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 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 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.

scholarly journals Management of Blue Gum Chalcid (Leptocybe invasa Fisher & La Salle (Hymenoptera: Eulophidae) infestation on different species of Eucalyptus trees in Kalu district, Eastern Amhara, Ethiopia

2020 ◽  
Vol 13 (3) ◽  
pp. 197-214
Author(s):  
Tigabu Redae Alle ◽  
Adane Tesfaye Lema ◽  
Seid Muhie Dawud
Keyword(s):  
Tree Species ◽  
Insect Pests ◽  
Block Design ◽  
Insect Pest ◽  
Eucalyptus Camaldulensis ◽  
Pest Infestation ◽  
Randomized Complete Block Design ◽  
Leptocybe Invasa ◽  
Control Application ◽  
Blue Gum

The recently introduced chalcid pest known as the Blue Gum Chalcid (BGC) (L. invasa) is currently one of the major insect pests of Eucalyptus tree species in Ethiopia. A research was conducted in Kalu district, South Wollo, Eastern Amhara, Ethiopia, the main objective of which was to evaluate the effectiveness of synthetic insecticides, hoeing and water showering options against BGC. Two parallel experiments were conducted in the nursery and in the field. Eucalyptus camaldulensis, E. saligna, E. viminalis, E. citrodora and E. globulus were considered in the nursery at Chorisa. One to three-year old E. camaldulensis plantations were considered at Tikuro plantation site. At the nursery, seven treatments and at the field 10 treatments were tested in a Randomized Complete Block Design (RCBD) with three replications from January to February 2019, where treatments were applied 3 times at 15-day intervals. Results from the 1-year old plantation revealed that application of Dimethoate 40%, Carbofuran 3G and Dimethoate 40% + hoeing followed by Carbofuran 3G + hoeing and Thiamethoxam 25WG were effective in checking the BGC insect pest infestation. In the 3-year old plantation, Carbofuran 3G significantly reduced the infestation followed by Dimethoate 40%. At the nursery, Dimethoate 40% and Carbofuran 3G reduced the infestation followed by Carbofuran 3G + Dimethoate 40% and thiamethoxam 25WG. Water showering and hoeing did not reduce BGC infestation in all cases at the field plantations. Treatments that received synthetic insecticides and hoeing had low infestation, the reason for which was the insecticide rather than the hoeing, because the hoeing alone didn’t differ from the control. Application of Dimethoate 40% and Carbofuran 3G with hoeing and weeding activities were recommended to manage and limit BGC insect pest infestations.

scholarly journals Tree species richness as the element of structure and diversity in mixed stands of beech and valuable broadleaves

2012 ◽  
pp. 157-172
Author(s):  
Branko Stajic ◽  
Milivoj Vuckovic
Keyword(s):  
Species Richness ◽  
Tree Species ◽  
Woody Species ◽  
Forest Stands ◽  
Expected Number ◽  
Mixed Stands ◽  
Species Richness And Diversity ◽  
Number Of Species ◽  
Tree Species Richness ◽  
Ecological Unit

In our forest science and forest operations, the tree species richness and diversity of woody species in forest stands are most often evaluated based on the total number of tree species, which is a methodologically partly inadequate approach. For this reason, the quantification and the evaluation of diversity of woody species in mixed forests of beech with valuable broadleaves in the area of the National Park ?Djerdap? were analyzed by five different indices of tree species richness: number of species (S index), two indices of the species richness (R1 and R2), expected number of species in the sample with equal numbers of trees (E(S84)), and expected number of species in the sample with equal areas (E(S0,25ha)). The results showed that the level of woody species diversity in forest stands depended on the applied index characterizing the tree species richness. It was concluded that the tree species richness and diversity were the highest in the stands of ecological unit B (E(S84)=8.6 species) and in the stands of ecological unit G (E(S0,25ha)=9.4 species), and they were the lowest in the stands of ecological unit V (E(S84)=5.8 species, E(S0,25ha)=5.5 species).

scholarly journals Effect of Climate Change on Introduced and Native Agricultural Invasive Insect Pests in Europe

Insects ◽  
2021 ◽  
Vol 12 (11) ◽  
pp. 985
Author(s):  
Sandra Skendžić ◽  
Monika Zovko ◽  
Ivana Pajač Živković ◽  
Vinko Lešić ◽  
Darija Lemić
Keyword(s):  
Climate Change ◽  
Biological Invasion ◽  
Insect Pests ◽  
Abiotic Factors ◽  
Insect Pest ◽  
Diet Breadth ◽  
Economic Damage ◽  
Pest Species ◽  
Invasive Insects ◽  
Factors Affecting

Climate change and invasive species are major environmental issues facing the world today. They represent the major threats for various types of ecosystems worldwide, mainly managed ecosystems such as agriculture. This study aims to examine the link between climate change and the biological invasion of insect pest species. Increased international trade systems and human mobility have led to increasing introduction rates of invasive insects while climate change could decrease barriers for their establishment and distribution. To mitigate environmental and economic damage it is important to understand the biotic and abiotic factors affecting the process of invasion (transport, introduction, establishment, and dispersal) in terms of climate change. We highlight the major biotic factors affecting the biological invasion process: diet breadth, phenological plasticity, and lifecycle strategies. Finally, we present alien insect pest invasion management that includes prevention, eradication, and assessment of the biological invasion in the form of modelling prediction tools.

Comparative analysis of throughfall event response for 6 different forest stands

2021 ◽  
Author(s):  
Theresa Blume ◽  
Lisa Schneider ◽  
Janek Dreibrodt ◽  
Andreas Güntner
Keyword(s):  
Tree Species ◽  
Structural Changes ◽  
High Temporal Resolution ◽  
Forest Stands ◽  
Mixed Stands ◽  
Data Set ◽  
Rainfall Events ◽  
Structural Controls ◽  
Precipitation Characteristics ◽  
North Eastern

<p>Rainfall redistribution by forest canopies differs between tree species and can play an important role for tree water availability and groundwater recharge. A thorough understanding of these relationships will improve our ability to predict future impacts of climate and forest structural changes on the water balance of forest stands.</p><p>In the TERENO observatory in the Müritz National Park (north-eastern Germany), throughfall was continuously measured at 7 sites with different dominant tree species and ages: young and old beech, young and old pine, and the mixed stands oak/beech, pine/beech, and pine/oak/beech. To this end, 5 trough-based throughfall monitoring systems with a total collecting area of 6.6 m² per site were installed at each site. Furthermore, stemflow was measured with tipping buckets at 5-10 trees per site. This added up to a total at 40 trees (18 pines, 15 beeches, 7 oaks) providing a unique high-temporal resolution data set of stemflow response. This dataset covers almost 5 years, offering a good data base for detailed event analyses.</p><p>During the measurement period we identified 534 rainfall events. However, to maintain good comparability, we removed all events where more than one of the five trough systems per site failed, which left us with 346 rainfall events for throughfall and 184 rainfall events for stemflow. Due to the large number of events we were able to compare winter and summer events as well as the influence of different precipitation characteristics. Statistical models were used to investigate forest-stand specific relationships between throughfall and meteorological conditions. The comparison of these relationships between the forest stands offered additional insights into forest structural controls of throughfall. </p>

scholarly journals Dynamics of health status of forest stands on research plots in the Šumava National Park

2012 ◽  
Vol 49 (No. 7) ◽  
pp. 333-347
Author(s):  
S. Vacek ◽  
K. Matějka ◽  
J. Mayová ◽  
V. V Podrázský
Keyword(s):  
Health Status ◽  
National Park ◽  
Stand Structure ◽  
Insect Pests ◽  
Mixed Forest ◽  
Forest Stands ◽  
Spruce Stands ◽  
Damage Dynamics ◽  
Natural Stands ◽  
Forest District

The paper summarises an evaluation of the health status dynamics of allochthonous spruce stands in the Modrava Forest District and of natural stands in the Plešný Forest District. Analysis is based on dendroecological reactions of particular tree individuals in the stand structure. The tree damage was evaluated annually (during the period 1997–2002), based especially on defoliation. Natural and semi-natural, especially mixed forest stands with dominant beech in the Plešný Forest District territory were most tolerant, allochthonous secondary spruce stands in the Modrava Forest District area were least tolerant. The damage dynamics was limited by the activity of insect pests (bark beetle – Ips typographus). Damage caused by ozone occurred much more often in 2002 compared to 1999. The most damaged species were sycamore and rowan tree.

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