When observing a tree, we are easily attracted by its majestic trunk, colorful leaves, beautiful flowers, strange fruits or seeds, and thus ignore some specific details. This is human nature. After all, if you don’t look at such obvious features, why don’t you look at the details first? This is really a waste of time.
But sometimes, this "mo" is of great use.
It is now the depth of winter. When I observed the branches of the Platanus , there was really nothing to see except the "balls" swaying in the wind and the winter buds that had lost the protection of their petioles. While I was lost in thought, I suddenly saw circles of threads on it. I looked carefully and saw that these were not bud scale marks!
The circles of "threads" on the branches of the sycamore tree are bud scale marks
Bud scales are scale-like abnormal leaves wrapped around the buds for protection. The traces left after the bud scales fall off are called bud scale scars. They are often arranged in a ring around the stem. Generally, the bud scale marks on the terminal buds are more obvious. After the lateral buds grow into side branches, the bud scale marks are not obvious at the branch axils. The obvious bud scale marks on the side branches are the bud scale marks on the terminal buds of the side branches.
Bud scale mark diagram
Bud scale marks have no obvious internodes and are very dense. They are easy to distinguish from leaf marks , so the age and annual growth of the branches can be judged based on them. The terminal buds unfold once every spring, and each time the bud scales fall off, they will leave several circles of marks, so count the number of bud scale marks on the branch, and add 1 to get its age.
There are 2 bud scale marks from top to bottom, plus 1, the age of this branch is 3 years
I was very happy with this discovery and decided to use this method to calculate the age of this tree. But it soon ran into difficulties, because this method can still be used for branches that are one or two years old, three or four years old, or even five or six years old. No matter how large the branches are, they will be very subtle or invisible, so this method can only be used to estimate the age of smaller branches.
This is a 5-year-old branch, and the bud scale marks on it are no longer obvious.
This aroused my interest in determining the age of big trees.
When talking about this issue, many people will immediately think of: annual rings! I have asked 5 people this question, and the answer is without exception.
Yes, this is a very intuitive method, but they ignored the simplest and most direct method, which is to find a way to find the specific date when the tree was planted! This should also be the most accurate method.
Annual rings are actually not very accurate. Not to mention the great limitations of cutting down trees or using wood drills. Some trees, such as citrus trees and some trees in tropical areas, sometimes have annual rings that grow several times a year, and sometimes only grow once every few years. They are "false annual rings"; and even trees with "true annual rings" will also change due to insect damage or environmental impact, so this can only be used for estimation.
There are many "false growth rings" in trees.
There is another method that looks very scientific, and that is the "growth factor method". Multiply the tree's diameter by the average growth factor for trees of that species to find the tree's age.
The growth factor of a tree is the growth rate calculated by measuring the diameter and width of the tree's annual growth. Because the growth factors of different trees depend on the environment in which the trees grow. For example, trees in forests grow faster than trees in cities, so this method can only get an estimate, which is not very accurate.
It should be noted here that the diameter of the tree should be taken as the diameter 1.4 meters above the ground.
Every small detail of biology reveals the password of life. As long as you have a pair of eyes that are good at observation and a brain that is diligent in thinking, you can have insight into everything.
