scholarly journals Importance of the first thinning in young mixed Norway spruce and European beech stands

2017 ◽  
Vol 63 (No. 6) ◽  
pp. 254-262 ◽  
Author(s):  
Novák Jiří ◽  
Dušek David ◽  
Slodičák Marian ◽  
Kacálek Dušan
Keyword(s):  
Norway Spruce ◽  
Basal Area ◽  
European Beech ◽  
Static Stability ◽  
Diameter Distribution ◽  
Mixed Stands ◽  
Lower Altitude ◽  
Commercial Thinning ◽  
Dead Trees ◽  
Study Sites

Experimental results from the first thinning in mixed stands are not broadly experienced by forestry practice. To extend the experience with the thinning of a mixed stand, we studied thinned and unthinned mixtures of Norway spruce with European beech on two study sites in the Czech Republic, which represented different conditions: Všeteč (age of 19–35 years) – originally beech dominated site at 440 m a.s.l. and Deštné (age of 17–33 years) – originally spruce with beech site at 990 m a.s.l. Spruce and beech were mixed individually or in small groups. As the for number of trees, mixtures were 35–54% beech and 46–65% spruce at a lower altitude and 7–30% beech and 70–93% spruce at a higher altitude. In the period 1997–2013, we observed annually: mortality, diameter at breast height of all trees and height of trees (minimum 30 individuals) that represented diameter distribution. Results showed that the growth and development of young mixed spruce/beech stands were positively influenced by the first pre-commercial thinning on both locations. The most pronounced effect of thinning consisted in a decreased amount of basal area of dead trees. On control plots, salvage cut accounted for 34 and 46%, while on thinned plots it reached only 7–8% (thinned from above) and 18% (thinned from below) of basal area periodic increment during the 16-year study period. In contrast, diameter distribution was still relatively wide (i.e. an important amount of thin trees was left) at the end of observations on all plots of both study sites. Thinned stands also showed the better static stability (expressed as an h/d ratio) of dominant spruces compared to unthinned stands on both locations. Additionally, thinning supported the spruce share at a lower altitude and the  beech share at a higher altitude.

scholarly journals Species Mixing Regulation with Respect to Forest Ecosystem Service Provision

Forests ◽  
2018 ◽  
Vol 9 (10) ◽  
pp. 632 ◽  
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.

scholarly journals Over- and Underyielding in Time and Space in Experiments with Mixed Stands of Scots Pine and Norway Spruce

Forests ◽  
2018 ◽  
Vol 9 (8) ◽  
pp. 495 ◽  
Author(s):  
Lars Drössler ◽  
Eric Agestam ◽  
Kamil Bielak ◽  
Małgorzata Dudzinska ◽  
Julia Koricheva ◽  
...  
Keyword(s):  
Norway Spruce ◽  
Scots Pine ◽  
Tree Species ◽  
Mixed Forest ◽  
Stand Age ◽  
Mixed Species ◽  
Mixed Stands ◽  
Mixing Effect ◽  
Individual Site ◽  
Study Sites

Pine-spruce forests are one of the commonest mixed forest types in Europe and both tree species are very important for wood supply. This study summarized nine European studies with Scots pine and Norway spruce where a mixed-species stand and both monocultures were located in an experimental set-up. Overyielding (where growth of a mixed stand was greater than the average of both monocultures) was relatively common and often ranged between 0% and 30%, but could also be negative at individual study sites. Each individual site demonstrated consistent patterns of the mixing effect over different measurement periods. Transgressive overyielding (where the mixed-species stand was more productive than either of the monocultures) was found at three study sites, while a monoculture was more productive on the other sites. Large variation between study sites indicated that the existing experiments do not fully represent the extensive region where this mixed pine-spruce forest can occur. Pooled increment data displayed a negative influence of latitude and stand age on the mixing effect of those tree species in forests younger than 70 years.

A longitudinal height–diameter model for Norway spruce in Finland

2004 ◽  
Vol 34 (1) ◽  
pp. 131-140 ◽  
Author(s):  
Lauri Mehtätalo
Keyword(s):  
Norway Spruce ◽  
Mixed Model ◽  
Basal Area ◽  
Tree Height ◽  
Growth Patterns ◽  
Diameter Distribution ◽  
Stand Age ◽  
Canopy Layer ◽  
Mixed Model Approach ◽  
D Model

A height–diameter (H–D) model for Norway spruce (Picea abies (L.) Karst.) was estimated from longitudinal data. The Korf growth curve was used as the H–D curve. Firstly, H–D curves for each stand at each measurement time were fitted, and the trends in the parameters of the H–D curve were modeled. Secondly, the trends were included in the H–D model to estimate the whole model at once. To take the hierarchy of the data into account, a mixed-model approach was used. This makes it possible to calibrate the model for a new stand at a given point in time using sample tree height(s). The heights may be from different points in time and need not be from the point in time being predicted. The trends in the parameters of the H–D curve were not estimated as a function of stand age but as a function of the median diameter of basal area weighted diameter distribution (dGm). This approach was chosen because the stand ages may differ substantially among stands with similar current growth patterns. This is true especially with shade-tolerant tree species, which can regenerate and survive for several years beneath the dominant canopy layer and start rapid growth later. The growth patterns in stands with a given dGm, on the other hand, seem not to vary much. This finding indicates that the growth pattern of a stand does not depend on stand age but on mean tree size in the stand.

scholarly journals Drought Stress Reaction of Growth and Δ13C in Tree Rings of European Beech and Norway Spruce in Monospecific Versus Mixed Stands Along a Precipitation Gradient

Forests ◽  
2017 ◽  
Vol 8 (6) ◽  
pp. 177 ◽  
Author(s):  
Cynthia Schäfer ◽  
Thorsten Grams ◽  
Thomas Rötzer ◽  
Aline Feldermann ◽  
Hans Pretzsch
Keyword(s):  
Drought Stress ◽  
Norway Spruce ◽  
Tree Rings ◽  
European Beech ◽  
Stress Reaction ◽  
Precipitation Gradient ◽  
Mixed Stands

Soil respiration in pure and mixed stands of European beech and Norway spruce following removal of organic horizons

2005 ◽  
Vol 35 (11) ◽  
pp. 2756-2764 ◽  
Author(s):  
Werner Borken ◽  
Fritz Beese
Keyword(s):  
Soil Respiration ◽  
Norway Spruce ◽  
Forest Type ◽  
Mineral Soil ◽  
European Beech ◽  
Large Contribution ◽  
Mixed Stands ◽  
Organic C ◽  
C Stocks ◽  
Beech Stand

Soil respiration was measured in adjacent pure and mixed stands of European beech (Fagus sylvatica L.) and Norway spruce (Picea abies (L.) Karst.) at Solling, Germany. Forest type had a significant effect on soil respiration, which was highest in the pure beech stand and lowest in the pure spruce stand. Both throughfall and soil temperature increased with the proportion of beech. Additionally, microbial respiration and biomass in the organic (O) horizons increased sequentially from the pure spruce to the pure beech stand, suggesting that abiotic and biotic factors enhanced the decomposition of litter under beech. Because the spruce litter decomposition rate was low, carbon (C) stocks of the O horizons increased with the proportion of spruce, from 1.6 to 5.1 kg C·m–2. The removal of the O horizons decreased soil respiration by 31%–45%, indicating a large contribution of the mineral soil and roots to total soil respiration. Turnover times of organic C in the O horizons ranged between 5.5 years in the pure beech stand and 20.6 years in the pure spruce stand. Our results suggest that tree species conversion may alter the turnover of soil organic matter, and thus the sequestration of organic C in the O horizons.

scholarly journals Landscape-Scale Mixtures of Tree Species are More Effective than Stand-Scale Mixtures for Biodiversity of Vascular Plants, Bryophytes and Lichens

Forests ◽  
2019 ◽  
Vol 10 (1) ◽  
pp. 73 ◽  
Author(s):  
Steffi Heinrichs ◽  
Christian Ammer ◽  
Martina Mund ◽  
Steffen Boch ◽  
Sabine Budde ◽  
...  
Keyword(s):  
Norway Spruce ◽  
Scots Pine ◽  
Tree Species ◽  
Vascular Plants ◽  
European Beech ◽  
Landscape Scale ◽  
Gamma Diversity ◽  
Mixed Stands ◽  
Scale Mixtures ◽  
Species Mixtures

Tree species diversity can positively affect the multifunctionality of forests. This is why conifer monocultures of Scots pine and Norway spruce, widely promoted in Central Europe since the 18th and 19th century, are currently converted into mixed stands with naturally dominant European beech. Biodiversity is expected to benefit from these mixtures compared to pure conifer stands due to increased abiotic and biotic resource heterogeneity. Evidence for this assumption is, however, largely lacking. Here, we investigated the diversity of vascular plants, bryophytes and lichens at the plot (alpha diversity) and at the landscape (gamma diversity) level in pure and mixed stands of European beech and conifer species (Scots pine, Norway spruce, Douglas fir) in four regions in Germany. We aimed to identify compositions of pure and mixed stands in a hypothetical forest landscape that can optimize gamma diversity of vascular plants, bryophytes and lichens within regions. Results show that gamma diversity of the investigated groups is highest when a landscape comprises different pure stands rather than tree species mixtures at the stand scale. Species mainly associated with conifers rely on light regimes that are only provided in pure conifer forests, whereas mixtures of beech and conifers are more similar to beech stands. Combining pure beech and pure conifer stands at the landscape scale can increase landscape level biodiversity and conserve species assemblages of both stand types, while landscapes solely composed of stand scale tree species mixtures could lead to a biodiversity reduction of a combination of investigated groups of 7 up to 20%.

Do biomass removal and structure-enhancing treatments influence deadwood characteristics following commercial thinning in spruce plantations in New Brunswick, Canada?

2015 ◽  
Vol 45 (10) ◽  
pp. 1407-1418 ◽  
Author(s):  
Kwadwo Omari ◽  
David A. MacLean
Keyword(s):  
New Brunswick ◽  
Picea Glauca ◽  
Woody Debris ◽  
Basal Area ◽  
Status Quo ◽  
Commercial Thinning ◽  
Dead Trees ◽  
Biomass Removal ◽  
The Status ◽  
Intensively Managed

Effects of commercial thinning on downed coarse woody debris (CWD) and standing dead trees (snags) were examined in six intensively managed 22- to 30-year-old white spruce (Picea glauca (Moench) Voss) plantations in northern New Brunswick, Canada. Four alternative treatments were applied: (i) an unthinned control and three commercial thinning 40% basal area removals, with (ii) slash and tops remaining on the site (status quo), (iii) most of the branches and tops extracted from the site (biomass removal), and (iv) clumps of unthinned trees left, with one-half of the trees in each clump girdled to create snags (enhanced structure). Three years after thinning, CWD volume increased by 14%–27% in the status quo and enhanced structure treatments, by 6% in the biomass removal treatment, and by 0.1% in the unthinned treatment. Mean snag volume changed little, i.e., less than 1 m3·ha−1 among treatments, and stumps of thinned trees were 4.6–4.9 m3·ha−1. The girdled trees added 0.7 m3·ha−1 of snags, and 1.3 m3·ha−1 is expected to be added from girdling the remaining live trees in the unthinned clumps in 2016. The girdled trees and future to-be-girdled trees added up to 50% of the new deadwood in the enhanced structure treatments, but thinning treatments did not significantly affect total deadwood. The results indicate that commercial thinning produced fine debris but had little effect on overall deadwood amount. Girdling trees during commercial thinning, at the intensity used in this study, is unlikely to produce sufficient snags. Leaving islands and clumps during harvest before plantation establishment would be a more effective way of adding structure.

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