scholarly journals Species Mixing Proportion and Aridity Influence in the Height–Diameter Relationship for Different Species Mixtures in Mediterranean Forests

Forests ◽  
2022 ◽  
Vol 13 (1) ◽  
pp. 119
Author(s):  
Diego Rodríguez de Prado ◽  
Jose Riofrío ◽  
Jorge Aldea ◽  
Felipe Bravo ◽  
James McDermott ◽  
...  
Keyword(s):  
Mixed Forest ◽  
Aridity Index ◽  
Tree Height ◽  
National Forest Inventory ◽  
Future Climate Change ◽  
Climate Change Scenarios ◽  
Mediterranean Forests ◽  
Forest Stands ◽  
Mixed Stands ◽  
Species Mixtures

Estimating tree height is essential for modelling and managing both pure and mixed forest stands. Although height–diameter (H–D) relationships have been traditionally fitted for pure stands, attention must be paid when analyzing this relationship behavior in stands composed of more than one species. The present context of global change makes also necessary to analyze how this relationship is influenced by climate conditions. This study tends to cope these gaps, by fitting new H–D models for 13 different Mediterranean species in mixed forest stands under different mixing proportions along an aridity gradient in Spain. Using Spanish National Forest Inventory data, a total of 14 height–diameter equations were initially fitted in order to select the best base models for each pair species-mixture. Then, the best models were expanded including species proportion by area (mi) and the De Martonne Aridity Index (M). A general trend was found for coniferous species, with taller trees for the same diameter size in pure than in mixed stands, being this trend inverse for broadleaved species. Regarding aridity influence on H–D relationships, humid conditions seem to beneficiate tree height for almost all the analyzed species and species mixtures. These results may have a relevant importance for Mediterranean coppice stands, suggesting that introducing conifers in broadleaves forests could enhance height for coppice species. However, this practice only should be carried out in places with a low probability of drought. Models presented in our study can be used to predict height both in different pure and mixed forests at different spatio-temporal scales to take better sustainable management decisions under future climate change scenarios.

scholarly journals Distribution of the timber quality attribute ‘knot surface’ in logs of Fagus sylvatica L. from pure and mixed forest stands

2021 ◽  
Author(s):  
Kirsten Höwler ◽  
Torsten Vor ◽  
Peter Schall ◽  
Peter Annighöfer ◽  
Dominik Seidel ◽  
...  
Keyword(s):  
Fagus Sylvatica ◽  
Mixed Forest ◽  
European Beech ◽  
Forest Stands ◽  
Species Identity ◽  
Mixed Stands ◽  
Mixed Forests ◽  
Climate Conditions ◽  
Timber Quality ◽  
Positive Effects

AbstractResearch on mixed forests has mostly focused on tree growth and productivity, or resistance and resilience in changing climate conditions, but only rarely on the effects of tree species mixing on timber quality. In particular, it is still unclear whether the numerous positive effects of mixed forests on productivity and stability come at the expense of timber quality. In this study, we used photographs of sawn boards from 90 European beech (Fagus sylvatica L.) trees of mixed and pure forest stands to analyze internal timber quality through the quality indicator knot surface that was quantitatively assessed using the software Datinf® Measure. We observed a decrease in knot surface with increasing distance from the pith as well as smaller values in the lower log sections. Regarding the influence of neighborhood species identity, we found only minor effects meaning that timber qualities in mixed stands of beech and Norway spruce (Picea abies (L.) H. Karst.) tended to be slightly worse compared to pure beech stands.

Competition theory — science and application in mixed forest stands: review of experimental and modelling methods and suggestions for future research

2013 ◽  
Vol 21 (2) ◽  
pp. 71-84 ◽  
Author(s):  
Guy R. Larocque ◽  
Nancy Luckai ◽  
Shailendra N. Adhikary ◽  
Arthur Groot ◽  
F. Wayne Bell ◽  
...  
Keyword(s):  
Mixed Forest ◽  
Single Species ◽  
Experimental Designs ◽  
Competitive Interactions ◽  
Future Research ◽  
Relative Importance ◽  
Forest Stands ◽  
Management Scenarios ◽  
Mixed Stands ◽  
Individual Tree

Competition in forest stands has long been of interest to researchers. However, much of the knowledge originates from empirical studies that examined the effects of competition. For instance, many studies were focused on the effects of the presence of herbaceous species on the development of tree seedlings or the decrease in individual tree growth with increases in stand density. Several models that incorporate competitive effects have been developed to predict tree and stand growth, but with simplified representations of competitive interactions. While these studies provided guidance useful for forest management, they contributed only partially to furthering our understanding of competitive mechanisms. Also, most competition studies were conducted in single-species stands. As competitive interactions occurring in mixed stands are characterized by a higher degree of complexity than those in single-species stands, a better understanding of these mechanisms can contribute to developing optimal management scenarios. The dynamics of forest stands with at least two species may be affected not only by competition, but also by facilitation or complementarity mechanisms. Thus, knowledge of the mechanisms may provide insight into the relative importance of intra- versus inter-specific competition and whether competition is symmetric or asymmetric. Special attention to the implementation of field experimental designs is warranted for mixed stands. While traditional spacing trials are appropriate for single-species stands, the examination of competitive interactions in mixed stands requires more complex experimental designs to examine the relative importance of species combinations. Forest productivity models allow resource managers to test different management scenarios, but again most of these models were developed for single-species stands. As competitive interactions are more complex in mixed stands, models developed to predict their dynamics will need to include more mechanistic representations of competition.

scholarly journals The importance of forest structure to biodiversity–productivity relationships

2017 ◽  
Vol 4 (1) ◽  
pp. 160521 ◽  
Author(s):  
Friedrich J. Bohn ◽  
Andreas Huth
Keyword(s):  
Species Distribution ◽  
Forest Structure ◽  
Basal Area ◽  
Tree Height ◽  
National Forest Inventory ◽  
National Forest ◽  
Forest Stands ◽  
Annual Productivity ◽  
Structure Indices ◽  
Modelling Approach

While various relationships between productivity and biodiversity are found in forests, the processes underlying these relationships remain unclear and theory struggles to coherently explain them. In this work, we analyse diversity–productivity relationships through an examination of forest structure (described by basal area and tree height heterogeneity). We use a new modelling approach, called ‘forest factory’, which generates various forest stands and calculates their annual productivity (above-ground wood increment). Analysing approximately 300 000 forest stands, we find that mean forest productivity does not increase with species diversity. Instead forest structure emerges as the key variable. Similar patterns can be observed by analysing 5054 forest plots of the German National Forest Inventory. Furthermore, we group the forest stands into nine forest structure classes, in which we find increasing, decreasing, invariant and even bell-shaped relationships between productivity and diversity. In addition, we introduce a new index, called optimal species distribution, which describes the ratio of realized to the maximal possible productivity (by shuffling species identities). The optimal species distribution and forest structure indices explain the obtained productivity values quite well ( R 2 between 0.7 and 0.95), whereby the influence of these attributes varies within the nine forest structure classes.

scholarly journals Empfindlichkeit typischer Schweizer Waldbestände auf den Klimawandel

2015 ◽  
Vol 166 (6) ◽  
pp. 408-419 ◽  
Author(s):  
Nicolas Bircher ◽  
Maxime Cailleret ◽  
Markus Huber ◽  
Harald Bugmann
Keyword(s):  
Climate Change ◽  
Tree Species ◽  
Forest Ecosystems ◽  
Elevation Gradient ◽  
National Forest Inventory ◽  
Climatic Conditions ◽  
Deciduous Tree ◽  
Future Climate Change ◽  
Forest Stands ◽  
Site Specific

Sensitivity of typical Swiss forest stands to climate change In Switzerland, first climate-induced changes of forest ecosystems can be observed. However, it is widely unknown how and to what extent the typical (widespread) forest stands will respond to future climate change. With the data of the third National forest inventory and the forest succession model ForClim we examined the development 71 typical stands under current and future climatic conditions (A2 emission scenario) with and without management, respectively. The simulations show a weak response until the middle of the century. In contrast, an increased sensitivity towards the end of the century becomes apparent, expressed by declines of basal area at lower elevations, respectively increases at higher elevations. The responses of forest stands are depending on site-specific characteristics. For example, Norway spruce is expected to decline up to higher elevations. Our results show an increase of deciduous tree species in higher elevation zones, particularly if management is applied. The impacts of climate change on important forest ecosystems services vary along a bioclimatic elevation gradient. Thereby, current forest management shows approaches how to at least partly counteract adverse effects of climate change. However, target- and site-specific strategies are needed and, particularly with regard to lower elevations, more knowledge on the potential of tree species to adapt is required.

Tree Diversity and Forest Resistance to Insect Pests: Patterns, Mechanisms, and Prospects

2021 ◽  
Vol 66 (1) ◽  
pp. 277-296 ◽  
Author(s):  
Hervé Jactel ◽  
Xoaquín Moreira ◽  
Bastien Castagneyrol
Keyword(s):  
Tree Species ◽  
Insect Pests ◽  
Insect Pest ◽  
Insect Herbivory ◽  
Mixed Forest ◽  
Diet Breadth ◽  
Tree Diversity ◽  
Forest Stands ◽  
Mixed Stands ◽  
Diversity Effects

Ecological research conducted over the past five decades has shown that increasing tree species richness at forest stands can improve tree resistance to insect pest damage. However, the commonality of this finding is still under debate. In this review, we provide a quantitative assessment (i.e., a meta-analysis) of tree diversity effects on insect herbivory and discuss plausible mechanisms underlying the observed patterns. We provide recommendations and working hypotheses that can serve to lay the groundwork for research to come. Based on more than 600 study cases, our quantitative review indicates that insect herbivory was, on average, lower in mixed forest stands than in pure stands, but these diversity effects were contingent on herbivore diet breadth and tree species composition. In particular, tree species diversity mainly reduced damage of specialist insect herbivores in mixed stands with phylogenetically distant tree species. Overall, our findings provide essential guidance for forest pest management.

scholarly journals Assessing the Hydroclimatic Movement under Future Scenarios Including both Climate and Land Use Changes

Water ◽  
2021 ◽  
Vol 13 (8) ◽  
pp. 1120
Author(s):  
Sinae Kim ◽  
Hakkwan Kim ◽  
Kyeung Kim ◽  
Sang-Min Jun ◽  
Soonho Hwang ◽  
...  
Keyword(s):  
Land Use ◽  
Land Use Change ◽  
Water Resource Management ◽  
Global Climate Model ◽  
Land Use Changes ◽  
Aridity Index ◽  
Future Climate ◽  
Future Climate Change ◽  
Climate Change Scenarios ◽  
Future Scenarios

In this study we simulated the watershed response according to future climate and land use change scenarios through a hydrological model and predicting future hydroclimate changes by applying the Budyko framework. Future climate change scenarios were derived from the UK Earth system model (UKESM1), and future land use changes were predicted using the future land use simulation (FLUS) model. To understand the overall trend of hydroclimatic conditions, the movements in Budyko space were represented as wind rose plots. Moreover, the impacts of climate and land use changes were separated, and the watersheds’ hydroclimatic conditions were classified into five groups. In future scenarios, both increase and decrease of aridity index were observed depending on the watershed, and land use change generally led to a decrease in the evaporation index. The results indicate that as hydroclimatic movement groups are more diversely distributed by region in future periods, regional adaptation strategies could be required to reduce hydroclimatic changes in each region. The results derived from this study can be used as basic data to establish an appropriate water resource management plan and the governments’ land use plan. As an extension of this study, we can consider more diverse land use characteristics and other global climate model (GCMs) in future papers.

scholarly journals THE IMPACT OF SHARE PARTICIPATION OF PINE AND SPRUCE ON INVENTORY INDICES OF MIXED FOREST STANDS

2017 ◽  
Vol 7 (1) ◽  
pp. 49-58 ◽  
Author(s):  
Данилов ◽  
Dmitriy Danilov ◽  
Беляева ◽  
Nataliia Beliaeva ◽  
Мартынов ◽  
...  
Keyword(s):  
Initial Density ◽  
Coniferous Forest ◽  
Mixed Forest ◽  
Average Height ◽  
Leningrad Region ◽  
Forest Types ◽  
Forest Stands ◽  
Mixed Stands ◽  
The Impact ◽  
Groups Of Forest Types

The influence of composition on the dynamics of inventory indices of the mixed modal forest stands is considered: ridges with the groups of forest types of middle subzone of taiga in the territory of the Leningrad region, for 60 year period. The course of growth of pine and spruce in the mixed stand is due to the composition of the stand, which affects the entire life cycle of its development. Analysis of forest inventory data at the test plots has shown that the median line for the average height and diameter has the distinction of growth from tabular reference data. Differences in the dynamics of growth in valuation metrics over the study period is due to the initial density of pine, then spruce, and the degree of difference in the age of trees. The variability of average heights and diameters on the experimental plots is influenced by the share of particular species in the composition of the stand. The stand composition significantly affects average diameter and height of tiers, composing the mixed coniferous forest that was confirmed by single-factor analysis of variance. The sum of the areas of the cross sections at the pine tier of the virtually at all experienced objects increases up to the age of 100-120 years, and in spruce this dependence is shown only up to the age of 80-85 years. Pine tier depending on the initial density has a greater impact on the composition of the mixed stands than spruce. This can be considered as a fact of environmental compliance of the conditions of the types: ridges with groups of forest types, for successful growth of pine. In mixed stands, untouched by commercial logging, the spruce element, quantitatively not exceeding the pine one, are stunted and produce less stock

scholarly journals The Salem simulator version 2.0: a tool for predicting the productivity of pure and mixed forest stands and simulating management operations

2021 ◽  
Vol 1 ◽  
pp. 61
Author(s):  
Raphaël Aussenac ◽  
Thomas Pérot ◽  
Mathieu Fortin ◽  
Francois de Coligny ◽  
Jean-Matthieu Monnet ◽  
...  
Keyword(s):  
Environmental Conditions ◽  
Management Strategies ◽  
Mixed Forest ◽  
National Forest Inventory ◽  
Diameter Distribution ◽  
Pure Stand ◽  
Distribution Models ◽  
Mixed Stands ◽  
Support Tool ◽  
Forest Managers

A growing body of research suggests mixed-species stands are generally more productive than pure stands as well as less sensitive to disturbances. However, these effects of mixture depend on species assemblages and environmental conditions. Here, we present the Salem simulator, a tool that can help forest managers assess the potential benefit of shifting from pure to mixed stands from a productivity perspective. Salem predicts the dynamics of pure and mixed even-aged stands and makes it possible to simulate management operations. Its purpose is to be a decision support tool for forest managers and stakeholders as well as for policy makers. It is also designed to conduct virtual experiments and help answer research questions. In Salem, we parameterised the growth in pure stand of 12 common tree species of Europe and we assessed the effect of mixture on species growth for 24 species pairs (made up of the 12 species mentioned above). Thus, Salem makes it possible to compare the productivity of 36 different pure and mixed stands depending on environmental conditions and user-defined management strategies. Salem is essentially based on the analysis of National Forest Inventory data. A major outcome of this analysis is that we found species mixture most often increases species growth, in particular at the poorest sites. Independently from the simulator, foresters and researchers can also consider using the species-specific models that constitute Salem: the growth models including or excluding mixture effect, the bark models, the diameter distribution models, the circumference-height relationship models, as well as the volume equations for the 12 parameterised species. Salem runs on Windows, Linux, or Mac. Its user-friendly graphical user interface makes it easy to use for non-modellers. Finally, it is distributed under a LGPL license and is therefore free and open source.

scholarly journals Mapping current and potential future distributions of the oak tree (Quercus aegilops) in the Kurdistan Region, Iraq

2020 ◽  
Vol 9 (1) ◽  
Author(s):  
Nabaz R. Khwarahm
Keyword(s):  
Climate Change ◽  
Habitat Suitability ◽  
Environmental Variables ◽  
Climate Changes ◽  
Future Climate ◽  
Annual Precipitation ◽  
Future Climate Change ◽  
Climate Change Scenarios ◽  
Kurdistan Region ◽  
Oak Tree

Abstract Background The oak tree (Quercus aegilops) comprises ~ 70% of the oak forests in the Kurdistan Region of Iraq (KRI). Besides its ecological importance as the residence for various endemic and migratory species, Q. aegilops forest also has socio-economic values—for example, as fodder for livestock, building material, medicine, charcoal, and firewood. In the KRI, Q. aegilops has been degrading due to anthropogenic threats (e.g., shifting cultivation, land use/land cover changes, civil war, and inadequate forest management policy) and these threats could increase as climate changes. In the KRI and Iraq as a whole, information on current and potential future geographical distributions of Q. aegilops is minimal or not existent. The objectives of this study were to (i) predict the current and future habitat suitability distributions of the species in relation to environmental variables and future climate change scenarios (Representative Concentration Pathway (RCP) 2.6 2070 and RCP8.5 2070); and (ii) determine the most important environmental variables controlling the distribution of the species in the KRI. The objectives were achieved by using the MaxEnt (maximum entropy) algorithm, available records of Q. aegilops, and environmental variables. Results The model demonstrated that, under the RCP2.6 2070 and RCP8.5 2070 climate change scenarios, the distribution ranges of Q. aegilops would be reduced by 3.6% (1849.7 km2) and 3.16% (1627.1 km2), respectively. By contrast, the species ranges would expand by 1.5% (777.0 km2) and 1.7% (848.0 km2), respectively. The distribution of the species was mainly controlled by annual precipitation. Under future climate change scenarios, the centroid of the distribution would shift toward higher altitudes. Conclusions The results suggest (i) a significant suitable habitat range of the species will be lost in the KRI due to climate change by 2070 and (ii) the preference of the species for cooler areas (high altitude) with high annual precipitation. Conservation actions should focus on the mountainous areas (e.g., by establishment of national parks and protected areas) of the KRI as climate changes. These findings provide useful benchmarking guidance for the future investigation of the ecology of the oak forest, and the categorical current and potential habitat suitability maps can effectively be used to improve biodiversity conservation plans and management actions in the KRI and Iraq as a whole.

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