Priraščanje navadne smreke (Picea abies (L.) Karst.) in evropskega macesna (Larix decidua Mill.) na nekdanjih novinah v koprivni v Karavankah

Based on previous measurements from 1962 to 2017 on forest research plots located on former slash-and-burn farming areas in the cadastral municipality of Koprivna, the diameter and height increment as well as volume increments of the two main tree species - spruce and larch - were calculated. These set-aside natural research plots have a smaller mean basal area diameter, but the number of trees is higher than in comparable managed forests. Due to the high-density of tree stands over the past thirty years, radial increment of spruce and larch has declined. To determine the influence of environmental factors on radial growth of spruce and larch, a dendrochronological analysis was conducted. According to the dendrochronological analysis of radial increment of trees, the number of years with a negative response has been higher since 1984.

Growth of Vegetative Organs of Picea abies (L.) Karst. in Anthropogenic Environment

The studies were carried out in stands of various degree of devastation: in the city, suburban forests and forests of the green zone. Recreational loads strongly affect the sanitary condition of spruce forests. The number of healthy trees decreases to 30–42 % with increasing recreational digression, while the number of declining and dead trees increases to 15–36 %. The state of tree stands in the forests of the green zone is estimated at 1.2–1.5 points, and 2.1–2.7 points in the suburban forests. No declining and dead trees were found in the forests of the green zone, and in the suburban forests their share was 15 and 36 % of the total number, respectively. Therefore, generally, spruce suburban forests are classified as weakened. Approximately 59 % of the area of suburban forests is in the III stage of recreational digression, and 19 % – in the IV stage. Growth studies of P. abies showed that the features of these processes are determined mainly by the seasonal variability of climatic factors. Studies have shown that the features of growth processes of P. abies are determined mainly by seasonal variation of meteorological factors. It was found that the earliest growth of shoots and needles begins and ends in the urban environment. The year-by-year variability in the timing of these phenophases reaches 1–2 weeks. Soil compaction as a result of recreational loads has a particularly negative effect on the intensity of tree growth and annual growth of vegetative organs. Shoots of P. abies in green forests (undisturbed stands) are longer than in suburban and urban plantations by 2–30 % and 6–17%, respectively. The longest needles (16.6–19.7 mm) are formed in the forests of the green zone. In urban plantations this value is 12.8–15.0 mm. The smallest needle packing was found in the city conditions, characterized by the maximum degree of recreational digression. Here, the annual radial increment of the trunk of P. abies under the influence of recreational loads decreases by 16–20 % compared to the forests of the green zone. The sequence in the growth phenophases does not depend on the degree of environmental disturbance. The shoots are the first to grow (in May), young needles after 1 or 2 weeks, and then the formation of wood in the lower part of the trunk begins. The sequence in stopping the growth processes is as follows: shoots, needles, trunks. For citation: Kishchenko I.T., Olkhina E.S. Growth of Vegetative Organs of Picea abies (L.) Karst. in Anthropogenic Environment. Lesnoy Zhurnal [Russian Forestry Journal], 2021, no. 3, pp. 59–72. DOI: 10.37482/0536-1036-2021-3-59-72

Growth Relationships in Silver Fir Stands at Their Lower-Altitude Limit in Romania

This study presents the biometric relationships among various increments that is useful in both scientific and practical terms for the silvicultural of silver fir. The increments recorded in the biometric characteristics of trees are a faithful indicator of the effect of silvicultural work measures and of environmental conditions. Knowing these increments, and the relationships among them, can contribute to adaptations in silvicultural work on these stands with the purpose of reducing risks generated by environmental factors. We carried an inventory based on tree increment cores. The sample size was determined based on both radial increment and height increment variability of the trees. The sample trees were selected in proportion to their basal area on diameter categories. Current annual height increment (CAIh) was measured on felled trees from mean tree category. For CAIh we generated models based on the mean tree height. Percentages of the basal area increment and of form-height increment were used to compute the current annual volume increment percentage (PCAIv). For the mean tree, the CAIh estimated through the used models had a root-mean-square error (RMSE) of 0.8749 and for the current annual volume increment (CAIv) the RMSE value was 0.1295. In even-aged stands, the mean current volume increment tree is a hypothetical tree that may have the mean basal area of all the trees and the form-height of the stand. Conclusions: The diameter, height, and volume increments of trees are influenced by structural conditions and natural factors. The structures comprising several generations of fir mixed with beech and other deciduous trees, which have been obtained by the natural regeneration of local provenances, are stable and must become management targets. Stable structures are a condition for the sustainable management of stands.

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

A Novel Approach to Evaluate the Effect of Neighboring Trees and the Orientation of Tree Social Area on Stem Radial Increment of Norway Spruce Trees

Tree growth depends on many factors such as microsite conditions, vitality, and variations in climate and genetics. It is generally accepted that higher growth indicates both an economic benefit and better vitality of any tree. Here we use a modified approach of evaluating tree social area to study mutual tree competition based on the orientation and shape of trees social area. The investigation was performed in nine Norway spruce stands in the Czech Republic. The objective of this study performed from 2008 to 2012 was to quantify relative tree radial increments with respect to the lowest and highest competition found in specific sectors of tree social area (AS). Specific groups of trees (tree classes) were evaluated according to their classes (dominant, co-dominant and sub-dominant) and their composition status in ninety-degree sectors of AS using established classifying rules. The results showed that a spatially-available area (AA) is an inappropriate parameter for predicting tree growth, whereas AS provided robust explanatory power to predict relative radial growth. Tree size was observed as an important indicator of relative radial increments. A significantly positive correlation was found for a radial increment of sub-dominant trees with the lowest competition from western directions; whereas a negative correlation was observed when the lowest competition was observed from eastern directions. For dominant trees, there was an evident growth reaction only when more than 50% of the AS was oriented towards one of the cardinal points. Individual differences in the orientation of tree AS may be important parameters with regard to competition and its spatial variability within an area surrounding a particular tree and deserve more detailed attention in tree growth models and practice.

Components of the Increment Dynamics of Early and Late Wood of Quercus robur Stem in the Upland Oak Forest of the Southern Forest-Steppе

The stem radial increment contains information on the tree growth, development, and condition. The early and late wood increment has essential features. The increment dynamics contains monotonous and cyclic components. Retrospective and predictive assessments of growth and development of a tree and a stand based on the patterns of radial increment are possible. The purpose of the article is to analyze the properties of the components and their contribution to the increment dynamics of oak early and late wood, depending on the favorability of growth period and the crown development. The research object was the artificial upland oak forest of the first quality class (pure in composition). Two periods of growth were considered: 1st – favorable (1968–1996) and 2nd – unfavourable (1997–2014). We studied three groups of oak, each group of 10 trees. The groups were distinguished by the development of crown (original classification) and its dynamics. The stem cores were taken at a height of 1.3 m from the southeast side. Indicators of radial increment were defined in the images of cores scanned at 1200 dpi resolution. Three components of the dynamics were identified: a long-term trend and cyclic components with 12- and 2–5-year cycles. The variability of cyclic components of the dynamics of early wood increment was more than twice lower, than that of the late wood. The contribution of the component with 2–5-year cyclicity to the dynamics of early and late wood increment prevails during the favorable period of growth. The contribution of the component with 12-year cyclicity increases during the unfavorable period and the more, the less developed the crowns. The transition of the radial increment to a lower level occurred during the minimum of the component with 12-year cyclicity. There is no significant correlation between early and late wood increment of the component with 2–5-year cyclicity, which makes the major contribution to their ratio. The correlation between early and late wood increment of other components is closer during the unfavorable period and with a decline in crown development. The correlation between the early and late wood increment of the previous year is closer than that of the same year.