Kraft Classes Research Articles

CENOTIC ROLE OF INFECTIOUS DISEASES IN ABIES SIBIRICA LEDEB. STANDS IN THE SOUTH CENTRAL SIBERIA

Background. Degradation of Abies sibirica Ledeb.-dominated forests in the South Central Siberia is a reflection of the global trend of coniferous forest ecosystems decline. Nevertheless, the role of infectious diseases in coniferous forests degradation and dieback is often underestimated.
 Research aim. To assess the coenotic role of infectious diseases in fir-dominated stands in the South Central Siberia, considering the differentiation in trees.
 Materials and methods. The research was based on a survey of A. sibirica-dominated forest stands growing in Biryusinsky forest management unit of the Krasnoyarsk Krai government-owned publicly funded “Emelyanovskoye forestry”. Research methods included a detailed (instrumental) forest pathological examination, macroscopic diagnostics of tree diseases, graph analytics and statistical analysis of tree diameter distribution series, evaluation of disease manifestation indicators.
 Results. Stem rot and fir broom rust are typical diseases increasing the risk of windsnap and trees weakening. The prevalence of fir broom rust was over 10%. Rust fungus intermediate hosts in the forest floor determine the degree of damage to a stand. Fir broom rust randomly affected trees of different age and diameters. The bacterial blight in fir forests mainly affected trees of I-II Kraft classes causing their gradual dying. The bacterial blight in the study area was of low infection degree (up to 20%). The most dangerous was the root rot caused by Armillaria mellea s.l. that affected trees of different cenotic roles causing their group dieback.
 Conclusion. Dendropathogenic organisms are an important endogenous factor influencing the state of dark coniferous forests with a predominance of A. sibirica in the South Central Siberia. Their cenotic role is unequal. The most significant are pathogens causing necrosis and cancer diseases, and especially the root pathogen A. mellea, which leads to weakening and dying of a large number of trees of different status in the stand structure.

Spring and autumn phenology in sub-mesothermal beech stands from the southwestern extremity of the Carpathians

The research carried out was aimed to assessing the phenological behavior of beech (Fagus sylvatica L.) in the southwestern area of the Carpathians, in submesothermal forest sites, differentiated from the majority mesothermal ones of this species. The data obtained may be used for predicting the phenological changes of the species, especially in the Carpathian area, under the future influence of expected climate change. Assessments for spring and autumn phenology (buds burst -BB and foliation, flowering and leaves senescence) were carried out on a transect with a difference in altitude of 1000 meters, in phenological research areas located at 200 m, 700 m and 1200 m. At each altitude level, 100 trees of I and II Kraft classes were phenologically characterized: 50 trees on the south-facing slope (sunny exposure) and 50 on the north-facing slope (shade exposure).The phenological data were interpreted in relation to climate data recorded in each area by a HOBO U23 Pro v2 sensor. The site conditions of submesothermal climate in the low altitude area led to DOY (day of the year) values below 100. The phenological differentiation of populations is evident in relation with the altitude, while at the same altitudinal level the influence of the exposure was much lower. The gradiental values by altitude sectors highlighted the nonlinearity of the development of foliation phenophase, the value being lower in the first 500 m, where the beech is under the impact of the submesothermal climate. It has been proven both the dependence of the foliation onset depending on the cumulation of temperatures in relation to the DOY moment and also on the values recorded throughout the vegetative rest. The altitudinal gradiental values resulting for flowering in the first and second altitudinal half of transect also differentiate the stands, but are lower than that resulting for BB. The leaves senescence has a delay of 1.8 up to 2.4 days per 100 meters altitude, and the length of the vegetation season is reduced more sharply in the upper half of the analyzed altitudinal transect. The sub-mesothermal climate could be involved in condensation of spring phenophases in the stands of the lower half of the researched area. Our data may be used for predicting the phenological changes, especially in the Carpathian area, under the expected climate change.

Occurrence of European Mistletoe (Viscum album L.) on Forest Trees in Poland and Its Dynamics of Spread in the Period 2008–2018

As recently reported, European mistletoe has become an important agent of damage to forest trees in Central Europe. To document the extent of its impact, host and environmental preferences, as well as spatial and temporal dynamics, we have analyzed the results of 10 years of annual assessments of tree damage in level 1 plots of country-wide national forest monitoring. Mistletoe was found on 12 forest tree species, most frequently on silver fir and Scots pine, much less often on birches and deciduous admixture species. Common beech, pedunculate, and sessile oaks, as well as coniferous admixture species, were found to be free from the parasite. Mistletoe was more common on larger trees, mainly those in the 1st and 2nd Kraft classes, characterized by a higher DBH value than trees without V. album. Infestation was also age-dependent with low numbers of infested trees in young age classes and a much higher proportion of infested trees being over 80–100 years in age. Defoliation of trees colonized by mistletoe was found to be significantly higher than in trees free from the parasite, confirming the adverse effect of infestation on tree health. The increase of relative incidence of tree infestation by mistletoe in forests in Poland was high throughout the entire period 2008–2018 and significant for the most threatened host species: silver fir, Scots pine, and birches. It was also found that spread direction was from west to east and that the occurrence of V. album shows clear regionalization. The most endangered forests were located within a 200 km wide zone ranging through lowland Central Poland from the border with Germany down to the border with Ukraine and Belarus. The highest concentration occurred in the Western part of the country. Outside this zone (to the north and south) the mistletoe was much less abundant as expressed by the amount of injuries caused by the parasite or infested trees per plot.

Health condition parameters for deciduous trees in the forest stands of Trostyanetske Forest Enterprise

The aim of research was to evaluate the variability and relations with forest health condition its main parameters (defoliation, dieback and epicormic shoots occurrence) in seven tree species: Norway maple (Acer platanoides L.), black alder (Alnus glutinosa L.), silver birch (Betula pendula Roth.), European ash (Fraxinus excelsior L.), English oak (Quercus robur L.), small-leaved lime (Tilia cordata Mill.), and white elm (Ulmus laevis Pall).
 Research was carried out in 2018 in Trostyanetske Forest Enterprise (Left-bank Forest Steppe; Sumy region). Diameter (DBH), Kraft class, and category of health condition were assessed for each tree. Defoliation, dieback and epicormic shoots occurrence were evaluated as proportion of trees with respective symptoms. Severity of each parameter of tree health condition was estimated using respective scores.
 No tree species is defoliated over 50%. A birch is characterized by the lowest health condition index (1.6) for living trees, dieback (10%), epicormic shoots occurrence (15.9%) and recently died trees proportion (0.7%), but high proportion of trees died over year ago (10.7%). An oak is characterized by the highest health condition index (2.1), proportion of trees with dieback (45.4%) and epicormic shoots (21.7%). Proportion of trees with dieback is 21.5 to 25% for alder, lime and maple, a bit higher for elm and ash (30.9 and 31.3% respectively).
 DBH, Kraft class, and health condition index significantly correlate with health condition parameters of analyzed tree species, but the most of correlations are very slight and slight. Correlation between health condition index and defoliation score is significant, positive and high for all tree species (from 0.78 for alder to 0.9 for birch). Correlation between health condition index and dieback score is positive and significant for all tree species, is slight for ash, birch, lime, and alder, and moderate for maple, oak and elm. Correlation between health condition index and epicormic shoots occurrence is significant and positive for all tree species except birch, but is very slight in all cases except elm, where it is slight.

Slenderness of trees in black locust stands

Abstract This paper investigates the slenderness of black locust (Robinia pseudoacacia) trees in relation to the biosocial status of the trees, stand age class, crown parameters and habitat type. The research material was collected on 35 research plots in the Sława Śląska, Sulechów and Głogów forest districts in western Poland and comprises 1058 trees. For each tree, we measured height (h) as well as diameter at breast height (d) and determined its biosocial status (Kraft class), crown length (CL) and relative crown length (rCL). The age class and habitat type were assessed at the plot level. Because the obtained values for slenderness (s=h/d) diverged significantly from the normal distribution, we used Kruskal-Wallis and Mann-Whitney tests to investigate the influence of the above-mentioned parameters on the h/d ratio. Black locust slenderness ranged from 0.31 to 1.95 with an average of 0.91 (standard deviation 0.24). It furthermore differed significantly between Kraft classes (the higher the biosocial status, the lower the slenderness) and age classes (the older the trees, the lower their slenderness). We also found a significant effect of the habitat type (in oligotrophic sites trees formed more slender trunks than in mesotrophic sites) and crown parameters on the h/d ratio (decreasing with increasing crown length and relative crown length). The obtained results suggest that the slenderness of black locust does not differ substantially from native broadleaved trees in Poland.

Assessment of tree vitality, biomass and morphology of Scots pine (Pinus sylvestris L.) root systems growing on reclaimed landfill waste after zinc and lead flotation

Abstract The stability of introduced stands depends not only on aboveground but also on the belowground biomass. Results from reclaimed sites often indicate good growth of the aboveground part of stands, but data on the development of root systems are still lacking. Our aim was to assess the vitality of trees, their biomass and the morphology of the root systems of Scots pine (Pinus sylvestris L.) introduced on reclaimed landfill waste after zinc and lead flotation in Bukowno (southern Poland). The landfill site was reclaimed 20 years ago and reclamation treatments involved isolation and covering with mineral substrate layers (110–150 cm thickness) which formed a technogenic soil profile. Four research plots (10 m × 10 m) were set up in pure pine stands where soil profiles consisted entirely of flotation waste. Trees on the plots were assayed according to the Kraft and IUFRO classification system. In total, 15 trees of average growth parameters and bio-sociological position (I and II Kraft class) were selected for biomass and root system analyses and the root systems were excavated, washed, measured, weighed and photographed. Our results support pine as a useful species in reforestation of post-mining areas. However, although pine trees were characterised by good vitality, their root systems were shallow and their depth reduced by up to 60 cm due to strong skeletal loamy substrate. Individual root biomass ranged from 1.2 to 9.1 kg and was comparable to pine root biomass on other reclaimed mining sites. This indicates that during restoration, the thickness of the substrate covering the flotation waste should be increased or the amount of skeletal substrate in the top layers of technosol reduced.

CHANGES OF RADIAL GROWTH IN PINE STAND DAMAGED BY FIRE IN WEST POLISSYA

The authors have estimated the consequences of surface fire in 2012 on 50-year-old pure pine stand in Polissya by dendrochronological methods. In the course of study we have detected depression of pine radial growth that was intensified by droughts and worsening of sanitary tree state after damaging stand by forest fire. Criterias of anomality of weather conditions were calculated on basis of deviation temperature and precipitation from long-term average series of temperature and precipitation (1945-2015).Some features of formation of tree rings in damaged by fire stand including dependence on categories of sanitary state of trees and Kraft classes. Decrease of radial growth was heightened with worsening of tree state. Decrease of width tree rings was revealed at comparison period after fire with period before one: for broken trees by 44 %, very broken trees by 49 % and for dying trees by 75 %. Radial growth didn't recover till state before fire and saved clearly hierarchy tendency: dominant trees had the biggest radial growth and sub-dominant trees had less growth. In damaged stand after fire decrease of width of late (by 68 %) and early wood (by 47 %) we detected at comparison the period after fire and the period before fire. In control stand appropriate values were 8 % and 11 %. Regression model regarding dependence of index radial growth from height of deposit on stems was built.

Changes in consortial links of aphyllophoroid fungi and Quercus robur L. in the recreational forests of the green zone of city

Recreational degradation of forest ecosystems of the green zone of the town Uman was described on the example of the forest array «Belogrudivska Dacha». The vitality and health conditions of Quercus robur L. and species, systematic, trophic, spatial compositions of xylotrophic fungi were investigated. Changes in the compositions of xylotrophic fungi and Q. robur were indicated an intensification of degradation processes in fresh maple oak. However, the entwinement between the development and distribution of xylotrophic fungi with the degree of damage and drying of trees, the intensity of recreational load did not found. This effect was indirect. The consorts links of Q. robur and xylotrophic fungi essentially depend on the amount of available substrate and evaporation from the soil surface, density of canopy, the projective coverage of herb stratum, in general, the forestry and mensurational characteristics of the stands. These components determine the development of forest ecosystems, the formation of myco-horizons of trees, the rate of accumulation of wood of various categories of substrates, which favorable for the settlement and development of xylotrophic fungi, certain levels of organization of consorts. The deterioration of the conditions of growth and development of Q. robur in fresh maple oak, drying and degradation of canopy cause changes in the composition of the consorts of these trees and xylotrophic fungi due to violation of the conditions of the forest environment, changes in the quantitative and qualitative characteristics of the substrates, their distribution in time and space. Recreational impact was essentially neutralized due to the complex composition and large buffer capacity of the forest ecosystem, a large number of mechanisms for its sustainability, and the ability to quickly restore degraded elements and links of the forest. Highly productive young and medieval medium-attractive woodlands of Q. robur of recreational forests of the woodland part of the green zone of city Uman, affected a moderate and medium recreational impact. The territory of the tract has the first (75 %) and second (25 %) stage of recreational degradation. This was primarily due to the close location of the city, suburban villages, main transport networks and the availability of forest for the population. Species diversity of investigated fungi in all experimental plots acquired rather high values. Such indicators testified to the stability of xylomycocenosis to the existing recreational impact, unlike other, more vulnerable structural and functional components of the forest ecosystem: herb stratum, underbrush, undergrowth, soil surface. At all studied experimental plots of the tract, the best development of xylomycobiota was in the trees of the highest Kraft classes. According to the state categories in the investigated plots, weakened and strongly weakened trees were prevailed, in which the maximum number of species and findings of fungi was detected. The findings of xylotrophic fungi on the recently dead stands was minimal. The analysis of the vegetation under ombraregime has shown that subaridophytes and subomorophytes were predominated. In the medium- and low-transformed experimental plots, the magnitude of the ecological amplitude under ombraregime is slightly higher than that of the highly transformated experimental plot. This indicates a greater evaporation from the surface of the soil with an increase in the degree of recreational transformation. A significant change in the forest environment and substratum fund due to the intense degradation of the ecosystem may limit the development and spread of xylotrophic fungi.

Thinning increases drought tolerance of European beech: a case study on two forested slopes on opposite sides of a valley

European beech (Fagus sylvatica L.) is one of the economically most important broadleaved tree species in Central Europe. However, beech shows high drought sensitivity and calls for profound research to test its ability to cope with limited water resources. Here, we investigated the drought tolerance of beech to the 2003 drought as influenced by Kraft class, aspect and thinning intensity. Annual basal area increment data of 126 sample trees from southwest Germany were used to assess the variability of drought tolerance indices, by comparing three social classes (predominant, dominant and co-dominant), two contrasting sites [a dry southwest (SW) aspect and a moist northeast (NE) aspect], and three treatments [control, strong thinning (stand basal area 15 m2 ha−1) and very strong thinning (stand basal area 10 m2 ha−1)] in mature beech stands. Our results show that the co-dominant and dominant trees had lower growth recovery and lower growth resilience after the drought, compared to the predominant trees. The differences between aspects pointed to a growth–drought tolerance trade-off, in which trees on the SW aspect displayed lower growth rates but higher resilience indices than trees on the moist NE aspect. Furthermore, our results suggest that the resistance to and resilience after the 2003 drought significantly increased for the thinned trees. Our results provide novel insights into the linkage between the forest stand management and drought tolerance of beech under contrasting sites. We conclude that thinning can partially alleviate effects of severe drought on European beech forests in southwest Germany and can be applied as an adaptive measure to increase the mitigation potential of beech stands.

The influence of spruce on acidity and nutrient content in soils of Northern Taiga dwarf shrub–green moss spruce forests

Presently, among the works considering the influence of forest trees on soil properties, the idea that spruce (Picea abies) promotes the acidification of soils predominates. The aim of this work is to assess the effects of spruce trees of different ages and Kraft classes on the acidity and content of available nutrient compounds in the soils under boreal dwarf shrub–green moss spruce forests by the example of forest soils in the Kola Peninsula. The soils are typical iron-illuvial podzols (Albic Rustic Podzols (Arenic)). Three probable ways of developing soils under spruce forests with the moss–dwarf shrub ground cover are considered. The soils under windfall–soil complexes of flat mesodepressions present the initial status. The acidity of organic soil horizons from the initial stage of mesodepression overgrowth to the formation of adult trees changed nonlinearly: the soil acidity reached its maximum under the 30–40-year-old trees and decreased under the trees older than 100 years. The contents of nitrogen and available nutrients increased. The acidity of the mineral soil horizons under the trees at the ages of 110–135 and 190–220 years was comparable, but higher than that under the 30–40-year-old trees. The differences in the strength and trends of the trees’ effect on the soils are explained by the age of spruce trees and their belonging to different Kraft classes.

Allocation of oaks to Kraft classes based on linear and nonlinear kernel discriminant variables

Summary A method of discriminant variable determination was used to visualize the division of oak trees into Kraft classes. Usual discriminant variables and several types of kernel discriminant variables were studied. For this purpose the traits of oak (Quercus L.) trees, measured on standing trees, were used. These traits included height of tree, breast height diameter and crown projection area. The use of the Gaussian kernel and modified Gaussian kernel enabled the clearest division into Kraft classes. In particular, the latter method proved to be the most effective.

Tree crown size as a measure of tree biosocial position in 135-year-old oak (Quercus L.) stand

Abstract The paper presents an attempt to apply measurable traits of a tree – crown projection area, crown length, diameter at breast height and tree height for classification of 135-year-old oak (Quercus L.) trees into Kraft classes. Statistical multivariate analysis was applied to reach the aim. Empirical material was collected on sample plot area of 0.75 ha, located in 135-year-old oak stand. Analysis of dimensional traits of oaks from 135-year-old stand allows quite certain classification of trees into three groups: pre-dominant, dominant and co-dominant and dominated ones. This seems to be quite promising, providing a tool for the approximation of the biosocial position of tree with no need for assessment in forest. Applied analyses do not allow distinguishing trees belonging to II and III Kraft classes. Unless the eye-estimation-based classification is completed, principal component analysis (PCA) method provided simple, provisional solution for grouping trees from 135-year-old stand into three over-mentioned groups. Discriminant analysis gives more precise results compared with PCA. In the analysed stand, the most important traits for the evaluation of biosocial position were diameter at breast height, crown projection area and height.

Динаміка стану та структура сосняків в умовах забруднення атмосфери викидами Рівненського відкритого акціонерного товариства «Азот»

Представлено результати дослідження протягом 1993-2013 рр. стану та просторової структури сосняків в умовах аеротехногенного забруднення в Поліссі. Вивчено середньовікові сосняки, що розташовані на відстані 4,5-25 км від Рівненського ВАТ «Азоту» і складають екологічний ряд за рівнем забруднення. Встановлено, що через погіршення стану та падіння приросту зменшилися розмір та частка крон у висоті дерева і як наслідок – знизилася потужність біогоризонту фотосинтезу сосняків. За гострого пошкодження гірший стан був надпанівних та панівних дерев, а за хронічного він найгірший у нижній частині намету. Зі зростанням пошкодження дерев вирівнюються у висоті і порушується співвідношення груп класів Крафта. Зростає відсоток дерев,які мають парасолькоподібну форму крони, що є свідченням передчасного старіння дерев унаслідок дії аеротехногенного забруднення.

Long-term effects of liming on health and growth of a Masson pine stand damaged by soil acidification in Chongqing, China.

In the last decades, the Masson pine (Pinus massoniana) forests in Chongqing, southwest China, have increasingly declined. Soil acidification was believed to be an important cause. Liming is widely used as a measure to alleviate soil acidification and its damage to trees, but little is known about long-term effects of liming on the health and growth of declining Masson pine forests. Soil chemical properties, health condition (defoliation and discoloration), and growth were evaluated following application of limestone powder (0 (unlimed control), 1, 2, 3, and 4 t ha−1) in an acidified and declining Masson pine stand at Tieshanping (TSP) of Chongqing. Eight years after liming, in the 0–20 cm and 20–40 cm mineral soil layers, soil pH values, exchangeable calcium (Ca) contents, and Ca/Al molar ratios increased, but exchangeable aluminum (Al) levels decreased, and as a result, length densities of living fine roots of Masson pine increased, with increasing dose. Mean crown defoliation of Masson pines (dominant, codominant and subdominant pines, according to Kraft classes 1–3) decreased with increasing dose, and it linearly decreased with length densities of living fine roots. However, Masson pines (Kraft classes 1–3) in all treatments showed no symptoms of discoloration. Mean current-year twig length, twig dry weight, needle number per twig, needle length per twig, and needle dry weight per twig increased with increasing dose. Over 8 years, mean height increment of Masson pines (Kraft classes 1–3) increased from 5.5 m in the control to 5.8, 6.9, 8.3, and 9.5 m in the 1, 2, 3, and 4 t ha−1 lime treatments, and their mean DBH (diameter at breast height) increment increased from 3.1 to 3.2, 3.8, 4.9, and 6.2 cm, respectively. The values of all aboveground growth parameters linearly increased with length densities of living fine roots. Our results show that liming improved tree health and growth, and these effects increased with increasing dose.

Assessment of sanitary conditions in stands of Norway spruce (Picea abies Karst.) damaged by spruce bud scale (Physokermes piceae Schrnk.)

Spruce bud scale (Physokermes piceae Schrnk.) affects tree growth directly and indirectly. Direct injury appears in the form of tissue damage, as insects suck sap from tree phloem. Indirect injury appears as “honeydew”, which results in negative effects on tree growth. Plant sap is saturated with various carbohydrates called photosynthates that are difficult for scaly insects to digest. Therefore it is secreted in excrements, which are subsequently a food source for the black sooty mold (Apiosporium pinophilum Fuckel). The fungus covers needles blocking stomata, causing decreased transpiration and photosynthesis. An inexplicable wither of Norway spruce was reported in Latvia during 2010 due to black sooty mold. However, spruce bud scale was not evident. In 2011, mass propagation of spruce bud scale was observed following the 2010 Norway spruce loss. One objective of this research was to determine if Kraft tree growth classes could be applied to establish the factors responsible for tree foliage damage. Six 21 - 40 year old (second age class) Norway spruce stands were evaluated. Two circular sample plots with a 7.98 m radius, and a 200-m2 area were randomly established per each forest stand hectare. Diameter at breast height (dbh, 1.3 m), and height of approximately 30 trees was measured to model a trend. For all trees, Kraft class, and foliage damage level caused by spruce bud scale and black sooty mold were determined. Significant differences were not observed in tree damage levels among stands, however significant differences among damage levels in different Kraft classes were detected (F = 3.45 > Fcrit. = 2.80, α = 0.05 > P = 0.02) found. Overall damage intensity was 29.3 %. Total forestry loss was 1153 LVL (1640 EUR) for all surveyed stands (10 ha), and 115 LVL (164 EUR) per hectare.

Assessments of tree crown condition of two Masson pine forests in the acid rain region in south China

After two decades of monitoring forest health in Europe, in response to concern for negative effects of air pollution, a similar worry is now increasing in China. In a co-operative project between Chinese and Norwegian researchers a forest monitoring was implemented in the acid rain region in south China. During 2000–2004 two small watersheds were monitored: TieShanPing (TSP) near ChongQing City and LuChongGuan (LCG) near GuiYang City. They are covered by Masson pine ( Pinus massoniana) forest. The methodology of the European intensive forest monitoring programme (ICP-Forests level-II) was adopted; including crown assessments, foliar chemistry, air and soil chemistry, and more. This paper presents results of this co-operative project. Considerable forest damage was revealed by monitoring the crown condition of Masson pine trees. The average defoliation percentage for all assessed trees (predominant, dominant and co-dominant pines, corresponding to Kraft classes 1–3) in the more acidified TSP was over 40% and remained stable throughout the monitoring period, accompanied by an extremely high mortality in some years. In contrast, the defoliation in the less acidified LCG was relatively low but increased considerably, from 16% to around 40%, within the 4 monitoring years. The significance of air pollution for the forest damage remains uncertain. The annual SO 2 concentration in TSP and LCG is about 2 and 4 times higher than the critical level of 20 μg m −3 given in the LRTAP convention for effects on forests. Therefore the air pollution effects cannot be ruled out as contributing factors for forest damage. However, this cannot be substantiated based on the presented monitoring data since none of the specific symptoms of air pollution damage were observed. Furthermore, an analysis of the monitoring data did not reveal any significant correlation between defoliation and the soil chemical properties. It is noteworthy that the evident agents that were identified are capable of causing the observed forest damage. These agents were insect attacks and climatic stress. It is possible that the forest damage has complex causes.