Effects of age and site quality on the distribution of biomass in Scots pine (

Trees ◽  
1996 ◽  
Vol 10 (4) ◽  
pp. 231 ◽  
Author(s):  
P. Vanninen ◽  
Hanna Ylitalo ◽  
Risto Sievänen ◽  
Annikki Mäkelä
Keyword(s):  
Forests ◽  
2021 ◽  
Vol 12 (10) ◽  
pp. 1336
Author(s):  
Andrzej Borkowski

The pine shoot beetles Tomicus piniperda L. and T. minor Hartwig are sympatric species that occur on Scots pine in two habitats. Feeding by the beetles in tree crowns causes significant losses in tree growth and disturbs the crown’s proper development. A review of the subject literature showed that there had been no previous studies of interspecific competition in stands with different degrees of crown damage. The aim of this work was to assess the resource partitioning of stems by the two species in stands with damaged and undamaged crowns. Data were collected in the years 1992–2008 in stands containing Scots pine located at different distances from timber yards. A total of 259 natural traps were laid, and measurements of height and diameter at breast height were made for 900 pines. The surface area of each stem was divided into 20 equal sections by making a division lengthwise (into units) and laterally (into an upper and lower part). In total, 90,501 egg galleries of pine shoot beetles were counted on 9560 stem sections. Feeding by pine shoot beetles in the crowns of pines reduces site productivity and the nutritional suitability of stems. The results of niche segregation indicate pine shoot beetles exhibited spatial specialization in the use of resources. prefers the thicker part of the stem, and T. minor the thinner part. The population of T. piniperda on the trap logs was described using a multiple linear regression model with three explanatory variables. As a result of regression modelling, from the set of variables representing characteristics of habitats, trees and trap logs and the parameters of infestation, the following explanatory variables were selected: range of colonisation of a trap log (rc), site quality class (sqc), and crown undamaged (cu). The explanatory variables included in the MLRM model explain to a significant degree (p < 0.05) the niche breadth of T. piniperda on trap logs. In all validated plots, the mean real and model values for the niche of T. piniperda on the trap logs are similar (p > 0.5), confirming the high accuracy of the developed model.


Trees ◽  
1996 ◽  
Vol 10 (4) ◽  
pp. 231-238 ◽  
Author(s):  
Petteri Vanninen ◽  
Hanna Ylitalo ◽  
Risto Sievänen ◽  
Annikki Mäkelä

Silva Fennica ◽  
2018 ◽  
Vol 52 (5) ◽  
Author(s):  
Jaakko Repola ◽  
Hannu Hökkä ◽  
Hannu Salminen

The aim of this study was to develop individual-tree diameter and height growth models for Scots pine, Norway spruce, and pubescent birch growing in drained peatlands in Finland. Trees growing in peatland sites have growth patterns that deviate from that of trees growing in mineral soil sites. Five-year growth was explained by tree diameter, different tree and stand level competition measures, management operations and site characteristics. The drainage status of the site was influencing growth directly or in interaction with other variables. Site quality had a direct impact but was also commonly related to current site drainage status (need for ditch maintenance). Recent thinning increased growth of all species and former PK fertilization increased growth of pine and birch. Temperature sum was a significant predictor in all models and altitude for spruce and birch. The data were a subsample of the 7th National Forest Inventory (NFI) sample plots representing northern and southern Finland and followed by repeated measurements for 15–20 yrs. Growth levels predicted by the models were calibrated using NFI11 data to remove bias originating from the sample of the modelling data. The mixed linear models technique was used in model estimation. The models will be incorporated into the MOTTI stand simulator to replace the current peatlands growth models.


2021 ◽  
Vol 49 (1) ◽  
pp. 20-33
Author(s):  
Besim Balić ◽  
Aida Ibrahimspahić ◽  
Ćemal Višnjić ◽  
Vahid Hadžiabdić

UDK: 630*52:519.233.5]:582.475(497.6) As the result of sporadic afforestation of not-grown forest land in the past, today in B&H we have significant areas of even-aged forest plants of Scots pine of different ages. Estimate of yield capabilities of habitats/sites of these stands is one of very real issues in even-aged management planning for this tree species. In order to get the clear idea on the value of yield of even-aged stands, it is necessary to conduct long-term researches on permanent experimental plots. Considering that for the results of those researches it is necessary to wait approximately for the duration of production periods for specific tree species, to gain orientation solutions of the problem we can apply short-term researches – using temporary experimental plots set in stands of different ages. Members of the Forest Management Department of Forestry Faculty in Sarajevo in a period from 1985 to 1990 gathered data on temporary experimental plots in existing even-aged forest plantations of spruce, Scots pine and black pine in order to research their growth, structural and production characteristics. Part of those data for Scots pine is used for making of this document. Objective of this research was, based on data on measurement of 77 experimental plots positioned in even-aged not-tended plantations of Scots pine Bosnia-wide, to reach relevant information on the value of wood volume depending on their age and site quality, and to create the most favourable regression model for assessment of volume of large wood value based on known values of the stand taxation elements that could be easily and quickly determined. Besides this, in this document by comparing gained results with appropriate data from other authors we have evaluated productivity of even-aged not-tended forest plantations of Scots pine in B&H.


2002 ◽  
Vol 22 (8) ◽  
pp. 537-552 ◽  
Author(s):  
C. Wirth ◽  
E.-D. Schulze ◽  
V. Kusznetova ◽  
I. Milyukova ◽  
G. Hardes ◽  
...  

1993 ◽  
Vol 71 (7) ◽  
pp. 1421-1428 ◽  
Author(s):  
Trond Histøl ◽  
Olav Hjeljord

We recorded forage and habitat use by radio-collared moose, Alces alces (L.), in southeastern Norway. Migrating and resident moose preferred different habitats during winter. Migrating animals used habitats of lower site quality than did resident animals. Migrating animals also used Scots pine (Pinus silvestris L.) forests more often and had a higher proportion of pine and common birch (Betula pubescens L.) in their diet than did resident animals. Increased browsing pressure from both migrating and resident animals was evident at the end of the winter from an increase in twig diameter at the point of browsing, breakage of stems, heavy browsing of common birch, and more extensive searching for forage. Rebrowsing of previously browsed trees by resident moose and, to a lesser extent, by migrants was recorded during March. Snow depths were similar on the winter ranges of resident and migrating moose.


2011 ◽  
Vol 55 (1) ◽  
pp. 46-59 ◽  
Author(s):  
Kjell Andreassen ◽  
Bernt-Håvard Øyen

Abstract Thirteen Nordic stand growth models have been validated by use of a test data set from long-term research plots in Norway. The evaluated data was from time-series of even-aged, pure stands of Norway spruce, Scots pine and birch (silver birch and downy birch). In selected models from Finland, Norway and Sweden measures of site productivity, mean tree size and various stand characteristics are represented. Different models display both strengths and weaknesses in their predicting ability. Several measures of precision and bias have been calculated and the models are ranked due to their performance. We observed site quality, stand density and average tree size as the three main components in the models. Basal area increment model for spruce from Sweden had the lowest standard deviation with 23%. The mean R2 between residuals and stand characteristics from this model was also low (1.3%), which indicates that independent variables are well included. For Scots pine and birch, Finnish volume increment models showed the best fit to the Norwegian test data, with a R2 between residuals and stand characteristics of 2.8 and 6.7%, respectively. Several of the models from Sweden and Finland predicted the growth as well as stand models frequently in use in Norway. The results indicated that similar forest conditions and traditional even-aged forest management practice in the Nordic countries could be seen as a suitable basis for developing a joint family of growth models. By careful recalibration of existing models, a reasonable accuracy could be achieved and the prediction bias could be reduced.


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