Legacy effects of initial density on Scots pine (Pinus sylvestris L.) stand structure: evidence from three decades of undisturbed development

Abstract

Initial planting density and spacing are key silvicultural decisions that influence forest stand development over long-time horizons, yet their long-term effects under non-managed conditions remain insufficiently documented. This study analyses a unique long-term experiment examining the undisturbed development of artificially regenerated Scots pine (Pinus sylvestris L.) stands established under seven initial spacing variants in western Poland. Since planting in 1974, all stands have been left unmanaged, allowing natural processes such as competition and self-thinning to shape stand structure over more than three decades. Tree biometric characteristics, spatial and non-spatial structural indices, and biosocial structure were assessed at different stages of stand development. Results show that initial spacing strongly influenced tree diameter, height, crown length, mortality rates, spatial patterns, and social differentiation during early stand development. However, density-dependent self-thinning progressively reduced differences among spacing variants, leading to convergence in stand density and tree-size diversity by age 35 years. Non-spatial indices of size diversity remained generally low and were not enhanced by non-management. In contrast, spatial structure and social stability showed more persistent responses, particularly in stands established at wide, regular spacing. The findings indicate that spontaneous natural processes in even-aged Scots pine stands do not necessarily increase size diversity, highlighting that non-management alone is unlikely to generate structurally diverse stands during early stand development. Initial spacing decisions, however, can exert long-lasting effects on individual tree growth and spatial organisation, providing important guidance for adaptive silvicultural strategies under changing environmental conditions.

Keywords

Pinus sylvestris / Initial density / Stand structure / Structural indices / Forest adaptation

References

[1] Adamic M, Diaci J, Rozman A, Hladnik DLong-term use of uneven-aged silviculture in mixed mountain Dinaric forests: a comparison of old-growth and managed stands. Forestry (Oxf), 2017, 90: 279-291.

[2] Allen MG, Burkhart HEGrowth-density relationships in loblolly pine plantations. For Sci, 2018, 65(3): 250-264.

[3] Ara M, Barbeito I, Elfving B, Johansson U, Nilsson UVarying rectangular spacing yields no difference in forest growth and external wood quality in coniferous forest plantations. For Ecol Manage, 2021, 489: 119040.

[4] Ameray A, Bergeron Y, Valeria O, Girona MM, Cavard XForest carbon management: a review of silvicultural practices and management strategies across boreal, temperate and tropical forests. Curr for Reports, 2021, 7245-266.

[5] Ameztegui A, Cabon A, De Cáceres M, Coll L (2017) Managing stand density to enhance the adaptability of Scots pine stands to climate change: A modelling approach. For Ecol Manage 356:141–150. https://doi.org/10.1016/j.ecolmodel.2017.04.006

[6] Anderson S, Knapp BO, Kabrick JMStand-density effects on aboveground carbon dynamics in secondary Pinus and Quercus forests of central USA. For Sci, 2023, 69: 213-227.

[7] Baddeley A, Rubak E, Turner RSpatial point patterns. Methodology and applications with R, 2019, New York: CRC Press, p 828.

[8] Beker CDynamika naturalnego wydzielania się drzew w drzewostanach sosnowych. Sylwan, 2005, 12: 45-52

[9] Beniušiene L, Šilinskas B, Beniušis R, et al.Scots pine stem parameters in sites with different stand densities in Lithuania. Forests, 2020, 11: 716.

[10] Bottero A, D'Amato AW, Palik BJ, Dradfors JB, Fraver S, Battaglioa MA, Asherin LADensity-dependent vulnerability of forest ecosystems to drought. J. Applied Ecology, 2017, 541605-1614.

[11] Brang P, Spathelf P, Larsen JB, Bauhus J, Bončína A, Chauvin C, Drössler G-Güemes C, Heiri C, Kerr G, Lexer MJ, Mason B, Mohren F, Mühlethaler U, Nocentini S, Svoboda MSuitability of close-to-nature silviculture for adapting temperate European forests to climate change. Forestry, 2014, 87: 492-503.

[12] Brzeziecki BIndices of stand structural diversity. Sylwan, 2002, 148(4): 69-79

[13] Burkhart HE, Tomé MModeling forest trees and stands, 2012, Dordrecht: Springer, 458.

[14] Ceitel J (1982) Changes in the microclimate of the air layer near the ground and the morphology of trees with the growth of pine crops established at different initial trusses (in Polish). Dissertation, Akademia Rolnicza w Poznaniu

[15] Czachorowski MDrozdowski S (2021) Management of Scots pine (Pinus sylvestris L) stands under changing environmental and social conditions. Sylwan, 2021, 5: 371-379

[16] Damgaard C, Weiner JDescribing inequality in plant size or fecundity. Ecology, 2000, 81(4): 1139-1142.

[17] del Río M, Pretzsch H, Alberdi I, Bielak K, Bravo F, Brunner A, Condés S, Ducey MJ, Fonseca T, Lüpke NV, Pach M, Peric S, Perot T, Souidi Z, Spathelf P, Sterba H, Tijardovic M, Tomé M, Vallet P, Bravo-Oviedo ACharacterization of the structure, dynamics, and productivity of mixed-species stands: review and perspectives. Eur J for Res, 2016, 135: 23-49.

[18] del Rio M, Bravo-Oviedo A, Pretzsch H, Lof M, Ruiz-Peinado R (2017) A review of thinning effects on Scots pine stands: from growth and yield to new challenges under global change. For Syst 26(2): eR03S. https://doi.org/10.5424/fs/2017262-11325

[19] Europe FState of Europe's Forests, 2026, 2025: 228.

[20] Fahlvik N, Ekö PM, Petersson NEffects of precommercial thinning strategies on stand structure and growth in a mixed even-aged stand of Scots pine, Norway spruce and birch in southern Sweden. Silva Fenn, 2015, 49(3): 1-17.

[21] Ford EDCompetition and stand structure in some even-aged plant monocultures. J Ecol, 1975, 63(1): 311-333.

[22] Forrester DILinking forest growth withstand structure: tree size inequality, tree growth or resource partitioning and the asymmetry of competition. For Ecol Manag, 2019, 447139-157.

[23] Gadow KV, Zhang CY, Wehenkel C, Pommerening A, Corral-Rivas J, Korol M, Myklush S, Hui GY, Kiviste A, Zhao XHPukkala T, von Gadov KForest structure and diversity. Continuous cover forestry, 2012, New York: Springer, 29-85.

[24] Gil WThe influence of initial spacing on growth and survival of Scots pine in 40 years period of cultivation in varied habitat conditions. Lesn Pr Badaw, 2014, 75(2): 117-125.

[25] Harms WR, DeBell AS, Whitesell CDStand and tree characteristics and stockability in Pinus taeda plantations in Hawaii and South Carolina. Can J for Res, 1994, 24: 511-521.

[26] Helliwell DDauerwald. Forestry, 1997, 40(4): 375-380.

[27] Jandl R, Spathelf P, Bolte A, Prescott CEForest adaptation to climate change - is non-management an option?. Ann for Sci, 2019, 76: 48.

[28] Jagodziński AM, Oleksyn JEcological consequences of silviculture at variable stand densities III. Stand Growth Dev Sylwan, 2009, 5375-85

[29] Jagodziński AM, Oleksyn JEcological consequences of silviculture at variable stand densities III. Stand stability, phytoclimate and biodiversity. Sylwan, 2009, 53: 219-230

[30] Jaworski AHodowla lasu. Sposoby zagospodarowania, odnowienie lasu, przebudowa i przemiana drzewostanów, 2011, Warszawa: Powszechne Wydawnictwo Rolnicze i Leśne

[31] Jelonek T, Pazdrowski W, Tomczak A, Szaban JThe effect of social position of tree in the stand and site on wood quality of Scots pine (Pinus sylvestris L.). Electron J Pol Agric Univ, 2008, 11(2): 10.

[32] Kadavy J, Kneifl M, Federova B, Bartunek JEvaluation of transformation from even-aged to selection forest by means of Gini index. J for Sci, 2017, 63: 476-484.

[33] Kenkel NCPattern of self-thinning in jack pine: testing the random mortality hypothesis. Ecology, 1988, 641017-1024.

[34] Keren S, Svoboda M, Janda P, Nagel TARelationships between structural indices and conventional stand attributes in an old-growth forest in Southeast Europe. Forests, 2020, 11: 4.

[35] Keren S, Diaci J, Motta R, Govedar ZStand structural complexity of mixed old-growth and adjacent selection forests in the Dinaric Mountains of Bosnia and Herzegovina. For Ecol Manage, 2017, 400531-541.

[36] Keren S, Medarević M, Obradović S, Zlokapa BFive decades of structural and compositional changes in managed and unmanaged montane stands: a case study from South-East Europe. Forests, 2018, 9: 479.

[37] Kholdaenko YA, Babushkina EA, Belokopytova LV, Zhirnova DF, Koshurnikova NN, Yang B, Vaganov EA (2023) The more the merrier or the fewer the better fare? Effects of stand density on tree growth and climatic response in a scots pine plantation. Forests 14:915. https://doi.org/10.3390/f14050915

[38] Laroque GR, Marshall PLCrown development in red pine stands. I. Absolute and relative growth measures. Can J for Res, 1994, 24(4): 762-774.

[39] Lee YJ, Lenhart JDInfluence of planting density on diameter and height in east Texas pine plantations. South J Appl for, 1998, 22(4): 241-244.

[40] Lexerød NL, Eid TAn evaluation of different diameter diversity indices based on criteria related to forest management planning. For Ecol Manage, 2006, 22217-28.

[41] Liziniewicz M, Ekö PM, Agestam EEffect of spacing on 23-year-old lodgepole pine (Pinus contorta Dougl. var. latifolia) in southern Sweden. Scand J for Res, 2012, 27(4): 361-371.

[42] Malinauskas AThe influence of the initial density and site conditions on Scots pine growth and wood quality. Balt for, 1999, 5: 8-19

[43] McClain KM, Morris DM, Hills SC, Buse LSThe effects of initial spacing on growth and crown development for planted northern conifers: 37-year results. For Chron, 1994, 70: 174-182.

[44] McGown KI, O'Hara KL, Youngblood APatterns of size variation over time in ponderosa pine stands established at different initial densities. Can J for Res, 2016, 46: 101-113.

[45] Millar CI, Stephenson NL, Stephens SLClimate change and forests of the future: managing in the face of uncertainty. Ecol Appl, 2007, 17(8): 2145-2151.

[46] Murphy SJ, Wiegand T, Comita LSDistance-dependent seedling mortality and long-term spacing dynamics in a neotropical forest community. Ecol Lett, 2017, 20(11): 1469-1478.

[47] Na M, Sun X, Zhang Y, Sun Z, Rousk JHigher stand densities can promote soil carbon storage after conversion of temperate mixed natural forests to larch plantations. Eur J for Res, 2021, 140: 373-386.

[48] Novák J, Slodicak M, Kacalek D, Dušek DThe effect of different stand density on diameter growth response in Scots pine stands in relation to climate situations. J for Sci, 2010, 56(10): 461-473.

[49] Niemistö PInfluence of initial spacing and row-to-row distance on the growth and yield of silver birch (Betula pendula). Scand J for Res, 1995, 10: 245-255.

[50] Nilson K, Lundqvist LEffect of stand structure and density on development of natural regeneration in two Picea abies stands in Sweden. Scand J for Res, 2001, 16: 253-259.

[51] O’Hara KL, Ramage BSSilviculture in an uncertain world: utilizing multi-aged management systems to integrate disturbance. Forestry, 2013, 86: 401-410.

[52] O'Hara KMultiaged silviculture. Managing for complex forest stand structures, 2014, Oxford: Oxford University Press

[53] Pommerening A, Grabarnik PIndividual-based methods in forest ecology and management, 2019, Switzerland: Springer, 411.

[54] Pretzsch HForest dynamics, growth and yield, 2009, Heidelberg: Springer-Verlag, 670.

[55] Puettmann K, Coates KD, Messier CA critique of silviculture. Managing for complexity, 2009, Washington-Covelo-London: Island Press, 207.

[56] Ramage BS, Mangana IJConspecific negative density dependence in American beech. For Ecosyst, 2017, 4: 8.

[57] R Core Team (2022) R: A language and environment for statistical computing. R Foundation for Statistical Computing, Vienna, Austria. https://www.R-project.org/

[58] Salminen H, Varmola MInfluence of initial spacing and planting design on the development of young Scots pine (Pinus sylvestris L.) stands. Silva Fenn, 1993, 27(1): 21-28.

[59] Sedjo R, Sohagen BCarbon sequestration in forests and soils. Annu Rev Resour Econ, 2012, 4127-144.

[60] Sekretenko OP, Gavrikow VLCharacterization of the tree spatial distribution in small plots using pair correlation function. For Ecol Manage, 1998, 102: 113-120.

[61] Sharma M, Burkhart HE, Amateis RLSpacing rectangularity effect on the growth of loblolly pine plantations. Can J for Res, 2002, 32: 1451-1459.

[62] Singini EJ, Drew D, Dzikiti SStand density modulates drought sensitivity via physiological trait plasticity in co-occurring Eucalyptus species. For an Int J for Res, 2025

[63] Smith DM, Larson BC, Kelty MJ, Ashton PMSThe practice of silviculture. Applied forest ecology, 1997, New York: Wiley & Sons, Inc., p 560.

[64] Sobachkin RS, Sobachkin DS, Buzykin A (2005) The Influence of Stand Density on Growth of Three Conifer Species. In: Binkley, D., Menyailo, O. (eds) Tree Species Effects on Soils: Implications for Global Change. NATO Science Series IV: Earth and Environmental Sciences 55. Springer, Dordrecht. https://doi.org/10.1007/1-4020-3447-4_14

[65] Spathelf P, Ammer CForest management of Scots pine (Pinus sylvestris L.) in northern Germany-a brief review of the history and current trends. Forstarch, 2015, 86: 59-66.

[66] Spies TAForest structure: a key element of the ecosystem. Northwest Sci, 1998, 72: 34-39

[67] Steckel M, Moser WK, del Río M, Pretzsch H (2020) Implications of reduced stand density on tree growth and drought susceptibility: a study of three species under varying climate. Forests 11:627. https://doi.org/10.3390/f11060627

[68] Sun H, Diao S, Liu R, Forrester D, Soares A, Saito D, Dong R, Jiang JRelationship between size inequality and stand productivity is modified by self-thinning, age, site and planting density in Sassafras tzumu plantations in central China. For Ecol Manage, 2018, 422: 199-206.

[69] Szmyt J, Korzeniweicz RDo natural processes at the juvenile stage of stand development differentiate the spatial structure of trees in artificially established forest stands?. For Res Pap, 2014, 75: 171-179

[70] Szmyt J (2019) Ocena dynamiki struktury drzewostanów sosnowych (Pinus sylvestris L.) objętych różnym postępowaniem hodowlanym. Wydawnictwo Uniwersytetu Przyrodniczego w Poznaniu, p 326.

[71] Szmyt JHodowla lasu wobec zmian klimatycznych – wyzwania, ograniczenia, perspektywa. Sylwan, 2020, 164: 881-895

[72] Szmyt JGroup selection system as alternative management of Scots pine (Pinus sylvestris L.) forests facing climate change. Eur J for Res, 2024, 144: 133-148.

[73] Szmyt J, Zabielski M (2010) Spatial differentiation of trees of different size classes in pine (Pinus sylvestris L.) stands with different initial densities. For Res Papers 71:267–277. https://doi.org/10.2478/v10111-010-0023-0

[74] Szymański SDynamika rozwoju niekierowanych młodników sosnowych. Pr Kom Nauk Roln i Leśn, 1963, 13: 341-403

[75] Szymański S (2001) Ekologiczne podstawy hodowli lasu. Państwowe Wydawnictwo Rolnicze i Leśne, Warszawa, p 478.

[76] Thiffault N, Hoepting MK, Fra J, Lussier JM, Laroque GRManaging plantation density through initial spacing and commercial thinning: yield results from a 60-year-old red pine spacing trial experiment. Can J for Res, 2021, 51: 181-189.

[77] Tun TN, Guo J, Fang S, Tian YPlanting spacing affects canopy structure, biomass production and stem roundness in poplar plantations. Scand J for Res, 2018, 33(5): 464-474.

[78] Turrión D, Fornieles F, Bautista SClumped or regular? The role of thinning pattern on pine growth and soil water content in dense Aleppo pine post fire stand. New for, 2021

[79] Uhl E, Biber P, Ulbricht M, Heym M, Horváth T, Lakatos F, Gál J, Steinacker L, Tonon G, Ventura M, Pretzsch PAnalysing the effect of stand density and site conditions on structure and growth of oak species using Nelder trials along an environmental gradient: experimental design, evaluation methods, and results. For Ecosyst, 2015

[80] Wertz B, Bembenek M, Karaszewski Z, Ochał W, Skorupski M, Strzeliński P, Węgiel A, Mederski PSImpact of stand density and tree social status on aboveground biomass allocation of Scots pine Pinus sylvestris L.. Forests, 2020, 11(7): 765.

[81] Wikle JL, D’Amato AW, Palik BJ, Woodall ChW, Evans KS, Nagel LMStructural outcomes of climate adaptation treatments in two contrasting northern temperate forests. For Ecol Manage, 2024, 562: 121932.

[82] Yao J, Zhang X, Zhang C, Zhao X, von Gadow KEffects of density dependence in a temperate forest in northeastern China. Sci Rep, 2016, 632844.

[83] Zaide BOptimal stand density: a solution. Can J for Res, 2004, 34846-854.

[84] Zenner EK, Hibbs DEA new method for modeling the heterogeneity of forest structure. For Ecol Manage, 2000, 12975-87.

[85] Zhao D, Kane M, Borders BFGrowth responses to planting density and management intensity in loblolly pine plantations in the southeastern USA lower coastal plain. Ann for Sci, 2011, 68: 625-635.

Rights & permissions

The Author(s)