Forestry Tree Species Research Articles

Trees outside forest (TOFs) aids in mitigating global climatic change through carbon sequestration: Example from academic institutional landscapes

TOF including urban and other plantations like road side, homestead gardens, residential areas or in various institutional or academic landscapes make positive contribution to living conditions of different towns and cities. The present work reports the amount of biomass and its contribution to carbon stock of different woody perrennials in the campus of Uttar Banga Krishi Viswavidyalaya, West Bengal, India. The study was carried out by enumerating the entire study area for volume estimation and further calculation was done through validated methodologies. A total of 1816 numbers of individuals with dbh ≥ 10 cm of 95 woody perennials species belonging to 79 genera and 38 families were enlisted. Out of 95 species, the contribution was dominated by 52 forestry tree species followed by road side plantation (21) and fruit crops (14). A total of 812.211 Mg ha−1 of biomass was recorded from the woody tree species with 79.40% contribution from above ground biomass (AGB) and 20.60% (BGB) below ground biomass. In the AGB forestry tree species showed dominance in terms of contribution (322.95 Mg ha−1) followed by plantation crops (169.695 Mg ha−1), road side plantation (107.069 Mg ha−1) and least by fruit crops (45.190 Mg ha−1). The overall carbon stock found was 403.176 Mg Cha−1 with highest contribution from forestry tree species (200.53 Mg Cha−1) followed by plantation crops (106.720 Mg C ha−1) and least by fruit crops (28.470 Mg Cha−1). The study recommends plantaion of more and more woody species across the academic landscapes especially with threatened category flora for conservation and carbon sequestration for mitigating global climate change. TOFs will have to play an important role for sustaining future generations due to shrinking of other forest landuse systems.

Young Silver Birch Grows Faster and Allocates Higher Portion of Biomass into Stem Than Norway Spruce, a Case Study from a Post-Disturbance Forest

The aim of the paper was to compare young silver birch (Betula pendula Roth.) and Norway spruce (Picea abies L. Karst) growing at the identical site, from the point of contribution of tree components to their aboveground biomass stock, their wood density, radial increment and aboveground biomass production. Our research activities were performed in the High Tatra Mts., which belong to the Tatra National Park (TANAP), Northern Slovakia. Currently, the substantial part of the TANAP territory is covered by post-disturbance young forests which have been growing there since the large-scale windstorm episode in November 2004. Our study combined non-destructive repeated tree measurements performed at two transects in 2016–2020, with destructive tree sampling of twenty 14-year-old individuals for each species. From the gathered data, we derived models estimating standing stock and annual production of aboveground biomass in individual tree components (foliage, branches, stem bark and stem wood), using diameter at breast height (DBH) as a predictor. The results showed contrasting contributions of tree compartments to aboveground biomass stock between birch and spruce. While spruce trees had four times higher contribution of foliage than birches, the reverse situation (1.5-fold difference) was observed for stem over bark biomass. At the same time, birch trees had a 40% greater diameter increment and a 30% denser stem wood than spruce. As for aboveground biomass production, the contribution of the stem as an economically important component was greater in birch than spruce. The results suggest that, in the young growth stage, birch may be advantageous over spruce in both ecological and production properties. Therefore, we believe that strengthening research activities focused on birch ecology and production issues would bring practical recommendations for better utilization of this tree species in forestry and wood-processing industry sectors

Identification and Estimation of Poplar Species Area in Haryana and Punjab State Using Geo-Informatics

Poplar is a very prominent taxonomical group of tree species in plantation forestry in India. It occurs in natural forests also. However, its population in natural stands is small and is gradually declining. Bu1k of the plantations are composed of populous deltoids, an exotic species. The area coverage and productivity of this species is bound to increase further, due to concerted research and development efforts aiming at its genetic improvement. Indigenous poplars occur only in the mountains and are still to acquire greater role and share in afforestation/reforestation programmes and conservation. Poplar, the common name for trees of the genus Populous, is a common sight in forests along waterways, around agricultural lands, throughout the Northern Hemisphere. It is species of trees which is mainly used for wood production and also for paper production. Poplar species is found in the Northern region of India. Today Poplar is main component in the farmer’s life of Punjab and Haryana state. Popular plantations are done in various aspects of farming. Income dependency of farmers life is depends on also agriculture based technology. To Identify Poplar species in Haryana and Punjab state, remote-sensing and GIS based technology is used. Identification of Poplar species is done through State level and district level. For district level LISS - 4 image is used. Poplar species mapping are prepared for the 4 districts of Punjab state i.e. Rupnagar, ShaheedBhagatsingh Nagar, Nawashahr and Ludhiana and 3 districts of Haryana i.e. Yamunanagar, Karnal and Kurushetra. For state level Sentinel-2 image is used.

Growth dynamics of fast-growing tree species in mixed forestry and agroforestry plantations

In recent years, plantations of fast-growing tree species have emerged as a possible way to meet the increasing demand for biomass for renewable energy in Europe. Agroforestry plantations including fast-growing tree species could be an attractive option because they reduce land competition for biomass and food production while providing forest benefits. Today, the species interactions that determine whether a given mixture will be more productive than the corresponding monocultures are still poorly understood. Our objective was to assess the performance of fast-growing trees, i.e. poplar (Populus nigra × P. deltoides) and alder (Alnus glutinosa), in association with herbaceous species either N2-fixing species (succession alfalfa (Medicago sativa) and clover (Trifolium pratense)) or graminoids (succession of wheat (Triticum aestivum) – triticale (Triticosecale) – temporary grassland consisting of mixtures of perennial ryegrass (Lolium perenne) and fescue (Festuca ovina)), respectively, and in association together. We compared tree growth in mixed stands to growth in the respective tree monocultures. An experimental plantation composed of three blocks including the different treatments was set up in 2014 in northeastern France. In the forest mixture, poplar and alder were planted in alternating rows, and in the agroforestry plots, every second line of trees was replaced by the crops. No fertilizers (of any kind) were used during the experiments. During six growing seasons, tree growth (height and diameter at breast height) was monitored monthly in the agroforestry stands, the forest mixture stand and the two tree monocultures. By the end of 2019, poplar stem height in association with N2-fixing crops (alfalfa, then clover) was higher than in the forest mixture and the monoculture. During the warmest growing season with a marked dry period in June-July (2018), poplar height growth rate in the agroforestry treatment was between three and five times higher than for the poplars in the monoculture and the forest mixture. A facilitation process in the agroforestry plantations could explain this result due to a significant enrichment of the soil in nitrogen by the N2-fixing crops. This result only appeared several years after tree planting, and management actions were necessary in order to control the strong competition between crops and trees during the early stages. In the forest mixture, poplars associated with alders were smaller than in their monoculture, in spite of a stratification of the canopies of the two species. For alders, tree growth did not appear to be affected by either an association with graminoids or with poplar.

Three-dimensional convolutional neural network model for tree species classification using airborne hyperspectral images

Airborne hyperspectral remote sensing data with both rich spectral and spatial features can effectively improve the classification accuracy of vegetation species. However, the spectral data of hundreds of bands brings about problems such as dimensional explosion, which poses a huge challenge for hyperspectral remote sensing classification based on classical parameters models. Deep learning methods have been used for remotely sensed images classification in recent years, but the popular HSI datasets including Kennedy Space Center, Indian Pines, Pavia University scene and Salinas scene, have low spatial resolution, significant differences between categories, and regular boundaries. When applied to the classification of forestry tree species, the accuracy often decreases because the spectral response of different plants of the same family and genus are very similar, especially under the fragmented species distribution, complex topography and the occluded canopy. So we collect new data sets, selected Gaofeng State Owned Forest Farm in Guangxi province in south China as the research area and adopted the airborne hyperspectral data obtained by the LiCHy system of the Chinese Academy of Forestry to explore an improved three-dimensional convolutional neural network(3D-CNN) model for tree species classification. The proposed model uses raw data as input without dimension reduction or feature screening, and simultaneously extracts spectral and spatial features. After the 3D convolutional layer, the captured high-level semantic concept is a joint spatial spectral feature representation, so we can turn it into a one-dimensional feature as a new input to learn a more abstract level of expression. The widely used earlystop method is also used to prevent overfitting. The proposed model is a lightweight, generalized, and fast convergence classification model, by which the short-time and large-area of multiple tree species classification with high-precision can be realized. The result shows that the 3D-1D CNN model can shorten the training time of the 3D CNN model by 60% and achieve a classification accuracy of 93.14% within 50 ha in 6.37 min, which provides a basis for the classification of tree species, the mapping of forest form and the inventory of forest resources.

Relative contribution of plant traits and soil properties to the functioning of a temperate forest ecosystem in the Indian Himalayas

Plant-soil interactions are a major determinant of changes in forest ecosystem processes and functioning. We conducted a trait-based study to quantify the contribution of plant traits and soil properties to above- and below-ground ecosystem properties in temperate forest in the Indian Himalayas. Nine plant traits (leaf area, specific leaf area, leaf water content, leaf dry matter content, leaf carbon (C), nitrogen (N), phosphorus (P), leaf C/N, and leaf N/P) and eight soil properties (pH, moisture, available N, P, potassium (K), total C, N, P) were selected for determination of their contribution to major ecosystem processes (above-ground biomass C, soil organic C, soil microbial C, soil microbial N, soil microbial P, and soil respiration) in temperate forest. Among the plant traits leaf C, N, P, and leaf N/P ratio proved to be the main contributors to above-ground biomass, explaining 20–27% of variation. Leaf N, P, and leaf N/P were the main contributors to below-ground soil organic C, soil microbial C, soil microbial N, soil microbial P, and soil respiration (explaining 33% of variation). Together, the soil properties, pH, available P, total N and C explained 60% of variation in above-ground biomass, while pH and total C explained 56% of variation in soil organic C. Other soil properties (available P, total C and N) also explained much of the variation in soil microbial C (52%) and soil microbial N (67%), while soil pH explained some of variation in soil microbial N (14%). Available P, total N, and pH explained soil microbial P (81%), while soil respiration was only explained by soil total C (70%). Thus, leaf traits and soil characteristics significantly explaining variations in above- and below-ground ecosystem processes and functioning in temperate forest in the Indian Himalayas. Consequently, tree species for afforestation, restoration, and commercial forestry should be carefully selected, as they can influence the climate change mitigation potential of forest in terms of C stocks in biomass and soils.

First record of off-season flowering in Populus deltoides from India: paradigm of climate change indicator

Populus deltoides is a fast-growing woody species possessing plethora of industrial applications. This species evolutionarily developed unisexual male and female catkin inflorescence on separate trees. Flowering usually occurs during early spring before the development of foliage, where buds appear near axils or at the extending shoots. In 2019, surveys were undertaken to study the flowering pattern of P. deltoides in the states of Punjab, Haryana, Uttar Pradesh and Uttarakhand in northern India. Interestingly, an anomalous flowering behaviour (appearance of off-season male catkins during autumn, i.e. October) was observed in a plantation trial at Kapurthala, Punjab. The male catkins were 2.7-3.1 ± 0.07cm long and 0.3-0.5 ± 0.03cm wide, which is significant for flowering and liberation of pollen grains. Preliminary results suggested that climatic factors, such as episodes of high or low temperature and the precipitation variation forcing the tree species to behave differently. Unearthing the climate-driven off-season flowering in other tree species alluded the stimulation of phytohormones, such as gibberellic and salicylic acid concentrations influencing the flowering time, therefore, needs further investigation in case of P. deltoides. Overall, this work provides early clues of changing climatic scenario altering the flowering pattern of a tropical forestry tree species.

An Overview on the Importance of Acacia nilotica (L.) Willd. Ex Del.: A Review

Egyptian mimosa or Acacia nilotica or Vachellia nilotica is a leguminous and complex species tree of great socio-economic and ecological significance in the world. It is called as Bagaruwa in Hausa and is a great source of livelihood. A. nilotica is an agroforestry and urban forestry tree species, which provide fruits, timber, fodder, gums and other services such shade, beauty, soil improvement. It is used for climate change mitigation, adaptation and phytomediation. Every part of the plant is medicinal. This paper reviews the perception and usage on taxonomy, socio-economic and ecological importance of Acacia nilotica. This attempted to compile and document information on different aspects of this important plant species and its potential uses from the literature. The study provides a base line information about the societal and ecological benefit derived from Egyptian mimosa, which is constitutes a management tool for the conservation of the species. This study recommends the use of Acacia nilotica trees in planting programmes.

Evaluating Variation in Seed Quality Attributes in Pinus Patula Clonal Orchards using Cone Cluster Analysis

Clonal seed orchards are majorly established for the production of seed of known quality attributes. However, these seed sources often cross-pollinate over the years, forming new varieties of unknown seed quality traits. Given the long period that it takes forestry tree species to naturalize through provenance trials, it is desirable to develop rapid techniques for assessing seed quality traits to support the expansion of clonal seed sources. We evaluated the variability in seed quality among Pinus patula clonal seed orchards based on three physical cone characteristics (length, diameter, and weight) using cluster analysis and Principal Component Analysis. The results indicated that cone length was the significant component controlling for the groupings, with width and weight having almost similar influencing power as factors. Cluster analysis identified five optimal natural groupings out of a possible 14 clusters. The optimal groups had values that could easily be used in the grading of cones. The results suggest that cluster analysis holds promise for tree improvement specialists as a rapid, unbiased, and novel technique for assessing clonal seed material at a reasonably affordable cost. It is expected that future seed harvests in Pinus patula seed orchards will target cone length as an indicator of superior seed quality.

Scanning RNA-Seq and RAD-Seq approach to develop SNP markers closely linked to MALE STERILITY 1 (MS1) in Cryptomeria japonica D. Don.

Cryptomeria japonica is a major forestry tree species in Japan. Male sterility of the species is caused by a recessive gene, which shows dysfunction of pollen development and results in no dispersed pollen. Because the pollen of C. japonica induces pollinosis, breeding of pollen-free C. japonica is desired. In this study, single nucleotide polymorphism (SNP) markers located at 1.78 and 0.58 cM to a male sterility locus (MS1) were identified from an analysis of RNA-Seq and RAD-Seq, respectively. SNPs closely linked to MS1 were first scanned by a method similar to MutMap, where a type of index was calculated to measure the strength of the linkage between a marker sequence and MS1. Linkage analysis of selected SNP markers confirmed a higher efficiency of the current method to construct a partial map around MS1. Allele-specific PCR primer pair for the most closely linked SNP with MS1 was developed as a codominant marker, and visualization of the PCR products on an agarose gel enabled rapid screening of male sterile C. japonica. The allele-specific primers developed in this study would be useful for establishing the selection of male sterile C. japonica.

Effect of age and spacing on biomass production in forest plantations

ABSTRACT The aim of this study was to determine the effect of age and plant spacing on biomass production of four forestry tree species: Acacia mearnsii De Wild, Eucalyptus grandis W. Hill ex Maiden, Mimosa scabrella Benth, and Ateleia glazioviana Baill. The following spacings of plants at the ages of 1, 3, and 5 years after planting were considered: 2.0 × 1.0 m, 2.0 × 1.5 m, 3.0 × 1.0 m, and 3.0 × 1.5 m. The study was installed in randomized complete block design. Biomass was determined by weighing different components of the trees after harvesting. Plant spacing affected biomass production of forestry trees at different ages after planting. Dense spacings produced larger quantities of biomass than less dense spacing. The tree species differed in biomass production: Eucalyptus grandis produced the largest quantity (325.1 t ha-1), followed by Acacia mearnsii (239.3 t ha-1), Mimosa scabrella (53.4 t ha-1), and Ateleia glazioviana (32.1 t ha-1). Wood biomass represented the biomass component with the largest production over time, which showed an increasing proportion throughout the age groups, followed branch, leaf, and bark biomass.

Uses and ecosystem services of trees outside forest (TOF)-A case study from Uttar Banga Krishi Viswavidyalaya, West Bengal, India

Trees outside Forest (TOF) play a critical role in conservation of floristic diversity apart from being reservoirs of other ecosystem services. TOF includes all the trees, attained 10 cm or more diameters at breast height, available on lands, which is not notified as forests. The present study was conducted in the Pundibari campus of Uttar Banga Krishi Viswavidyalaya to document the available tree diversity and their potential uses and ecosystem services. A total of 1816 numbers of individuals with dbh ≥ 10 cm of 95 woody perennials species were inventoried belonging to 79 genera and 38 families. The contribution among number of individuals was dominated by Mangifera indica with (9.19%). The overall dominant family was Fabaceae represented by 11 species followed by Arecaceae and Meliaceae. The contribution of inventoried 95 species was dominated by forestry tree species followed by road isde plantation, fruit crops and plantation crops respectively. The highest number of individuals among forestry plantation was for Terminalia arjuna (121) followed by Gmelina arborea (114) and Tectona grandis (95). The documented species were dominated by endemic flora (66.31%) and exotic flora (33.68%). Majority of the species (54) were of timber value, followed by food (50), fodder (36) and ethno-medicine (39). Based on the contribution to ecosystem services all the 95 species have the potential to sequest carbon followed by 46 species to provide beautification in the form of avenue/ornamental/roadside. The tree species richness and their potential ecosystem services documented in the present study can be a baseline study for further assessment of such landscapes and their significance under threatning environmental conditions.

Vegetative propagation and application of clonal forestry in Brazilian native tree species

Abstract: Understanding the mechanisms involved in tree species maturation, related mainly to ontogenetic age effects, has contributed significantly to the vegetative propagation process of Brazilian native tree species, with consequent application of clonal forestry. A number of methodologies has been developed to rescue and vegetatively propagate these species for silvicultural and environmental restoration purposes. However, the types and purposes of propagation, as well as the choice of suitable processes and propagules considering the intended objectives, still need to be better aligned. In addition, there is an evident knowledge gap and great potential regarding the use of native tree species in Brazilian clonal forestry, indicating the need of a greater interaction between studies on the vegetative propagation and vigor of these materials in the field. Therefore, this review aims to help understand the different types of techniques used and their application on the vegetative propagation and clonal forestry of Brazilian native tree species, besides proposing a schematic sequence of the stages involved in these processes for productive and environmental purposes.

Cryopreservation of Fagus crenata seeds: estimation of optimum moisture content for maintenance of seed viability by Bayesian modeling

Fagus crenata Blume is an important forestry tree species that plays a key biological role in natural forests. Because F. crenata forests are declining under global warming, the conservation of seed resources is necessary to maintain sustainable regeneration. We examined the capability of seed cryopreservation to achieve semi-permanent preservation of the F. crenata genetic resource. Seeds at 7%–26% moisture content (MC) exhibited greater than 64% viability, with developing radicles growing at 22 °C in 16 h photoperiods following chilling at 2 °C for 2 months. These seeds were then stored cryogenically at –170 °C for 6 months; cryopreservation at 26% MC reduced seed viability to 12%, whereas dry seeds (7%–14% MC) maintained viability and were comparable with seeds that had neither been dried nor cryopreserved. Drying seeds to 6% MC reduced viability to 47%; following cryopreservation, the viability of these seeds with such a low MC was 36%. Using a Bayesian model, we then determined that the optimal range of MC for the cryopreservation of F. crenata seeds was 9%–12%. We conclude that cryopreservation is feasible for the long-term storage of F. crenata seeds, drying of the seeds to the range of optimal MC retains high viability during cryogenic storage.

Seasonality matters—The effects of past and projected seasonal climate change on the growth of native and exotic conifer species in Central Europe

Norway spruce is one of the economically most important tree species in Central European forestry. However, its high susceptibility to droughts poses a strong challenge to its cultivation under future conditions with likely more frequent and prolonged droughts and shifts in the seasonal climate. To compensate for expected losses of forest areas suitable for the cultivation of spruce, more drought-tolerant species are required. Silver fir and Douglas fir are two potential candidates, which promise lower drought susceptibility and equal or even higher yield when compared to Norway spruce.Using the Black Forest as a regional case study, we assessed the effects of seasonal climate change, including drought stress, on tree-ring width formation of these three economically relevant conifer species over the last 60 years. In addition, we projected potential species-specific growth changes under different climate change scenarios until 2100.Our results suggest that both silver fir and Douglas fir will possibly experience growth increases in a warmer future climate, as predicted under the 4.5 and 8.5 Representative Concentration Pathway (RCP) climate change scenarios, whereas growth of spruce is expected to decline. Moreover, drought susceptibility in silver fir and Douglas fir is lower than in spruce, as shown for past drought events, and their ability to benefit from milder winters and springs could play a major role in their capacity to compensate for drier summers in the near to mid-term future. This study highlights the need to advance our understanding of the processes that drive drought resistance and resilience in tree species to guide management strategies in the face of climate change.

Comparative Study of Transpiration in Cooling Effect of Tree Species in the Atmosphere

Trees create microclimate under their crowns in comparison to the outside ambient atmosphere, which is a result of physical as well as physiological functions of the tree. The cooling produced by trees varies with species due to variation in several anatomical, structural and physiological attributes of the species. Transpiration is one of the most significant physiological functions performed by plants, which affects cooling produced by a tree under its shade. When solar energy impinges on the leaf, water emerges from its surface through transpiration taking the latent heat to convert it into water vapour. This leads to a rise in humidity of the atmosphere and reduction in temperature of the leaf. To remain leaf in equilibrium, it takes heat from the surrounding atmosphere resulting in reduction in temperature of surroundings. Since, transpiration takes place through stomata which are normally located on the ventral side of the leaf, this reduction in temperature is more experienced beneath the crown of the tree. Therefore, the present study was carried out to analyze the role of transpiration in cooling effect of five forestry tree species. The cooling produced by tree species under their shades has been found positively correlated to the transpiration rate whereas the rate of transpiration has responded positively to the ambient temperature and water conductance. However, no definite relationship has been found between frequency of open stomata and the rate of transpiration.

Comparative Study of Cooling under Shades of Some Forestry Tree Species with Respect to Ambient Temperatures

Trees create microclimate under their crowns in comparison to the outside ambient atmospheric temperature. Sun is the pivotal source of radiant energy reaching the earth atmosphere of which heat is more important than light. The radiant energy reaches the ground without any barricade whereas the tree crown impedes it in reaching the earth’s surface. During the day, when insolation impinges on tree crown, a portion of it is reflected back to the space, other portion is absorbed by the canopy increasing the temperature of leaves and the remaining part reaches the ground penetrating through the crown. Thus, a significant coolness is experienced under the shade of trees in comparison to open sunshine, with qualitative variations. The cooling produced by trees under their shades varies with species to species due to variation in several anatomical, structural and physiological attributes of the species. Climate is changing more rapidly prominently due to human activities especially indiscriminate felling of trees and it is feared that it will create problems on availability of energy, water and food security. Economic value takes over ecological benefits in selection of species in plantation programmes and this might have been due to the lack of scientific data about varying effectiveness of ecological services bestowed by different species. In the present study, an endeavor has been made to understand as to how a tree is integrated to the effects on atmosphere and responses to changing conditions with respect to differential cooling produced by five selected forestry tree species belonging to different categories. Analysis of data has come out with gradation of the sample species in respect to their cooling effect in the atmosphere in terms of yearly, quarterly, monthly and diurnal basis.

Molecular Characterization of Arbuscular Mycorrhizal Fungi in an Agroforestry System Reveals the Predominance of Funneliformis spp. Associated with Colocasia esculenta and Pterocarpus officinalis Adult Trees and Seedlings.

Pterocarpus officinalis (Jacq.) is a leguminous forestry tree species endemic to Caribbean swamp forests. In Guadeloupe, smallholder farmers traditionally cultivate flooded taro (Colocasia esculenta) cultures under the canopy of P. officinalis stands. The role of arbuscular mycorrhizal (AM) fungi in the sustainability of this traditional agroforestry system has been suggested but the composition and distribution of AM fungi colonizing the leguminous tree and/or taro are poorly characterized. An in-depth characterization of root-associated AM fungal communities from P. officinalis adult trees and seedlings and taro cultures, sampled in two localities of Guadeloupe, was performed by pyrosequencing (GS FLX+) of partial 18S rRNA gene. The AM fungal community was composed of 215 operational taxonomic units (OTUs), belonging to eight fungal families dominated by Glomeraceae, Acaulosporaceae, and Gigasporaceae. Results revealed a low AM fungal community membership between P. officinalis and C. esculenta. However, certain AM fungal community taxa (10% of total community) overlapped between P. officinalis and C. esculenta, notably predominant Funneliformis OTUs. These findings provide new perspectives in deciphering the significance of Funneliformis in nutrient exchange between P. officinalis and C. esculenta by forming a potential mycorrhizal network.

Extraction of Genomic DNA from Inner Bark of Cedrus deodara (Roxb.) G. Don for RAPD Study

Genomic DNA extraction from forestry tree species require young leaf samples to obtain high-quality DNA for molecular based study. For some study, leaf samples must be collected from remote areas and are difficult to transport long distances. We developed alternative method of DNA extraction from inner bark of Cedrus deodara. We used 2.5% PVP for removal of phenolic compound and apply high concentration of sodium chloride to removes polysaccharides. Extracted DNA gives positive amplification with PCR using random amplification of polymorphic DNA (RAPD) markers.

Acorns of introduced Quercus rubra are neglected by European Jay but spread by mice

Northern Red Oak (Quercus rubra L.; native in North America) is regarded as an invasive species in Central Europe, where it is the most common non-indigenous broad-leafed tree species in forestry. The species’ impact on native ecosystems and thus its future management are discussed controversially. Because dispersal is an important step in an invasion process, we studied whether European Jays (Garrulus glandarius L.) and mice, both main dispersers of native oaks in Europe, mediate the dispersal of Q. rubra seeds. Morphological characteristics of Q. rubra and native Q. robur L. acorns were quantified according to their implications for dispersal. We tested experimentally whether and to what extent mice and jays collect acorns of both oak species and if their behavior depends on choice options (dual choice vs. no-choice). Acorns were offered on feeding platforms, controlled by scouting cameras. Results showed that Q. rubra acorns have a thicker pericarp, a rounder shape and a higher dry weight compared to acorns of Q. robur. In the behavioral assays jays avoided acorns of Q. rubra if they were offered together with those of Q. robur (dual choice) as well as when Q. rubra acorns were offered alone (no-choice). This selection behavior could be caused by the differences in morphological traits observed between the acorns of the two species. In contrast to jays, mice took acorns of both oak species likewise indicating that seed morphology does not affect the attractiveness of Red Oak acorns for rodents. In conclusion, Quercus rubra is collected by animals in Central Europe to a considerable amount but dispersal should be restricted to moderate distances mediated by mice, leading mainly to stabilizing and increasing existing populations rather than founding of new ones.