The age of mature Abies alba Mill. trees in the Białowieża Forest and the onset of their seed production

Aleh Marozau; Kamil Pilch; Piotr Borowik; Tomasz Oszako

doi:10.2478/ffp-2026-0012

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The age of mature Abies alba Mill. trees in the Białowieża Forest and the onset of their seed production

Folia Forestalia Polonica

Volume 68 (2026): Issue 3 (September 2026)

By: Aleh Marozau , Kamil Pilch , Piotr Borowik and Tomasz Oszako

Open Access

|Sep 2026

Figures & Tables

Location of the study population in the Białowieża Forest (modified after Sokołowski 2004)

Collecting an increment core with a Pressler borer at the tree base (photo by A. Marozau)

Table 1.

Parameters of age and growth of the new generation of A. alba

Height, at which the number of annual rings in 2020 was counted (cm)	$\frac{Period of regeneration establishment}{Age group number}$								Average number of years required for regeneration to reach a certain height
	$\frac{1990 - 1994}{1}$	$\frac{1995 - 1997}{2}$	$\frac{1998 - 2000}{3}$	$\frac{2001 - 2003}{4}$	$\frac{2004 - 2006}{5}$	$\frac{2007 - 2009}{6}$	$\frac{2010 - 2012}{7}$	$\frac{2013 - 2016}{8}$
	$\frac{average number of years required to reach height \pm standard deviation}{coefficient of variation (%)}$
5	$\frac{3.5 \pm 0.5}{14.3}$	$\frac{3 \pm 0.4}{13.3}$	$\frac{3 \pm 0.6}{20}$	$\frac{2.8 \pm 0.5}{17.8}$	$\frac{2.5 \pm 0.5}{20}$	$\frac{2.4 \pm 0.5}{20.5}$	$\frac{2.3 \pm 0.5}{21.7}$	$\frac{2 \pm 0.3}{15}$	2.7≈3
10	$\frac{6.4 \pm 0.9}{14}$	$\frac{6.2 \pm 1}{16.1}$	$\frac{6.1 \pm 1.6}{26.2}$	$\frac{5 \pm 0.8}{16}$	$\frac{5.4 \pm 1.1}{20.4}$	$\frac{4.9 \pm 0.9}{18.4}$	$\frac{4.7 \pm 0.5}{10.6}$	$\frac{4.6 \pm 0.9}{19.5}$	5.4≈5
15	$\frac{9.2 \pm 1.2}{13}$	$\frac{8.7 \pm 1.1}{12.6}$	$\frac{8.7 \pm 1.9}{21.8}$	$\frac{7.8 \pm 0.9}{11.5}$	$\frac{7.9 \pm 1}{12.6}$	$\frac{8.5 \pm 0.9}{10.6}$	$\frac{7.6 \pm 0.9}{11.8}$	-*	8.3≈8
20	$\frac{12 \pm 1.4}{11.7}$	$\frac{11 \pm 1.3}{11.8}$	$\frac{11.7 \pm 2.3}{16.2}$	$\frac{10 \pm 1.2}{12}$	$\frac{10.2 \pm 1.2}{10.8}$	$\frac{11 \pm 1.4}{12.7}$	-	-	11.0=11
25	$\frac{14.3 \pm 1.6}{11.2}$	$\frac{13.5 \pm 1.7}{12.6}$	$\frac{14.6 \pm 2.4}{15.7}$	$\frac{11.9 \pm 1.2}{10}$	$\frac{12.8 \pm 1.1}{8.6}$	-	-	-	13.4≈13
30	$\frac{16.4 \pm 2}{12.2}$	$\frac{15.8 \pm 2.5}{15.8}$	$\frac{16.5 \pm 2.5}{14.5}$	$\frac{13.6 \pm 1.3}{10}$	$\frac{14.2 \pm 0.8}{5.6}$	-	-	-	15.3≈15
35	$\frac{18.8 \pm 2.1}{11.2}$	$\frac{16.9 \pm 1.9}{11.2}$	$\frac{17.7 \pm 2.2}{14.1}$	$\frac{14.8 \pm 1.1}{7.4}$	$\frac{15 \pm 0}{0}$ **	-	-	-	16.6≈17
40	$\frac{20 \pm 2.3}{11.5}$	$\frac{18.5 \pm 2}{10.8}$	$\frac{18.2 \pm 2.1}{12}$	$\frac{15.3 \pm 0.8}{5.2}$	-	-	-	-	18.0=18
45	$\frac{21.4 \pm 2.1}{9.8}$	$\frac{19.2 \pm 2}{10.4}$	$\frac{17.6 \pm 1.5}{5}$	$\frac{16.3 \pm 0.8}{4.9}$	-	-	-	-	18.6≈19
50	$\frac{22.7 \pm 2.3}{10.1}$	$\frac{19.6 \pm 1.4}{7.1}$	$\frac{17.6 \pm 1.7}{11.9}$	$\frac{16 \pm 1}{6.2}$	-	-	-	-	19.0=19
55	$\frac{23.1 \pm 2.3}{9.9}$	$\frac{20.6 \pm 1.5}{7.3}$	$\frac{18.3 \pm 1}{8.9}$	$\frac{16.7 \pm 1.2}{7.2}$	-	-	-	-	19.7≈20
60	$\frac{24.2 \pm 2.5}{10.3}$	$\frac{21.4 \pm 1.7}{7.9}$	$\frac{19.3 \pm 1.1}{9.6}$	$\frac{16.5 \pm 0.7}{4.2}$	-	-	-	-	20.3≈20
65	$\frac{25.1 \pm 2.2}{8.8}$	$\frac{21.7 \pm 1.6}{7.4}$	$\frac{19.3 \pm 1.2}{5.6}$	$\frac{17 \pm 0}{0}$ **	-	-	-	-	20.8≈21
70	$\frac{25.3 \pm 2.5}{9.9}$	$\frac{21.5 \pm 1.3}{6}$	$\frac{20.3 \pm 1.4}{6.5}$	$\frac{17 \pm 0}{0}$ **	-	-	-	-	21.0=21
75	$\frac{24.7 \pm 1.5}{6.1}$	$\frac{22.5 \pm 1.2}{5.4}$	$\frac{20 \pm 0}{0}$ **	-	-	-	-	-	22.2≈22
80	$\frac{25.5 \pm 2.1}{8.2}$	$\frac{22 \pm 1}{4.5}$	$\frac{20 \pm 0}{0}$ **	-	-	-	-	-	22.5≈23
85	$\frac{26.5 \pm 2.1}{7.9}$	$\frac{22.7 \pm 0.6}{2.6}$	$\frac{21 \pm 0}{0}$ **	-	-	-	-		23.4≈23
90	$\frac{26.5 \pm 2.1}{7.9}$	$\frac{23 \pm 0}{0}$ **	$\frac{21 \pm 0}{0}$ **	-	-	-	-	-	23.5≈24
95	$\frac{29 \pm 0}{0}$ **	$\frac{23 \pm 0}{0}$ **	-	-	-	-	-	-	26.0=26
100	$\frac{30 \pm 0}{0}$ **	-	-	-	-	-	-	-	30

* – regeneration has not yet reached this height.

** – the age group at a given counting height is represented by one specimen.

Table 2.

The calculated real age of mature silver fir trees and their establishment years

Tree ID	Tree age at sampling height in March 2021 based on the tree ring data	Tree ring sampling height (cm)	Calculated number of years required to reach the sampling height	Calculated real tree age in 2026	Year of trees establishment
A	75	40	18	99	1927
B	81	38	18	105	1921
C	78	22	12	96	1930
D	80	16	9	95	1931
J	64	15	8	78	1948
E	79	20	11	96	1930
1	83	52	19	108	1918
2	79	17	9	94	1932
3	76	29	15	97	1929
4	73	29	15	94	1932
5	73	30	15	94	1932
6	61	33	16	83	1943
8	78	29	15	99	1927
9	85	22	12	103	1923
H	76	12	7	89	1937
G	85	14	7	98	1928
F	79	29	15	100	1926
10	84	21	11	101	1925
20	75	8	4	85	1941
11	80	33	16	102	1924
12	76	47	19	101	1925
13	78	29	15	99	1927
14	74	27	14	94	1932
15	81	12	12	99	1927
I	78	10	5	89	1937
16	80	35	17	103	1923
19	75	35	17	98	1928
17	83	20	11	100	1926
18	79	23	12	97	1929
Mean	77.5	-	12.9	96.4	1930
Standard deviation	5.34		4.17	6.57	6.57
Standard error	0.99		0.77	1.22	1.22
Coefficient of variation, %	6.9		32.3	6.8	0.3
Median	78		14.0	98	1928
Minimum	61	8	4	78	1948
Maximum	85	52	19	108	1918
Confidence intervals (confidence level 95%)	75.6-79.4	-	11.4-14.4	94.0-98.8	1928-1932

Silver fir seedlings on 24 April 2024 at the study plot (photo by A. Marozau)

(A) Example of an increment core from a mature silver fir tree (ID G, Tab. 2); (B) Silver fir site chronology (blue line), 1936–2020, derived from 29 mature trees sampled at 8–52 cm above ground level. Light gray lines represent individual series; dotted line shows sample depth. RWI = ring-width index (photo and graph by K. Pilch)

Changes in the growth dynamics of silver fir regeneration depending on the time of its appearance

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DOI: https://doi.org/10.2478/ffp-2026-0012 | Journal eISSN: 2199-5907 | Journal ISSN: 0071-6677

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Language: English

Page range: 152 - 163

Submitted on: May 29, 2026

Accepted on: Aug 1, 2026

Published on: Sep 16, 2026

Published by: Forest Research Institute

In partnership with: Paradigm Publishing Services

Keywords:

silver fir,

tree age,

dendrochronology,

natural regeneration,

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© 2026 Aleh Marozau, Kamil Pilch, Piotr Borowik, Tomasz Oszako, published by Forest Research Institute
This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 License.

Volume 68 (2026): Issue 3 (September 2026)

The age of mature Abies alba Mill. trees in the Białowieża Forest and the onset of their seed production

Figures & Tables

Figure 1.

Figure 2.

Table 1.

Table 2.

Figure 3.

Figure 4.

Figure 5.

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