Hurricane effects on climate-adaptive silviculture treatments to longleaf pine woodland in southwestern Georgia, USA

Abstract The Adaptive Silviculture for Climate Change (ASCC) network tests silvicultural treatments to promote ‘resistance’ or ‘resilience’ to climate change or speed ‘transition’ to new forest types. Based on projected increases in air temperatures and within-season dry periods in southeastern USA, we installed resistance, resilience and transition treatments involving species selection and varied intensities of density reduction, plus an untreated control, in mixed longleaf pine-hardwood woodland in southwest Georgia USA. Within a year of treatment a tropical cyclone, Hurricane Michael, exposed the site to the unforeseen climatic stress of >44-m s−1 winds. We measured inventory plots post-cyclone and compared the data to pre-storm and pre-treatment values. We analysed stand density index (metric SDI, species maximum value = 1000), stand complexity index (SCI), composition and individual tree characteristics. The ASCC treatments decreased both SDI (from 220 to 124 in the transition treatment) and SCI. The cyclone did not greatly decrease SDI (mean decrease 4.5 per cent) and decreased SCI only in the Controls. Xeric hardwoods were more prone to damage than other functional groups, and ordination showed that the cyclone shifted species composition to greater longleaf pine dominance. Taller trees were more likely to be damaged, except in the resilience treatment, which had a relatively large representation of shorter, more easily damaged xeric hardwoods. The open canopy of the longleaf-hardwood woodland, only 22 per cent of maximum SDI before treatment, evidently fostered wind-firmness, thereby limiting the destructive effect of the cyclone. The sensitivity of xeric hardwoods to hurricane damage suggests that there may be a trade-off between wind tolerance and drought tolerance among functional groups. Maintaining a mixture of drought and wind-resistant species, as in the resilience treatments, may provide broader insurance against multiple climate change impacts in longleaf pine and other forested systems dominated by a single foundation species.

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What evidence exists on the effects of competition on trees’ responses to climate change? A systematic map protocol

Environmental Evidence ◽

10.1186/s13750-021-00249-5 ◽

2021 ◽

Vol 10 (1) ◽

Author(s):

Juliana G. de S. Magalhães ◽

Mariano M. Amoroso ◽

Bruce C. Larson

Keyword(s):

Climate Change ◽

Tree Growth ◽

Full Text ◽

Species Interactions ◽

Forest Type ◽

Climate Change Impacts ◽

Species Selection ◽

Growth Responses ◽

Systematic Map ◽

Individual Tree

Abstract Background Projections of climate change impacts upon forests are likely inaccurate if based on the premise that only climate controls tree growth. Species interactions control growth, but most research has ignored these effects on how trees respond to climate change. Climate change is inducing natural species selection. However, this selection does not occur at the community level. Species selection starts with competition amongst individual trees. Competition is an individual-to-individual antagonistic interaction that, if severe, can constrain the presence of trees within a particular environment. Thus, climate change impacts individual tree selection within forests. Projecting climate change impacts on forests should account for the effects of climate on tree growth and the effects of competition. The inclusion of competition can increase the predictive power of simulations. Methods We propose a protocol to systematically map the available literature on climate change impacts on forests and produce a comprehensive list of methods applied to measure competition and model the competition effects on tree growth responses to climate change. This systematic map is not limited to any country or continent or specific tree species or forest type. The scope of the search focuses on time (when the evidence was published), location (geographic location of the evidence) and research design (competition indices and modelling methods). We will evaluate articles at three levels: title, abstract and full text. We will conduct a full-text assessment on all articles that pass a screening at the title and abstract stages. We will report the extracted evidence in a narrative synthesis to summarize the evidence’s trends and report knowledge gaps.

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The impact of Hurricane Michael on longleaf pine habitats in Florida

10.1101/736629 ◽

2019 ◽

Cited By ~ 2

Author(s):

Nicole E. Zampieri ◽

Stephanie Pau ◽

Daniel K. Okamoto

Keyword(s):

Climate Change ◽

Large Scale ◽

Tree Mortality ◽

Size Structure ◽

Longleaf Pine ◽

Pinus Palustris ◽

Climate Change Impacts ◽

The North ◽

Integral Role ◽

The Impact

AbstractThe longleaf pine (Pinus palustris) ecosystem of the North American Coastal Plain (NACP) is a global biodiversity hotspot. Disturbances such as tropical storms play an integral role in ecosystem maintenance in these systems. However, altered disturbance regimes as a result of climate change may be outside the historical threshold of tolerance. Hurricane Michael impacted the Florida panhandle as a Category 5 storm on October 10th, 2018. In this study, we estimate the extent of Florida longleaf habitat that was directly impacted by Hurricane Michael. We then quantify the impact of Hurricane Michael on tree density and size structure using a Before-After study design at four sites (two wet flatwood and two upland pine communities). Finally, we identify the most common type of tree damage at each site and community type. We found that 39% of the total remaining extent of longleaf pine habitat was affected by the storm in Florida alone. Tree mortality ranged from 1.3% at the site furthest from the storm center to 88.7% at the site closest. Most of this mortality was in mature sized trees (92% mortality), upon which much of the biodiversity in this habitat depends. As the frequency and intensity of extreme events increases, management plans that mitigate for climate change impacts need to account for large-scale stochastic mortality events in order to effectively preserve critical habitats.

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Dynamic coupling of allometric ratios to a process-based forest growth model for estimating the impacts of stand density changes

Forestry An International Journal of Forest Research ◽

10.1093/forestry/cpaa002 ◽

2020 ◽

Vol 93 (5) ◽

pp. 601-615

Author(s):

Rüdiger Grote ◽

David Kraus ◽

Wendelin Weis ◽

Rasmus Ettl ◽

Axel Göttlein

Keyword(s):

Climate Change ◽

Early Development ◽

Stand Density ◽

Climate Change Impacts ◽

Forest Growth ◽

Canopy Layer ◽

Mature Trees ◽

Development Stages ◽

Allometric Relations ◽

Forest Growth Model

Abstract Process-based models are increasingly applied for simulating long-term forest developments in order to capture climate change impacts and to investigate suitable management responses. Regarding dimensional development, however, allometric relations such as the height/diameter ratio, branch and coarse root fractions or the dependency of crown dimension on stem diameter often do not account for environmental influences. While this may be appropriate for even-aged, monospecific forests, serious biases can be expected if stand density or forest structure changes rapidly. Such events occur in particular when forests experience disturbances such as intensive thinning or during early development stages of planted or naturally regenerated trees. We therefore suggest a calculation of allometric relationships that depends primarily on neighbourhood competition. Respective equations have been implemented into a physiology-based ecosystem model that considers asymmetric competition by explicit simulation of resource acquisition and depletion per canopy layer. The new implementation has been tested at two sites in Germany where beech (Fagus sylvatica) saplings have either been planted below a shelterwood of old spruces (Picea abies) or grown under clear-cut conditions. We show that the modified model is able to realistically describe tree development in response to stand density changes and is able to represent regeneration growth beneath a gradually decreasing overstorey of mature trees. In particular, the model could represent the faster crown size development in saplings until full ground coverage is established and a faster height growth afterwards. The effect enhances leaf area and thus assimilation per tree and increases carbon availability for stem growth at early development stages. Finally, the necessity to consider dynamic allometric relations with respect to climate change impacts is discussed, and further improvements are suggested.

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Assessing climate risk to support urban forests in a changing climate

10.32942/osf.io/g96fs ◽

2021 ◽

Author(s):

Manuel Esperon-Rodriguez ◽

Paul Rymer ◽

Sally Power ◽

David Barton ◽

Paloma Cariñanos ◽

...

Keyword(s):

Climate Change ◽

Tree Mortality ◽

Urban Forestry ◽

Urban Forests ◽

Climate Change Impacts ◽

Urban Environments ◽

Species Selection ◽

Changing Climate ◽

Species Vulnerability ◽

Tree Dieback

The management of urban forests is a key element of resilience planning in cities across the globe. Urban forests provide ecosystem services as well as other nature-based solutions to 4.2 billion people living in cities. However, to continue to do so effectively, urban forests need to be able to thrive in an increasingly changing climate. Trees in cities are vulnerable to extreme heat and drought events, which are predicted to increase in frequency and severity under climate change. Knowledge of species’ vulnerability to climate change, therefore, is crucial to ensure provision of desired ecosystem benefits, improve species selection, maintain tree growth and reduce tree mortality, dieback and stress in urban forests. Yet, systematic assessments of causes of tree dieback and mortality in urban environments are rare. We reviewed the state of knowledge of tree mortality in urban forests globally, finding very few frameworks that enable detection of climate change impacts on urban forests and no long-term studies assessing climate change as a direct driver of urban tree dieback and mortality. The effects of climate change on urban forests remain poorly understood and quantified, constraining the ability of governments to incorporate climate change resilience into urban forestry planning.

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