The productivity of boreal forests in Eastern North America is predicted to increase with warming under sufficient moisture supply. Here D’Orangeville et al. study seven tree species and predict that growth enhancements may be seen up to 2 °C warming, but would decline if temperatures exceed this.
Forests in the Anthropocene
Forests are multifaceted ecosystems that perform an array of essential functions that both directly and indirectly impact humanity. They act as a nexus of the Earth system’s climate, hydrology and biogeochemical cycles. This function is all the more relevant in the Anthropocene, an epoch characterised by humanity’s impact on our planet, given the vast amounts of carbon locked up in tree biomass that help buffer against anthropogenic carbon emissions to the atmosphere. Forests are also hubs of biodiversity that provide essential resources and services to communities, but they are vulnerable to degradation and deforestation. The study of forests, which also includes their restoration, conservation and sustainable use, thus encompasses a broad suite of scientific disciplines, and research in this field is becoming increasingly interdisciplinary.
This collection has been curated by the Earth science and Ecology editorial teams at Nature Communications in the hope that it will provide a helpful resource for researchers and decision makers in this increasingly interdisciplinary field. The collection is divided into four themes: climate-forest feedbacks, the forest-human interface, the forest carbon sink, and communities and ecosystems. This collection will be updated with new research and opinion pieces on a regular basis.
The editorial accompanying this collection discusses our evolving history with forests and how science can guide us towards living sustainably with these key ecosystems.
The effect of plants on future extreme heat events under elevated carbon dioxide (CO2) is unclear. Here, the authors show that CO2 plant physiological effects lead to increases in heat waves within a suite of climate model simulations, suggesting that vegetated areas are at risk of increased heat extremes.
Resource acquisition and reproductive strategies of tropical forest in response to the El Niño–Southern Oscillation
It has been suggested that tree phenology may be regulated by climatic oscillations. Here, Detto et al. present a 30 year tropical forest dataset that suggests leaf and fruit production is coordinated with ENSO cycles, with greater leaf fall observed prior to El Niño followed by greater seed production.
Depending on where and when it occurs, vegetation cover change can affect local climate by altering the surface energy balance. Based on satellite data, this study provides the first data-driven assessment of such effects for multiple vegetation transitions at global scale.
Deforestation carbon emissions from the Brazilian Amazon have declined steeply, but how much drought-induced forest fire emissions add to this process is still unclear. Here the authors show that gross emissions from forest fires are more than half as great as those from deforestation during drought years.
Plant growing season increases under a warming climate, but it is not known whether this will alter plant exposure to frost days. Here Liu et al. investigate trends in the Northern Hemisphere over 30 years and find increased exposure to frost days in regions that have longer growing seasons.
The climate impacts of deforestation due to changes in biogenic volatile organic compound emissions, which act as short-lived climate forcers (SLCFs), are poorly understood. Here the authors show that including the impact SLCFs increases the projected warming associated with idealised deforestation scenarios.
Inter-annual and decadal changes in teleconnections drive continental-scale synchronization of tree reproduction
Climate oscillations affect weather on different temporal-spatial scales, which poses difficulty in understanding how they influence tree reproduction. Here Ascoli et al. show relationships between low- and high-frequency components of the NAO and masting in two European tree species across multiple decades.
Forest productivity in southwestern Europe is controlled by coupled North Atlantic and Atlantic Multidecadal Oscillations
The North Atlantic Oscillation (NAO) drives biological responses in terrestrial ecosystems through oscillatory modes of climatic variability. Here, the authors show how landscape scale productivity responses to NAO are contingent upon the Atlantic Multidecadal Oscillation in southwestern Europe.
Drought has a major influence on plant distribution. Here, Swenson et al. show that a similar gene expression response to experimental drought outperforms traditional functional traits and phylogenetic relatedness as a predictor of co-occurrence of tree species in a natural stand.
Relatively little is understood about seasonal effect of climate change on the Amazon rainforest. Here, the authors show that Amazon forest loss in response to dry-season intensification during the last glacial period was likely self-amplified by regional vegetation-rainfall feedbacks.
Forests impact continental-scale moisture recycling, but their impact on regional-scale cloud cover is little known. Here, using satellite observations, Teuling et al. illustrate enhanced cloud cover over regional forested areas in western Europe due to the establishment of a forest-breeze circulation.
Many species show a time-lagged response to climate change, a phenomenon called climatic debt. Here, Bertrand and colleagues show that climate severity and plant tolerance to climate warming mainly influence the climatic debt of forest herbaceous plant communities.
The forest-human interface
Rainforest conversion to plantations driven by global demand for agricultural products generates high environmental costs. Here, the authors show that the high oil palm plantation production efficiency is associated with decreased carbon storage and slower organic matter cycling that affect ecosystem services.
Expansion of rubber plantations threatens tropical forest carbon stocks and biodiversity, but may be dis-incentivised using carbon finance. Here, Warren-Thomas et al. use forest and agricultural data for Cambodia to show that carbon prices of $30–$51 per tCO2 are needed to match forest protection costs.
Afforestation is often used to increase terrestrial carbon sequestration and restore ecosystem services. Here, the authors show that afforestation can also neutralize soil pH by lowering pH in alkaline soil but raising pH in acid soil, thus further promoting the restoration of ecosystem functions.
The expansion of agriculture and rangelands can cause ecological spillover effects across cultivated-natural ecosystem boundaries. Here, Luskin et al. show irruptions of oil palm-subsidized wild boar alter the abundance and diversity of understory trees >1 km into a primary forest reserve in Malaysia.
Land use and land cover change has led to more frequent hot, dry summers in parts of the mid-latitudes. Here the authors use an Earth system model to show that regions converted to crops and pastures experience hot, dry summers 2 to 4 times more frequently than they would if native forests had remained.
Industrial mining contributes to deforestation in the Amazon, and the extent of effect could occur beyond areas of land explicitly permitted for mining. Here, Sonter et al. show that deforestation in 70-km buffer zones around mines has led to an estimated 9% of Brazilian Amazon deforestation since 2005.
Land-use choices follow profitability at the expense of ecological functions in Indonesian smallholder landscapes
Small-scale farmers in Southeast Asia are increasingly turning to monocultures of oil palm and rubber to maximize income. Clough and colleagues demonstrate that this land-use change in Indonesia comes at a cost to a wide array of ecosystem functions and biodiversity.
China’s Grain for Green Program is the world’s largest reforestation program, encompassing tens of millions of hectares since 1999. Here, Hua et al. show that the majority of areas have been reforested with tree monocultures, but that planting mixed forests could increase animal biodiversity without imposing additional economic costs.
Restoration of degraded ecosystems is known to enhance biodiversity and vegetation structure. Using a global meta-analysis, Crouzeilles et al. identify the drivers of restoration success in forest ecosystems at both the local and landscape scales.
The forest carbon sink
Forests of the Amazon Basin have experienced frequent and severe droughts in recent years with significant impacts on their carbon cycling. Here, using satellite LiDAR samples from 2003 to 2008, the authors show the long-term legacy of these droughts with persistent loss of carbon stocks after the 2005 drought.
Carbon losses from deforestation and widespread degradation offset by extensive growth in African woodlands
Degradation—the loss of carbon stored in intact woodland—is very difficult to measure over large areas. Here, the authors show that carbon emissions from degradation in African woodlands greatly exceed those from deforestation, but are happening alongside widespread increases in biomass in remote areas.
The recovery of North American forests is likely to impact their capacity as a carbon sink. Here, Zhu et al. show a growth in aboveground biomass in various climate change scenarios, with these forests expected to sequester no more than 22% more carbon than current levels by the 2080s.
Invasive alien pests can cause large-scale forest mortality and release carbon stored in forests. Here the authors show that climate change increases the potential range of alien pests and that their impact on the carbon cycle could be as severe as the current natural disturbance regime in Europe’s forests.
The existence of a pan-tropical forest carbon sink remains uncertain due to the lack of data from Asia. Here, using direct on-the-ground observations, the authors confirm remaining intact forests in Borneo have provided a long-term carbon sink, but carbon net gains are vulnerable to drought and edge effects.
Reliable estimates of the total forest carbon (C) pool are lacking due to insufficient information on dead organic matter (DOM). Here, the authors estimate that the current DOM C stock in China is 925 ± 54 Tg and that it grew by 6.7 ± 2.2 Tg C/yr over the past two decades primarily due to increasing forest area
Vast quantities of carbon stored in tropical forests are threatened by deforestation. Here, using high resolution satellite data, Brinck et al. examine how edge effects influence carbon emissions and they find an additional 10.3 Gt of carbon are released by deforestation when including fragmentation effects.
Defaunation is linked to the decline of tree species that depend on large animals for seed dispersal, but it is unclear if this affects carbon storage. Here the authors show that defaunation effects on carbon storage vary across continents, driven by relationships between seed dispersal strategies and adult tree size.
Evaluating the convergence between eddy-covariance and biometric methods for assessing carbon budgets of forests
Site-level quantification of Net Ecosystem Production (NEP) and associated components rely on eddy covariance and biometric methods. Here these techniques are compared for global forest carbon fluxes, revealing differences in NEP, but similar estimates of ecosystem respiration and gross primary production.
Communities and ecosystems
Biodiversity change can impact ecosystem functioning, though this is primarily studied at lower trophic levels. Here, Schuldt et al. find that biodiversity components other than tree species richness are particularly important, and higher trophic level diversity plays a role in multifunctionality.
As remote sensing technology improves, it is now possible to map fine-scale variation in plant functional traits. Schneider et al. remotely sense tree functional diversity, validate with field data, and reveal patterns of plant adaptation to the environment previously not retrievable from plot data
Earth system model simulations of future climate in the Amazon show little agreement. Here, the authors show that biases in internally generated climate explain most of this uncertainty and that the balance between water-saturated and water-limited evapotranspiration controls the Amazon resilience to climate change.
Deforestation and edge effects around cleared areas impact forest stability. Here, the authors examine human impacts on Amazonian forest-savanna bistability and show that tree cover bimodality is enhanced in regions close to human activities and is nearly absent in regions unaffected by human activities.
Dust is an important nutrient source to landscapes, but often the source of dust is poorly constrained. Here, the authors quantify the origin of different dust sources in the Sierra Nevada by analysing dust composition and suggest exogenic dust may drive nutrient budgets in montane ecosystems.
Invasive brown treesnakes decimated the forest bird community on the island of Guam. Now, Rogers and colleagues document the indirect effects of the snake on trees, linking snake-initiated bird loss to reduced seed dispersal and plant recruitment on Guam compared to nearby uninvaded islands.
Compositional diversity of rehabilitated tropical lands supports multiple ecosystem services and buffers uncertainties
Land use becomes more diverse when it considers uncertain interactions of multiple ecosystem services. Here, Knoke and colleagues show that uncertainty plays a larger role if ecosystem services are optimized only for a single service, or if services correlate.
Jack-of-all-trades effects drive biodiversity–ecosystem multifunctionality relationships in European forests
How biodiversity is linked to multiple ecosystem functions is not fully understood. Here, the authors show that a new mechanism, which they term the 'jack-of-all-trades' effect, best explains patterns of tree diversity and ecosystem multifunctionality in European forests.