OPINIONS OF SAMPLERS AND OTHERS

The people doing the sampling provided verbal and written observations and opinions of the stress detection glasses. Other persons that have tried the stress detection glasses provided some additional input/opinions. These are summarized below.

Sampler’s Comments
It became evident that the dead or dying plants had a more orange or red appearance.

The signs of mortality were more evident without glasses than with the use of the glasses.

On the first day of the experiment I was able to detect stress in two plants that I could not see with the naked eye. As the test went on, many of the plants showed noticeable signs of stress with the glasses, and no signs without the glasses.

Group D showed plants having signs of mortality but this was also detected without the glasses.

....when the sun was at your back and directed on to the plants it enhanced the colors more.

The glasses did enhance the mortality but the mortality could be detected without the glasses.

The usefulness of the glasses for detecting stress varied by type of plant, time of day, direction, and cloud cover.

Group F showed more yellowing but showed better without the glasses.

The colors were more enhanced with the glasses.

There were certain times of the day that the glasses seemed most effective. During the early afternoon and late evening the glasses worked better than they did in the mid-afternoon. The light colors were more apparent in the early morning and late afternoon. There was not this distinct difference when it was the middle of the day.

Overall the glasses helped me detect stress in the plants that I was not able to see with the naked eye.

Although the plant stress could be observed at about the same time with and without the UV glasses, the stress was more apparent with the glasses for some plant types.

My observation is that a user may find these glasses helpful in detecting mortality. However, there will be a learning curve in seeing these differences.

These glasses may only be good for specific species.

The glasses tended to conceal stress in plants with yellow-green leaves.

I would only use these glasses in conjunction with other science.

I think the glasses are a useful tool for some types of plants, not necessarily to detect stress sooner, but to see it easier.

Others
Bill Radtke, Michigan Department of Natural Resources. Surveying a variety of causal agents in both hardwood and conifer forests.

They did seem to be useful. After a period of acclimation and comparison I did learn to interpret the information garnered via the glasses.

Our application requires the constant transfer of information to a quad map and soon to a computer tablet. The stress detection glasses are so dark that constant removal or lifting of the clip-on lenses is required. This problem could be eliminated by leaving the bottom half or “bifocal” area of the lenses clear.

Bill Befort, Minnesota Department of Natural Resources. Sketch-mapping during aerial surveys.

Entire landscapes viewed from the air are far from uniform; there is a very wide range of perfectly normal variation and contrast, unrelated to plant damage, that must be instantly and continuously recognized and factored out by the observer as he flies along. The symptoms of vegetation damage are not the strongest contrasts in the general landscape, but some of the subtlest, and they are also far from uniform. Because stress detection glasses substantially alter the visual appearance of the landscape, they add a great deal to the baseline mental interpretation workload that the observer must handle merely to stay oriented and factor out inessentials, while any enhancement they provide to vegetation stress symptoms is likely to be lost in the clutter. In brief, they create more problem than they solve.

I’ve settled on amber (not yellow) “blue-blocker” sunglasses for sketch-mapping.

Keith Windell, Missoula Technology and Development Center. Evaluating fire damaged trees.

In the very short period of time I had them on (about 5 or 10 minutes per session) my eyes never did totally adjust to the color scheme (rose) you see through the glasses. I started to feel disoriented (and even sick) so discontinued using them.

The dead needles in the tree crowns stood out but at 50 to 100 feet I didn’t feel like I could make a decent call on whether the trees were mortally stressed or not.

Although an experienced user of these glasses would no doubt be more confident with their decisions (leave vs. cut) I think there will always be a high degree of subjectivity in this approach....