How can trees tell us about climate change?
By Sulhat Salehin
How can trees tell us about climate change?Looking at the peculiarities of the rings inside a tree, scientists can tell how old the tree is, and the weather type at each time of the year.
By understanding the difference between weather and climate, we can know what tree tells us.
Weather is a specific event – such as a rainstorm or a hot day – that occurs in a short period. Weather can be tracked in a few hours or days. Climate is a long period of weather conditions.
Usually, older trees can give an idea of what the climate of that region was like before the weather was recorded on Earth or in that region.
But to understand what the trees tell us, we need to know the weather and climate differences.
Weather is the state of heat and temperature, wind flow, wind pressure, storm-rain, etc. in a given period, i.e., one, two, or three years which occurs in a short period. Climate, the weather condition is prevailing in an area over a long period.
Scientists at the U.S. National Meteorological Council have been monitoring the weather since 1891. But the trees have a long history of climate change. Usually, trees can live for hundreds of years and thousands of years.
Scientists use trees to learn about past climates by studying tree rings. If you’ve ever seen a tree stump, you’ve probably noticed that there are several rings on the stump, which looks a lot like a bullseye (target).
These rings can tell us what the weather was like in each year of the tree’s life and how old it is. Light-colored rings mark wood characteristics that grow in spring and early summer, while dark-colored rings mark those that grow late in summer and after summer. A light ring and a dark ring are equal to one year of the life of a tree.
The tree ring’s color and width can give an idea of the climatic conditions of that region in the previous period.
As trees become more sensitive to local climates such as rainfall and temperature, they begin to give scientists an idea of the local climate of that region in the past.
As the tree rings are wider, the rings are usually thinner in warmer and more rainy years and in winter and dry years. But when the tree faces a natural disaster like drought, the trees grow very little that year.
Locally recorded temperature and precipitation are obtained from the nearest weather station being used to compare with local plants. However, ancient trees can give an idea of the climate of the region before the record measurements.
Methuselah is the oldest living tree in the world. It is a 5,000 years old Bristlon pine tree found in the White Mountains of California.
In most cases, only 100 to 150 years of daily weather records are collected. Thus, significant sources for scientists to know about the climate hundreds of thousands of years ago are trees, corals, and ice cores.
Do we have to cut down any trees to see the rings?
Not at all, you can calculate the rings of a tree by collecting a sample of it with the help of an instrument called increment borer. Bora pulls out a thin strip of wood that can go in the middle of the tree.
Later, when you pull the tree’s bark, those bundles of wood can be counted, and it does not cause any damage to the tree, but the tree stays healthy and strong.
In Uttar Pradesh, any student can learn how to take a core sample of a tree through an advanced bora machine in the Mantilla’s National Forest.