The words “science” and “nature” are often used together, yet they are often thought of as very different concepts. Science is a laboratory with beakers, test tubes, and microscopes, while Nature is a museum of plants, animals, and rocks. However, everything we know about our natural world has been learned through scientific investigation.
The first step in the scientific method is to identify a "problem."
The leaves of several deciduous trees dried up and turned brown and are either falling to the ground or hanging on the branches. Why is this happening?
Then you gather information:
The leaves of deciduous trees die and fall off during the fall and winter months. Leaves also die and fall off when the entire tree dies due to age, trauma, diseases, and pests.
Next, you form a testable question (aka, a hypothesis):
If the phenomenon is caused by a disease or pest, you will be able to see a relationship among the kinds of trees affected.
In question form… Are they all the same species of tree and is every individual of that/those species in the forest brown?
Now you need to come up with a way to find the answers:
Use field guides and dichotomous keys to identify the afflicted trees.
Use field guides and dichotomous keys to identify the apparently healthy trees in the same area.
What did you find out? (This is simply the observation. We often move so quickly from making an observation to drawing an inference that we do not realize that they are two separate steps.)
30% of the brown trees are flowering dogwood. 55% of the brown trees are oak species. 10% of the brown trees are hickory species, and 5% of the brown trees are maples. Green, apparently healthy dogwoods, oaks, hickories, and maples were observed in the area.
What do you think this means? (This is the conclusion or inference that you draw based on your observations. Often, results can be interpreted multiple ways. Always, the inference inspires further investigation to which the scientific method can be applied.)
This phenomenon is occurring in several species of trees, therefore, the trees are most likely not contracting a pathogen or pest that affects whole populations of a species such as Dutch Elm Disease, or Emerald Ash Borers. A disease or pest that attacks many kinds of trees would attack all compatible trees in the area, so it is unlikely that the brown, dead leaves are the result of a disease or pest.
Hmm… [And the Scientific Process begins again]
Problem: Did the trees die? Or did they go dormant early?
Information: We know that deciduous trees appear to be dead in the winter because their leaves turn brown and usually fall off. We know that below the bark, the part of the tree that grows new cells, called the cambium, is moist and green in dormant trees, and brown and dry in dead trees.
Hypothesis: If the trees are alive, but dormant, we will observe a healthy cambium layer.
Procedure: Use a small tool such as a pocket knife or a fingernail to cut away a small section of bark to examine the cambium.
Results: 95% of the trees tested have a green, moist cambium under the bark. 5% of the trees are brown, dry, and brittle beneath the bark.
Conclusion: Most of the brown trees have stopped photosynthesizing but are still alive. They have gone dormant in response to some kind of stress. A few trees have died. The dead trees may have been unhealthy to begin with and so were unable to endure the environmental stress. Those few trees may have even been dead before the phenomenon was observed, or died of an unrelated problem.
Further inquiries: We may want to know if the early dormancy impacts other organisms in the forest, or if the openings in the canopy allow other plants to grow, or if the deciduous trees will grow again before the fall. Then we may want to know how long deciduous trees can be dormant before they become unhealthy and die. The process of scientific investigation is continual.
In short, the more we know, the more there is to know. Nature is full of questions waiting to be asked and answered using the scientific method.
