Multiple climate records were broken in 2016, according to a report published by the World Meteorological Organization this morning. Hearing about record high global temperature, exceptionally low sea ice, and persistent sea level rise was admittedly not the best start for celebrating the fifth International Day of Forests. Yet we need to be reminded about the vital and fragile links between atmospheric processes and forest functioning. As climate change rages on, we can expect hydrological cycles to become increasingly imbalanced around the globe. Especially tropical rainforests will consequently suffer. On the more hopeful side, scientists have now discovered that maintaining as high as possible forest complexity in tropical rainforests could buffer the negative impacts of climate change.
"It is difficult to rate the importance of the different soil functions, since all are vital to our well-being to some extent. However, the function of supporting food and agriculture worldwide is fundamental for the preservation and advancement of human life on this planet." – Food and Agriculture Organization of the United States (FAO).
The multiple roles of soil often go unnoticed. During time spent carrying out research for this blog I came across the following quote which I feel really captures the relevance of soil health for the One Health concept:
‘The health of soil, plant, animal and man is one and indivisible’.
This was actually said seven decades ago by Lady Eva Balfour, one of the first women to study agriculture at an English University, who went on to found the Soil Association in 1946. Yet it seems that on many levels we are still to realise the connectedness between health in soils, plants, animals and people.
With the global population estimated to reach 9 billion by 2050, there has been much debate around the issues of nutrition and food security. Amid these concerns, a report published on May 6 by the International Union of Forest Research Organizations (IUFRO), calls for greater consideration of the use of forests as a food source as well as for biodiversity conservation. The report, titled “Forests, Trees and Landscapes for Food Security and Nutrition” was presented at the UN Forum on Forests and is a result of the collaboration of more than 60 scientists from around the world.
Forests cover approximately 4 billion hectares of the Earth's surface, equivalent to a third of it's total land area. According to the WWF, between 12-15 million hectares of forests are lost every year due to human impacts, such as deforestation. It is estimated that forest loss is responsible for around 15% of global carbon emissions. Being able to accurately measure these emissions is important to develop a strategy to mitigate against the impacts of climate change. Until now, it has been difficult for researchers to monitor the world's carbon stocks and how they vary over time. However, a team of researchers from the Carnegie Airborne Observatory of Stanford University (CAO) have developed an airborne LiDAR (Light Detection and Ranging) system that can measure how much carbon is stored in forests and where human activities including deforestation are releasing it.
2012 has been an interesting year for those concerned with woods and forests. We’ve seen the outputs from the Independent Panel on Forestry and we’ve had the British Woodlands Survey - not to mention ash dieback. A recent conference gave voice to those woodland workers, owners, and managers who took part in the survey, providing a fresh perspective on the importance of woodlands. For woodland owners, woodlands are much less profitable today than they were 50 years ago. Thankfully, the recent fashion for wood-burning stoves has led to demand for wood fuel that provides a welcome income.
However, woods and forests provide much more to us than products alone and a key message of the conference was that Britain needs to revive its wood culture – the awareness and appreciation of woodlands and forests. They are essential habitats for both wildlife and humans, somewhere to escape to and enjoy whether it be walking, bird watching or biking.
The conference featured a great diversity of speakers from both Oxford and Cambridge University, the Sylva Foundation, the Woodland Trust, the Forestry Commission, the Earth Trust, Natural England and the Crown Estate, and also views from forest managers, forest owners and even BBC presenters!
Studies on ‘natural’ and ‘forced’ migration of forests threatened by climate change.
A multi-European project trying to anticipate the effects of climate change on forests is taking shape. In parts of Europe, established forest trees are showing signs of vulnerability – such as drought stress – as their ‘climate niche’ changes. An ambitious long-term project hopes to work out which species will provide the best natural environments and commercial forestry prospects for the future.
Thousands of trees are being planted at 37 locations on the west Atlantic, covering a length of 1600 miles from the Azores to Scotland. Forest Research (part of the Forestry Commission), the UK partner in the ‘Reinforce’ project, is planting 30 species at various sites in England, Scotland and Wales. The species include familiar trees like English oak, Scots pine, silver birch and sweet chestnut as well as less usual species such as Atlas cedar and Macedonian, maritime and Monterey pines from the Mediterranean, Eastern Europe and California.
As to the time-scale of the project, growth data and responses to climatic variables like temperature and soil water will be collected and analysed regularly, but it could be 50 years before any meaningful data can be gathered for mature trees. With climate change now evident, there’s no time for delay…
Watch a video of the research on the BBC website.
The trial coincides with the findings of a 4-year survey of 15 coniferous species in 34 different ecoregions in western Canada and the USA(1,2). Remote sensing of large areas showed that a huge natural migration of trees has already started across much of the west due to global warming, insect attack, diseases and fire, and many tree species are projected to decline or die out in regions where they have been present for centuries, while others move in and replace them. Forests are reshaping in a visible display of ‘survival of the fittest’.
Existing species are losing their competitive edge and opportunistic species are taking over. More than half of the evergreen species were found to be experiencing a significant decrease in their competitiveness in 6 ecoregions. The study projected that in some cases, once-common species such as lodgepole pine will be replaced by other trees, with perhaps a range expansion of ponderosa pine or Douglas-fir. Other areas may shift completely out of forest into grass savannah or sagebrush desert. In central California, more than half of the species now present would not be expected to persist in the climate conditions of the future (approx. 2-4°C warmer by 2080, drier summers, and wetter spring and autumn seasons).
Some of these changes are already happening quite fast and over huge areas – at a rate fast enough to detect at the landscape level – remarkable for forests.
1. Waring, R. H.; Coops, N. C.; Running, S. W. Predicting satellite-derived patterns of large-scale disturbances in forests of the Pacific Northwest Region in response to recent climatic variation. Remote Sensing of Environment (2011) Vol. 115 No. 12 pp. 3554-3566.
2. Coops, N. C.; Waring, R. H. Estimating the vulnerability of fifteen tree species under changing climate in Northwest North America. Ecological Modelling (2011) Vol. 222 No. 13 pp. 2119-2129 [10.1016/j.ecolmodel.2011.03.033]
Oregon State University news
Much attention has focused on what plants will be able to grow where as the effects of climate change are felt. A key factor that plays into that analysis is what effect climate change will have on diseases and weeds.Two new papers in CAB Reviews look at those two elements and show that that the picture is a complex and sometimes surprising one.
Sukumar Chakraborty (from CSIRO Plant Industry) and co-authors note that modelling experiments suggest that the range of key pathogenic fungi may shift significantly towards the poles as a result of global warming. The impacts of raised CO2 and temperature together are more difficult to estimate, as raised CO2 may increase the vigour of some trees and crops. From certain studies it seems that C3 plants, such as cereals, may suffer from increased numbers of pathogens with increased CO2, while C4 plants (most other crops and trees) may not. Chakraborty and colleagues write that minor changes in climate can tip the balance in favour of an exotic species, and the same may be true of disease outbreaks. Import risk analysis will need to take into account changes in the risks of establishment of pests and pathogens as the climate alters.
Examining the 12 most serious weeds, Xianshong Wang (from Indiana University-Purdue University Indianapolis) and Jacqueline Mohan (from the University of Georgia) suggest the competitiveness of weeds at higher temperatures and CO2 levels may be affected greatly by water availability. Most of the weeds will be expected to be boosted by rising temperatures. Field bindweed may become a more serious weed in drier regions, while it may be outcompeted in well-watered soils. Purple nutsedge may suffer because of expected reductions in moisture and rising soil nitrogen.
Wang and Mohan point out that the move to biofuels may exacerbate some of the projected weed problems: “Altered land use and the unforeseen consequences of energy plants may have a greater impact on the seriousness and injuriousness of weeds and weed-crop interactions than the effects of other global environmental changes, including rising CO2, global warming and more frequent and severe droughts.”
Effects of global environmental changes on weeds by Xianzhong Wang, J.E .Mohan
CAB Reviews: Perspectives in Agriculture, Veterinary Science, Nutrition and Natural Resources, 2008, 3, No. 067, 20 pp.
Impacts of global change on diseases of agricultural crops and forest trees by S. Chakraborty, J .Luck, G. Hollaway, A. Freeman, R. Norton, K.A. Garrett, K. Percy, A. Hopkins, C. Davis, D.F. Karnosky
CAB Reviews: Perspectives in Agriculture, Veterinary Science, Nutrition and Natural Resources, 2008, 3, No. 054, 15 pp.