Oak Stands Research Articles

Unele aspecte privind studiul creșterilor în diametru la goruneturile de provenienţă vegetativă (lăstari) din Republica Moldova

It is known that the growth rate of a tree, respectively, a stand, during its life differs from one period of life to another. Thus, the growth rate is more accelerated at the beginning of life, so that, achieving the peak of growth in volume, this rate gradually decreases, becoming more and more weak in old age, until the tree stand passes into a state of decrepitude. This variation in the process of accumulation of wood biomass makes the economic efficiency of the tree, respectively, the stand, which varies depending on the development phase, i.e. its age. This increase in volume, usually expressed by the current annual growth of the tree, respectively, the stand at the level of measurement unit and transferred to total yield, ultimately defines its economic efficiency, which in turn varies according to the amplitude of the variation of the growth index. In this context, the purpose of this aper was to evaluate the diameter increments of sessile oak stands (Quercus petraea Liebl.) of vegetative origin from shoots in the Republic of Moldova in relation to the yield class, age and generation originating from shoots, as well as in relation to the composition and consistency of the stand at the level of physical-geographical areas and phytoclimatic levels.

Asymmetric character displacement in mixed oak stands.

Ecological character displacement (ECD) refers to a pattern of increased divergence at sites where species ranges overlap caused by competition for resources. Although ECD is believed to be common, there are few in-depth studies that clearly establish its existence, especially in plants. Thus, we have compared leaf traits in allopatric and sympatric populations of two East Asian deciduous oaks: Quercus dentata and Quercus aliena. In contrast to previous studies, we define sympatry and allopatry at a local scale, thereby comparing populations that can or cannot directly interact. Using genetic markers, we found greater genetic divergence between the two oak species growing in mixed stands and inferred that long-term gene flow has predominantly occurred asymmetrically from the cold-tolerant species (Q. dentata) to the warm-demanding later colonizing species (Q. aliena). Analysis of leaf traits revealed greater divergence in mixed than in pure oak stands. This was mostly due to the later colonizing species being characterized by more resource-conservative traits in the presence of the other species. Controlling for relevant environmental differences did not alter these conclusions. These results suggest that asymmetric trait divergence can take place where species coexist, possibly due to the imbalance in demographic history of species resulting in asymmetric inter-specific selection pressures.

Evaluation of Multiple Forest Service Based on the Integration of Stand Structural Attributes in Mixed Oak Forests

In order to understand forest services at stand level through the integration of structural attributes, forest structures in three main stand types were analyzed based on various structural attributes relating to the services of habitat conservation, timber production and soil water conservation in Loess Plateau, China. Forty sample plots with similar site and environment conditions were established in three types of oak stands. Twenty-two indexes such as stand density, mean DBH, mean height, etc., were selected to analyze the relationship between structural attributes and forest service. With a core set of structural attributes selected by principal component analysis, the link between the service and structural attributes and the compatibility between each service was analyzed using correlation analysis. The results show that the oak–broadleaf mixed forest has the highest structural complexity index (SCI), indicating the best habitat conservation among others, while the oak–pine mixed forest and pure oak forest have the highest timber value in different scenarios of timber price, indicating the largest potential for timber production. Little differences were found between stand types regarding the indicators for soil water conservation. The structural attributes that had a positive correlation with habitat conservation (e.g., number of shrub species, species richness of canopy layer, the proportion of broadleaves and snag density) were identified to be negative for timber production; while the attributes that had a positive correlation with timber production (e.g., stand density and proportion of pine and oaks) were found to be negative for habitat conservation. The results of the trade-off analysis showed that timber production tends to be conflicting with the other two non-timber forest services. In order to enhance the provisioning of multiple services, it was suggested to implement the interventions that could balance these services, such as structural retention and single-tree selective logging. This study could contribute to the theoretical base for the decision making in the multi-purpose sustainable management of oak forests in China.

Geometric Morphometrics use in the examination of subgenus Quercus leaf shape variation in Algeria

Abstract The latest findings on the taxonomic review of Quercus faginea Lam. complex using ‘traditional morphometrics’, demonstrating that the species is represented in Algeria by both Q. faginea and Q. canariensis Willd. Significant variations of the leaf form were also discernible among both species. In this study, the landmark-based geometric morphometrics analysis was used to assess the shape variation of the leaves found on oak stands. 2,600 leaves per 13 stands were collected and scanned, and then using Tps range and MorphoJ software, 11 landmarks—that represent the leaf morphological features—were recorded on leaf images. Shape components and non-forms variations were obtained through a full Procrustes fit followed by creating a leaf-superimposed configuration. Principal component analysis, canonical variate analysis, and discriminate analysis were used to statistically evaluate the leaf shape variability. The results revealed no clear distinction between the two species based on leaf shape. Climate change and environmental factors also appear to have possibly caused a divergent morphological evolution; a reduced leaf size with enduring indumentum—among other Q. faginea traits—could be an efficient mean of adapting to Mediterranean xeric conditions.

A novel method for assessing the threat to oak stands from geometrid defoliators

Oak forests are of great ecological and socioeconomic values but are declining in many regions due to abiotic and biotic factors, including crown damage by defoliating insects. In Europe, several geometrid species reach outbreak densities and are then able to cause severe oak defoliation. Prior to control measures, the threat posed by defoliators must be reliably assessed to limit the treated area and consequently to minimize the negative environmental impacts and the costs of the insecticide application. Few methods have been developed so far to assess the threat to oak forests from geometrids, most of which have proven to be unreliable and/or labour-consuming. In this paper, we present a new method for predicting crown damage from geometrid defoliators based on the density of their flightless females assessed with the use of collar traps installed on tree trunks. The studies were conducted in 2014–2020 in 68 oak stands in Poland. Using beta regression, we estimated the relationship between the density of geometrid females (from genera: Operophtera, Erannis, Agriopis, Alsophila and Apocheima) in collar traps and subsequent defoliation caused by their progeny (i.e. larvae). We then proposed threshold numbers of female density to predict different levels of defoliation and calculated the numbers of collar traps that would be required to detect the threshold density of geometrid females indicating expected defoliation >30%. The new method allows forest managers to monitor populations of different species and phenological groups of geometrids and predict the threat (expected defoliation) to oak forests from these insects.

Single- and Double-Entry Volume Equations for Turkey Oak (Quercus cerris L.) Stands in Bursa Regional Directorate of Forestry

Single- and Double-Entry Volume Equations for Turkey Oak (Quercus cerris L.) Stands in Bursa Regional Directorate of Forestry

Oak Decline Syndrome in Korean Forests: History, Biology, and Prospects for Korean Oak Wilt

Oak decline syndrome has been observed in South Korea and Japan and variously referred to as Korean oak wilt (KOW) and Japanese oak wilt (JOW). We reviewed aspects of the historical occurrence of KOW, disease cycle, and its potential causes. KOW has been seen principally in Mongolian oak (Quercus mongolica Fisch. ex Ledeb.). The first occurrence of KOW was in 2004 in Seongnam, South Korea. KOW is associated with the fungus Raffaelea quercus-mongolicae, which is vectored by the ambrosia beetle Platypus koryoensis. In addition, it has been suggested that yeasts have evolved a symbiotic relationship with the vector without antagonism for the pathogenic fungus. The number of trees in Korea killed by KOW increased to about 331,000 in 2011, but then decreased to about 157,000 in 2019. We hypothesized that trees infected by R. quercus-mongolicae accumulate phenolic compounds in the sapwood and the vector (P. koryoensis) beetles then avoid these trees. Therefore, the number of hosts available for the beetle after a KOW outbreak decrease due to accumulation of phenolic compounds in the wood, although most oak trees survive outbreaks. Therefore, P. koryoensis beetles move longer distances after outbreaks to find susceptible host trees. Novel occurrence of KOW in Korea may be due to either (1) an increase in tree age (size) in Korean oak stands, for which the beetle has a known preference or (2) climate change, which may be increasing the number of weakened or stressed trees, for which P. koryoensis also shows a preference.

FORESTRY LAND USE OF THE BUSK FORESTRY ENTERPRISE: HISTORICAL AND GEOGRAPHICAL FEATURES AND CURRENT STATE

The research is devoted to the study of forestry land use in the zone of activity of the Busk forestry enterprise. A comprehensive geographical study of forests in the territory of Male Polissia as a whole and its individual parts is relevant both from an ecological and economic point of view. Its importance is growing in the context of the administrative reform and improvement of the land resources of the established communities and the consolidation of forestry enterprises announced in 2021. Today, Ukraine is not able to provide its own needs in timber and is one of the least forested countries in Europe. The territories of Male Polissia, including the newly formed Busk and Krasne and neighboring territorial communities, are promising for afforestation, in particular plantations.
 The authors of the article believe that it is possible to understand the modern structure of land resources only through the prism of history. For these reasons, the study used cartographic materials of different times, which made it possible to trace the development of several forests from the end of the 18th century to the present. The study was carried out on four time slices: the map by Friedrich von Mieg of the late 18th century, the topographic map of the Austro-Hungarian Empire at the end of the 19th century, the topographic map of the Military Geographical Institute of the 30s of the 20th century. and a modern satellite image of Google.
 The zone of activity of the Busk forestry enterprise fully covers the territory of the Busk and Krasne territorial communities and is partially located on the lands of the Dobrotvir, Novyi Yarychiv, Kamianka-Buzka, and Hlyniany communities. The forests of the studied region are part of nine forestries of Tadani, Hrabova, Verbliany, Polonychna, Kutkir, Ozhydiv, Sokolia, Neznaniv, Bolozhyniv. The largest areas are Tadani - 3917 hectares and Verbliany - 3603 hectares of forestry, and the smallest is Polonychna forestry, with an area of 1456 hectares. In the zone of activity of the study forestry enterprise, the forestry enterprise " Halsillis " also operates, uniting collective farm forests. The average forest cover of the study region is 20.9%. The highest forest coverage is observed in the north-west of the zone of activity of the Busk forestry enterprise.
 In the process of research, the authors developed statistical and stock materials of the forestry enterprise. On the basis of these data, maps of the species composition, age structure and timber stock in the context of forest areas were built and analyzed. The geospatial features of pine, black alder and oak stands have been revealed. Based on the processing of the cadastral map, promising areas for afforestation are proposed.
 As a result of the study, it was found that the characteristic features of forestry in the region are: uneven forest cover of the study area; significant fragmentation of the forest fund in the southern part of the forestry enterprise; location of large forest areas in the northwestern part of the forestry enterprise; dominance in stands of such species as pine, oak, alder; a slight increase in the forest cover of certain territories due to the creation of pine forest plantations on non-land areas and the active expansion of black alder forests on waterlogged pastures.
 Analysis and generalization of taxation materials made it possible to establish that the age structure of forests is dominated by medieval (44.7%) and plantations - 24.5%, young forests occupy 19.4%, and only 11.4% of the area covered by forests falls on mature ones and overgrown plantings. Such an age structure indicates intensive forest management on the territory of the forestry enterprise over the past decades and the active work of foresters on the formation of the species composition of forests.
 We have studied the division of the forest fund into categories. It has been established that the largest area of the forest fund of the Busk forestry enterprise is occupied by operational forests - 22202.1 hectares (87.8%). Protective forests account for 1.5% of the total forest area of the study region. The share of recreational forests in the structure of the forest fund is 9.5%. The forest supply of the population in the Krasne united territorial community averages 0.12 hectares/person, in Busk are 0.61 hectares/person.
 The total stock of wood in the forestry enterprise is 4576.36 thousand m³. In the structure of reserves, 52.7% is occupied by conifers. Hardwood and softwood species each account for 23.7% of the wood reserves of the study region. In geospatial terms, the distribution of wood reserves is extremely uneven and correlates with forest areas.
 Keywords: forest; wooded area; forestry enterprise; forest categories; forest tract; species composition; age structure of the forest.

Microclimatic conditions drive summer flight phenology of Platypus cylindrus in managed cork oak stands

AbstractThe oak pinhole borer, Platypus cylindrus F., mainly colonizes oaks (Quercus sp.), and it is considered among the most serious pests of cork oak (Quercus suber L.). Despite being traditionally considered as a secondary pest in thermophilic oak woodlands, outbreaks seem to be more frequent throughout the Mediterranean Basin thus becoming a growing forest health concern. In the Iberian Peninsula, this insect mainly attacks cork oaks (Q. suber) causing intense stress to mature trees specially after cork harvesting season. In this study, we investigated the summer flight phenology of P. cylindrus in six stands located in north‐eastern Spain. We recorded the number of insects trapped in pheromone‐baited traps from late April to early September of 2021, and computed sex ratio, average date of flight and season flight curve in each plot. We fitted a GAM model to evaluate how population dynamics are driven by date and climatic factors. A total of 1795 insects were collected during the sampling period. Population peaks occurred from late May to mid‐August. The fitted GAM predicted changes in the number of captures throughout the summer varying with microclimatic conditions. In addition, diversity of trapped non‐target Curculionidae resulted moderate with low evenness including either ambrosia or bark beetles. This study represents the first attempt at modelling P. cylindrus flight, thus providing insights into the association between climate, pests and forestry.

Growth and Development Dynamics of Young Holm Oak (Quercus Ilex L.) Stands after Shelterwood Cutting in Open Forest Road Conditions

The Mediterranean forest region has been exposed to anthropogenic impacts for centuries, and the constant biotic and abiotic factors, together with increasing climate change, have hindered the proper management of forest ecosystems. This study presents the results of multiyear, systematic, specific and practical monitoring of the conversion of holm oak coppices using the principles of the shelterwood system. It also presents the growth and development dynamics of the stand on a permanent experimental plot from 1997 to 2017. The research was performed in the Eumediterranean vegetation zone of coniferous forest (Forest Management, Buzet branch, Pula Forestry Office, Magran Cuf management unit, compartment 83a). The plot has all the properties of a holm oak and manna ash forests (Orno-Quercetum ilicis H-ić/1956/1958). The basic elements of stand structure were monitored: diameter at breast height (DBH), tree height, horizontal crown projection, crown ground shading (light) and the appearance and abundance of all woody vegetation, with special emphasis on the growth and development of young generations of holm oak from seed. The paper also describes the threats limiting growth, development and survival of holm oak from seed (strong shooting tendencies of coppiced holm oak and bay laurel trees, excessive presence of shrubs). Forest management requires effective, timely and repeated tending to thin stands (already under the canopy), while also protecting young trees from wild game. The statistical method of interpolation determined the trends of stand development; trend equation with coefficient of determination (R2) is very high. This indicates the growth and development of the stand in the direction of renewal of holm oak stands. Shelterwood cutting, with regular and timely tending of young generations of trees through a seven-year regeneration period, resulted in a high quality young high forest of holm oak, the first of its kind in the broader Mediterranean area. The indigenous stands of holm oak, as the fundamental climatogenic coniferous species of the Mediterranean species, have multiple roles such as protection from erosion, resilience to biotic and abiotic factors and forest fires, tourism and landscape functions, and other general forest functions, and therefore deserve intensive and ongoing research. Holm oak stands also play a part in conserving genetic and biological diversity, the potential and persistence of forest ecosystems, improving stand structure, stability and resilience of forest ecosystems to climate change, and in the long-term increase the commercial value of forest stands in the Croatian Mediterranean.

Ceratocystiopsis quercina sp. nov. Associated with Platypus cylindrus on Declining Quercus suber in Portugal.

Simple SummaryThe presence of the oak pinhole borer, the insect Platypus cylindrus, in Portuguese cork oak stands has drastically increased in the past few decades. This beetle excavates long galleries in the trunk while inoculating fungi (called ambrosia fungi) transported in special organs (mycangia) that will serve as food source for its offspring. The combined action of extensive boring into the heartwood and the inoculation of fungi leads to an increase in tree mortality. A new ambrosial fungus, Ceratocystiopsis quercina, was isolated from the insects’ mycangia and from wilting trees, namely from the staining patches it causes on wood.Platypus cylindrus is the most common ambrosia beetle in stands of Quercus suber in Portugal. This insect farms specialized fungi in sapwood galleries, using its mycangia to carry and store these organisms. Some ectosymbiotic fungi carried by P. cylindrus are phytopathogenic and cause extensive tree mortality and severe economic losses. To understand the role of P. cylindrus fungal symbionts in stands of Q. suber we examined beetle galleries present in declining and/or dying cork oak trees during field surveys. Logs with active galleries were obtained in situ and from captured emerging beetles. Insects were aseptically dissected, and their mycangia and intestine were retrieved. Morphological and molecular profiles of fungal isolates obtained from cultured insect parts were carried out to accurately characterize and identify isolated fungi. Molecular characterizations were performed with DNA sequence data from four loci, i.e., LSU, SSU, 5.8S-ITS2-28S, and TUB. Morphological results consistently showed a collection of Ophiostoma-like fungal axenic isolates, while phylogenies inferred that this collection constitutes an undescribed taxon reported herein for the first time in association with P. cylindrus in Portuguese cork oak stands. The novel species was erected as Ceratocystiopsis quercina sp. nov. and constitutes a new phytopathogenic fungal species associated with symptoms of vegetative cork oak decline.

Long-Term Productivity of Monospecific and Mixed Oak (Quercus petraea [Matt.] Liebl. and Quercus robur L.) Stands in Germany: Growth Dynamics and the Effect of Stand Structure

Wood production is one of the most important ecosystem service that forests provide to society. However, under changing climatic conditions, this appears to be subject to increasing uncertainties. In the present study we analyzed how long-term productivity of oak (Quercus petraea [Matt.] Liebl. and Quercus robur L.) stands has developed, how oak behaved on tree and stand level depending on the stand structure and which trade-offs can be observed. For the analyses, data from 147 long-term monospecific and mixed stands were investigated, which have been regularly recorded since 1898. Firstly, long-term stand productivity has increased up to 21% until 2020 as compared to 1960. This trend was observed for both, monospecific as well as mixed oak stands. Secondly, stand productivity was on average 19% higher in mixed compared to monospecific oak stands. This superiority can be explained by higher stand densities, a vigorous understory and the admixture of beech in particular. With increasing age, the observed positive effect of stand density was higher. Thirdly, individual oak productivity slowed down under interspecific competition, especially in young to mid-aged stands. In this context, the productivity of individual oaks depended strongly on their social position within the stand. Fourthly, in terms of growth partitioning larger trees contributed most in young oak stands, regardless of mixture. In order to preserve oak as a productive component of future mixed forests, the results suggest a silvicultural promotion of oak. Consistent management of dominant and vital oaks can achieve high productive trees while maintaining the positive characteristics of highly structured and mixed forests. A vigorous secondary stand can increase overall stand productivity at lower densities and allows silvicultural flexibility at the stand level. Creating vertical stand structure to reduce competition has only a limited positive effect on productivity of individual oaks that is highly related to its social status. Special attention should still be paid to beech as admixed tree species, which can continue to crowd oak even at higher stand ages.

Gas Exchanges and Accumulation of Osmolites in Declined Persian Oak Stands in Ilam Province (Case study: Gchan and Sheshdar Forest Area)

Gas Exchanges and Accumulation of Osmolites in Declined Persian Oak Stands in Ilam Province (Case study: Gchan and Sheshdar Forest Area)

Environmental Effects among Differently Located and Fertile Sites on Forest Basal-Area Increment in Temperate Zone

Environmental properties differently influence the growth of forest tree species. The antagonistic effects of variable environmental properties classify the forest response according to various tree compositions among different sites. The division of the forest response was assessed in 52 stands arranged into 26 types of 13 site management populations (MPs) in 5 areas in the Czech Republic territory. The assessment was performed using time-series multiple regressions of basal-area increment from pure immature stands of Norway spruce (Picea abies), Scots pine (Pinus sylvestris), oaks (Quercus sp.), ash (Fraxinus excelsior) and willows (Salix sp.) dependent on the interpolated average temperatures, annual precipitation, atmospheric concentrations of SO2, NOx and O3 and soil properties over the period 1971–2008 at p < 0.05. Site MPs differentiated the forest response to a greater extent than tree species. The response of the forests was significantly distributed by means of the montane, upland and waterlogged sites. The multiple determination index (r2) ≥ 0.6 indicated an adaptable tree increment but an interval of r2 between 0.80–0.92 implied forest sensitivity to variability in environmental properties on non-waterlogged sites. The index r2 < 0.6 suggested a fluctuating forest increment that reflects environmental variability inconsistently. The fluctuating increment most affected the spruce and pine stands grown from upland to submontane locations. Montane spruce stands, as well as rock pines, appeared to be one of the most sensitive ones to environmental change. Floodplain forests seemed as adaptable to variable environmental properties.

Estimation of coarse woody debris stocks in forest ecosystems of «Tsyrkunivskyi forest» and «Dergachivskyi forest» Emerald network objects (Kharkiv region)

The estimation of coarse woody debris stocks in forest ecosystems of «Tsyrkunivskyi forest» and «Dergachivskyi forest» Emerald network objects was performed. Estimation was conducted based on State Forest Inventory data of State enterprise «Kharkiv Forest Research Station» forest fund. Data of dead wood in forest stands of eighteen tree species were analyzed. The stock of the following components of coarse woody debris was studied: standing dead wood, fallen dead wood. Data analysis was performed using MS Excel 2016 software. It was found that the total area of forest stands in which standing dead wood was found during forest inventory was 9984.6 ha, or 49.6%, of the total forest area; for fallen dead wood corresponding indicators were 2662.5 ha (13.2%). The total stock of coarse woody debris was 20761 m3, which is concentrated in the stands of pedunculate oak (Quercus robur L.) (75.6%) and Scots pine (Pinus sylvestris L.) (11.1%). Standing dead wood prevailed (80.1%) fallen dead wood (19.9%) in the structure of dead wood volume. Mean volume of standing dead wood by forest type was from 1.3 m3 ·ha–1 (dry maplelinden dibrova) to 33.3 m3 ·ha–1 (wet maple-linden sudibrova), fallen dead wood — from 1.0 m3 ·ha–1 (dry maple-linden dibrova) to 11.5 m3 ·ha–1 (wet maple-linden dibrova). In oak stands mean volume of standing dead wood was 1.4 m3 ·ha–1, fallen dead wood — 1.3 m3 ·ha–1. Obtained results indicate that in general, the dead wood volumes in forest ecosystems in studied Emerald network objects estimated based on State Forest Inventory data, are quite low compared to the forest ecosystems of other protected areas, where one of the priorities are the natural complexes protection and biodiversity conservation. It may be associated with the influence of forestry activities in studied protected areas.

On the state of the pedunculate oak plants (Quercus robur L.) of the orenburg climatype

The degradation of oak forests is an acute problem throughout the territory of the Russian Federation. Pedunculate oak is a valuable and durable tree species. The stability of oak forests is largely determined by biotypic characteristics. However, in recent years, anthropogenic impact is the main reason for the drying out of oak forests, which leads to the death of resistant pedunculate oak climatypes. The article presents the results of a study of pure stands of low-stemmed pedunculate oak on the territory of the Orenburg region. The silvicultural characteristics of plantings are given, their phytocenotic structure is described. It was found that in dry oak forests and oak undergrowth the stand was characterized by a low growth class, in fresh oak forests the highest growth class was noted. The plant density varied significantly from 0.3 to 0.7. In dry oak forests, the density index tended to decrease with age. The maximum plant density was observed at the junction of ripe and overmature ages, at the age of 60 years. The state of pure pedunculate oak stands on the territory of the Orenburg region can be assessed at the moment as satisfactory, but requires significant measures to promote seed reforestation.

Investigating the spatiotemporal changes of land use/land cover and its implications for ecosystem services between 1972 and 2015 in Yuvacık.

This study aims to determine the spatiotemporal changes of land use/land cover and ecosystem services in a 12,092.1ha of Yuvacık planning unit (PU), by focusing on carbon storage, soil loss, water production, biodiversity, and forest fire vulnerability. Stand type maps and forest management plans designed in 1972, 2004, and 2015 were used to reveal the changes over 43years. The results pointed out obvious changes in terms of the occurrence of private and cadastral forests as new types of land use, disappearance of coppice and pure oak stands, and the transformation of 99% of open lands into residential areas. Furthermore, degraded forests decreased considerably and mixed forests rose sharply by 117.2%. The outputs were highly related to the increase by 42% (5194.9ha) of dense forest and shifting of 2548ha from thinner development stage to mature stages during the period. With respect to ecosystem services, carbon storage in forest ecosystems went up by 19.3 Gg over 43years. Moreover, soil loss declined significantly from 1.1 billion tons year-1 to 108,549 tons year-1, and water production decreased considerably from 1.8 billion to 2.7 million m3 year-1. According to the Shannon evenness index, there was an increase by 0.3 and 0.2 successively. Biodiversity parameters such as tree density jumped from 18 to 46ha-1 in thicker development classes (more than 36cm dbh) and positive developments in biodiversity chain noticed. Afterward, Yuvacık PU was classed in 2nd class of high wildfire vulnerability due to range of fire sensitivity index (5.22-6.88).

Growth of Deciduous and Evergreen Species in Two Contrasting Temperate Forest Stands in Korea: An Intersite Experiment.

Poor seedling establishment and growth can be a result of the limitation of light and soil resources in the forest understory. Here, we investigate the interacting effects of stand and soil characteristics on the seedling growth of deciduous species (Fraxinus rhynchophylla and Zelkova serrata) and evergreen species (Pinus koraiensis) through a 3-year intersite experiment in two contrasting forest stands. Seedlings were grown in both oak and pine stands using two different soil types, i.e., gray-brown forest soil (GB) and red-yellow forest soil (RY). Soil physicochemical properties, light intensity, tree-seedling height, root-collar diameter (RCD), and biomass growth were analyzed between two stands and/or soil types. Light availability was generally more abundant in the pine stand (mean: 1074.08 lx or 20.25%) than the oak stand (mean: 424.33 lx or 9.20%) throughout the year. The height and RCD growth of fast-growing and deciduous F. rhynchophylla and Z. serrata were higher in the pine than in the oak stand, particularly in GB soil. The growth of the slow-growing and evergreen P. koraiensis was not affected by the forest stand, except for its higher root growth in the oak stand and RY soil. Therefore, abundant light availability can enhance the growth and seedling establishment of F. rhynchophylla and Z. serrata in the pine-stand understory. Contrarily, P. koraiensis may be planted in the understory regardless of light condition, but with a slower growth rate.

Microclimatic Alteration after Logging Affects the Growth of the Endangered Lichen Lobaria pulmonaria.

Microclimatic conditions are important in determining lichen distribution at small scale, and may determine whether the species persist when the surrounding environmental conditions have drastically changed. This is the case with forest management, since a sudden variation of microclimatic conditions (increase of solar radiation, temperature, wind and a reduction of humidity) may occur after logging. In this study, the combined effect of forest logging and microclimatic conditions on the growth probabilities and growth rates of the model species Lobaria pulmonaria was assessed in mixed oak stands. To this purpose, 800 fragments of L. pulmonaria (<1 cm) were transplanted in logged and unlogged stands for two years. Young and adult fragments were positioned on Turkey oak boles according to distance from the ground (100 and 50 cm) and aspect (north and south). The results, evaluated by generalized linear mixed models on a yearly basis, highlighted differences in growth—particularly on isolated trees in the logged stand. South-exposed samples in the logged stand showed a low probability of growth, while samples transplanted north in the unlogged stand showed higher growth probabilities. However, the highest annual growth coefficients corresponded to south-exposed samples 50 cm from the ground in the unlogged stand. In general, higher growth rates were observed in young thallus fragments when compared with adult ones. Beyond confirming the importance of microclimate for lichen ecology, these results could be implemented in conservation actions to preserve L. pulmonaria populations in logged forests.

Predicting forest stand attributes using the integration of airborne laser scanning and Worldview-3 data in a mixed forest in Turkey

The aim of this study is to examine the capability of the combined LiDAR/WorldView-3 data in estimating the plot-level stand attributes (stem number-N, mean diameter-D, mean height-H, basal area-BA and volume-V) in a complex forest located in the northwest of Turkey. Total 135 plots were measured to determine the forest attributes. Prediction models were developed at three levels which are: i) the general level for all stands (including all plots), ii) forest type level (coniferous forest, broad-leaved forest), and iii) tree species level (Black pine stands, Maritime pine stands, Oak stands, Mixed stands). Multiple Linear Regression (MLR) and Random Forest (RF) modelling approaches were tested to predict stand attributes. The MLR regression modelling showed that the stand attributes were estimated with R 2 ranging from 0.71 (N and V in Mixed) to 0.94 (H in Maritime pine) at tree species level, from 0.73 (BA in Broadleaved) to 0.95 (H in Conifer) at forest types level and from 0.77 (V) to 0.89 (H) at general level. The RF modelling indicated that the stand attributes were estimated with R 2 ranging from 0.69 (V in Mixed and Oak) to 0.94 (H in Maritime pine) at tree species level, from 0.72 (N in Broadleaved) to 0.95 (H in Conifer) at forest types level and from 0.81 (N and V) to 0.88 (D) at general level. The mean height had the highest prediction accuracy for almost all levels in both approaches. However, the stem number and basal area were generally estimated with the lower accuracies. The homogeneous coniferous stands provided the higher estimation accuracy than the broadleaved stands. Our results showed that the modelling approaches used here provide different performance for predicting different stand attributes. While the MLR approach performed better in estimating the stand attributes at the tree species level, the RF approach towards the general level provided higher accuracy estimation. In conclusion, the combination of aerial laser scanning and high resolution satellite data has high potential for predicting stand attributes in complex forest ecosystems.