Pre-commercial thinning in naturally regenerated stands of European beech (Fagus sylvaticaL.): effects of thinning pattern, stand density and pruning on tree growth and stem quality

The objective of this paper was to investigate the impact of initial spacing and pre-commercial thinning (PCT) on tree growth, characteristics and stem quality in plantation-grown jack pine (Pinus banksiana Lamb.) after 58 years of growth. Four spacings including three initial spacings without PCT treatment, i.e., 1.52 × 1.52 m (5 × 5 ft), 2.13 × 2.13 m (7 × 7 ft) and 2.74 × 2.74 m (9 × 9 ft) and one initial spacing with PCT treatment (5 × 5 ft thinned to 7 × 7 ft at age 14), were chosen to analyze diameter at breast height (DBH) distribution, survival, and various tree and stem quality characteristics (e.g., DBH, total tree height, stem volume, crown size, branch, taper, sweep and wobbling). Tree mortality during the first 25 growth years was quite low for all four spacings, while after 25 years, survival for the four spacings rapidly declined. The decrease in survival for spacing 5 × 5 was the steepest, followed by spacings 7 × 7, 9 × 9 and finally the PCT-treated stand. DBH distributions for all four spacings were significantly different from each other, and five years after PCT, the 5 × 5 to 7 × 7 spacings had a similar DBH distribution to that of the constant 7 × 7 spacing. Mean DBHs differed significantly among the initial spacings. The 5 × 5 spacing produced significantly smaller trees than did the other three spacings through the years, and the 9 × 9 spacing produced significantly larger trees. PCT had positive effects on DBH growth, and yielded longer merchantable stems and better stem quality. PCT had little effect on crown development. Initial spacing significantly affected diameter growth, crown width and branch development, commercial stem length and volume, stem taper and stem deformation. Narrower spacing produced smaller but better quality stems. Spacing 7 × 7 had the worst stem quality in terms of overall sweep and wave-like transversal deformation (wobbling). A narrow initial spacing followed by a PCT treatment may provide a compromise solution for both tree growth and stem quality. Key words: Initial spacing, thinning, survival, tree growth, stem quality

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How Does Radial Growth of Water-Stressed Populations of European Beech (Fagus sylvatica L.) Trees Vary under Multiple Drought Events?

Forests ◽

10.3390/f12020129 ◽

2021 ◽

Vol 12 (2) ◽

pp. 129

Author(s):

Tamalika Chakraborty ◽

Albert Reif ◽

Andreas Matzarakis ◽

Somidh Saha

Keyword(s):

Soil Water ◽

Fagus Sylvatica ◽

Tree Growth ◽

Radial Growth ◽

Basal Area ◽

European Beech ◽

Canopy Openness ◽

Fagus Sylvatica L ◽

The Impact ◽

Neighborhood Competition

European beech (Fagus sylvatica L.) trees are becoming vulnerable to drought, with a warming climate. Existing studies disagree on how radial growth varies in European beech in response to droughts. We aimed to find the impact of multiple droughts on beech trees’ annual radial growth at their ecological drought limit created by soil water availability in the forest. Besides, we quantified the influence of competition and canopy openness on the mean basal area growth of beech trees. We carried out this study in five near-natural temperate forests in three localities of Germany and Switzerland. We quantified available soil water storage capacity (AWC) in plots laid in the transition zone from oak to beech dominated forests. The plots were classified as ‘dry’ (AWC < 60 mL) and ‘less-dry’ (AWC > 60 mL). We performed dendroecological analyses starting from 1951 in continuous and discontinuous series to study the influence of climatic drought (i.e., precipitation-potential evapotranspiration) on the radial growth of beech trees in dry and less-dry plots. We used observed values for this analysis and did not use interpolated values from interpolated historical records in this study. We selected six drought events to study the resistance, recovery, and resilience of beech trees to drought at a discontinuous level. The radial growth was significantly higher in less-dry plots than dry plots. The increase in drought had reduced tree growth. Frequent climatic drought events resulted in more significant correlations, hence, increased the dependency of tree growth on AWC. We showed that the recovery and resilience to climatic drought were higher in trees in less-dry plots than dry plots, but it was the opposite for resistance. The resistance, recovery, and resilience of the trees were heterogeneous between the events of drought. Mean growth of beech trees (basal area increment) were negatively impacted by neighborhood competition and positively influenced by canopy openness. We emphasized that beech trees growing on soil with low AWC are at higher risk of growth decline. We concluded that changes in soil water conditions even at the microsite level could influence beech trees’ growth in their drought limit under the changing climate. Along with drought, neighborhood competition and lack of light can also reduce beech trees’ growth. This study will enrich the state of knowledge about the ongoing debate on the vulnerability of beech trees to drought in Europe.

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Disentangling the Legacies of Climate and Management on Tree Growth

Ecosystems ◽

10.1007/s10021-021-00650-8 ◽

2021 ◽

Author(s):

Laura Marqués ◽

Drew M. P. Peltier ◽

J. Julio Camarero ◽

Miguel A. Zavala ◽

Jaime Madrigal-González ◽

...

Keyword(s):

Climate Change ◽

Forest Management ◽

Tree Growth ◽

European Beech ◽

Ring Formation ◽

Silver Fir ◽

Past Climate ◽

Climate Conditions ◽

Ecological Memory ◽

Historical Forest

AbstractLegacies of past climate conditions and historical management govern forest productivity and tree growth. Understanding how these processes interact and the timescales over which they influence tree growth is critical to assess forest vulnerability to climate change. Yet, few studies address this issue, likely because integrated long-term records of both growth and forest management are uncommon. We applied the stochastic antecedent modelling (SAM) framework to annual tree-ring widths from mixed forests to recover the ecological memory of tree growth. We quantified the effects of antecedent temperature and precipitation up to 4 years preceding the year of ring formation and integrated management effects with records of harvesting intensity from historical forest management archives. The SAM approach uncovered important time periods most influential to growth, typically the warmer and drier months or seasons, but variation among species and sites emerged. Silver fir responded primarily to past climate conditions (25–50 months prior to the year of ring formation), while European beech and Scots pine responded mostly to climate conditions during the year of ring formation and the previous year, although these responses varied among sites. Past management and climate interacted in such a way that harvesting promoted growth in young silver fir under wet and warm conditions and in old European beech under drier and cooler conditions. Our study shows that the ecological memory associated with climate legacies and historical forest management is species-specific and context-dependent, suggesting that both aspects are needed to properly evaluate forest functioning under climate change.

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Biotic and Abiotic Determinants of Soil Organic Matter Stock and Fine Root Biomass in Mountain Area Temperate Forests—Examples from Cambisols under European Beech, Norway Spruce and Silver Fir (Carpathians, Central Europe)

Forests ◽

10.3390/f12070823 ◽

2021 ◽

Vol 12 (7) ◽

pp. 823

Author(s):

Anna Zielonka ◽

Marek Drewnik ◽

Łukasz Musielok ◽

Marcin K. Dyderski ◽

Dariusz Struzik ◽

...

Keyword(s):

Organic Matter ◽

Soil Organic Matter ◽

Norway Spruce ◽

Root Biomass ◽

Fine Root ◽

Stand Density ◽

European Beech ◽

Fine Root Biomass ◽

Silver Fir ◽

Beech Forests

Forest ecosystems significantly contribute to the global organic carbon (OC) pool, exhibiting high spatial heterogeneity in this respect. Some of the components of the OC pool in a forest (woody aboveground biomass (wAGB), coarse root biomass (CRB)) can be relatively easily estimated using readily available data from land observation and forest inventories, while some of the components of the OC pool are very difficult to determine (fine root biomass (FRB) and soil organic matter (SOM) stock). The main objectives of our study were to: (1) estimate the SOM stock; (2) estimate FRB; and (3) assess the relationship between both biotic (wAGB, forest age, foliage, stand density) and abiotic factors (climatic conditions, relief, soil properties) and SOM stocks and FRB in temperate forests in the Western Carpathians consisting of European beech, Norway spruce, and silver fir (32 forest inventory plots in total). We uncovered the highest wAGB in beech forests and highest SOM stocks under beech forest. FRB was the highest under fir forest. We noted a considerable impact of stand density on SOM stocks, particularly in beech and spruce forests. FRB content was mostly impacted by stand density only in beech forests without any discernible effects on other forest characteristics. We discovered significant impacts of relief-dependent factors and SOM stocks at all the studied sites. Our biomass and carbon models informed by more detailed environmental data led to reduce the uncertainty in over- and underestimation in Cambisols under beech, spruce, and fir forests for mountain temperate forest carbon pools.

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Developing Optimal Commercial Thinning Prescriptions: A New Graphical Approach

Northern Journal of Applied Forestry ◽

10.1093/njaf/22.3.170 ◽

2005 ◽

Vol 22 (3) ◽

pp. 170-174

Author(s):

KaDonna C. Randolph ◽

Robert S. Seymour ◽

Robert G. Wagner

Keyword(s):

Net Present Value ◽

Biological Response ◽

Stand Density ◽

Annual Increment ◽

Management Objectives ◽

Commercial Thinning ◽

Stand Density Management ◽

Growth Simulator ◽

Arcview Gis ◽

Final Harvest

Abstract We describe an alternative approach to the traditional stand-density management diagrams and stocking guides for determining optimum commercial thinning prescriptions. Predictions from a stand-growth simulator are incorporated into multiple nomograms that graphically display postthinning responses of various financial and biological response variables (mean annual increment, piece size, final harvest cost, total wood cost, and net present value). A customized ArcView GIS computer interface (ThinME) displays multiple nomograms and serves as a tool for forest managers to balance a variety of competing objectives when developing commercial thinning prescriptions. ThinME provides a means to evaluate simultaneously three key questions about commercial thinning: (1) When should thinning occur? (2) How much should be removed? and (3) When should the final harvest occur, to satisfy a given set of management objectives? North. J. Appl. For. 22(3):170 –174.

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Implications of Reduced Stand Density on Tree Growth and Drought Susceptibility: A Study of Three Species under Varying Climate

Forests ◽

10.3390/f11060627 ◽

2020 ◽

Vol 11 (6) ◽

pp. 627

Author(s):

Mathias Steckel ◽

W. Keith Moser ◽

Miren del Río ◽

Hans Pretzsch

Keyword(s):

Scots Pine ◽

Tree Growth ◽

Water Availability ◽

Ponderosa Pine ◽

Stand Density ◽

Stand Age ◽

Short Term ◽

Sessile Oak ◽

Site Water ◽

Positive Effect

A higher frequency of increasingly severe droughts highlights the need for short-term measures to adapt existing forests to climate change. The maintenance of reduced stand densities has been proposed as a promising silvicultural tool for mitigating drought stress. However, the relationship between stand density and tree drought susceptibility remains poorly understood, especially across ecological gradients. Here, we analysed the effect of reduced stand density on tree growth and growth sensitivity, as well as on short-term drought responses (resistance, recovery, and resilience) of Scots pine (Pinus sylvestris L.), sessile oak (Quercus petraea (Matt.) Liebl.), and ponderosa pine (Pinus ponderosa Douglas ex C. Lawson). Tree ring series from 409 trees, growing in stands of varying stand density, were analysed at sites with different water availability. For all species, mean tree growth was significantly higher under low compared with maximum stand density. Mean tree growth sensitivity of Scots pine was significantly higher under low compared with moderate and maximum stand density, while growth sensitivity of ponderosa pine peaked under maximum stand density. Recovery and resilience of Scots pine, as well as recovery of sessile oak and ponderosa pine, decreased with increasing stand density. In contrast, resistance and resilience of ponderosa pine significantly increased with increasing stand density. Higher site water availability was associated with significantly reduced drought response indices of Scots pine and sessile oak in general, except for resistance of oak. In ponderosa pine, higher site water availability significantly lessened recovery. Higher site water availability significantly moderated the positive effect of reduced stand density on drought responses. Stand age had a significantly positive effect on the resistance of Scots pine and a negative effect on recovery of sessile oak. We discuss potential causes for the observed response patterns, derive implications for adaptive forest management, and make recommendations for further research in this field.

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Species Mixing Regulation with Respect to Forest Ecosystem Service Provision

Forests ◽

10.3390/f9100632 ◽

2018 ◽

Vol 9 (10) ◽

pp. 632 ◽

Cited By ~ 4

Author(s):

Fabian Schwaiger ◽

Werner Poschenrieder ◽

Peter Biber ◽

Hans Pretzsch

Keyword(s):

Forest Management ◽

Groundwater Recharge ◽

Ecosystem Service ◽

Service Provision ◽

Quantitative Methods ◽

Basal Area ◽

Stand Density ◽

European Beech ◽

Stand Age ◽

Mixed Stands

The control and maintenance of species composition of mixed stands is a highly relevant objective of forest management in order to provide multifunctionality and climatic resilience. In contrast to this requirement there is, however, an evident lack of quantitative methods for mixture regulation. In this context, we propose an approach for the regulation of mixture proportions that has been implemented in a forest management model. The approach considers species-specific growth characteristics and takes into account the mixing effect on stand density. We present five exemplary simulations that apply the regulation. Each simulation maintains one of five desired species compositions. In these simulations, we consider the species European beech and Norway spruce under good site conditions, thus representing the most prominent mixed stands in Central Europe. Based on this model experiment, we analyze the potential benefit of controlled mixing regulation for achieving desired levels and combinations of ecosystem service provision, in particular productivity, diversity, and groundwater recharge. We found that a constant 50% basal area share of beech (equivalent growing space share of 80% to 70% depending on stand age) provided the most balanced supply of ecosystem services. Prominently, groundwater recharge considerably decreased when beech basal area shares were held below 50%. We discuss the ecological and practical implications of the regulation approach and different mixing shares.

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Scots Pine Stem Parameters in Sites with Different Stand Densities in Lithuania

Forests ◽

10.3390/f11070716 ◽

2020 ◽

Vol 11 (7) ◽

pp. 716

Author(s):

Lina Beniušienė ◽

Benas Šilinskas ◽

Ričardas Beniušis ◽

Marius Aleinikovas ◽

Edmundas Petrauskas ◽

...

Keyword(s):

Forest Management ◽

Scots Pine ◽

Management Practices ◽

Stand Density ◽

Management Tool ◽

Stem Height ◽

Bottom Part ◽

Branch Diameter ◽

Stem Wood ◽

Stem Quality

Background and Objectives: The aim of this study was to determine the effects of different stand densities and thinning regimes on stem quality parameters, mainly branch characteristics, of Scots pine (Pinus sylvestris L.) trees. The study provides some input to the discussion about Scots pine stem quality responses to different forest management practices in relatively young stands. Materials and Methods: Total tree height, height to the lowest live and dead branch, diameter at breast height (DBH), and diameter of all branches from the whorls located up to 6 m from the ground were measured. The linear regression models to predict branch diameter, as the main parameter for the stem quality assessment, were developed based on stand density and stem parameters. Results and Conclusions: DBH, branch diameter and number of branches up to 6-m stem height were significantly higher in the stands with the lowest density. These stem parameters showed a relatively clear downward trend from the lowest to the highest stand densities. The main identified variables which significantly affected stem quality, were branch diameter and diameter of the thickest branch in the bottom part of the stem, at least up to 3-m stem height. For practical use, the best fitted model was estimated when stand density, DBH, and branch diameter up to 3-m height were included in a single equation. The developed model for branch diameter could be used as a forest management tool for managing stem-wood quality.

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Tree Growth and Wood Quality in Pure Vs. Mixed-Species Stands of European Beech and Calabrian Pine in Mediterranean Mountain Forests

Forests ◽

10.3390/f11010006 ◽

2019 ◽

Vol 11 (1) ◽

pp. 6 ◽

Cited By ~ 3

Author(s):

Diego Russo ◽

Pasquale A. Marziliano ◽

Giorgio Macrì ◽

Giuseppe Zimbalatti ◽

Roberto Tognetti ◽

...

Keyword(s):

Tree Growth ◽

Mixed Model ◽

Linear Mixed Model ◽

Wood Quality ◽

European Beech ◽

Growth Patterns ◽

Mixed Species ◽

Area Index ◽

Mixture Effect ◽

Calabrian Pine

Mixed-species forests may deliver more forest functions and services than monocultures, as being considered more resistant to disturbances than pure stands. However, information on wood quality in mixed-species vs. corresponding pure forests is poor. In this study, nine plots grouped into three triplets of pure and mixed-species stands of European beech and Calabrian pine (three dominated by European beech, three dominated by Calabrian pine, and three mixed-species plots) were analysed. We evaluated tree growth and wood quality through dendrochronological approaches and non-destructive technologies (acoustic detection), respectively, hypothesizing that the mixture might improve the fitness of each species and its wood quality. A linear mixed model was applied to test the effects of exogenous influences on the basal area index (BAI) and the dynamic modulus of elasticity (MOEd). The recruitment period (Rp) was studied to verify whether wood quality was independent from stem radial growth patterns. Results showed that the mixture effect influenced both wood quality and BAI. In the mixed-species plots, for each species, MOEd values were significantly higher than in the corresponding pure stands. The mixture effect aligned MOEd values, making wood quality uniform across the different diameter classes. In the mixed-species plots, a significant positive relationship between MOEd and Rp, but also significantly higher BAI values than in the pure plots, were found for European beech, but not for Calabrian pine. The results suggest the promotion of mixing of European beech and Calabrian pine in this harsh environment to potentially improve both tree growth and wood quality.

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