Phenology

Phenology: I didn't know what the word meant until I had to apply for my current job. Even still, I didn't understand the full meaning of it until I began working here.

Phenology is the study of the timing of periodic changes in biology, as they relate to climate. Migration, breeding, flowering, root growth and leaf growth, metamorphosis - all of these are studied by phenologists. The research I am helping with involves plants, insects, and songbirds - a nice collection of trophic levels that might show some measurable interaction. My job is to look at the plants, and to collect the insect traps. I thought that I would be measuring stem lengths with a little ruler, or counting leaves. In retrospect I was quite naive. And here I was with a college degree in biology!

Fading bloom of Coptis laciniata,
called "cut-leaved goldthread".

Instead, I am grading each plant on two different scales of 1 to 6: 1 being no growth activity, and 6 being a mature stage. One scale is for vegetative growth; i.e., leaves, and the other scale is for reproductive growth: flowers or cones. Each classification is clearly defined; for example, vegetative 4 is "unfolding leaves" and vegetative 5 is "leaves unfolded, less than 75% full size". There are 16 different sites that we visit, in a variety of habitat types: north slopes, south slopes, old-growth, new growth, 3,000 feet, and 5,000 feet. An interesting idea, based off of previous work in these woods, is that micro-climate may have a profound affect upon phenology. In an attempt to factor that variable into the experiment, each site has a temperature and photoperiod sensor, and all of the study plants are located within 30 meter radius of that sensor. At each site, there are about 50 individually tagged and numbered plants. Some of the studied plants include the little yellow violet, Douglas fir, vine maple, rhododendron, and trillium. The species to be studied have been chosen for their relative ubiquity among sites, their ease of studying, their supposed importance to the forest, and their time range of growth activity. For instance, Snowqueen blooms very early, allowing a measure taken in April to be more than just all 1's ("no bud activity"). Vine maple is found at almost every site. And Oregon grape, which was used in the study last year, has been dropped because of its seemingly random flower activity.

But the study of phenology is giving me something more than a page of numbers, even something more than the beginning of what is, hopefully, a long-term study. As I have been watching individual plants, visiting them at least once a week, making notes of their growth, I feel that I have become aware of a pattern of the forest that I have never truly understood, in two ways. The first is the timing - if you had asked me when maples put out their leaves, I would say, "springtime". But I would not have realized that Douglas fir put out pollen cones before new needles, or been able to tell you that trilliums turn purple before their petals wither. I would have no idea when huckleberries started flowering. The second is in details - I had never paid attention to the way that vine maple leaves emerge, first from their reddish buds, encased in a thin green sheath, and then, elongating, suddenly pop out of their stockings and spend several days unfolding to flatness.

This is movement in the plant world! Here I can see plants as never before; I am beginning to know their changes in an intimate way. The only other growth of a biological organism that I have really consciously observed is in a puppy. I realize that this is the sort of thing "real naturalists" always write about - Thoreau, Leopold, authors like Wallace Stegner and Ivan Doig, people who are somehow (so it always seemed to me) magically aware of this aspect of the living world around them. I had never known how to begin in my self-imposed naturalist studies - now, the mechanism has fallen into my lap and focused my yearning eyes. What was missing from my earlier attempts at phenology - though I wouldn't have known what to call it, before?



Above: vegetative buds of Douglas-fir, Pseudotsuga menziesii. The buds on the right are close to breaking open.

Many of the key attributes of the study can be simplified and applied to almost any backyard.

1. Identification of species
2. Comparison of different species
3. Note-taking

Those are the most important ideas, but there are a couple more that have helped me to really develop an understanding for what is going on throughout the area:

4. Comparison across elevation gradients
5. Multiple individuals of the same species

The future of these plants is entirely unknown to me, and I feel like I am unraveling a mystery - what will bud break look like? When will the flowers open? How will the rhododendron leaves unfold themselves? Only time will tell...
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