Select a tree that has a visible a trunk and has lots of branches. A big tree that you like, either on your exercise route, maybe near your home. Find a seed from the tree (even better if the seed actually came from the grown tree), a sprouted seed, and a seedling.
Study each very carefully. It would help even more to have a text book on botany available and learn the names and interior structure of the various structures you are seeing. As you read and study the plants in detail (even using a microscope if you have one) you will begin to gain insight into how the plant functions, how it grows, how it circulates fluids, how it changes sunlight into sugars. This need not take more than a couple of good study sessions.
Spend some time observing the tree. What kinds of birds visit the tree? Do any actually live there? What insects are associated with the tree? Butterflies? Spiders? Ants? Bees? Any animals associated with the tree other than people? Do the tree fountain experiment.
Sit under the tree and feel the cool air. The dome-shape of trees acts as an air-foil, creating negative pressure above the tree compared with the atmospheric pressure below the tree. This forces an updraft through the leaves, promoting transpiration and cooling all of the creatures that sit within the wind torus.
When you feel you "know" the tree, sit in a quiet place so you can see the seed, the sprouted seed, the seedling and the tree.
Begin by looking at each and realizing that the tree, the big one, actually came from a small seed just exactly like the one you have.
The sprouted seed and the seedling will help you concentrate and understand how the process of development happened. Use your knowledge from your encyclopedia or botany book to enhance your vision and the depth of your understanding of the process.
Close your eyes and concentrate on the 4 phase cycle of becoming. Let yourself imagine you see a torus around the tree as, in your mind, you watch it grow from seed to tree. See the torus expanding as the tree grows.
Move your mind through the cycle, while using either plain English words (flowing together, weaving into one being, expanding outward, moving through time) or a mantra (Om Mani Padma Hum) or feelings associated with the process (Love, Joy, Peace, Harmony).
Then open your eyes and associate these feelings and these thoughts with the process of becoming of the tree.
As you visualize the torus structure focus on the understanding that this is not fiction, but is actually happening. Your eyes can't see the tree growing, but is really is. The tree actually is circulating the water, minerals, air, sunlight even if this circulation is beyond the horizons of your direct perceptions. It is NOT beyond your knowing. You understand the flow into the plant, how the plant changes this flow inside its own focus, how it expands out, unfurling itself, how it seeks to correct its position relative to gravity and the sun. You can't see this behavior directly but you see it happening in the form of the plant itself.
Study your own feelings and understandings as you continue this exercise. Do it as many times as you like. Repeat the mantra in your mind, when you visualize each part of the process. Do this also on the next exercises with the tree.
Once you feel accomplished at this, move on to the second level.