Just like how we don’t like it too hot or too cold, tree species also have preferences as to where they prefer to grow.
Every species on the planet has an ideal environment that they like to live in — cedars like a wet soil while ponderosa pines prefer drier conditions.
But what if that environment is slowly changing over time? The effects of climate change are undeniably here.
This summer, twelve weather stations in BC shattered their daily maximum temperature records. 2017 was a record year for wildfires in BC, both in hectares burned and dollars spent. What does this mean for our trees? What happens when an area that used to be cooler and wetter become hotter and drier?
B.C. is not just going to stand by and find out. Our province is taking climate change adaptation by the horns with AMAT – Assisted Migration Adaptation Trial.
Assisted migration is the human-assisted movement of a particular species outside of their normal residential or growing range.
The environment is always changing, but historically this change has been a very slow process. To better understand how our trees are “on the move,” let’s imagine a scenario close to home.
Western hemlock found in Skatteboo Reach, near Glade, have lived comfortably in a low to mid-elevation habitat for many years. Now imagine that, over time, the temperatures are rising.
Trees found at lower elevation will spread seeds which may not survive because it is too hot and dry. Trees in the middle elevation will likely not be affected right away. Individuals living in the higher elevation will have success at spreading their seeds in this new warmer climate, where they would not have survived before.
This phenomenon is happening naturally. The difference here is that climate change is expediting the process to a point where trees cannot respond quickly enough.
In contrast, wildlife can move quickly if need be while trees are stuck. To address this, British Columbia is experimenting with taking seeds from one geographical area and planting them into another – sometimes 200m higher in elevation! The hope is that when the trees are mature in 80 years, the environment will have changed as they thought and the trees will be well adapted for survival in their new location.
Between 2009 and 2012, seeds from 15 tree species were planted at 48 different test sites ranging from northern California to southern Yukon. The seeds were planted at sites with conditions that researchers believe will eventually be appropriate – be it drier, wetter, warmer, colder. Test sites are being monitored every five years with the objective to gauge both their success and how the environment is changing. Are conditions changing and the trees succeeding as predicted?
As with any story, there are two sides to this climate adaptation experiment. It could work like scientists predict and we’ve done a good thing. However, what if the environment doesn’t change like we thought and the introduced species still do really well and crowd out other vegetation? We’ve seen this many times when an invasive species, by accident or intentionally, gets established in a new location.
Another argument is a moral one. Are we playing God? Should we let nature run its course regardless of the effects of climate change? Humans have a history of trying our hand at controlling nature and having it backfire.
Remember when we introduced deer to Haida Gwaii, only to have them become a problem? The experts are attempting to gain a glimpse into the future and make what they think are the appropriate changes. Only time will reveal the fate of our trees.
Kayla Zaretzki and Carmen Scott are second-year Recreation, Fish and Wildlife students at Castlegar’s Selkirk College.
