Current Forestry Reports最新文献

Purpose of Review

Agroforestry and urban forestry have evolved mainly as separate disciplines, although they share a long history of tree cultivation in man-made environments. Here, we review their common threads, exploring how trees in both systems interact with and shape their environments. We examine common themes and methodologies – ranging from tree growth dynamics to environmental stressors, ecosystem services provision, and questions of governance – and identify opportunities for synergies between these fields.

Recent Findings

We emphasize the potential of agroforestry and urban forestry for enhancing multifunctional landscapes. Geographical divides in research are evident, with agroforestry predominantly studied in the Global South and urban forestry receiving more attention in the Global North. However, significant research gaps provide avenues for collaboration, for instance, addressing challenges in capturing the monetary and socio-cultural value of ecosystem services and environmental justice considerations.

Summary

In light of the growing need for integrated approaches in addressing contemporary challenges, from climate change mitigation and adaptation to community well-being, our review explores what these research fields can learn from each other and provides recommendations for fostering greater interdisciplinary dialogue and new avenues for collaborations in a meaningful and synergistic manner, aiming to advance policy, research, and practice in agroforestry and urban forestry.

Purpose of Review

The aim of this literature review was to bring together the most relevant and recent research information on the fuel consumption and CO₂ emissions caused by the fully mechanized cut-to-length (CTL) harvesting machinery when applied to industrial roundwood. A specific aim of this review was to describe the effect of different independent variables on fuel consumption in fully mechanized CTL wood-harvesting operations.

Recent Findings

The review showed that the engine power of CTL forest machines accounts for most of the variance in the hourly fuel consumption of both harvesters and forwarders. We underline that the cubic-metre-based fuel consumption of CTL forest machines is correlated to the same factors that affect work productivity. Among all influencing factors, the average stem size, removal intensity and silvicultural treatment have the strongest effect on the fuel consumption per m³ incurred with felling-processing, whereas forwarding distance, removal intensity and payload size are the main drivers of fuel consumption per m³ as incurred with extraction. Further influencing factors are soil type (mineral soil or peatland), use of tracks, assortment type and machine size. Together with those factors, the role of the machine operator remains crucial and is dependent on two separate skills: the capacity to achieve high productivity, and that to apply fuel-saving driving techniques.

Summary

The easiest way to reduce the carbon footprint of CTL harvesting machines is to increase the productivity of the harvesting work, for example by giving machine operator-specific training to utilize more efficient work methods and economic energy-efficient driving techniques. Furthermore, several other measures to reduce the carbon footprint of CTL harvesting operations were discussed in this review. Finally, we recommend that all essential variables that have a significant impact on the productivity of harvesting work, fuel consumption and CO₂ emissions are reported in study papers in the future.

Abstract

Purpose of Review

In this review, we synthesise current knowledge on trade-offs among traits in key fitness dimensions and identify major research gaps with the intention of laying the groundwork for a rapid advance in tree breeding for multiple objectives as a key contribution to the sustainability of planted forests in the future.

Recent Findings

Trade-offs among growth, reproduction, defence, stress tolerance and product quality predicted theoretically have been reported experimentally in many breeding programmes. Among these trade-offs, the genetic linkage between resistance against biotic threats and growth (or other relevant traits) is particularly critical for the current and future management of forest genetic resources. Maintaining tree growth and wood quality in the novel environments of the future requires the assessment of genetic correlations of target traits with phenology, closely linked to survival to temperature extremes. Improving our current knowledge on the genetic trade-offs of drought tolerance as a breeding objective in forest trees obligates a more precise definition of both the specific traits and the experimental conditions. Published evidence suggests that common target traits in breeding programmes may trade-off with reproductive success and fire-adaptation, and the simultaneous improvement of growth and wood quality traits still remains as a constraint in traditional tree breeding.

Summary

Changing environments combined with pests and diseases are challenging plantation forestry worldwide, which implies an urgent need to develop new improvement strategies to build the resilience of forestry for our future environments. It is essential to have a better understanding of how traits interact, especially those important for production, climate and biotic threat resilience, but much of the information is still missing. Since many key trade-offs are affected by the environment, we need new studies under novel environments to forecast levels of multi-trait integration in breeding populations.

Purpose of Review

The collective virome of forest trees can be considered to include not only plant viruses, but also viral communities harbored by all tree-associated organisms. In this review, we will concentrate on reviewing recent developments in the two fields of forest tree virology that have received the most research input during the last 5 years: (1) current knowledge of virus diseases affecting forest trees and their causal agents and (2) fungal viruses (mycoviruses) and properties that are required for utilizing them for biocontrol purposes.

Recent Findings

The discovery of plant and mycoviruses has been revolutionized during the last few years due to high-throughput sequencing (HTS). This has altered our view of virus diversity and prevalence, but also their host ranges, transmission routes, and host effects. Utilization of HTS has greatly expanded our knowledge of plant virus diversity and disease etiology in forest trees and revealed the commonness of cross-kingdom transmission events between fungi, oomycetes, plants, and arthropods. Research on mycoviruses has also identified several new mycoviruses that restrict the growth or virulence of forest pathogenic fungi.

Summary

Gaining knowledge of the collective virome of forest ecosystems is essential not only for understanding virus evolution and diversity but also for improving our understanding on virus impacts, and our ability for biocontrol-based and environmentally friendly management of viral and fungal diseases that affect economically important plants and beneficial insects, and for preventing possible disease outbreaks in the future. Virus infections play a central role in plant health, but viral symptoms on forest trees remain often unrecognized and may be confused with other biotic or abiotic damages. However, recent studies have revealed previously unknown viruses as causes of forest tree symptoms and suggest that viruses are responsible for far greater economic losses than recognized earlier. However, many knowledge gaps still need to be filled, particularly on the diversity of viruses that infect different species of forest trees, their irregular distribution within the plant, their mode of transmission, epidemiology and choice of hosts also regarding crop plants, their effect on the metabolism of their host tree, and their interaction with other microorganisms. Mycovirus research has already deciphered detailed information on many critical properties that affect utilizing them for biocontrol purposes. Still, more knowledge is needed concerning mycoviral transmission mode and stability in field conditions, the level of host tolerance against mycoviral infection, and the occurrence of interspecies mycovirus transmission in nature, and safety issues related to these topics.

Purpose of Review

We aimed to summarize the evidence linking multi-purpose forest management (MPF) to bird nesting and fledging success in temperate and boreal forests and to identify outstanding research gaps. Forest birds are in decline worldwide, but an ongoing move from production-oriented management towards MPF, integrating biodiversity conservation with other uses, may help counteracting these trends. The effects of MPF on bird diversity and abundance are well-studied, but less is known about effects on bird demographics.

Recent Findings

We retrieved 101 studies, reporting 342 outcomes of MPF for nesting and fledging success. Due to the heterogeneity of the studies, we opted for a systematic mapping approach, accompanied by vote-counting and narrative review. Studies covered 11 types of MPF and 151 bird species. The most frequently studied interventions were overstorey retention and prescribed burning, but research was markedly biased towards temperate North America. Most outcomes (79.5%) were non-significant, and studies often found that breeding success was driven by ecological processes at both broader and finer scales than management interventions. Thus, managing for breeding success likely requires complementary management actions at various scales. Nonetheless, significant positive and negative outcomes of MPF were also found, inclusively affecting species of conservation concern, highlighting the variability and context-dependence of MPF effects.

Summary

In order to foster effectiveness of MPF for forest birds, future research should focus on a set of under-researched interventions and regions, as well as on ecosystem-wide experiments accounting for functional links between bird abundance, demographics, nest predation, and food supply.

Purpose of Review

To describe how general prescriptions to protect temperate and boreal forests against pests have been affecting the conservation of insect diversity, (2) to identify potential conflicts between biodiversity conservation actions and pest control, and (3) to provide future directions to reconcile forest pest management with insect conservation.

Recent Findings

Despite dealing with the same habitats and organisms, forest pest management and insect conservation have been separate disciplines, often pursuing conflicting goals. However, there is a large intersection between the two, as interventions to control pests can have repercussions on biodiversity and vice versa. In several regions, forest pest management is shifting from reactive measures to contain on-going outbreaks to proactive strategies to create forest landscapes that are more resistant and resilient against pests in the long-term. These developments suggest a possible convergence between pest management and insect conservation objectives.

Summary

Several reactive measures adopted to control pests can cause negative impacts on non-target insects, although effects are sometimes localized and often context-dependent. Following ecological, economic, and social considerations, pest management has been evolving towards diversifying forests across multiple spatial scales to reduce the severity of outbreaks and the risk of damage. Such strategies concur with multiple conservation goals to increase insect diversity across intensive forest landscapes. Insect conservation has traditionally targeted saproxylic organisms, neglecting the conservation of other insect guilds and seldom assessing side effects on pests. Despite some important knowledge gaps, we propose complementary approaches to combine multiple diversification strategies at the landscape scale to reconcile pest management with insect conservation.

Purpose of Review

The objective quantification of stand density (SD) is necessary for predicting forest dynamics over space and time. Despite the development of various synthetic representations of SD, consensus remains elusive regarding a primary integrated measure due to contrasting data sources, statistical modeling methods, and distinct regional variations in forest structure and composition. One of the most enduring and robust measures of SD is Reineke’s (1933; J. Ag Res. 46, 627-638) stand density index (SDI), which has long formed the basis for the prediction of stand development concerning self-thinning processes in single-species, even-aged stands and stand density management diagrams (SDMDs). Thus, this review tracks the development of different methodologies and necessary data for properly estimating SDI, including its application in complex forests and adaptive management contexts.

Recent Findings

Limitations of SDI in its earliest form have led to important modifications centered on refinement and expanding its application beyond even-aged, single-species stands to multi-cohort, mixed composition stands. Statistical advances for better determination of the maximum size-density boundary line have also been applied to SDI estimates using the ever-expanding availability of remeasured field data including large-scale, national forest inventories. Other innovations include the integration of regional climate information and species functional traits, e.g., wood specific gravity, drought, and shade tolerance.

Summary

In this synthesis, we describe the attributes of SDI that have promulgated its use as a leading measure of SD for nearly 90 years. Recent applications of robust statistical techniques such as hierarchical Bayesian methods and linear quantile mixed modeling have emerged as the best performing methods for establishing the maximum size-density boundary, especially those incorporating ancillary variables like climate.

Abstract

Purpose of Review

In tandem with China’s rapid urbanisation and economic growth, some negative impacts on the eco-environment and human wellbeing have arisen, such as the urban heat island effect, air pollution and lack of recreational spaces. To address the degradation of urban eco-environment and improve residents’ quality of life simultaneously, China’s central government launched the National Forest City action in 2004, which essentially promotes urban forests as nature-based solutions (UF-NBS) and contributes to achieving sustainable development goals. Whilst this key national action has been implemented for about two decades, it has received limited scholarly attention within and beyond China. This paper is the very first to summarise comprehensively the development of the action, focusing on its rationale, evaluation and management.

Recent Findings

By establishing urban forests as cost-effective solutions to various environmental and social issues, the action integrates novel knowledge and best practices accumulated in Europe and North America into China’s traditional ideology, pertinent to the human-nature relationship in urban landscape design, and further adapts and renovates these to the country’s unique socioeconomic context. It highlights the multi-functionality of urban forests underpinned by a set of key performance indicators covering both qualitative and quantitative aspects of the National Forest City’s planning, construction, management and review. Additionally, it reflects a dynamic interaction within the science-policy-practice continuum hinged on field experiments, knowledge transfer, public engagement, policy agenda and greening actions. Challenges, such as unbalanced geographical distribution and KPIs on ecological integrity and functionality of urban forests, should be addressed for further refining and scaling-up this action.

Summary

China’s National Forest City action promotes UF-NBS as a pathway to sustainable urbanisation, serving as a demonstrative exemplar for other developing and developed countries that may wish to avoid their dependence on traditional development pathways. This paper sheds light on how to implement urban forests as effective and sustainable NBS to addresses global societal challenges.