Recruitment of European beech, Norway spruce and silver fir in uneven-aged forests : optimal and critical stand, site and climatic conditions

Trifković, Vasilije (author), Bončina, Andrej (author), Ficko, Andrej (author)

Tree recruitment models are important for predicting the dynamics of uneven-aged forests. Previous studies of recruitment of European beech, Norway spruce and silver fir have shown different ecological amplitudes of these species. However, recruitment in uneven-aged stands and the values of environmental factors at which the greatest and poorest recruitment can be expected remain poorly explained. The main objectives of this study were to 1) explain how 39 stand, site and climatic factors and their interactions influence the number of recruited trees in uneven-aged forests; 2) determine the optimal and critical ranges of influential factors, including stand basal area, number of trees, proportion of tree species, shade casting, soil pH, site productivity, temperature and precipitation; and 3) estimate the maximum expected response of recruitment to changes in stand density while controlling for the effect of other limiting factors. A Tobit censored regression model was used to consider that the observed range of the number of recruited trees is censored at zero. The models were parametrized and validated using 30,963 forest inventory plots (200 m2 each) in uneven-aged forests in Slovenia. The models, which used 9 stand, 6 site and 3 climatic factors, explained 15 %, 10 % and 8 % of the total variation of the number of recruited spruce, fir and beech, respectively. Stand structure was the most important factor, with stand basal area (BA) and the proportion of the studied species having the greatest effect. Site factors including soil pH and rockiness were important for fir recruitment. The number of recruited beech and spruce was positively influenced by decadal precipitation. Higher temperatures decreased recruitment of spruce. Beech was the only species sensitive to shade casting. Recruitment of beech was higher if shade was imposed by tree species other than beech. The optimal and critical ranges of limiting factors differ between species. The model suggests that the optimal stand basal area for recruitment of beech is ≤ 19 m2/ha, which is higher than that for spruce (≤ 16 m2/ha) but lower than that for fir (≤ 28 m2/ha). The maximum predicted response of the studied species to changes in stand basal area shows that stand density control is efficient for regulating recruitment of spruce and beech, but not for fir. The suggested sensitivities and threshold values may be used in individual tree growth models or simulation–optimization studies in support of forest management decisions.

• Language: English
• Keywords: ingrowth, Fagus sylvatica, Picea abies, Abies alba, recruitment potential, Tobit model
• Work type: Article
• Typology: 1.01 - Original Scientific Article
• Organization: BF - Biotechnical Faculty
• Publication status: Published
• Publication version: Author Accepted Manuscript
• Publication date: 01.02.2023
• Year: 2023
• Number of pages: 13 str.
• Numbering: Vol. 529, art. 120679
• PID: 20.500.12556/RUL-142940
• UDC: 630*6
• ISSN on article: 1872-7042
• DOI: 10.1016/j.foreco.2022.120679
• COBISS.SI-ID: 132318979
• Publication date in RUL: 05.12.2022

Record is a part of a journal

• Title: Forest ecology and management
• Publisher: Elsevier
• ISSN: 1872-7042
• COBISS.SI-ID: 23393541

Licences

• License: CC BY-NC-ND 4.0, Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International
• Link: http://creativecommons.org/licenses/by-nc-nd/4.0/
• Description: The most restrictive Creative Commons license. This only allows people to download and share the work for no commercial gain and for no other purposes.

Secondary language

• Language: Slovenian
• Keywords: bukev, smreka, jelka

Projects

• Funder: ARRS - Slovenian Research Agency
• Project number: V4-2014-2020
• Name: Razvoj modelov za gospodarjenje z gozdovi v Sloveniji

• Funder: ARRS - Slovenian Research Agency
• Project number: P4-0059-2020
• Name: Gozd, gozdarstvo in obnovljivi gozdni viri