Density is the quality indicator of tree trunk wood and bark and has significant advantages over the other physical properties. Scots pine (Pinus sylvestris L.), as well as other coniferous species, belongs to a group of plants having low density. Today the information regarding the quality parameters of phytomass components is enough, but it cannot be used for studies on bioproduction of pine plantations formed in the conditions of Steppe.
The aim of the study was to calculate the Scots pine natural and basic trunk wood and bark density in the condition of Northern Steppe of Ukraine.
Materials and Methods
To investigate the quality parameters of aboveground phytomass components, temporary sample plots were laid in Scots pine stands within Northern Steppe of Ukraine. The natural and basic trunk wood and bark density were calculated using the method of data collection and processing by Lakyda (2002). The samples of wood in a bark (2–3 cm thickness) from 21 model trees on the relative stem heights 0h; 0.1h; 0.25h; 0.5h; 0.75h were collected and investigated. The average natural and basic density calculated based on local density data using the special program PLOT.
The average natural trunk wood density was 831 kg ·(m3)-1, the bark density was
661 kg ·(m3)-1. The average basic trunk wood density was 414 kg ·(m3)-1, the bark density was
317 kg ·(m3)-1. The wood density increased with the increasing tree biometric parameters such as age, diameter, and height. The basic trunk bark density had a larger variation along the trend line, compared with the basic trunk wood density.
Determination of the basic statistics of biometric indices of trees and data of the Scots pine basic trunk wood and bark density showed the prevalence of negative asymmetry and the corresponding displacement of the distribution curve to the left. The average natural wood density has direct correlation with tree diameter and height and inverse relationship with the age. Natural bark density had an inverse relationship with biometric parameters in all investigated cases. In the study of the correlation ratio of the average basic density, the direct correlation was found in almost all variants of both wood and bark components, with the exception of density and height relationship, where the correlation was inverse.
Two-factor models of the dependence of natural and basic average trunk wood density of Scots pine from tree age, diameter and height were developed using regression analysis. In the case of combining such factors as diameter and height and height and age, the obtained models of average natural wood density had low determination factors. The twice-higher determination rate is set in the model for determining the basic wood density depending on investigated biometric parameters.
The average basic trunk wood density of Scots pine increased with tree age, diameter and height. The basic bark density characterized by a declining type depending on the tree age, diameter and height. The obtained results of the estimation of Scots pine quality indices of trunk wood and bark can be used for calculation of the aboveground phytomass, carbon deposits volumes and energy potential of trees and pine stands in the conditions of the Northern Steppe of Ukraine.
2 Figs., 5 Tables, 15 Refs.