scholarly journals A methodological approach for the assessment of basic crown parameters in Scots pine stands

2021 ◽  
Vol 27 (1) ◽  
Author(s):  
Vidas Stakėnas ◽  
Iveta Varnagirytė-Kabašinskienė ◽  
Audrius Kabašinskas

Among other measurement techniques applied for the assessment of leaf area index, direct methods are still valued as the most accurate measures and often implemented as calibration tools. Even though more attention has been given to indirect measurements of tree crown properties in forest ecosystems over the last decades, the present study was designed to discuss the direct (destructive) and indirect (non-destructive) methods used for the assessment of crown measures in the stands defoliated from 20 to 90%. The stands with similar stand characteristics and representing relatively wide range of defoliation served as an appropriate target for the assessment of foliage mass variations. Overall, this study showed that the foliage mass or its surface area and defoliation at the stand level can be determined by the conventional methods used for the assessment of defoliation in forest monitoring programme as well as the PAR transmission methods. The findings showed that needle surface area decreased with the increase of tree defoliation; however, the changes of branch and stem surface areas were insignificant. Otherwise, the branch and shoot area contribute significantly to the total vegetation surface area at least in Scots pine stands. This study also strengthened the idea that the indirect measurement of vegetation area index underestimated vegetation area index at least in Scots pine stands defoliated less than 60%. The multivariate regression models were developed using tree diameter at breast height and tree crown defoliation ranges to estimate needle surface area. Keywords: Pinus sylvestris, crown defoliation, needle area index, regression model

1994 ◽  
Vol 14 (7-8-9) ◽  
pp. 981-995 ◽  
Author(s):  
P. Stenberg ◽  
S. Linder ◽  
H. Smolander ◽  
J. Flower-Ellis

2018 ◽  
Vol 64 (No. 12) ◽  
pp. 514-522
Author(s):  
Viktoriia Lovynska ◽  
Petro Lakyda ◽  
Svitlana Sytnyk ◽  
Mykola Kharytonov ◽  
Iryna Piestova

Leaf area index (LAI) of Scots pine (Pinus sylvestris Linnaeus) in the Northern Steppe of Ukraine was estimated. LAI estimated directly (LAI d, destructive sampling) was compared with LAI determined by digital hemispherical photography (indirect method, LAI id) in Scots pine stands. The studies to determine LAI were performed in pine stands of the age ranging from 57 to 87 years. The high coefficient of determination between needle weight and crown diameter as dependent variables and stand age as an independent variable was found at the tree level. LAI values of the stands estimated by the direct method were higher than those obtained by the indirect method on average by 8.8%. The results obtained by both methods were used for LAI determination from allometric relationships with tree mensuration parameters and stand biometric characteristics. There was a more significant relationship between LAI id values and tree crown diameter, basal area of stands as independent variables.


2003 ◽  
Vol 29 (3) ◽  
pp. 314-323 ◽  
Author(s):  
Miina Rautiainen ◽  
Pauline Stenberg ◽  
Tiit Nilson ◽  
Andres Kuusk ◽  
Heikki Smolander

1988 ◽  
Vol 53 ◽  
Author(s):  
C. De Schepper

The  study describes the natural regeneration state of a forest on coarse sandy  soils. The natural regeneration was studied in three different ecological  conditions: in 30 to 60 year old Scots pine stands, in a 62 year old mixed  stand of pedunculate oak and red oak, and on the free field.     The analysis of the regeneration groups revealed that the first settler  maintained a dominant social position during the following years after the  settlement. The structural basis is consequently laid out early. This means  that the forest practice has to consider the very first phase of the  regeneration as determining for the following evolution of the regeneration  groups.


1987 ◽  
Vol 52 ◽  
Author(s):  
N. Lust

In 70  years old homogeneous Scots pine stands, bordered by a hardwood belt, an  analysis was made about the spontaneous ingrowth of natural seedlings. The  analysis involved especially the following points: species and stem number,  influence of the hardwood belts, diameter and height distribution, age,  growth and structure. From the age of 30 years, a spontaneous regeneration of  hardwoods established in Scots pine stands. There are on average 7,000 plants  per ha, 80 % of which are black cherry and another fair number are red oak  and pedunculate oak. The regeneration has an average age of 25 to 30 years,  it is uneven aged, contains several diameter and height classes and has  already partially penetrated the upper stratum.     The spontaneous ingrowth allows to convert in a simple way the homogeneous  coniferous stands into mixed hardwood stands.


2013 ◽  
Vol 289 ◽  
pp. 255-268 ◽  
Author(s):  
M. van Oijen ◽  
C. Reyer ◽  
F.J. Bohn ◽  
D.R. Cameron ◽  
G. Deckmyn ◽  
...  

2018 ◽  
Vol 11 (2) ◽  
pp. 206-211 ◽  
Author(s):  
L Kenina ◽  
A Bardulis ◽  
R Matisons ◽  
R Kapostins ◽  
A Jansons

Author(s):  
Valentyna Meshkova ◽  
Ivan Bobrov

Outbreaks of bark beetles have increased in recent years in various regions. Pine engraver beetle (Ips acuminatus (Gyllenhal, 1827); Coleoptera: Curculionidae: Scolytinae) is most common in the pine forests of many European countries. Research on its biology and spread carried out in different natural conditions, phases of pest outbreak and considered various parameters to characterize the population of the pest and forest health condition. The aim of the research was to compare the health condition of Scots pine stands and population parameters of I. acuminatus in its two generations in pure and mixed stands in Polissya and Forest-steppe parts of Sumy region. Research was carried out in 2017 in the pure Scots pine stands and mixed stands with Scots pine and other forest species in Polissya (State Enterprise "Seredyno-Budsky Agroforest Economy"; State Enterprise "Seredyno-Budsky Forest Economy") and Forest-steppe parts (State Enterprise "Velykopysarivske Agroforest Economy"; State Enterprise "Okhtyrske Forest Economy") of Sumy region at 26 sample plots. In sample plots, parameters of forest health condition and bark beetle population were assessed in June and in September, after completion of development of spring and summer generation of I. acuminatus.  By most of the parameters assessed, significant differences between sample plots in Forest-Steppe and Polissya parts of Sumy region were not found. In pure Scots pine stands the mean area of bark beetles’ foci and bark beetles’ production were larger in Forest-steppe in June, and the density of Ips acuminatus nuptial chambers in June and September. In pure Scots pine stands the area of I. acuminatus focus, the number of colonized trees, the proportion of recently died trees, health condition indices, the density of egg galleries and nuptial chambers as well as young beetle’s production increased from June to September. In mixed stands the focus area, the number of colonized trees and health condition index increased insignificantly, and population parameters of I. acuminatus decreased from June to September. Pure Scots pine stands changed the health condition from "severely weakened" to "drying up" in three months, and mixed ones remained in the "weakened" category. In pure pine stands, the density of egg galleries and beetles of the young generation increased for three months from the lower limit of a moderate level to a high level, the density of nuptial chambers – from low to a high level. In mixed stands, all population parameters of I. acuminatus correspond to a low population level. The parameters characterizing the investigated foci of I. acuminatus in the Sumy region significantly correlated with the participation of pine in the stand composition, and in September the correlation is closer than in June. The data obtained indicate the feasibility of creating predominantly mixed pine stands.


Sign in / Sign up

Export Citation Format

Share Document