Influence of juvenile and mature wood on anatomical and chemical properties of early and late wood from Chinese fir plantation

The proportion of juvenile wood affects the utilization of wood seriously, and the transition year of juvenile wood (JW) and mature wood (MW) plays a decisive role in the rotation and the modification of wood. To find out the demarcation of JW and MW, the tracheid length (TL) and microfibril angle (MFA) of early wood (EW) and late wood (LW) from four Chinese fir clones were measured by optical microscopy and X-ray diffraction. Then the data were analyzed by the k-means clustering method. The correlation and the differences among wood properties between JW and MW were compared. Results indicated that the LW showed better properties than that of EW, but the anatomical differences between EW and LW did not influence the demarcation of JW and MW. The cluster analysis of TL and MFA showed that the transition year was in the 16th year and the transition zone of EW and LW was different among clones. The MW has longer and wider tracheid, thicker cell walls, and smaller MFA. In terms of chemistry, MW had a higher content of holocellulose, α-cellulose, less content of extract, but no significant difference in lignin content compared with JW. The stabilization of chemical components was earlier than that of the anatomic properties. Correlation analysis showed that there were strong correlations between the chemical composition and anatomical characteristics in JW and MW. In general, compared with chemical components, anatomical indicators were more suitable for JW and MW demarcation. The differences and correlations between JW and MW properties provide a theoretical basis for wood rotation and planting.

Formation of pine wood density depending on the parameters of annual ring and latitudinal zoning

The article presents the results of studies of changes in wood density depending on annual ring width and its characteristics. Density is a basic indicator for assessing operational and technical properties of wood. At the same time, density is characterized by certain variability within the same species, depending on annual ring characteristics, influenced by environmental factors, age of trees and position in the trunk. The purpose of this study is to establish the formation of density depending on annual ring width and late wood for Scots pine (Pinus sylvestris L.) wood in the central European part of Russia. Density research was made using the specimens with one annual ring by the method of buoyancy. Absolute values of the annual ring of early and late wood were measured in cores. It was found that wood density is only influenced by late wood width in the annual ring, being under strict genetic control. In the southern taiga zone correlation between density and late wood width is varying between 0.49-0.66 and it is less than in the forest-steppe zone. The correlation of density with annual ring width in the southern taiga zone is 0.5. It is less than in the forest-steppe zone (0.57-0.81).

INFLUENCE OF THE ENVIRONMENTAL POLLUTION ON THE DISTRIBUTION AND POLYMERIZATION DEGREE OF CELLULOSE IN BARK AND WOOD FROM SCOTS PINE (PINUS SYLVESTRIS L.) STEM

The pine stems were cut from three different polluted environments – Ist trees degradation degree (weak pollution), IInd trees degradation degree (strong pollution) and IIIrd trees degradation degree (connected with very strong pollution). On the basis of obtained results it was stated that environmental pollution caused changes in late wood participation, as well as distribution of cellulose on the stem cross- and longitudinal section. It also changed cellulose content in bark from the butt-end section, which was about 26% regardless the degradation degree. The environmental pollution caused also an increase of viscometric average polymerization degree of cellulose in heartwood in relation to heartwood adjacent sapwood and sapwood from butt-end section. Regardless the degradation degree, cellulose polymerization degree in heartwood adjacent sapwood from the middle part of the stem was higher in comparison to sapwood and heartwood. Moreover, the environmental pollution caused the increase of viscometric average polymerization degree of cellulose in bark. The polymerization degree of cellulose in bark from the butt-end section of IIIrd degradation degree stems was 22% and 23% higher in comparison to the Ist and IInd degradation degree.

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.

THE INFLUENCE OF MOTOR TRANSPORT POLLUTION ON THE GROWTH OF EUROPEAN LARCH

The results of an 18-year monitoring of the growth of European larch (Larixdecidua Mill.) in the zone of influence of the Moscow Ring Road (MKAD), one of the largest highways in the European part of Russia with a load of about 9 thousand cars per hour, are presented. The studies have been carried out on three trial plots located at 15, 35 and 100 m (control) from the highway. The morphometric parameters of European larch were determined 4, 8 and 18 years after planting four-year-old seedlings. Significant inhibition of European larch growth near the MKAD was revealed by height, trunk diameter, and crown parameters. The largest negative impact of the MKAD on its growth was manifested in the first 4 years after the creation of forest crops. The area of influence of the motorway on larch stands is about 40 m. Dendrochronological analysis of larch wood has showed that the total annual growth in the control section is significantly higher than in the area near the highway. Moreover, the growth of early wood in the area near the Moscow Ring Road is on average 23% higher than in the control one, the growth of late wood in the control area exceeds the growth in the area near the Moscow Ring Road by 34%. An analysis of the radial increment of European larch wood has showed that the growth of early wood is most closely related to the total amount of rainfall in May, June and July (correlation coefficient r = 0.33), of late wood to the amount of heat in August and September (r = - 0.44)

What Is the Carbon Origin of Early-Wood?

ABSTRACTSubstantial amounts of annual radiocarbon (14C) data have recently been produced with the purpose of increasing the time resolution of 14C records used for constructing the calibration curve and for studying the occurrence of abrupt cosmic-ray events. In this study, we investigate if it is possible to resolve sub-annual scale changes in the atmospheric 14C content by measuring radiocarbon in early-wood and late-wood fractions from Danish oak. The tree-ring samples span the period 1954–1970 CE, hereby covering the peak of the bomb pulse. A least squares test comparing the atmospheric 14C content and the new sub-annual 14C record from Danish tree rings reveals that by measuring early-wood and late-wood fractions, it may be possible to resolve sub-annual variations in past atmospheric 14C levels.

Postpyrogenic Development of Young Pine Stand in Forest-Steppe

Purpose of the work is to study the response of the radial growth of pine in the young to the effects of fires. Methods. Comparative ecological methods, taxation, standard dendrochronological methods, statistical, correlation and regression analyzes were used. Results. The study was conducted in a clean, young pine stand, which was damaged by wildfire in 2011. The wildfire occurred in favorable weather conditions (the vegetation season was warm and humid), which led to mitigating the effects of fire on the plantings. It was revealed that the radial increment of damaged trees in the year of wildfire (2011) was less than the tree rings at the control by 20%. During 2012-2017 increase of the radial growth of damaged trees was revealed because about 30% of trees were drying and living trees got extra light and reveal. Radial growth of survived trees reached the level as before the wildfire. Late wood responded faster to fire damage. Conclusions. The wildfire led to the death of weakened trees, significantly speeding up the process of natural thinning of the stand. The recovery of the radial growth of surviving trees occurred in 2014. Restoration of the radial growth of trees, survivors, occurred in 2014. It is advisable to use the proportion of late wood to assess the state of plantations after a wildfire.

Anisotropy of transversal swelling of Serbian spruce wood (Picea omorika (Pancic) Purkyně)

The paper presents the results of analysis of anisotropy of transverse swelling of the Serbian spruce wood. The analysis included six trees that come from plantations and nine trees from natural stands of Serbian spruce, and a total of 3098 samples were tested. The results show a change in transversal anisotropy at the height of the tree, as well as its change in radius. The dependence of this property on the growth rings width, the participation of late wood and the density of wood was determined by regression analysis.