Climate Change Bad for Walnut Trees
by healthypages on 18/03/2012 - 03:08 pm |
The Purdue University is warning that Walnut trees may be disastrously affected by climate change. In particular it is extreme weather events such as drier and warmer summers
Two researchers, professor of forestry and natural resources, Douglass Jacobs and a former doctoral student under Jacobs, Martin-Michel Gauthier spent over 5 years studying the effects of climate on the walnut tree and discovered that they have very specific needs in order to flourish. In particular they find it difficult to survive droughts.
They are also cautious of late frosts and cope with the possibility of one by sprouting leaves a month later than most other trees.
It is this very defence mechanism that could leave the walnut trees vulnerable, as any extreme weather event could lead the tree to sprout leaves that would then all be killed off in the late Spring frost. Such an event could also kill the tree
Walnut trees are important in Indiana due to their contribution to the local economy as they are used for veneer and lumber and in some parts for their nuts.
Jacobs said that "Walnut is really restricted to sites not too wet or dry. It has an extremely narrow range." He added that "We suspect and predict that climate change is going to have a real impact on walnuts. We may see some type of decline of the species."
Indiana relies heavily on walnut trees. In 2010 over a $1 billion was paid for over 500,000 tons of the nuts by California. The Hardwood Tree Improvement and Regeneration Center in Purdue valued the walnut logs at $11 million, said project leader Charles Michler. They represented 15% of all logs sold within Indiana.
Michler said, "Walnut is probably the most important species in the hardwood products industry today." To try and overcome the sensitivity of the walnut they are trying to breed a type that is more versatile in varying climates. To do this they are focusing on seeds from mature trees in the hope that the seeds will have gained some of the defense mechanisms the older trees have attained.
Michler explained saying, "That could be the strategy that trees have," adding that "The trees that are mature now may be affected by climate change, but the seeds they produce may be adapting through genetic changes."