Improved guidelines for any-aged forestryOA

Any-aged forest management(AAF) is a means to reduce clear-felling without compromising profitability or timber production.The concept of AAF is to choose between clear-felling or thinning one harvest at a time based on what is better at that time in terms of the management objectives for the forest.No permanent choice is made between rotation forest management(RFM) and continuous cover forestry(CCF).Optimized AAF is never less profitable than RFM or CCF because all cutting types of both RMF and...     

Relationship between species diversity and tree size in natural forests around the Tropic of CancerOA

Although numerous hypotheses have been proposed to explain the patterns of species diversity of forests at local and landscape levels,it is still difficult to predict the alpha diversity of species,especially in tropical and subtropical natural forests where trees of different sizes and shapes are highly mixed.Size might characterize species diversity,and the possible correlation between these variables may contribute to the development of easy-to-use growth indicators to predict diversity and t...     

Selection and evaluation of suitable tree species in dry and dusty mining areas of Northwest ChinaOA

To select drought-resistant and dust-tolerant native species suitable for use in the rehabilitation of major coal bases in northwest China, nine tree species were identified for growth rates, biomass, harm index, and physiological indices under drought and high dust stress conditions. The results showed that, in the dust resistance index system, the order was Caragana korshinskii > Amorpha fruticosa > Sabina vulgaris > Hedysarum scoparium > Tamarix chinensis > Ammopiptanthus mongo...     

Comparative analysis of thinning techniques in pine forestsOA

Thinning is a necessary and complex forestry activity. The complexity increases due to theoretical disagreements, contradictory recommendations, and errors of modern practice, which require confirmation through longtime experiments. This article presents a summary of experimental results from plantations established 20–30 years ago and explains concepts of the theory, methods, and regime of thinning in permanent sample plots of pine stands in Gatchinsky forest of the Leningrad region. The resear...     

Problems with models assessing influences of tree size and inter-tree competitive processes on individual tree growth:a cautionary taleOA

In forest growing at any one site,the growth rate of an individual tree is determined principally by its size,which reflects its metabolic capacity,and by competition from neighboring trees.Competitive effects of a tree may be proportional to its size;such competition is termed ’symmetric’ and generally involves competition below ground for nutrients and water from the soil.Competition may also be’asymmetric’,where its effects are disproportionate to the size of the tree;this generally involves ...     

Multi-temporal NDVI analysis using UAV images of tree crowns in a northern Mexican pine-oak forestOA

The use of unmanned aerial vehicles(UAV) for forest monitoring has grown significantly in recent years,providing information with high spatial resolution and temporal versatility.UAV with multispectral sensors allow the use of indexes such as the normalized difference vegetation index(NDVI),which determines the vigor,physiological stress and photo synthetic activity of vegetation.This study aimed to analyze the spectral responses and variations of NDVI in tree crowns,as well as their correlation...     

Contribution of biophysical and climate variables to the spatial distribution of wildfires in IranOA

This study investigated the relationship between climate and biophysical variables in burned areas in Iran.The fire burned area(FBA) product(Fire CCI 5.1.1),land surface temperature(MOD11C3C),vegetation index(MOD13A1),and climate variables such as temperature,wind speed,relative humidity,and volumetric soil moisture from the ERA5 reanalysis dataset were used.Pearson correlation coefficient was used to determine the relationship between biophysical and climate variables and fire occurrence.The re...     

Responses of arid plant species diversity and composition to environmental factorsOA

An oasis is a unique natural landscape in arid and semi-arid areas,significant for regulating regional microclimates and hydrological processes in deserts.However,little is known regarding the response of natural oasis plants communities to various environmental factors.Nineteen sample plots(50 m×50 m) were selected in the Daliyabuyi Oasis in the Taklimakan Desert hinterland based on the location of groundwater monitoring wells and 76 vegetation quadrats(25 m × 25 m) were established.A two-way i...     

Leaf recognition using BP-RBF hybrid neural networkOA

Plant recognition has great potential in forestry research and management.A new method combined back propagation neural network and radial basis function neural network to identify tree species using a few features and samples.The process was carried out in three steps:image pretreatment,feature extraction,and leaf recognition.In the image pretreatment processing,an image segmentation method based on hue,saturation and value color space and connected component labeling was presented,which can ob...     

Spatial pattern analysis of forest trees based on the vectorial markOA

Analysis of spatial patterns to describe the spatial correlation between a tree location and marks(i.e., structural variables), can reveal stand history, population dynamics, competition and symbiosis. However, most studies of spatial patterns have concentrated on tree location and tree sizes rather than on crown asymmetry especially with direct analysis among marks characterizing facilitation and competition among of trees, and thus cannot reveal the cause of the distributions of tree locations...     

Surveillance of pine wilt disease by high resolution satelliteOA

Pine wilt disease caused by the pinewood nematode Bursaphelenchus xylophilus has led to the death of a large number of pine trees in China. This destructive disease has the characteristics of bring wide-spread, fast onset, and long incubation time. Most importantly, in China, the fatality rate in pines is as high as 100%. The key to reducing this mortality is how to quickly find the infected trees. We proposed a method of automatically identifying infected trees by a convolution neural network a...     

Within-and between-population variations in seed and seedling traits of Juglans mandshuricaOA

In order to quantify within-and between-population variation in seed and seedling traits of Juglans mandshurica and reveal the relationship among genetic and environmental variations and select elite families, samples of 50 J. mandshurica families from five natural populations in Liaoning Province, northeast China, were taken to measure seed and seedling traits. The results show that all seed traits varied significantly among families within the population, but only kernel weight and kernel rate...     

Soil respiration in a natural forest and a plantation during a dry period in the PhilippinesOA

Climate change is forecast to increase the frequency of extreme hot temperatures and dryer days and is anticipated to have profound impacts on the global carbon budget.Droughts are expected to alter soil respiration(R_s) rates,but the scarcity of data preclude a reliable estimate of this response and its future trajectory.A field experiment using an automated soil respiration machinery(LI-8100A) was conducted in a natural forest and a plantation during a dry period in the Philippines,w...     

Variability in the climate-radial growth correlation of Pinus massoniana of different diameter classesOA

The physiological characteristics of trees change with age, suggesting that growth-related climate signals vary over time. This study aimed to clarify the impacts of different diameter classes on the chronological characteristics of Pinus massoniana Lamb. and its response to climatic factors. Chronologies of P inus massoniana were established in small diameter(14.1 cm), middle diameter(27.3 cm), and large diameter(34.6 cm) trees according to dendrochronology. The results show that:(1) radial gro...     

Bark content variations and the production of Populus deltoides as a source of bioenergy under temperate climate conditionsOA

Bark biomass as an energy source has a high economic value. Bark content variations and production helps recognize the potential of this bioenergy source spatially before harvesting. The percentage of fresh and dry bark in Populus deltoides grown under a monoculture system was examined in the temperate region of northern Iran. Diameter at breast height(DBH) and total height data were analyzed based on an initial inventory. Ten sample trees were felled, separated into 2 m-segments, and weighted i...     

Exceptionally high genetic variance of the doubled haploid(DH) population of poplarOA

Doubled haploid(DH) plants have been widely used for breeding and biological research in crops.Pop ulus spp.have been used as model woody plant species for biological research.However,the induction of DH poplar plants is onerous,and limited biological or breeding work has been carried out on DH individuals or populations.In this study,we provide an effective protocol for poplar haploid induction based on an anther culture method.A total of 96 whole DH plant lines were obtained using an F₁     

Molecular characterization and functional analysis of daf-8 in the pinewood nematode,Bursaphelenchus xylophilusOA

Bursaphelenchus xylophilus,causal agent of pine wilt disease,causes extensive damage worldwide.Strategies are needed to inhibit population growth or block the spread of the invasive nematode to control pine wilt disease.The gene daf-8 plays crucial roles in larval development and dauer formation in Caenorhabditis elegans,but little is known about its orthologue in B.xylophilus.In the present molecular characterization and functional analysis of daf-8 in B.xylophilus(Bx-daf-8),RT-qPCR showed that...     

Soil organic carbon storage in forest restoration models and environmental conditionsOA

The scale of forest and landscape restoration is expected to increase during the UN Decade on Ecosystem Restoration and its contribution to the provision of critical ecosystem services to society. Several models of forest restoration may improve ecosystem services, including soil organic carbon(SOC) storage. A review was carried out to access:(1) the variability of SOC storage between worldwide forest restoration models and,(2) the effects of climate, soil class, soil texture, and vegetation typ...     

Characterizing prediction errors of a new tree height model for cut-to-length Pinus radiata stems through the Burr Type Ⅻ distributionOA

Unlike height-diameter equations for standing trees commonly used in forest resources modelling,tree height models for cut-to-length(CTL) stems tend to produce prediction errors whose distributions are not conditionally normal but are rather leptokurtic and heavy-tailed.This feature was merely noticed in previous studies but never thoroughly investigated.This study characterized the prediction error distribution of a newly developed such tree height model for Pin us radiata(D.Don) through the th...