the major tree species of conifer forest in Hengduan Mountains. We collected tree ring samples from four sites near the timberlines and analyzed the relationship between principle components (PC#1) of four chronologies and climatic variables by using response function analysis (RFA), redundancy analysis (RDA) and moving interval analysis (MIA). A. georgei growth was affected by both temperature (positive effects) and precipitation (negative effects). Specifically, the radial growth of A. georgei was significantly and positively correlated with current July and previous November temperature (detected by both RFA and RDA), while precipitation of current June and September inhibited tree growth (detected by RDA). More rapid warming in recent 20 years (1990–2010) clearly enhanced growth responses to July and November temperature, whereas the relationship was weaken for June and September precipitation according to MIA. Under the climate trend of the study area, if the increasing temperature could offset the negative effects of excessive precipitation, A. georgei radial growth would likely benefit from warming, the dynamics of conifer forest should also consider indirect impacts of climate change.
Tue, 24 July 2018
ARTICLE Download: 130| View: 132| Comments: 0 | doi:10.20944/preprints201807.0439.v1
Subject: Biology, Forestry Keywords: climate change; temperature stress; drought; elevated CO2; soil water; forest succession; mechanistic landscape model; LANDIS-II; PnET-Succession
Online: 24 July 2018 (05:34:08 CEST)
1) Background: Climate change may subject forests to climate conditions to which they are not adapted. Elevated temperatures reduce net photosynthesis by increasing respiration rates and increasingly long droughts dramatically increase morbidity. CO2 enrichment enhances productivity, but it is not clear to what extent CO2 enrichment can offset the negative effects of elevated temperatures and longer droughts. 2) Methods: We used a mechanistic landscape model to conduct controlled simulation experiments manipulating CO2 concentration, temperature, drought length and soil water capacity. 3) Results: We found that elevated CO2 stimulates productivity such that it dwarfs the negative effect caused by elevated temperature. Energy reserves were not as strongly mitigated by elevated CO2, and mortality of less competitive cohorts increased. Drought length had a surprisingly small effect on productivity measures, but had a marked negative effect on mortality risk. 4) Conclusions: Elevated CO2 compensated for the negative effect of longer droughts in terms of productivity measures, but not survival measures.
Fri, 13 July 2018
ARTICLE Download: 216| View: 209| Comments: 0 | doi:10.20944/preprints201807.0243.v1
Subject: Biology, Forestry Keywords: Habitat types, visual differences, landscape characteristics.
Online: 13 July 2018 (17:07:05 CEST)
The unique qualities of areas with natural landscape features help provide sustainability. Moreover, their different vegetation covers and ecosystems contribute to the preservation of their visual attraction. In recent years, the demand for natural areas has not only been seen at a recreational level, but has also become associated with the conservation and sustainability of those areas. Although the concept of sustainability is expressed from an ecological point of view, studies indicate that the visual aspect is also an important component. Thus, in this study, a visual quality assessment was carried out which considered both objective and subjective evaluations of different habitat types. Efteni lake-wetland and Melen Ağzı dunes (Düzce), Anzer, Ayder, and Çat Düzü highlands (Rize), and Sultanmurat and Taşli highlands (Trabzon) were selected as the study areas. A visual quality analysis was conducted with a total of 43 participants (23 students, 16 local inhabitants and four lecturers) in order establish their preferences in areas with different landscape characteristics. For the determination of the visual qualifications of these areas, a total of 24 photographs showing typical images representing each habitat type (three photographs for each) were employed. Taking perceptual parameters into consideration, assessment of visual quality was made according to the points given to each photo by the participants. Consequently, differences in visual quality were found to be influenced by the demographic status of the participants, differences in habitat types, recreational trends and the conservation status of the habitats.
Tue, 10 July 2018
ARTICLE Download: 160| View: 189| Comments: 0 | doi:10.20944/preprints201807.0177.v1
Subject: Biology, Forestry Keywords: weed control; competing vegetation; yield modelling; E. globulus
Online: 10 July 2018 (12:04:37 CEST)
Several studies have quantified the responses of Eucalyptus globulus plantations to weed control on its early development (2-3 years after establishment). However, long-term results of competing vegetation effects have been rarely incorporated into growth and yield models that forecast the long-term effects of reducing the intensity of competing vegetation control and its interaction with site resource availability on stem volume production close to rotation age. We compared several models predicting stand stem volume yield of Eucalyptus globulus plantations established across a water and fertility gradient growing under different intensity levels of free area of competing vegetation maintained during the first 3 years of stand development. Four sites were selected encompassing a gradient in rainfall and amount of competing vegetation. Treatments were applied at stand establishment and were monitored periodically until age 9 years. Competing vegetation control intensity levels considered 0, 5, 20, 44 and 100% weed-free cover around individual E. globulus seedlings. Maximum competing vegetation biomass production during the first growing season were 2.9, 6.5, 2.2 and 12.9 Mg ha-1, for sites ranging from low to high annual rainfall. As expected, reductions in volume yield at age 9 years were observed as competing vegetation control intensity decreased during the first growing season. A strong relationship was established between stem volume yield loss and the intensity of competing vegetation control, the amount of competing vegetation biomass produced during the first growing season and mean annual rainfall. The slope of the relationship was different among sites and was related mainly to water and light limitations. Our results, suggest that the biomass of competing vegetation (intensity of competition) affecting site resource availability, contribute to observed long-term effects on E. globulus plantations productivity. The site with the lowest mean annual rainfall showed the highest volume yield loss at age 9 years. Sites with highest rainfall showed contrasting results related to the amount of competing vegetation biomass.
Tue, 3 July 2018
ARTICLE Download: 317| View: 175| Comments: 0 | doi:10.20944/preprints201807.0042.v1
Subject: Biology, Forestry Keywords: species, edible, food bearing, diversity, neighborhoods, urban forest
Online: 3 July 2018 (12:10:53 CEST)
In Africa, 80% of households in urban areas are food insecure and is coupled with a dramatically changing urban food culture towards increased consumption of sugary and fatty foods. Consequently, incidences of obesity and undernourishment in many African cities are becoming escalating. Urban and peri-urban forestry emerges as a complementary measure to contribute towards elimination of urban hunger and improved nutritional security. However, there is scanty knowledge about the composition, diversity and socioeconomic contributions of urban food trees in African cities and this hinders policy discussions integrating urban forestry into the food security discourse. This paper examines the diversity and composition of the urban forest and food trees of Accra and sheds light on perceptions of urbanites regarding food tree cultivation and availability in the city. Using a mixed methods approach, about 105 respondents in six neighbourhoods of Accra were interviewed while over 200 100-m2 plots were surveyed across five land use types. Twenty-two out of the 70 woody species in Accra are edible. The food tree abundance in the city is about half of the total number of trees enumerated. The species richness and abundance of the edible trees and all trees in the city were significantly different among land use types (p<0.0001) and neighbourhood types (p<0.0001). The diversity of food bearing tree species was much higher in the poorer neighbourhoods than in the wealthier neighbourhoods. Respondents in wealthier neighbourhoods indicated that tree and fruit tree cover of the city was generally low and showed greater interests in cultivating fruit trees and expanding urban forest cover than poorer neighbourhoods. These findings demonstrate the need for urban food policy reforms that integrate urban grown tree foods in the urban food system/culture.
Tue, 26 June 2018
ARTICLE Download: 156| View: 248| Comments: 1 | doi:10.20944/preprints201806.0429.v1
Subject: Biology, Forestry Keywords: Mixed forests; Questionnaire Survey; Ecosystem Services; Stepwise Regression; Climate Change
Online: 26 June 2018 (15:48:31 CEST)
Scientific studies had shown that mixed forests of silver fir (Abies alba Mill.) and European beech (Fagus sylvatica L.) provide higher ecosystem services than monospecific forests. Mixed forests are known for their high resilience to climate change impacts and superior biodiversity compared to monospecific forests. In many countries, promotion of mixed forests in forest management is becoming a government policy since they can contribute to fulfill the Sustainable Development Goals set by the United Nation, respectively Goal 13 and 15. However, not much is known about public perceptions on mixed forests compared to monoculture forests. Our study on ecosystem services provided by mixed and monospecific forests in southwest Germany fill this gap. Based on a survey with 520 valid responses we analyzed people’s perception on 18 different supporting, cultural, regulating and provisioning ecosystem services measured by Likert scale. Stepwise regression analyses show relations between social profiles (gender, age, education, profession) and preferences on respondents’ perceptions. Our findings show that people perceive that mixed forests provide better cultural, regulating and supporting ecosystem services than monospecific forests of fir and beech whereas provisioning services were perceived as being equally or better provided by monospecific forests. Significant effects towards a positive perception on ecosystem services provided by mixed forests were mainly influenced by the perceived abundance of old trees, feeling of pleasantness in mixed forests, age, profession, and education. Our findings indicate that there is a high public support for the promotion of silver fir and beech mixed forests in Southwest Germany.
Thu, 3 May 2018
ARTICLE Download: 248| View: 309| Comments: 0 | doi:10.20944/preprints201805.0066.v1
Subject: Biology, Forestry Keywords: biomass yield; carbon storage; growth pattern; poplar; short-rotation coppices; seasonal trends
Online: 3 May 2018 (11:10:21 CEST)
It is required to manage sustainable Short-Rotation Coppices (SRCs) as an important role on carbon sink and bioenergy output, because most of SRCs were established in reclaimed land in South Korea. However, during the last three years, growth pattern of the SRCs was remarkably changed with soil condition. This study aimed to identify the sustainability of SRCs on carbon storage, biomass and fuel pellet production, monitoring the neighboring vegetation of SRCs by land-use exchange, physiological change of poplar on seasonal trend, and to evaluate whether poplar is suitable for making wood pellets. The calculated biomass yield per area of poplar grown was 103.07 Mg per total area (55.6 ha), and volumes of carbon dioxide absorption was estimated to be 330 Mg CO2. Wood pellet quality based on the criteria scored third grade, indicating that poplar is suitable for manufacturing fuel pellets. Moreover, monitoring of the flora distribution in SRCs revealed changes in species composition. As halophyte was increased during drought, soil organic matter, net growth and total chlorophyll of poplar were significantly decreased. These findings indicated that photosynthesis and growth pattern of SRCs may be negatively affected by microclimate and will provide valuable information for effective management of SRCs.
ARTICLE Download: 197| View: 284| Comments: 0 | doi:10.20944/preprints201805.0063.v1
Subject: Biology, Forestry Keywords: forest certification; market segmentation; cluster analysis; motivation schemes
Online: 3 May 2018 (09:21:17 CEST)
Forest certification is considered a viable market-based policy instrument to promote forest sustainability. It has an important role of play in meeting the objective of modern forestry development in China, which is to sustain ecological and environmental benefits of forests. To understand differences in attitudes, opinions, and interests in forest certification, this study segmented respondents of a landowner’s survey in Shandong, China based on their level of interest in participating in forest certification under different program requirements. Multivariate cluster analysis revealed three distinct groups: likely-, potential-, and unlikely-landowners. We further examined the heterogeneity of these groups in terms of their demographics, ownership characteristics, management objectives, and perceived benefits and challenges with adopting forest certification. The results suggested the necessity of differentiating landowners in formulating and designing specific motivation-based incentives and tailor outreach efforts and communication strategies to improve their interests in forest certification. Findings are useful and interesting to forest policymakers interested in promoting forest certification among landowners in China and other countries facing similar circumstances.
Mon, 22 January 2018
ARTICLE Download: 364| View: 627| Comments: 0 | doi:10.20944/preprints201801.0205.v1
Subject: Biology, Forestry Keywords: Forest rehabilitation, humic acid fertilizer, relative height growth rate, soil chemical properties
Online: 22 January 2018 (17:34:43 CET)
Field experiments were carried out during 2011-2014 at the Research and Experimental Center to Combating Desertification located in the Elsen Tasarkhai station of central Mongolia. The study was aimed to identify the effects of oxidized brown coal humic acid fertilizer on the relative growth rate of several trees for forest rehabilitation. The trees used were Populus sibirica, Salix ledebouriana and Acer tataricum. The experiment was carried out with the concentrations of 2,000, 10,000 and 20,000 mg L-1 of humic acid fertilization treatments. The measurement of relative height growth rate (RHGR) was conducted for a period of 4 years. The treatments showed significant differences within humic fertilizer concentrations which differed depending on the species. Compared to the monthly RHGR over the study, the treatment of fertilizers were significantly better for tree growth. P. sibirica in the 10,000 and 20,000 mg L-1 humic acid fertilizers had significant height growth rates. In addition, when the humic acid treatments were compared to control, A. tataricum decreased over the years which were statistically significant for high growth rate and a positive effect of humic acid fertilization treatments was observed. Furthermore, results showed that oxidized brown coal humic acid fertilizers as organic fertilizer can have a positive effect for the growth of A. tataricum during the study years. The results showed that the soil chemical properties EC, CO2, NO3, and K2O were significant among all the treatments compared to the control. The effect on P2O5 statistically significantly increased among all the treatments. However, pH and Mg were not significant effect among all the treatments. Combining the results obtained from the oxidized brown coal humic acid fertilization with sustainable land management practices can help improve soil organics for environmental issues in degraded sandy soil regions.
Tue, 2 January 2018
ARTICLE Download: 347| View: 424| Comments: 0 | doi:10.20944/preprints201801.0011.v1
Subject: Biology, Forestry Keywords: plant nutrition; chemical fertilization; nutrient diagnosis; forest plantation; foliar nutrients
Online: 2 January 2018 (10:25:46 CET)
Pinus patula is one of the most planted wood conifer species worldwide; however, no foliar nutrient standards exist for this species up to date. The objective of the present study was to generate and verify two sets of foliar nutrient standards for nearly ten-year-old P. patula trees: critical nutrient concentrations and DRIS norms. Nutrients studied were N, P, K, Ca, Mg, Fe, Cu, Zn, Mn, and B. The reference standards were verified experimentally by installing two fertilization trials; one of them located in Huayacocotla, state of Veracruz and the other one in Aquixtla, state of Puebla, Mexico. Nutrient status of each fertilization trial was correctly predicted by critical nutrient values and DRIS as well. Both standards were able to detect the secondary growth-limiting nutrient deficiency in the Huayacocotla trial, where the primary limitation for growth was scarcity of solar radiation within tree crowns. The limiting nutrient in both experimental trials was K.
Thu, 12 October 2017
ARTICLE Download: 362| View: 592| Comments: 0 | doi:10.20944/preprints201710.0082.v1
Subject: Biology, Forestry Keywords: fuel reduction; slash pile; grinding operation; grapple excavator; horizontal grinder; simulation; Sierra Nevada; California; wildfire
Online: 12 October 2017 (11:45:44 CEST)
The processing of woody biomass waste piles for use as fuel instead of burning them was investigated. At each landing slash pile location, a 132 kW grapple excavator was used to transfer the waste piles into a 522 kW horizontal grinder. Economies of scale could be expected when grinding a larger pile, although the efficiency of the loading operation might be diminished. Here, three piles were ground and the operations were time-studied: Small (20 m long × 15 m wide × 4 m high), Medium (30 × 24 × 4 m), and Large (35 × 30 × 4 m) piles. Grinding the Medium pile was found to be the most productive at 30.65 bone dry tons per productive machine hour without delay (BDT/PMH0), thereby suggesting that there might be an optimum size of slash pile for a grinding operation. We also examined modeling of the excavator and grinder operations, and we observed that the constructed simulation model well-replicated the actual operations. Based on the modeling, we estimated that the productivity of grinding at a landing area of 710 m2 of slash pile location was 31.24 BDT/PMH0, which was the most productive rate.
Tue, 3 October 2017
ARTICLE Download: 551| View: 421| Comments: 0 | doi:10.20944/preprints201710.0017.v1
Subject: Biology, Forestry Keywords: forest stand parameters; SPOT-5 satellite image; textural and spectral features; topographic information; estimation model
Online: 3 October 2017 (16:33:25 CEST)
In recent years, remote sensing technology has been widely used to predict forest stand parameters. In order to compare the effects of different features of remote sensing images and topographic information on the prediction of forest stand parameters, multivariate stepwise regression analysis method was used to build estimation models for important forest stand parameters by using textural and spectral features as well as topographic information of SPOT-5 satellite images in northeastern Heilongjiang Province in China as independent variables. The study results show that the optimal window to predict forest stand parameters using textural features of SPOT-5 satellite image is 9×9; the ability of textural features was better than that of spectral features in terms of predicting forest stand parameters; with the inclusion of topographic information, the accuracy of prediction of all models was improved, of which elevation has the most significant effect. The highest accuracy was achieved when predicting the stand volume (SV) (R2adj=0.820), followed by basal area (BA) (R2adj =0.778), accuracy of both above models exceeded 75%. The results show that models combined use of textural, spectral features and topographic information of SPOT-5 images have a good application prospect in predicting forest stand parameters.
Mon, 2 October 2017
ARTICLE Download: 495| View: 519| Comments: 0 | doi:10.20944/preprints201710.0011.v1
Subject: Biology, Forestry Keywords: Pine pitch canker; Galicia; spore trap; air sampling; qPCR; seasonal dynamics
Online: 2 October 2017 (16:00:11 CEST)
The airborne inoculum of Fusarium circinatum, the fungal pathogen causing Pine Pitch Canker (PPC), is one of the main means of spread of the disease in forest stands and forest nurseries. Since this world-wide known pathogen was introduced in Europe, its biology in this newly infected area still remains scarcely known. To shed more light on this topic, we set an experiment on a naturally PPC infected forest of Monterey pine in Galicia (NW Spain) with the following two goals: (i) to describe the seasonal spore dispersal pattern during one year of regular sampling and (ii) to assess the spatial spore dispersal pattern around the infested plot. Portable rotating arm spore traps were used and complemented with meteorological measurements. The abundance of F. circinatum spores in the samples was evaluated by quantitative PCR (qPCR) with hydrolysis probe. The results showed almost permanent occurrence of the air inoculum throughout the whole year, being detected in 27 of the 30 samplings. No clear temporal trends were observed, but higher air inoculum was favoured by previous lower air temperatures and lower leaf wetness. Conversely, neither rainfall nor air humidity seemed to have any significant importance. The spatial spread of the inoculum was noted to be successful up to a distance of 1000 m in the wind direction, even with winds of just 5 m s-1. Our study shows that rotating arm spore traps combined with qPCR may be an efficient tool for F. circinatum detection.
Sat, 30 September 2017
ARTICLE Download: 471| View: 446| Comments: 0 | doi:10.20944/preprints201709.0168.v1
Subject: Biology, Forestry Keywords: lidar; forest inventory; k-NN; dbh distribution; diameter distribution; performance criteria; index; indices
Online: 30 September 2017 (05:45:21 CEST)
While lidar-based forest inventory methods have been widely demonstrated, prediction of tree diameters with lidar is not well understood. The performance metrics typically used in studies for prediction of diameters can be difficult to interpret and may not support comparative inferences between sampling designs or study areas. We evaluate a variety of lidar and k nearest neighbor (k-NN) strategies for prediction of tree diameter distributions using two indices which are easier to interpret and compare. The indices are based on the coefficient of determination (R2), and root mean square deviation (RMSD). These indices facilitate comparisons with alternative (non-lidar) inventory strategies, and with other project areas. We evaluate k nearest neighbors (k-NN) dbh density (relative frequency by dbh class) prediction strategies with lidar for 190 training plots distribute across the 800 km2 Savannah River Site in South Carolina, USA. We evaluate the performance of k-NN with respect to distance metrics, number of neighbors, predictor sets, and response sets. Amongst the examined strategies we found Mahalanobis distance with k = 3 neighbors performed best according to a number of criteria.
Thu, 21 September 2017
ARTICLE Download: 643| View: 453| Comments: 0 | doi:10.20944/preprints201709.0099.v1
Subject: Biology, Forestry Keywords: near-infrared spectroscopy; multivariate analysis; partial least-squares regression; floor litter; optimal wavelength selection
Online: 21 September 2017 (04:36:21 CEST)
Near-infrared spectroscopy (NIRS) was implemented to monitor the moisture content of broadleaf litters. Partial least-squares regression (PLSR) models, incorporating optimal wavelength selection techniques, have been proposed to better predict the litter moisture of forest floor. Three broadleaf litters were used to sample the reflection spectra corresponding the different degrees of litter moisture. Maximum normalization preprocessing technique was successfully applied to remove unwanted noise from the reflectance spectra of litters. Four variable selection methods were also employed to extract the optimal subset of measured spectra for establishing the best prediction model. The results showed that the PLSR model with the peak of beta coefficients method was the best predictor among all candidate models. The proposed NIRS procedure is thought to be a suitable technique for on-the-spot evaluation of litter moisture.
Tue, 5 September 2017
ARTICLE Download: 569| View: 475| Comments: 0 | doi:10.20944/preprints201709.0016.v1
Subject: Biology, Forestry Keywords: soil; Robinia pseudoacacia; PLFA; stand age; microbial community
Online: 5 September 2017 (15:28:05 CEST)
Phospholipid fatty acids (PLFAs) can be used as biomarkers for qualitative and quantitative analyses of soil microbial community diversity. In this study, we collected soil samples at 10-cm intervals to a depth of 1 m from Robinia pseudoacacia plantations of four different ages (10, 15, 25 and 40 years) in a loess area and analysed the soil microbial community structure by PLFA analysis. A total of 97 PLFAs were detected in soils of R. pseudoacacia plantations of different ages. The individual PLFA contents gradually decreased in the 0- to 40-cm soil layers, with little variation in the 40- to 100-cm soil layers. The individual PLFAs were similarly distributed in the soils of R. pseudoacacia plantations of different ages, and there was a clear variation with stand age and soil depth. The individual PLFA contents in the 0- to 20-cm soil layers were highest for the 25-year-old plantation, while those in the 20- to 40-cm soil layers were relatively high for the 25- and 40-year-old plantations; the 16:0 content was the highest among individual PLFAs. The total PLFA content and the PLFA contents of different microbial groups [bacteria, fungi, Gram-positive bacteria (G+), Gram-negative bacteria (G-) and actinomycetes] initially increased before decreasing in the soils of R. pseudoacacia plantations with increasing stand age, whereas these contents gradually decreased with increasing soil depth; the highest PLFA contents was found in the 25-year-old plantation. The total PLFA content and the contents of fungal, G- and actinomycete PLFAs in the soils of R. pseudoacacia plantations differed significantly among stands of different ages in the 0- to 10-cm, 10- to 20-cm and 30- to 40-cm soil layers, while no significant differences were found in the 20- to 30-cm soil layers; the G+ and bacterial PLFAs contents in each of the 0- to 40-cm soil layers were significantly different. The PLFA ratios between different microbial groups differed among the stands of different ages. The fungi/bacteria ratio showed a “decrease-increase-decrease” trend with stand age, while the G+/G- ratio showed an “increase-decrease” trend. The saturated/monounsaturated PLFA ratio initially decreased before plateauing, while the opposite trend was observed for the cyclopropyl/precursor ratio. The PLFA contents of different microbial groups were ranked as follows: bacteria > G- > G+ > actinomycetes > fungi. In the principle component analysis, 18:1ω9c, 10Me18:0, i17:0, a17:0, 18:1ω7c, 18:1ω5c and 18:0 made the greatest contribution to principal component 1, and a14:0, i14:0 3OH, i14:0, i14:1ω7c and 14:0 made the greatest contribution to principal component 2. In conclusion, soil nutrient status and other soil eco-environmental stress factors should be considered in 10- to 25-year-old (particularly ~15-year-old) plots for the management of R. pseudoacacia plantations to prevent forest soil degradation and improve forest stand quality, thereby achieving better soil and water conservation and environmental improvement in R. pseudoacacia plantations.
Tue, 18 July 2017
REVIEW Download: 693| View: 690| Comments: 0 | doi:10.20944/preprints201707.0051.v1
Subject: Biology, Forestry Keywords: natural disturbance; advance regeneration; planting; natural regeneration; uneven-aged silviculture
Online: 18 July 2017 (13:22:12 CEST)
Forest managers are often required to restore forest stands following natural disturbances, a situation that may become more common and more challenging under global change. In parts of Central Europe, particularly in mountain regions dominated by mixed temperate forests, the use of relatively low intensity, uneven-aged silviculture is a common management approach. Because this type of management is based on mimicking less intense disturbances, the restoration of more severe disturbance patches within forested landscapes has received little attention within the context of uneven-aged silviculture in the region. The goal of this paper is to synthesize research on the restoration of forests damaged by disturbances in temperate forests of Slovenia and neighbouring regions of Central Europe, where uneven-aged silviculture is practiced. We place particular emphasis on the most important biotic and abiotic drivers of post-disturbance regeneration, and use this information to inform silvicultural decisions about applying natural or artificial regeneration in disturbed areas. We conclude with guidelines for restoration silviculture in uneven-aged forest landscapes.
Wed, 24 May 2017
ARTICLE Download: 934| View: 1002| Comments: 0 | doi:10.20944/preprints201705.0178.v1
Subject: Biology, Forestry Keywords: aboveground biomass; GMM; allometry; biomass allocation; machine learning technique
Online: 24 May 2017 (10:28:21 CEST)
This paper presents new above-ground biomass (AGB) and biomass components equations for seventeen forest species in the temperate forests of northwestern Mexico. A data set corresponding to 1336 destructively sampled oak and pine trees was used to fit the models. Generalized method of moments was used to simultaneously fit systems of equations for biomass components and AGB, to ensure additivity. Additionally, the carbon content of each tree component was calculated by the dry combustion method, in a TOC analyser. The fitted equations accounted for on average 91, 83, 84 and 78% of the observed variance in stem wood and stem bark, branch and foliage biomass, respectively, whereas the total AGB equations explained on average 93% of the total observed variance in AGB. The inclusion of h or d2h as additional predictor in the d-only based equations systems slightly improved estimates of stem wood, stem bark and total above-ground biomass, and greatly improved the estimates produced by the branch and foliage biomass equations. The fitted equations were used to estimate AGB stocks at stand level from a database on growing stock from 429 permanent sampling plots. Three machine-learning techniques were used to model the estimated stand level AGB and carbon contents; the selected models were applied to map the AGB and carbon distributions in the study area, which yielded mean values of 129.84 Mg ha-1 and 63.80 Mg ha-1, respectively.
Mon, 13 March 2017
ARTICLE Download: 745| View: 643| Comments: 0 | doi:10.20944/preprints201703.0071.v1
Subject: Biology, Forestry Keywords: bent trees; tropical species; tree stability; wood; tropical wood
Online: 13 March 2017 (19:28:17 CET)
Bent trees have been observed during the early years in juvenile plantations (less than 5 years-old) of Tectona grandis in Costa Rica. The relationship between bending and the morphological characteristics of the trees was explored. An evaluation of bent trees was conducted in six juvenile plantations (8, 17, 27, 28, 31, and 54 months old) of Tectona grandis. Site 1 with 8-month-old plantations did not display any relationship with any tree morphological variable (diameter, height, and crown weight of tree), whereas for the sites 2, 3, and 4 with 17-, 27-, and 28-month-old plantations, respectively, all the tree morphological variables were statistically correlated with the bent trees. A multiple regression analysis showed that the most influential variables were height to crown base, crown weight, diameter, and total height of the tree. An evaluation of the bending risk factor (RF) was correlated with the height to crown base, crown weight, and form factor. The modulus of elasticity and chemical compositions of bent trees differed from those of straight trees. The causes of tree bending are complex, involving, among other factors, the morphology of the trees, plantation conditions, and other factors specific to the xylem, such as the specific gravity, modulus of elasticity, and presence of calcium and magnesium in the wood.
Sat, 3 December 2016
ARTICLE Download: 896| View: 938| Comments: 0 | doi:10.20944/preprints201612.0020.v1
Subject: Biology, Forestry Keywords: natural secondary forest; planted forest; vegetation biomass carbon; soil organic carbon
Online: 3 December 2016 (09:25:48 CET)
Forest ecosystems make a greater contribution to carbon (C) stocks than any other terrestrial ecosystem. To understand the role of regional forest ecosystems in global climate change and carbon exchange, forest C stock and its spatial distribution within the small (2,300 km2) Liuxihe River basin were analyzed to determine the different contributors to the C stock. Forest C stocks were quantified by measuring the biomass of trees, understory vegetation, litter and roots, as well as soil organic C, using data from field samples and laboratory experiments. The results showed that forests stored 38.04 Tg C in the entire basin, with secondary and planted forests accounting for 89.82% and 10.18%, respectively, of the stored C. Five types of forests, a subtropical evergreen broad-leaved forest, a subtropical coniferous and broad-leaved mixed forest, a subtropical coniferous forest, a timber forest, and a non-wood forest, stored 257.55 ± 15.01, 218.92 ± 9.59, 195.24 ± 18.29, 177.42 ± 17.55, and 117.86 ± 6.04 Mg C ha−1, respectively. In the forest ecosystem C stocks of the basin, soils averagely contribute about 73.78%, not including root underground biomass. It provides a comprehensive method for forest ecosystem carbon investigation and forest management in small basin scale.
Mon, 28 November 2016
ARTICLE Download: 1104| View: 870| Comments: 0 | doi:10.20944/preprints201611.0140.v1
Subject: Biology, Forestry Keywords: understory species; allometric biomass equation; species-specific and multispecies; temperate coniferous and broadleaved mixed forest; northeastern China
Online: 28 November 2016 (04:41:35 CET)
Understory plants are important components of forest ecosystem productivity and diversity. Compared to biomass models of overstory canopy trees, few are available for understory saplings and shrubs and therefore their roles in estimation of forest carbon pools are often ignored. In this study, we harvested 24 understory species including 4 saplings, 9 tree-like shrubs and 11 typical shrubs in coniferous and broadleaved mixed forest in northeastern China and developed the best fit allometric equations of above- and below-ground and total biomass by species-specific or multispecies using morphological measurements of basal diameter, height and crown area as independent variables. The result showed that single basal diameter, height or crown area had good explanatory power for both species-specific and multispecies (p<0.001). The best-fit models included only basal diameter in sapling and tree-like shrubs, and combinations of crown area, height, and basal diameter in typical shrubs. The logarithmic model was most desired among the 4 model forms of linear, quadratic, multiple linear and logarithmic, for species-specific and multispecies. The models we developed should help the estimation of forest ecosystem carbon stocks, especially for belowground component, and provide tools for quantification of individual species biomass of understory plants.
Thu, 24 November 2016
ARTICLE Download: 921| View: 1046| Comments: 0 | doi:10.20944/preprints201611.0123.v1
Subject: Biology, Forestry Keywords: co-management; livelihoods; conflicts; biodiversity conservation; sustainable development
Online: 24 November 2016 (11:25:34 CET)
Good governance in natural resource management (NRM) is one of the most challenging issues in developing countries that often inappropriately embedded in national policies and political agendas. It is, in fact, even more important for countries like Bangladesh with exceptionally high pressure and dependence on its natural resources for sustaining rural livelihoods. Globally, nowadays, good governance is considered as one of the key factor for achieving the goal of sustainable development and biodiversity conservation. Bangladesh, of late has responded to that global zeal by involving local communities in the management of country’s declining forest and other natural resources. The colonial legacy of the forestry sector of Bangladesh was planned and, managed as interim projects through donors’ prescriptions. Thus, institutions, management processes and conservation outcomes were problematic. The conventional approach adopted by colonial and post-colonial regimes for forest management also proved to be inefficient due to its top-down management system. The absolute dependency on donor support, and their prescription sometimes worsened the situation both ecologically and socially. Global, regional and local trends supported the need for a different dimension in the governance paradigms. The introduction of a pluralistic approach, known as co-management in protected areas (PAs) is an example of an attempt whereby shared governance mechanism are implemented to attain the desired goals of conservation that will also address the livelihoods and aspirations of communities living in and around PAs of the country. However, in designing future forest and PA regimes the concern of the external aid support and attached conditions remain a reality that needs to be addressed. Adequate attention should be given to our vanishing biodiversity, culture and community livelihoods through devising an appropriate governance mechanism recognizing and supporting local rights, access and participation in the environmental management. It is now time to mainstream the adhoc nature of governance according to our national conservation strategy and policy frameworks in order to achieve the goals and objectives of the Bangladesh NRM sector addressing the human and community right of people in the specific context of forest protected areas management.
Mon, 24 October 2016
ARTICLE Download: 1044| View: 973| Comments: 0 | doi:10.20944/preprints201610.0103.v1
Subject: Biology, Forestry Keywords: ordinary kriging; geostatistical analysis; spatial variability; Moso bamboo
Online: 24 October 2016 (09:48:08 CEST)
Moso bamboo is famous for fast growing and biomass accumulation, as well as high annual output for timber and bamboo shoots. These high outputs require high nutrient inputs to maintain and improve stand productivity. Soil nitrogen (N), phosphorus (P) and potassium (K) are important micronutrients for plant growth and productivity. Due to high variability of soils, analysing spatial patterns of soil N, P and K stocks is necessary for scientific nutrient management in Moso bamboo forests. In this study, soils were sampled from 138 locations across Yong’an City and ordinary kriging was applied for spatial interpolation of soil N, P and K stocks. Soil N stock showed a strong spatial dependence while soil N and P stocks presented a moderate spatial dependence, indicating soil N was mainly controlled by intrinsic factors while soil N and P stocks were controlled by both intrinsic and extrinsic factors. Different spatial patterns were observed for soil N, P and K stocks across the whole study area, indicating that fertilizations with different ratios of N:P:K should be applied for different sites to maintain and improve stand productivity. The total soil N, P and K stocks within 0-60 cm were 0.624, 0.020 and 0.583 Tg, respectively.