Biography

Education

  • Dr. forest. Göttingen University, Germany (2004)
  • M.Sc. Göttingen University, Germany (2002)
  • B.Sc. Göttingen University, Germany (2000)

Professional Experience

Prior to NIBIO I worked as Postdoctoral Research Associate at Oregon State University, USA (2005-2006) and Göttingen University, Germany (2007), as Lecturer at Freiburg University, Germany (2007-2013), and as Research Associate at the University of Maine, USA (2013-2020).
 
My research activities have covered the silvicultural manipulation of regeneration and growth dynamics of mixed species forests, limitations of the close-to-nature forest management paradigm in Central Europe, the ecology and silviculture of oak forests, as well as modeling the influence of forest management practices on stand dynamics and forest structure.

Selected publications

Kuehne C, Weiskittel AR, Granhus A. 2022. Examining approaches for modeling individual tree growth response to thinning in Norway spruce. For Ecosyst 9: 100060
 
Maleki K, Rasmus A, Kuehne C, McLean JP, Antón-Fernández C. 2022. Stand-level growth models for long-term projections of the main species groups in Norway. Scan J For Res 37(2): 130-143.
 
Kuehne C, McLean P, Maleki K, Antón-Fernández C, Rasmus A. 2022. A stand-level growth and yield model for thinned and unthinned even-aged Scots pine forests in Norway. Silva Fenn 56(1): 1062.
 
Annighöfer P, Mund M, Seidel D, Ammer C, Ameztegui A, Balandier P, Bebre I, Coll L, Collet C, Hamm T, Huth F, Schneider H, Kuehne C, Löf M, Petritan A, Petritan C, Schall P, Bauhus J. 2022. Examination of aboveground attributes to predict belowground biomass of young trees. For Ecol Manage 505: 119942.
 
Nosko P, Moreau K, Kuehne C, Major KC, Bauhus J. 2022. Does a shift in shade tolerance as suggested by seedling morphology explain differences in regeneration success of northern red oak in native and introduced ranges? J For Res 33(3): 949-962.
 
Kern CC, Kenefic LS, Kuehne C, Weiskittel AR, Kaschmitter SJ, D’Amato AW, Dey DC, Kabrick JM, Palik BJ, Schuler TM. 2021. Relative influence of stand and site factors on aboveground live-tree carbon sequestration and mortality in managed and unmanaged forests. For Ecol Manage 492: 119266.
 
Mäkinen H, Henttonen HM, Kohnle U, Kuehne C, Nöjd P, Yue C, Klädtke J, Siipilehto J. 2021. Site carrying capacity of Norway spruce and Scots pine stands has increased in Germany and northern Europe. For Ecol Manage 492: 119214.
 
Kohler M, Pyttel P, Kuehne C, Modrow T, Bauhus J. 2020. On the knowns and unknowns of natural regeneration of silviculturally managed sessile oak (Quercus petraea (Matt.) Liebl.) forests – a literature review. Ann For Sci 77: 101.
 
Kuehne C, Pyttel P, Modrow T, Kohnle U, Bauhus J. 2020. Seedling development and regeneration success after ten years following group selection harvesting in a sessile oak (Quercus petraea (Matt.) Liebl.) stand. Ann For Sci 77: 71.
 
Modrow T, Kuehne C, Saha S, Bauhus J, Pyttel PL. 2020. Photosynthetic performance, height growth, and dominance of naturally regenerated sessile oak (Quercus petraea [Mattuschka] Liebl.) seedlings in small-scale canopy openings of varying sizes. Eur J For Res 139: 41–52.
 
Kuehne C, Russell MB, Weiskittel AR, Kershaw Jr. JA. 2020. Comparing strategies for representing individual-tree secondary growth in mixed-species stands in the Acadian Forest region. For Ecol Manage 459: 117823.
 
Weiskittel AR, Kuehne C. 2019. Evaluating and modeling variation in site-level maximum carrying capacity of mixed-species forest stands in the Acadian Region of northeastern North America. For Chron 95(3): 171-182.
 
Kuehne C, Weiskittel AR, Legaard KR, Simons-Legaard EM. 2019. Development and comparison of various stand- and tree-level modeling approaches to predict harvest occurrence and intensity across the mixed forests in Maine, northeastern US. Scan J For Res 34(8): 739-750.
 
Puhlick JJ, Kuehne C, Kenefic LS. 2019. Crop tree growth response and quality after silvicultural rehabilitation of cutover stands. Can J For Res 49(6): 670-679.
 
Kuehne C, Weiskittel AR, Waskiewicz J. 2019. Comparing performance of contrasting distance-independent and distance-dependent competition metrics in predicting individual tree diameter increment and survival within structurally-heterogeneous, mixed-species forests of Northeastern United States. For Ecol Manage 433: 205–216.
 
Kuehne C, Puhlick J, Weiskittel A, Cutko A, Cameron D, Sferra N, Schlawin J. 2018. Metrics for comparing stand structure and dynamics between Ecological Reserves and managed forest of Maine, USA. Ecology 99: 2876.
 
Kuehne C, Weiskittel AR, Pommerening A, Wagner RG. 2018. Evaluation of 10-year temporal and spatial variability in structure and growth across contrasting commercial thinning treatments in spruce-fir forests of northern Maine, USA. Ann For Sci 75: 20.
 
Bose AK, Weiskittel AR, Kuehne C, Wagner RG, Turnblom E, Burkhart HE. 2018. Tree-level growth and survival following commercial thinning of four major softwood species in North America. For Ecol Manage 427: 355-364.
 
Bose AK Weiskittel AR, Kuehne C, Wagner RG, Turnblom E, Burkhart HE. 2018. Does commercial thinning improve stand-level growth of the three most commercially important softwood forest types of North America? For Ecol Manage 409: 683-693.
 
Drössler L, Fahlvik N,  Wysocka NK, Hjelm K, Kuehne C. 2017. Natural regeneration in a multi-layered Pinus sylvestris-Picea abies forest after target diameter harvest and soil scarification. Forests 8: 35.
 
Saha S, Kuehne C, Bauhus J. 2017. Lessons learned from oak cluster planting trials in central Europe. Can J For Res 47: 139-148.
 
Bose A, Weiskittel AR, Wagner RG, Kuehne C. 2016. Assessing the factors influencing natural regeneration patterns in the diverse, multi-cohort, and managed forests of Maine, USA. J Veg Sci 27: 1040-1050.
 
Weiskittel A, Kuehne C, McTague JP, Oppenheimer M. 2016. Development and evaluation of an individual tree growth and yield model for the mixed species forest of the Adirondacks Region of New York, USA. For Ecosyst 3: 26.
 
Kuehne C, Weiskittel AR, Wagner RG, Roth BE. 2016. Development and evaluation of individual tree- and stand-level approaches for predicting spruce-fir response to commercial thinning in Maine, USA. For Ecol Manage 376: 84-95.
 
Annighöfer P, Ameztegui A, Ammer C, Balandier P, Bartsch N, Bolte A, Coll L, Collet C, Ewald J, Frischbier N, Gebereyesus T, Haase J, Hamm T, Hirschfelder B, Huth F, Kändler G, Kahl A, Kawaletz H, Kuehne C, Lacointe A, Lin N, Löf M, Malagoli P, Marquier A, Müller S., Promberger S, Provendier D, Röhle H, Sathornkich J, Schall P, Scherer-Lorenzen M, Schröder J, Seele C, Weidig J, Wirth C, Wolf H, Wollmerstädt J, Mund M. 2016. Species-specific and generic biomass equations for seedlings and saplings of European tree species. Eur J For Res 135: 313-329.
 
Kuehne C, Karrie C, Forrester DI, Kohnle U, Bauhus J. 2015. Root system development in naturally regenerated Douglas-fir saplings as influenced by canopy closure and crowding. J For Sci 61: 406-415.
 
Kuehne C, Weiskittel AR, Fraver S, Puettman KJ. 2015. Effects of thinning induced changes in structural heterogeneity on growth, ingrowth, and mortality in secondary coastal Douglas-fir forests. Can J For Res 45: 1448-1461.
 
Kühne C, Jacob A, Gräf M. 2014. The practice of establishing and tending oak (Qercus petraea [Matt.] Liebl., Q. robur L.) stands – An interview-based study in the eastern Upper Rhine Plain, Germany. Forstarchiv 85: 179-187. In German
 
Saha S, Kuehne C, Bauhus J. 2014. Intra- and interspecific competition differently influence growth and stem quality of young oaks (Quercus robur L. and Q. petraea (Mattuschka) Liebl.). Ann For Sci 71: 381-393
 
Kuehne C, Nosko P, Horwath T, Bauhus J. 2014. A comparative study of physiological and morphological seedling traits associated with shade tolerance in introduced red oak (Quercus rubra L.) and native hardwood tree species in southwestern Germany. Tree Physiol 34: 184-193
 
Saha S, Kuehne C, Bauhus J. 2013. Tree species richness and stand productivity in low-density cluster plantings with oaks (Quercus robur and Q. petraea). Forests 4: 650-655
 
Kuehne C, Kublin E, Pyttel P, Bauhus J. 2013. Growth and form of Quercus robur and Fraxinus excelsior respond distinctly different to initial growing space: results from 24-year-old Nelder experiments. J For Res 24: 1-14
 
Major KC, Nosko P, Kuehne C, Campbell D, Bauhus J. 2013. Regeneration dynamics of non-native northern red oak (Quercus rubra L.) populations as influenced by environmental factors: a case study in managed hardwood forests of south-western Germany. For Ecol Manage 291: 144-153
 
Bauhus J, Puettmann KJ, Kühne C. 2013. Is close-to-nature forest management in Europe compatible with managing forests as complex ecosystems? In Messier C., Puettmann K., and Coates K.D. (eds.) Managing forests as complex adaptive systems. Building resilience to the challenge of global change. Routledge Abingdon, pp. 187-213
 
Briggs N, Kuehne C, Kohnle U, Bauhus J. 2012. Root system response of naturally regenerated Douglas-fir (Pseudotsuga menziesii) after complete overstory removal. Can J For Res 42: 1858-1864
 
Saha S, Kuehne C, Kohnle U, Brang P, Ehring A, Geisel J, Leder B, Muth M, Petersen R, Peter J, Ruhm W, Bauhus J. 2012. Growth and quality of young oaks (Quercus robur and Q. petraea) grown in cluster plantings in Central Europe: a weighted meta-analysis. For Ecol Manage 283: 106-118
 
Kühne C, Bauhus J, Hörnig T, Oh S. 2011. Effects of canopy closure, crowding and plant size on root system development in Douglas-fir saplings. Forstarchiv 82: 184-194. In German
 
Kuehne C, Donath C, Müller-Using SI, Bartsch N. 2008. Nutrient fluxes via leaching from coarse woody debris in a Fagus sylvatica forest in the Solling Mts., Germany. Can J For Res 38: 2405-2413
 
Kuehne C, Puettmann KJ. 2008. Natural regeneration in thinned Douglas-fir stands in western Oregon. J Sust For 27: 246-274
 
Kühne C, Bartsch N. 2007. Germination of acorns and development of oak seedlings (Quercus robur L.) following flooding. J For Sci 53: 391-399
 
Kühne C, Puettmann KJ. 2006. Large scale management experiments – new approaches to silvicultural research. Forstarchiv 77: 102-109. In German
 
Kühne C, Bartsch N, Röhrig E. 2005. Silvicultural management of floodplain forests of the Upper Rhine Valley in special consideration of Quercus robur L. Schriften aus der Forstlichen Fakultät der Universität Göttingen und der Niedersächsichen Forstlichen Versuchsanstalt 140. J.D. Sauerländer’s Verlag Frankfurt am Main. 139 p. In German
 
Kühne C, Bartsch N. 2005. Fructification and seedling development of pedunculate oak (Quercus robur) in floodplain forests of the Upper Rhine Valley. Forstarchiv 76: 16-23. In German
 
Kühne C, Bartsch N. 2004. On the natural regeneration of mixed stands of European beech (Fagus sylvatica) and Norway spruce (Picea abies) in the Solling Mts., Germany. Forst u. Holz 58: 3-7. In German
 
 

Read more

Abstract

Management of Scots pine (Pinus sylvestris L.) in Norway requires a forest growth and yield model suitable for describing stand dynamics of even-aged forests under contemporary climatic conditions with and without the effects of silvicultural thinning. A system of equations forming such a stand-level growth and yield model fitted to long-term experimental data is presented here. The growth and yield model consists of component equations for (i) dominant height, (ii) stem density (number of stems per hectare), (iii) total basal area, (iv) and total stem volume fitted simultaneously using seemingly unrelated regression. The component equations for stem density, basal area, and volume include a thinning modifier to forecast stand dynamics in thinned stands. It was shown that thinning significantly increased basal area and volume growth while reducing competition related mortality. No significant effect of thinning was found on dominant height. Model examination by means of various fit statistics indicated no obvious bias and improvement in prediction accuracy in comparison to existing models in general. An application of the developed stand-level model comparing different management scenarios exhibited plausible long-term behavior and we propose this is therefore suitable for national deployment.

To document

Abstract

Just as the aboveground tree organs represent the interface between trees and the atmosphere, roots act as the interface between trees and the soil. In this function, roots take-up water and nutrients, facilitate interactions with soil microflora, anchor trees, and also contribute to the gross primary production of forests. However, in comparison to aboveground plant organs, the biomass of roots is much more difficult to study. In this study, we analyzed 19 European datasets on above- and belowground biomass of juvenile trees of 14 species to identify generalizable estimators of root biomass based on tree sapling dimensions (e.g. height, diameter, aboveground biomass). Such estimations are essential growth and sequestration modelling. In addition, the intention was to study the effect of sapling dimension and light availability on biomass allocation to roots. All aboveground variables were significant predictors for root biomass. But, among aboveground predictors of root biomass plant height performed poorest. When comparing conifer and broadleaf species, the latter tended to have a higher root biomass at a given dimension. Also, with increasing size, the share of belowground biomass tended to increase for the sapling dimensions considered. In most species, there was a trend of increasing relative belowground biomass with increasing light availability. Finally, the height to diameter ratio (H/D) was negatively correlated to relative belowground biomass. This indicates that trees with a high H/D are not only more unstable owing to the unfavorable bending stress resistance, but also because they are comparatively less well anchored in the ground. Thus, single tree stability may be improved through increasing light availability to increase the share of belowground biomass.

To document

Abstract

Using periodic measurements from permanent plots in non-thinned and thinned Norway spruce (Picea abies (L.) H. Karst.) stands in Norway, individual-tree growth models were developed to predict annual diameter increment, height increment, and height to crown base increment. Based on long-term data across a range of thinning regimes and stand conditions, alternative approaches for modeling response to treatment were assessed. Dynamic thinning response functions in the form of multiplicative modifiers that predict no effect at the time of thinning, a rapid increase followed by an early maximum before the effect gradually declines to zero could not be fitted to initially derived baseline models without thinning related predictors. However, alternative approaches were used and found to perform well. Specifically, indicator variables representing varying time periods after thinning were statistically significant and behaved in a robust manner as well as consistent with general expectations. In addition, they improved overall prediction accuracy when incorporated as fixed effects into the baseline models for diameter and height to crown base increment. Further, more simply, including exponentially decreasing multiplicative thinning response functions improved prediction accuracy for height increment and height to crown base increment. Irrespective of studied attribute and modelling approach, improvement in performance of these extended models was relatively limited when compared to the corresponding baseline models and more pronounced in trees from thinned stands. We conclude that the largely varying and often multi-year measurement intervals of the periodic data used in this study likely prevented the development of more sophisticated thinning response functions. However, based on the evaluation of the final models’ overall performance such complex response functions may not to be necessary to reliably predict individual tree growth after thinning for certain conditions or species, which should be further considered in future analyses of similar nature.

Abstract

Stand-level growth and yield models are important tools that support forest managers and policymakers. We used recent data from the Norwegian National Forest Inventory to develop stand-level models, with components for dominant height, survival (number of survived trees), ingrowth (number of recruited trees), basal area, and total volume, that can predict long-term stand dynamics (i.e. 150 years) for the main species in Norway, namely Norway spruce (Picea abies (L.) Karst.), Scots pine (Pinus sylvestris L.), and birch (Betula pubescens Ehrh. and Betula pendula Roth). The data used represent the structurally heterogeneous forests found throughout Norway with a wide range of ages, tree size mixtures, and management intensities. This represents an important alternative to the use of dedicated and closely monitored long-term experiments established in single species even-aged forests for the purpose of building these stand-level models. Model examination by means of various fit statistics indicated that the models were unbiased, performed well within the data range and extrapolated to biologically plausible patterns. The proposed models have great potential to form the foundation for more sophisticated models, in which the influence of other factors such as natural disturbances, stand structure including species mixtures, and management practices can be included.

To document

Abstract

Across North America, forests dominated by Quercus rubra L. (northern red oak), a moderately shade-tolerant tree species, are undergoing successional replacement by shade-tolerant competitors. Under closed canopies, Q. rubra seedlings are unable to compete with these shade-tolerant species and do not recruit to upper forest strata. In Europe, natural regeneration of introduced Q. rubra is often successful despite the absence of fire, which promotes regeneration in the native range. Considering that understorey light availability is a major factor affecting recruitment of seedlings, we hypothesized that Q. rubra seedlings are more shade tolerant in the introduced range than in the native range. Morphological traits and biomass allocation patterns of seedlings indicative of shade tolerance were compared for Q. rubra and three co-occurring native species in two closed-canopy forests in the native range (Ontario, Canada) and introduced range (Baden-Württemburg, Germany). In the native range, Q. rubra allocated a greater proportion of biomass to roots, while in the introduced range, growth and allocation patterns favored the development of leaves. Q. rubra seedlings had greater annual increases in height, diameter and biomass in the introduced range. Q. rubra seedlings in the introduced range were also younger; however, they had a mean area per leaf and a total leaf area per seedling that were five times greater than seedlings in the native range. Such differences in morphological traits and allocation patterns support the hypothesis that Q. rubra expresses greater shade tolerance in the introduced range, and that natural regeneration of Q. rubra is not as limited by shade as in the native range. The ability of Q. rubra seedlings to grow faster under closed canopies in Europe may explain the discrepancy in regeneration success of this species in native and introduced ranges. Future research should confirm findings of this study over a greater geographical range in native and introduced ecosystems, and examine the genetic and environmental bases of observed differences in plant traits.

To document

Abstract

We compiled data from several independent, long-term silvicultural studies on USDA Forest Service experimental forests across a latitudinal gradient in the northeastern and north-central U.S.A. to evaluate factors influencing aboveground live-tree carbon sequestration and mortality. Data represent five sites with more than 70,000 repeated tree records spanning eight decades, five ecoregions, and a range of stand conditions. We used these data to test the relative influence of factors such as climate, treatment history (uneven-aged or no management), species composition, and stand structural conditions on aboveground live-tree carbon sequestration and mortality in repeatedly measured trees. Relative to no management, we found that uneven-aged management tended to have a positive effect on carbon sequestration at low stocking levels and in areas of favorable climate (expressed as a combination of growing season precipitation and annual growing degree days > 5 ◦C). In addition, losses of carbon from the aboveground live-tree pool due to tree mortality were lower in managed than unmanaged stands. These findings suggest that there may be conditions at which rate of sequestration in living trees is higher in stands managed with uneven-aged silviculture than in unmanaged stands, and that this benefit is greatest where climate is favorable.

To document

Abstract

The maximum size-density relationship describes site carrying capacity, i.e., the maximum number of trees of a given size that can be stocked per unit area (self-thinning line). We analysed whether the self-thinning lines of Norway spruce (Picea abies (L.) Karst.) and Scots pine (Pinus sylvestris L.) have remained unchanged over time in South Germany, Norway and Finland, i.e., over a wide climatic gradient from Central Europe up to the Arctic circle. The analyses are based on long-term growth and yield experiments measured on individual tree basis over several decades, the oldest experiments established during the early 20th century. The stochastic frontier analysis was used to analyse changes in the species-specific self-thinning lines. The results show that the self-thinning lines have shifted upwards over time in all the regions. Thus, currently stands sustain higher stand densities than in the past. The increase of the maximum density for a given average stem size was more pronounced for pine than for spruce, but similar in all studied geographical regions. In addition, increasing site index was associated with increasing site carrying capacity for spruce and pine in all regions. The results imply that environmental changes have altered site properties in similar fashion across the whole study region. In practical forestry, increased site carrying capacity will reduce mortality and loss of growing stock.

To document

Abstract

Key message This literature review identified the main factors for the success of different silvicultural approaches to regenerate sessile oak naturally and unveiled at the same time important knowledge gaps. Most previous studies were only short-term and restricted to a few factors and single locations. Hence, the findings of these studies are of limited explanatory power and do not allow to develop general, widely applicable management recommendations. Context Successful natural regeneration of sessile oak (Quercus petraea (Matt.) Liebl.) through silvicultural actions depends on a number of biotic, abiotic and management factors and their interactions. However, owing to a limited understanding about the influence of these critical factors, there is great uncertainty about suitable silvicultural approaches for natural oak regeneration, in particular regarding the size of canopy openings and speed of canopy removal. Aims This study aimed at critically evaluating documented information on natural regeneration of sessile oak. Specifically, we identified (i) the factors that determine the success of approaches for natural regeneration and (ii) evaluated the evidence base associated with different silvicultural approaches. Methods A comprehensive literature search was done considering relevant peer-reviewed publications of ISI-listed journals as well as non-ISI listed published papers and reports by practitioners. Out of more than 260 collected references, a set of 53 silvicultural ‘core publications’ was identified and analyzed using a catalogue of numeric and categorical evaluation criteria. Results The most important factors determining regeneration success extracted from the literature were light availability, presence of competing vegetation, initial oak seedling density, browsing of seedlings and intensity of stand tending measures. However, the review revealed also great uncertainty regarding the interactions between these factors and the magnitude of their influence. Most studies were of short duration and restricted to single locations. In only 20% of the experimental studies, the observation period exceeded five years. Total costs of regeneration efforts were quantified and reported in only two studies. This lack of data on the expenses of different approaches to natural oak regeneration appears to be one of the most crucial knowledge deficits revealed in this literature review. Conclusion Natural regeneration of sessile oak may be achieved under a wide range of canopy openings, if competing vegetation and browsing is negligible, seedling density is high and tending to remove competing vegetation is carried out consistently. However, since the silvicultural regeneration success depends on the interactions among these factors, which have often not been adequately considered, we caution against general recommendations for silvicultural systems developed from case studies and call for new long-term studies with comprehensive experimental designs.

To document

Abstract

Key message This study showed that regeneration success (presence of oaks ≥ 150 cm in total height) in artificial canopy openings of a mature mixed sessile oak stand was mainly driven by initial oak seedling density. Context Small-scale harvesting methods as practiced in close-to-nature forestry may disadvantage the regeneration of more light-demanding tree species including sessile oak (Quercus petraea [Mattuschka] Liebl.) and thus cause regeneration failure. However, owing to the short-term nature of many previous studies, regeneration success of sessile oak could not be properly ascertained. Aims This study examined oak seedling development over a time period of ten growing seasons in canopy openings of 0.05 to 0.2 ha in size created through group selection harvesting in a mature mixed sessile oak forest in southwestern Germany. We tried to answer the following research questions: (i) how do initial stand conditions relate to and interact with oak seedling density and seedling height growth, and (ii) what are the driving factors of regeneration success under the encountered site conditions. Methods We evaluated the influence of solar radiation, Rubus spp. cover, initial oak seedling density, and competition from other tree species on change in density and height of oak seedlings, as well as overall regeneration success (oak seedlings ≥ 150 cm in height). Results Regeneration success increased with initial oak seedling density and solar radiation levels and decreased with early Rubus spp. cover. Density and maximum height of oak seedlings was negatively related with competition of other woody species. Conclusion Results of our longer-term study demonstrate that forest management activities to regenerate sessile oak naturally are only successful in stands (i) without advance regeneration of other woody species and without established, recalcitrant ground vegetation, (ii) with a sufficiently high initial oak seedling density in larger patches following mast years, and (iii) where periodic monitoring and control of competing woody individuals can be ensured. Our findings further corroborate the view that natural regeneration of sessile oak in small-scale canopy openings is possible in principle.