Study reveals forest may adapt to climate change, but not quickly enough

Americas woodlands are headed for a difficult time Climate change is raising temperatures and lowering moisture levels across the country which is bad news for trees Researchers at UC Santa Barbara and University of Utah sought to determine how our sylvan ecosystems might fare in the near futureThe authors combined mathematical models and data collected by the US Forest Service and plant physiologists to understand the vulnerability of woodlands to drought Their findings suggest that while most forests have the potential to adapt to hotter dryer conditions they arent changing quickly enough to avoid the impending stress The study published in Global Change Biology serves as a benchmark for future forest research as well as a guide for conservation and managementWe were concerned to find that forests were not changing fast enough to avoid increased water stress due to climate change said first author Greg Quetin an assistant project scientist in the UCSB Department of Geography But there is hope as most forests in the continental US contained enough functional diversity to increase their drought tolerance through shifts in species compositionThere are a few ways forests can adapt to drier conditions Individual trees can alter their activity physiology and gene expression to the new conditions they face Droughttolerant species already present in the ecosystem can also become more dominant The forest composition can change as well with hardier species migrating in as more vulnerable species die off Evolution can also change species via natural selection although the effect will be negligible over the next century for such longlived organismsQuetin and his coauthors investigated whether the traits and species already present in the countrys forests are sufficient for them to acclimate to future climate change without widespread mortality Much of the data came from the Forest Inventory and Analysis program a comprehensive database run by the US Forest Service on the state of the countrys woodlands that has been standardized since the year 2000 This database includes forest inventory plots that document location species size density and health of trees as well as tree growth mortality and harvesting Quetin and his colleagues also used data from the Xylem Functional Traits Database where measurements of tree physiology and hydraulic traits are compiled crossreferencing this database with the Forest InventoryFinally the team developed a model that simulates a forests response to increased water stress The model predicts photosynthesis or CO2 in respiration and growth CO2 out as well as plant stress They also included an optimization technique to look at how changes to leaf area could mediate the stress caused by changing environmental conditions All the data to date suggest that leaf area is just the biggest lever that individual trees can throw to manage water stress said coauthor Lee Anderegg an assistant professor in the Department of Ecology Evolution and Marine Biology Forests in drier areas tend toward sparser canopies while forests in wetter climes can afford thick foliageThe researchers found that many of Americas forests have the capacity to adapt The model revealed that 8837 of the forests across the continental US have the trait and species diversity to acclimate to climate change and they are starting to However most werent adapting as quickly as the model predicted was necessary to avoid increased water stress and subsequent mortality Its concerning that we dont see the required shifts that our model predicts need to happen said coauthor Anna Trugman an assistant professor in the Department of Geography But I think theres still room for hope For instance biodiversity stood out in its ability to buffer the impact of climate change on a given forestTrees are slow movers as we know Trugman continued Ive seen the pace of those Ents in The Lord of the Rings Theyre still holding the Entmoot at the moment Anderegg added Higher carbon dioxide concentrations introduce a confounding factor in the teams calculations Plants lose water through the same pores that they use to take up carbon dioxideSo if theres more CO2 in the atmosphere plants can decrease the size of these pore openings and still acquire the carbon they need for photosynthesis This reduces the amount of water escaping from their leaves But the atmosphere is also dryer in a warming climate Anderegg explained so leaves lose more water Its a complex system with a lot of uncertainty and compensating factors which requires nuanced models to disentangle And the energy involved in transporting this water is far from negligible as the authors discovered in a previous paperThe team is now collecting their own data on changes in tree physiology following climatedriven fires in Sequoia National Park trying to empirically verify how much trees can adjust their physiology The authors are also investigating if trees can avoid future water stress entirely through changes to their leaf area and whether maximizing carbon gain or stress avoidance is more limiting Forests are already beginning to change Sparser canopies will become more common as the atmosphere becomes drier Woodlands will also likely have a different mix of species than they historically hadThese factors all impact forest carbon storage as well Forests currently sequester about 3037 of anthropogenic emissions but the group recently found that this would likely decrease under climate change Management strategies that encourage forests to adapt will be critical We need to be thinking about these forests not as static things that need to exist just as they are right now but as healthy things that need to change to keep up with the climate Anderegg saidFacilitating gradual change will help prevent abrupt catastrophic changes like wildfires and dieoffs that are detrimental to the forests wildlife and people living nearby Resource managers could begin planting areas with more droughttolerant species and conducting prescribed burns to promote healthy woodlands But most of all we need to mitigate climate change the authors said Our future depends on societys emission trajectory Climate adaptation is no easier than climate mitigation Quetin noted And less climate change means less adaptation is necessaryAlso Read Male cheetah Tejas dies at Kuno 7th death in last five monthsThis story has been sourced from a third party syndicated feed agencies Midday accepts no responsibility or liability for its dependability trustworthiness reliability and data of the text Midday managementmiddaycom reserves the sole right to alter delete or remove without notice the content in its absolute discretion for any reason whatsoever