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 ◽  
...  

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.

Forests ◽  
2019 ◽  
Vol 10 (1) ◽  
pp. 73 ◽  
Author(s):  
Steffi Heinrichs ◽  
Christian Ammer ◽  
Martina Mund ◽  
Steffen Boch ◽  
Sabine Budde ◽  
...  

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%.


Silva Fennica ◽  
2018 ◽  
Vol 52 (4) ◽  
Author(s):  
Hardo Becker ◽  
Jürgen Aosaar ◽  
Mats Varik ◽  
Gunnar Morozov ◽  
Kristiina Aun ◽  
...  

The main aim of the current study was to estimate the annual net nitrogen mineralization (NNM) flux in stands of different tree species growing on drained peatlands, as well as to clarify the effect of tree species, soil properties and litter on annual NNM dynamics. Three study sites were set up in May 2014: a downy birch ( Ehrh.) stand and a Norway spruce ( (L.) Karst.) stand in full-drained swamp (ODS) and a Scots pine ( L.) stand in full-drained swamp (MDS). The NNM flux was estimated using the method with incubated polyethylene bags. The highest value of NNM was found in stands that were growing on fertile ODS: 127.5 kg N ha yr and 87.7 kg N ha yr, in the downy birch stand and in the Norway spruce stand, respectively. A significantly lower annual NNM flux (11.8 kg N ha yr) occurred in the Scots pine stand growing in MDS. Nitrification was highest at fertile ODS sites and ammonification was the highest at the low fertility MDS site. For all study sites, positive correlation was found between soil temperature and NNM intensity. The difference in annual NNM between the downy birch stand and the Norway spruce stand growing on similar drained fertile peatlands was due to litter quality. The annual N input into the soil through leaf litter was the highest at the downy birch site where also the C/N ratio of litter was the lowest. The second highest N input into the soil was found in the spruce stand and the lowest in the pine stand.Betula pubescensPicea abiesOxalisPinus sylvestrisMyrtillusin situ–1–1–1–1–1–1


Forests ◽  
2020 ◽  
Vol 11 (9) ◽  
pp. 901 ◽  
Author(s):  
Patricia R. Torquato ◽  
Rodney E. Will ◽  
Bo Zhang ◽  
Chris B. Zou

Eastern redcedar (Juniperus virginiana L., redcedar) encroachment is transitioning the oak-dominated Cross-Timbers of the southern Great Plain of the USA into mixed-species forests. However, it remains unknown how the re-assemblage of tree species in a semiarid to sub-humid climate affects species-specific water use and competition, and ultimately the ecosystem-level water budget. We selected three sites representative of oak, redcedar, and oak and redcedar mixed stands with a similar total basal area (BA) in a Cross-Timbers forest near Stillwater, Oklahoma. Sap flow sensors were installed in a subset of trees in each stand representing the distribution of diameter at breast height (DBH). Sap flow of each selected tree was continuously monitored over a period of 20 months, encompassing two growing seasons between May 2017 and December 2018. Results showed that the mean sap flow density (Sd) of redcedar was usually higher than post oaks (Quercus stellata Wangenh.). A structural equation model showed a significant correlation between Sd and shallow soil moisture for redcedar but not for post oak. At the stand level, the annual water use of the mixed species stand was greater than the redcedar or oak stand of similar total BA. The transition of oak-dominated Cross-Timbers to redcedar and oak mixed forest will increase stand-level transpiration, potentially reducing the water available for runoff or recharge to groundwater.


Forests ◽  
2018 ◽  
Vol 9 (9) ◽  
pp. 559 ◽  
Author(s):  
Fernando García-Robredo

The research on mixed-species forestry has rapidly increased in recent decades because there is a growing interest in these types of stands for environmental reasons. Their positive influence on ecosystem biodiversity, stability and resilience, as well as their role in the new challenge brought up by the adaptation to global change, have been the object of many research works. However, the economic implications of mixed-species forest management have not deserved the same attention. The objective of this work is to study the effect of species interactions on productivity, and to economically assess this effect. This research is focused on the analysis of financial return and risk in even aged mixed stands of Pinus sylvestris and Fagus sylvatica in Northern Spain. Growth and yield projections for monospecific and mixed stands of Scots pine and European beech were made by means of a previous model developed from a set of the Spanish National Forest Inventory plots in the region of Navarre. Data from yield tables for both species were used. The effect of species proportion on total stand yield was assessed and transgressive overyielding was found for some mixing ratios. A data series on average stumpage price for both species in Spain over a 29-year period was compiled and the joint probability distribution of price data was used to generate 500 price scenarios. Different management alternatives based on species proportion and rotation age were considered and evaluated in terms of profitability and risk. Some management recommendations can be derived from the results obtained, which point at an optimum mixing ratio from 30% to 40% Scots pine and 70% to 60% European beech.


2009 ◽  
Vol 33 (-1) ◽  
pp. 49-57 ◽  
Author(s):  
Edward Feliksik ◽  
Sławomir Wilczyński

The Effect of Climate on Tree-Ring Chronologies of Native and Nonnative Tree Species Growing Under Homogenous Site ConditionsDendroclimatic studies were carried out in the experimental stands composed of many tree species situated in the Polish part of the Baltic sea-coast. Increment cores were taken from a 100-years old trees of 2 native species: Norway spruce (Picea abies (L.) Karst.), and Scots pine (Pinus sylvestrisL.) and 3 nonnative species: Douglas fir (Pseudotsuga menziesii(Mirb.) Franco), Sitka spruce (Picea sitchensis(Bong.) Carr.) and Silver fir (Abies albaMill.). Thirty trees of each species were cored. The relationships between the diameter increment and the thermal and pluvial conditions during the period from 1925 to 2005 were analyzed on the basis of standardized tree-ring chronologies and climatic data. It was found that precipitation and temperature of the growing season and months preceding that season affected the annual diameter increment of all investigated tree species. The current year winter and early spring temperatures as well as February and August precipitation had a similar effect on the variation of diameter increment of trees. On the other hand thermal and pluvial conditions of the current year June differentiated the increment rhythm of individual species. A very strong negative effect on diameter growth of trees was observed in the case of winter and early spring frosts. Norway spruce turned out to be a species most resistant to low temperatures. The investigated tree species, especially Norway spruce, was susceptible to water deficiency in the soil during spring and summer. In the case of Scots pine a high precipitation in June stimulated its growth. The diameter increments of Douglas fir, Sitka spruce, Scots pine, and Silver fir were more strongly connected with air temperature than with precipitation. So called all-species chronology of tree-ring width, constructed during this study, permitted to verify the factors having a similar effect on growth response of the investigated tree species. It reflected the mutual characteristics of diameter increments of trees of various species.


2001 ◽  
Vol 31 (2) ◽  
pp. 292-301 ◽  
Author(s):  
B Berg ◽  
V Meentemeyer

Litter fall data was available for 64 sites in Europe, most of them in Fennoscandia. Included were 48 sites with pine (Pinus spp.), mainly Scots pine (Pinus sylvestris L.), and 16 sites with spruce (Picea spp.), mainly Norway spruce (Picea abies (L.) Karst.). Regressions were calculated for needle and total litter fall against a set of climatic parameters, and the best simple relationships were obtained with annual actual evapotranspiration (AET) and other parameters including temperature, whereas for example, precipitation gave lower r values. For needle litter fall and AET using all data, the R2adj value was 0.635 (n = 64), and for needle litter for pine and spruce separately, the R2adj were 0.576 (n = 48) and 0.775 (n = 16), respectively. AET plus stand age gave highly significant relationships for both coniferous genera combined (R2adj = 0.683), and for pine and spruce separately the corresponding values were 0.655 and 0.843, respectively. Using all available data we found highly significant relationships between needle litter fall and total litter fall. For Fennoscandia, litter fall for Scots pine and Norway spruce were compared. AET versus needle litter fall gave highly significant relationships for Scots pine (R2adj = 0.448, n = 34) and for Norway spruce (R2adj = 0.678, n = 13); the relationships were significantly different from each other.


2004 ◽  
Vol 188 (1-3) ◽  
pp. 211-224 ◽  
Author(s):  
A Lehtonen ◽  
R Mäkipää ◽  
J Heikkinen ◽  
R Sievänen ◽  
J Liski

2020 ◽  
Vol 47 (1) ◽  
pp. 1-9
Author(s):  
Milan Barna ◽  
Angel Ferezliev ◽  
Hristo Tsakov ◽  
Ivan Mihál

AbstractWe investigated the current health condition (defoliation), state of natural regeneration, and mycoflora and phytopathogen-caused attacks in Scots pine forests (Pinus sylvestris L.) planted in the 1960s in areas affected by wind disturbances in the West Rhodope Mountains in Bulgaria. Some damage types (resin outflow and anthropogenic damage) were present to a low extent in the research plots (S – Selishte and PK – Pobit Kamak). Some were missing completely (damage by deer and other animals, the presence of lignicolous fungi and abiotic damage). The most important results of this study were the following: i) the occurrence of the bark beetle pest Tomicus minor Hartig (Coleoptera, Scolytinae) was recorded on average in 4.6 (S) and 2.3 (PK) of fallen shoots under the tree crown within 1 m diameter around the stem; ii) significant damage to tree crowns due to the loss of assimilation organs in Scots pine trees (28% – S and 39% – PK, respectively) was several times higher than that recorded in Norway spruce (Picea abies L.) (10%); iii) tree species composition resulting from natural regeneration showed 95–100% proportion of Norway spruce despite the predominance of Scots pine in the maternal stand. These observations might provide evidence of unsuitable environmental conditions in the studied localities for pine forests on the southern range of the natural P. sylvestris occurrence. Forest management in similar ecological and climatic conditions should aim at significant diversification of the forest stand structure by utilizing tree species suitable for the given ecosystems.


Silva Fennica ◽  
2021 ◽  
Vol 55 (4) ◽  
Author(s):  
Felicia Dahlgren Lidman ◽  
Emma Holmström ◽  
Tomas Lundmark ◽  
Nils Fahlvik

Timber production and profitability were evaluated for spontaneously-regenerated mixtures on two formerly clearcut areas. The abandoned areas developed into birch-dominated ( Roth and Ehrh.) stands with successional ingrowth of Norway spruce ( (L.) H. Karst.). An experiment with randomized treatments within blocks was established, using three management strategies and one unthinned control, resulting in variation in optimal rotation age, merchantable volume and species composition. The management strategies were evaluated based on total production (volume) by using measured growth data 42 years after clearcutting and the modelled future stand development. The long-term effects of spontaneous regeneration and management strategies were evaluated based on land expectation value (LEV) and compared with a fifth management strategy using artificial regeneration and intense thinnings. 12 years after treatment, at a stand age of 42 years, the unthinned control had produced the highest total stem volume. At interest rates of 2% or higher, the unmanaged forest was an economically viable strategy, even compared to an intensive management strategy with a preferred merchantable timber species. Interest rates clearly impacted the profitability of the different management strategies. This study shows that when spontaneous regeneration is successful and dense, the first competition release can have a high impact on the development of future crop trees and on the species mixture.Betula pendulaBetula pubescensPicea abies


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