Layla’s Blog BIO301

Trees have always been thought of as motionless. In reality, this is somewhat a myth. Research of Andean trees in mountain ranges actually shows a trend of upward and downward movement in trees over thousands of years. The current upward migration, however, may be proof that nature isn’t capable of keeping up with human-enacted global warming.

            A research group led by Kenneth Feeley has studied the current upward movement of trees in the Peruvian Amazon. Trees have moved upslope of 2.5 to 3.5 meters per year due to rising temperatures in the lower areas of the Andes mountain ranges. Tree species will migrate up to higher elevations where the temperature is cooler. This shift in trees isn’t necessarily one tree pulling its roots and leaves up the mountainside. Researchers instead measured the average elevation of one genus of tree and re-measured the average elevation over several years to observe a change. What’s alarming is the rate at which the trees are moving upwards in comparison to the temperature change. They’re just not quite fast enough.

“Trees are moving at a rate 25 times slower than how fast they should be moving upward to avoid climate effects,” said William Farfan, a member of Feeley’s research group. According to Farfan, the increasing global temperature is killing species in the lower regions of the Peruvian mountain ranges. These species may be larger and, as a result, lag behind the other trees in their migration up the mountain ranges. The consequence of these large trees dying out is that the Amazon slowly starts to lose portions of its important carbon sink.

Trees in the Amazon rainforests act as a massive reservoir for carbon storage simply due to the sheer amount of these trees that can fit within one unit of area. These diverse group of tree species pull large amounts of carbon dioxide out of the air, aiding in absorbing excess carbon from the atmosphere. Unfortunately, climate change has already taken its toll on the Amazon’s diverse variety of tree species. The rapid warming of the environment is killing off several larger species of trees that are not migrating fast enough to avoid the changing temperature.

“You lose biodiversity and the ecosystem’s services like carbon uptake from the atmosphere,” Farfan said.

The death of these slower moving tree species act as evidence that global warming is happening much more rapidly than previous periods of warming. Global temperatures tend to fluctuate by a degree Celsius every one thousand years. Several generations of trees are able to adapt to these fluctuations by moving their elevation to whichever is optimal for growth and survival. Within just the last century, the global temperature has increased by 1.5 degrees Celsius according to The Intergovernmental Panel on Climate Change. This rapid increase in global temperature isn’t what the Amazon’s ecosystem is used to adapting to.

“Life does a good job at adapting to slow changes but the climate is changing so much faster than it had ever changed before,” said Miles Silman, a biology professor at Wake Forest who’s also involved in tree migration research. The outlook on the survival of these lower-living species of trees is bleak due to this fast acceleration of global warming.

“Trees can only move as quickly as they naturally grow, live and die,” said Cassie Freund, a graduate student assisting in Dr. Silman’s research. “Unless trees really speed up the way in which they live and reproduce, it’s just not possible to move up that quickly”

Although there isn’t a way to rapidly treat the damage this global heating has already done to the biodiversity of the Andes forests, scientists have now refocused research towards the best implementation of reforestation and identifying threatened species. Wake Forest University created the Center for Amazonian Scientific Innovation and it has become one of the leading research programs for ecological and reforestation research in the Amazon and the Andes.

Researching these migration trends in specifically Amazonian plant life may seem beneficial solely to South America but this research is vital to combatting climate change worldwide. Even if this degradation of tree species diversity isn’t directly being observed in places like the United States, the whole world’s population relies heavily on the Amazon as one of the world’s largest carbon sinks. As the global temperature continues to rise and kill more trees in the Amazon, people around the world will lose more of the few natural resources we have to eliminate excess carbon in the atmosphere.

“We all depend on the services of these forests,” Farfan said. “Even if we are in the United States, we depend on the Amazon rainforest to sequester carbon. Everything is so interconnected. We all depend on those ecological services.”