Global climate warming is widely recognised as one of the major challenges facing the modern world. To halt, or at least slow, this process, multiple lines of action have been proposed, including the concept of proforestation, which relies on the natural capacity of forests to absorb CO₂, one of the principal greenhouse gases. Proforestation involves withdrawing comparatively young forests from management in order to maximise carbon storage in forest ecosystems. Against this background, the aim of this study was to examine how the withdrawal from silvicultural treatments of a young, even−aged Scots pine Pinus sylvestris stand established by artificial regeneration affected its stand volume, productivity, structural heterogeneity, the occurrence of deadwood, and the main growth parameters and allometric traits of Scots pine trees. The study was carried out in the Kampinoski National Park (KNP), in two ca. 60−year−old stands: one withdrawn from management ca. 40 years ago, and one subjected during the same period to standard tending operations (thinnings). In each stand, four square sample plots (25 m × 25 m) were established. All living and dead trees (standing and downed) were measured. Measurements involved all trees with diameter at breast height (DBH)
7 cm and included tree species identification, total height, height to the dead and live crown base, and the vertical extent of major stem morphological zones resulting from natural branch shedding. Field data were processed by BWINPro program, which was used to calculate key stand parameters (such as density, basal area, volume) and several structural diversity indices. Differences in morphological and allometric traits of Scots pine trees between experimental variants were tested using linear mixed−effects models. The results showed that after several decades of spontaneous development, the unmanaged stand exceeded the managed stand in total tree density, the volume of living and dead trees (and thus in the amount of carbon stored), and showed slightly higher structural heterogeneity. In contrast, the tended stand exhibited more favourable parameters of the dominant species (Scots pine), including a lower slenderness ratio (h/d) and longer crowns – traits that are critical for stand stability and resistance to detrimental biotic and abiotic factors. The managed stand clearly outperformed the unmanaged stand also in respect of the amount of wood harvested during silvicultural treatments. This amount was twice as high as the current difference in the total volume between the two studied stands.

Albrich, K., Seidl, R., Rammer, W. and Thom, D. (2022). From sink to source: Changing climate and disturbance regimes could tip the 21st century carbon balance of an unmanaged mountain forest landscape. Forestry, 96(3), 1-11. https://doi.org/10.1093/ forestry/cpac022.
Barredo, J., Brailescu, C., Teller, A., Sabatini, F., Mauri, A. and Janouskova, K. (2021). Mapping and assessment of primary and old-growth forests in Europe. EUR 30661 EN, Luxembourg: Publications Office of the European Union. https://doi.org/10.2760/797591.
Barton, A. and Keeton, W. (2018). Ecology and recovery of eastern old-growth forests. Washington, DC: Island Press. https://doi.org/10.5822/978-1-61091-891-6.
Bauhus, J., Puettmann, K. and Messier, C. (2009). Silviculture for old-growth attributes. Forest Ecology and Management, 258(4), 525-537. https://doi.org/10.1016/ j.foreco.2009.01.053.
Brang, P., Küchli, C., Schwitter, R., Bugmann, H. and Ammann, P. (2016). Waldbauliche Strategien im Klimawandel. In: A.R. Pluess, S. Augustin, P. Brang, eds. Wald im Klimawandel. Grundlagen für Adaptationsstrategien. Bundesamt für Umwelt BAFU, Bern Eidg. Haupt: Forschungsanstalt WSL, 341-365.
Brichta, J., Šimůnek, V., Bilek, L., Vacek, Z., Gallo, J., Drozdowski, S., Bravo-Fernandez, J.A., Mason, B., Roig Gomez, S., Hajek, V., … and Fuchs, Z. (2024). Effects of climate change on Scots pine (Pinus sylvestris L.) growth across Europe: Decrease of tree-Ring fluctuation and amplification of climate stress. Forests, 15, 91. https://doi.org/10.3390/f15010091.
Brooks, M.E., Kristensen, K., van Benthem, K.J., Magnusson, A., Berg, C.W., Nielsen, A., Skaug, H.J., Mächler, M. and Bolker, B.M. (2017). glmmTMB balances speed and flexibility among packages for zero-inflated generalized linear mixed modeling. The R Journal, 9(2), 378-400.
Brzeziecki, B. (2002). Wskaźniki zróżnicowania struktury drzewostanu [Indices of stand structural diversity]. Sylwan, 146(4), 69-79.
Brzeziecki, B. (2017). Puszcza Białowieska jako ostoja różnorodności biologicznej [Białowieża Forest as a biodiversity hotspot]. Sylwan, 161(12), 971-981. https://doi.org/10.26202/sylwan.2017128.
Brzeziecki, B., Bielak, K., Bolibok, L., Drozdowski, S., Zajączkowski, J. and Żybura, H. (2018). Structural and compositional dynamics of strictly protected woodland communities with silvicultural implications, using Białowieża Forest as an example. Annals of Forest Science, 75(3), 75-89. https://doi.org/10.1007/s13595-018-0767-x.
Brzeziecki, B. and Rostek, K. (2021). Wyzwania dla hodowli lasu w warunkach dynamicznych zmian klimatu. Lecture presented during the scientific session on: „Sylwan – dwa wieki historii leśnego czasopisma naukowego“ and „Wyzwania dla gospodarki leśnej w warunkach globalnych zmian w środowisku” on the occasion of the 120th Congress of Delegates of the Polish Forestry Society, 08-11.09.2021. Katowice, Poland.
Burschel, P. and Huss, J. (1997). Grundriss des Waldbaus. Berlin: Parey Buchverlag.
Bush, M., Flack, D., Lewis, H., Bohnenstengel, S., … and Zhang, H. (2025). The third met office unified model-JULES regional atmosphere and land configuration, RAL3, Geoscientific Model Development, 18, 3819-3855. https://doi.org/10.5194/gmd-18-3819-2025.
Callaghan, M., Schleussner, C.F., Nath, S., Lejeune, Q., … and Minx, J. (2021). Machine-learning-based evidence and attribution mapping of 100,000 climate impact studies. Nature Climate Change, 11, 966-972. https://doi.org/10.1038/s41558-021-01168-6.
Chazdon, R., Guariguata, M., 2016. Natural regeneration as a tool for large-scale forest restoration in the tropics: Prospects and challenges. Biotropica, 48(6), 716-730. https://doi.org/10.1111/btp.12381.
Chmura, D.J., Guzicka, M. and Rożkowski, R. (2021). Accumulation of standing aboveground biomass carbon in Scots pine and Norway spruce stands affected by genetic variation. Forest Ecology and Management, 496, 119476. https://doi.org/10.1016/j.foreco.2021.119476.
Cook-Patton, S.C., Leavitt, S.M., Gibbs, D., Harris, N., … and Griscom, B. (2020). Mapping carbon accumulation potential from global natural forest regrowth. Nature, 585, 545-550. https://doi.org/10.1038/s41586-020-2686-x.
Forrester, D.I., Tachauer, I.H.H., Annighoefer, P., Barbeito, I., Pretzsch, H., Ruiz-Peinado, R., Stark, H., Vacchiano, G., Zlatanov T., Chakraborty T., Saha, S. and Sileshi, G.W. (2017). Generalized biomass and leaf area allometric equations for European tree species incorporating stand structure, tree age and climate. Forest Ecology and Management, 396, 160-175. https://doi.org/10.1016/j.foreco.2017.04.01.
Forster, P., Smith, C., Walsh, T., Lamb, W., Lamboll, R., … and Zhai, P. (2023). Indicators of global climate change 2022: Annual update of large-scale indicators of the state of the climate system and human influence. Earth System Science Data, 15(6). https://doi.org/10.5194/essd-15-2295-2023.
Garbuliński, G. (2022). Charakterystyka morfologiczna i allometryczna drzew w pielęgnowanych i niepielęgnowanych drzewostanach sosnowych Kampinoskiego Parku Narodowego [Morphological and allometric characteristic of trees in thinned and unthinned Scots pine stands in Kampinos National Park]. Master’s Thesis. Warsaw: Manuscript in KHL SGGW.
Grassi, G., Fiorese, G., Pilli, R., Jonsson, K., Blujdea, V., Korosuo, A. and Vizzarri, M. (2021). Brief on the role of the forest-based bioeconomy in mitigating climate change through carbon storage and material substitution. European Commission’s Knowledge Centre for Bioeconomy.
Hartig, F. (2022). DHARMa: Residual diagnostics for hierarchical (multi-level / mixed) regression models. R package version 0.4.6. Available from: https://CRAN.R-project.org/package=DHARMa.
IPCC (2018). Global Warming of 1.5°C. An IPCC Special Report on the impacts of global warming of 1.5°C above pre-industrial levels and related global greenhouse gas emission pathways, in the context of strengthening the global response to the threat of climate change, sustainable development, and efforts to eradicate poverty. Intergovernmental Panel on Climate Change. Available from: https://www.ipcc.ch/sr15/ [accessed: 01.02.2026].
Jagodziński, A. (2011). Wyniki – retencja węgla w biomasie drzew i drzewostanów. In: Raport końcowy z realizacji tematu badawczego: Bilans węgla w biomasie drzew głównych gatunków lasotwórczych Polski. Kórnik, Poland.
Jagodziński, A.M., Dyderski, M.K., Gęsikiewicz, K. and Horodecki, P. (2019). Effects of stand features on aboveground biomass and biomass conversion and expansion factors based on a Pinus sylvestris L. chronosequence in Western Poland. European Journal of Forest Research, 138(4), 673-683. https://doi.org/10.1007/s10342-019-01197-z.
Jörgensen, K., Granath, G., Lindahl, B.D. and Strengbom, J. (2021). Forest management to increase carbon sequestration in boreal Pinus sylvestris forests. Plant and Soil, 466, 165-178. https://doi.org/10.1007/s11104-021-05038-0.
Lenth, R.V. (2024). emmeans: Estimated marginal means, aka least-squares means. R package version X.X.X. Available from: https://CRAN.R-project.org/package=emmeans.
Lewis, S., Wheeler, C., Mitchard, E. and Koch, A. (2019). Restoring natural forests is the best way to remove atmospheric carbon. Nature, 58(7750), 25-28. https://doi.org/10.1038/d41586-019-01026-8.
Luyssaert, S., Schulze, E.D., Börner, A., Knohl, A., Hessenmöller, D., Law, B., Ciais, P. and Grace, J. (2008). Old-growth forests as global carbon sinks. Nature, 455, 213-215. https://doi.org/10.1038/nature07276.
Moomaw, W., Masino, S. and Faison, E. (2019). Intact forests in the United States: Proforestation mitigates climate change and serves the greatest good. Frontiers in Forests and Global Change, 2, 27. https://doi.org/10.3389/ffgc.2019.00027.
Nagel, J. and Schmidt, M. (2006). The silvicultural decision support system BWINPro. In: H. Hasenauer, ed. Sustainable forest management. Growth models for Europe. Heidelberg, Berlin: Springer, 59-63.
R Core Team (2024). R: A language and environment for statistical computing. Vienna: R Foundation for Statistical Computing. Available from: https://www.R-project.org/.
Okła, Ł. (2022). Struktura niepielęgnowanych i pielęgnowanych drzewostanów sosnowych w Kampinoskim Parku Narodowym [Structure of unthinned and thinned pine stands in the Kampinos National Park]. Master’s Thesis. Warsaw: Manuscript in KHL SGGW.
Owadowska, E., Andrzejewska, A., Danyłow, J., Kłębowska, A., Marczak, D., Olszewski, A. and Pepłowska-Marczak, D. (2013). Kampinos Forest Biosphere Reserve. In: Biosphere reserves in Poland. Toruń: Nicolaus Copernicus University in Toruń, 144-164.
O’Brien, L., Schuck, A., Fraccaroli, C., Pötzelsberger, E., Winkel, G. and Lindner, M. (2021). Protecting old-growth forests in Europe – a review of scientific evidence to inform policy implementation. Bonn: European Forest Institute. https://doi.org/10.36333/rs1.
Robinson, N., Drever, C.R., Gibbs, D.A., Lister, K., Esquivel-Muelbert, A., … and Cook-Patton, S.C. (2025). Protect young secondary forests for optimum carbon removal. Nature Climate Change, 15, 793-800. https://doi.org/10.1038/s41588-025-02355-5.
Sabatini, F., Bluhm, H., Kun, Z., Aksenov, D., Atauri, J., … and Kuemmerle, T. (2021). European primary forest database v2.0. Nature: Scientific Data, 8, 220. https://doi.org/10.1038/s41597-021-00988-7.
Sabatini, F., Burrascano, S., Keeton, W., Levers, C., Lindner. M., … and Kuemmerle, T. (2018). Where are Europe’s last primary forests? Diversity and Distributions, 24(10), 1-14. https://doi.org/10.1111/ddi.12778.
Sabatini, F., Keeton, W., Lindner. M., Svaboda, M., Verkerk, P., … and Kuemmerle, T. (2020). Protection gaps and restoration opportunities for primary forests in Europe. Biodiversity Research, 26(12), 1646-1662. https://doi.org/10.1111/ddi.13158.
Schulze, E.D., Sierra, C., Egenolf, V., …. and Spellmann, H. (2020). The climate change mitigation effect of bioenergy from sustainably managed forests in Central Europe. GCB Bioenergy, 12, 186-197. https://doi.org/10.1111/gcbb.12672.
Stępień, E. and Jańczuk, P. (2002). Koncepcja oceny stabilności drzewostanów na przykładzie wybranego obiektu leśnego. Acta Scientiarum Polonorum. Silvarum Colendarum Ratio et Industria Lignaria, 1(1), 87-100.
Szmyt, J. (2019). Ocena dynamiki struktury drzewostanów sosnowych (Pinus sylvestris L.) objętych różnym postępowa-niem hodowlanym [Quantification of the dynamics of structure of Scots pine (Pinus sylvestris L.) stands under different silvicultural regimes]. Poznań: Wydawnictwo Uniwersytetu Przyrodniczego w Poznaniu.
Szymkiewicz, B. (1971). Tablice zasobności i przyrostu drzewostanów ważniejszych gatunków drzew leśnych, zestawione na podstawie tablic niemieckich, radzieckich i polskich. Warszawa: PWRiL.
UNFCCC. (2015). Report of the Conference of the Parties on its twenty-first session held in Paris from 30 November to 13 December 2015. United Nations Framework Convention for Climate Change. Available from: https://unfccc.int/process-and-meetings/conferences/past-conferences/paris-climate-change-conference-november-2015/cop-21/cop-21-reports [accessed: 01.02.2026].
Urban, J., Čermák, J. and Ceulemans, R. (2015). Above- and below-ground biomass, surface and volume, and stored water in a mature Scots pine stand. European Journal of Forest Research, 134, 61-74. https://doi.org/10.1007/s10342-014-0833-3.
Welle, T., Leinen, L., Bohr Y. E.-M.B. and Vorländer, A.K. (2020). Waldvision für die Europäische Union. Naturwald Akademie GmbH. Available from: https://naturwald-akademie.org/forschung/ projekte/waldvision-fuer-europa.
Węgiel, A. and Polowy, K. (2020). Aboveground carbon content and storage in mature Scots pine stands of different densities. Forests, 11, 240. https://doi.org/10.3390/f11020240.
Wężyk, P., Sroga, R. and Szwed, P. (2008). Precyzyjne pozycjonowanie pni drzew na kołowych powierzchniach próbnych przy użyciu urządzenia PosTex [PosTex precision positioning of tree trunks on circular inventory plots using the PosTex device]. Roczniki Geomatyki, 6(8), 109-118.
Zajączkowski, J. (1991). Odporność lasu na szkodliwe działanie wiatru i śniegu. Warszawa: Wydawnictwo Świat.
Zajączkowski, J., Brzeziecki, B., Perzanowski, K. and Kozak, I. (2013). Wpływ potencjalnych zmian klimatycznych na zdolność konkurencyjną głównych gatunków drzew w Polsce [Impact of potential climate changes on competitive ability of main forest tree species in Poland]. Sylwan, 157(4), 253-261. https://doi.org/10.26202/sylwan.2012134.