Trees are amazing in how they grow. They sprout in seemingly impossible locations and weather, from nuts, roots, and even fallen branches. They grow old and die, get diseases and perish, and also flourish and grow. They form heartwood, or "dead wood", sapwood, and pithy cores. They provide humans with lumber, as well as nuts and fruit, and shelter for humans and animals. Trees are used for products such as walking sticks, furniture, pencils, paper, etc.
One of the pictures below shows a recently pruned apple tree of ours, there is also an image of a diseased, burled, and dying large oak tree. The bark can grow thicker and more cracked as the tree grows older, and the roots can grow many feet deep. The pith is the absolute center of the tree, which in walnut and ash trees is hollow. The heartwood is the "dead wood" surrounding the pith, typically dryer and darker colored than the sapwood, which surrounds the heartwood in a ring. The heartwood is often considered the backbone of tree. The sapwood is usually more sappy and wet than the heartwood, and the growth rings are often farther apart there. On the outside of the sapwood is the inner bark, which is surrounded by the often harder outer bark. The grain of the wood is often considered as straws held together with glue. The "glue" is called lignin.
The "straws" are known as cellulose fibrils.
Saplings that I harvest are typically seven to twelve years old when I cut them. You can tell the age of trees by counting the number of growth rings. Each ring is one year. The leaves absorb sunlight through a process called photosynthesis, producing chlorophyl, which is what makes the leaves green, and drains from the leaves in the Autumn.
You can reach out and personalize your own hiking stick at https://docs.google.com/forms/d/e/1FAIpQLSfLGQBdXZ8rDE6T4mTnxhYZbZedua7P3FnvNyafNxAfgKjsIw/viewform
There is a quote below from my Grandpa.