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| Tom's Blog
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| 3/29/2008 | Planting a Prairie Today Kathie and I helped Madison Audubon plant part of the Browne Prairie, a new planting at the Goose Pond Sanctuary. Some parts of this prairie were planted last December, but the incredible weather prevented it to be completed. . Snow drifts and wet areas made most of the prairie inaccessible. When the snow had finally melted, the ground was too wet and muddy for good access. We needed a cold night so the ground was hard in the morning. Today turned out to be the day. We had to start early because the prediction was for sunny weather in the low 40s. The sun was guaranteed to soften up the ground. By 10:30 AM we were finished, which was fortunate, because the ground was starting to get muddy. Our group of volunteers planted smaller areas that because of snow could not be reached earlier. The areas had been marked off with cones. Each person had a bucket or two to get rid of. While we were doing this, a fertilizer spreader was used to finish up some of the low-lying areas. After all the seeds were planted, we spent an hour or so cleaning up the barn and getting all the buckets, seed bags, and other peripherals stored for the season.
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| 3/26/2008 | No burn on March 26 this year! Last year we did the major burn on our south-facing remnant prairies on March 26. The previous week had been unusually warm and everything was ready. According to my blog for that day (look it up from the archive list on the left) by 11:00 AM the temperature was in the upper 70s and the relative humdity about 50%. To keep from damaging the bur oaks, we did most of the burn as a backing fire. The first photo below shows the fire creeping slowly downhill through the savanna. The second photo shows the area after the burn was complete. Coverage was close to 100%. This year, when will we burn? Snow is predicted for tonight!
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| 3/19/2008 | Using GIS to Characterize our Oak Savannas In an earlier post I mentioned the tree database we are creating for our oak savannas, using GIS technology. As weather has permitted, we have logged (data logged, not cut!) all the trees on our ridge-top savannas greater than 10 inches in diameter. Each tree is marked with a permanent numbered aluminum disk, its diameter and species recorded, and a GPS waypoint recorded. The waypoints permit visualizing each tree on an air photo of Pleasant Valley Conservancy. The GPS data are uploaded to a computer and transfered to an Excel spreadsheet. This is the first step in converting the data to GIS shape files. There are also a lot of independent analyses I can do in Excel itself. The quantitative data confirm what I knew qualitatively. The white oaks are predominantly on the lower slopes and the bur oaks on the upper ridgetops. These locations correlate very well with the bedrock characteristics of our area. (Remember that we are in the Driftless Area, so there is no glacial till.) The soils on the ridgetops are derived from dolomite and the soils on the lower slopes from sandstones. Some of our earlier data are shown on the air photo of the March 10 post (scroll down below). Since that was made, we have completed cataloging all the trees in the savanna areas except those on the south-facing slope. A total of 31.5 acres have been cataloged, with a total of 969 trees (all species, all sizes) for an average of 30.7 trees per acre. Those oaks on the dolomite were almost solely bur or black oak, whereas those at the lower elevations, on sandstone, were white oaks. The GIS software permits some interesting analyses. For instance, I can set up a database query so that only the white oaks or only the bur oaks are displayed. The correlation with bedrock character is very high. When displaying only the black oaks, I get an interesting pattern. They tend to be in clusters, and absent from other areas. Why? When we were clearing the savannas of "undesirable" trees, black oaks were removed only if they were "crowding" bur or white oaks. Those areas with clusters of black oaks may exist because there were no burs or whites nearby. When clearing, we often had discussions with the contractor about whether or not certain black oaks should be removed. Kathie and I felt that if a black oak was not doing any harm, it should be left. It could always be removed later. (The cost of clearing was pretty high, so there was an economic consideration here as well.) Indeed, in oak savanna areas on sand, such as in the Central Sands of Wisconsin, black oaks are the predominant savanna oaks. I am just scratching the surface with these sorts of analyses. The ArcGIS software is extremely sophisticated and highly flexible, but there is an enormous learning curve. At this time of year, with burn season about to begin, I am not willing to spend the amount of time needed to really get the most out of the data. I can wait until next winter to do a lot of these analyses. My current plan now is to use the software to prepare a new, more accurate map of the Conservancy, a task for which this software is eminently suited. |
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| 3/15/2008 | The Greenhouse Plants are Starting to Grow There is still snow all over but spring has come for our greenhouse plants. The trays shown below contain a compost soil/potting soil mixture (autoclaved to destroy weed seeds) and were planted with seeds in mid-December. After watering the soil these trays were covered and placed in a cold room at 4 C in order to stratify the seeds. In early March the trays were moved to the greenhouse, where they are getting natural daylength and temperatures of 62 F at night and 75-80 F in the day. Within less than a week some of the trays were showing tiny shoots, and after two weeks we have seedlings in most of the trays. (Those without growth contain the same species that my germination tests showed had very low or nonexistent viability.) The milkweeds are especially vigorous, as they have been in past years. Even purple milkweed, the endangered species, is thriving.
Some people may know that I spent my academic career as a microbiologist, working in my later years primarily in microbial ecology. However, most people may not know that I started out as a botanist, receiving my Bachelor of Science degree at Ohio State University. I spent two summers at the Ohio Agricultural Experiment Station, and actually taught Botany 101 in my last year as a graduate student. I always loved a greenhouse, and as a teaching assistant spent quite a bit of time in greenhouses getting plants ready for student demonstrations. I migrated from botany as a graduate student, working first on the physiology of the morel mushroom, and later on the physiology of a yeast. I was enticed into mycology, and then microbiology, by the attractions of working with organisms that grew rapidly. With microorganisms I was able to carry out many experiments in the time I could do one with plant material. Early in my microbiology career, I worked on applied problems (antibiotics). Later I worked on the physiology, genetics, and molecular biology of bacteria, yeasts, and bacterial viruses. Finally, in mid-career I turned to microbial ecology and spent the rest of my research outdoors. I worked a lot in marine and freshwater environments, including Wisconsin lakes. However, the most exciting research I did was on microorganisms living in extreme environments in hot springs and geysers of Yellowstone National Park and other thermal areas throughout the world. It seems that I have now come full circle. I am working on plants again, both in the greenhouse and in prairie and savanna habitats. Although I had forgotten most of the botany I had learned, I still remembered enough so that I could begin to read the literature intelligently. Our greenhouse work is only a small fraction of the work we are doing on restoration ecology, but it is enjoyable work, especially on these cold days. This is the third spring that we have raised prairie and savanna plants in the greenhouse, and we have been pleased to see so many of those we planted at Pleasant Valley Conservancy in earlier years now thriving. |
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| 3/14/2008 | Why Does Burning Promote Prairie Growth? The photo shows the striking effect that a burn has on the growth of prairie grass. The left side of this prairie was not burned the previous spring, and the right side was. Notice how much taller the Indian grass (Sorghastrum nutans) is on the burned side.
The effect of burning has been known since prehistoric times. Research has explained why. The principal reason is that in burned prairies the thick thatch of detritus is eliminated, allowing the grasses to get a head start. In tallgrass prairies, the grasses may take as much as 30 days longer in the early growing season to emerge above the thick detritus. The thatch shades the shoots so that they are cooler and receive much less solar radiation. However, not all effects of burning are beneficial. Burns volatilize nitrogen from the prairie, and nitrogen is the principal plant nutrient limiting prairie growth. Research in Kansas has shown that a single prairie burn leads to a loss of nitrogen equivalent to about two years of nitrogen inputs from rainfall (the principal source of nitrogen on a prairie). Much of this nitrogen loss is probably made up by nitrogen fixation by both free-living and symbiotic soil microbes. A nice review of the effect of burning on productivity of tallgrass prairies is by Knapp, A.T. and T.R. Seastedt, BioScience 36: 662-668, Nov. 1986. |
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| 3/11/2008 | At Last---Back to Brush Cutting We knew that winter could not last forever, but I sometimes wondered. The longer days and higher sun angle are helping to melt the snow. We still do not have a snow-free Conservancy, but steep hills with good south exposure are now mostly snow-free. Today we started brush cutting again. In the morning we worked on the upper part of Unit 11 (11C), a fine bur oak savanna which had quite a bit of blackberries and scattered small honeysuckles. To reach there we had to trudge through about a foot of hard crust snow. In the afternoon, the snow had softened enough so that access to Unit 11 was difficult, so we switched to Unit 7 on the south slope, which was snow free. Our plan now is to continue brush cutting on a Tuesday/Thursday schedule. |
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| 3/10/2008 | Getting Going on GIS We have been setting up a database of our trees using GPS (we have a Garmin 76Cx unit). However, getting the data showing on a map of Pleasant Valley Conservancy was a major task, which I have finally conquered. I took a course in ArcGIS at UW-Madison (2 full days when the weather was still cold and icy). This course came with an evaluation copy of ArcGIS 9.2, the most recent version. The data in the Garmin (waypoints) can be downloaded using the Garmin-provided software. I was then able to copy the data to a Microsoft Excel spreadsheet, where it can be manipulated. I'll go into the complications of mapping in another post. The image below is a recent version, which shows the location of individual trees. The colors indicate which management unit the tree is in. The labels show the species. The air photo is from 2005 and was downloaded via a web site called wisconsinview.org. Although there are a number of sites which provide air photos for download, the photos in this one are orthophotos, which means that they contain the geographic coordinates. Without these coordinates, the ArcGIS software cannot properly display GPS data. (These files are huge. Don't even think of downloading without a broadband connection!)
There are lots of things one can do with GIS software. For instance, I can draw polygons around various units on the orthophoto and the software will instantly calculate areas. I can trace roads, trails, or fire breaks and get the distances. And lots of customized maps can be created. More detail later! |
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| 3/2/2008 | Seed Germination Data In an earlier post I discussed the seed germination work I am carrying out this winter. This experiment is now completed and I have analyzed the data. The results are interesting, in some cases gratifying, and in other cases disturbing. Thanks to Susan Slapnick for "tending" this experiment while Kathie and I were on vacation! The table below is a summary of the data. This represents germination percentages from two petri plates, each of which had 25 seeds. The milkweed seeds of all four species had high viability. This agrees with my data from previous years and indicates that seed viability is not the problem in getting these species going at a restoration. The seeds of purple milkweed (an endangered species) were obtained from a vigorous population growing in our forbs garden. The seeds of the other species were collected from free-ranging populations, either at Pleasant Valley or at Black Earth Rettenmund Prairie. The high viability of the Indian grass seeds is gratifying. The seeds of this species were all collected at Pleasant Valley Conservancy, a lot by volunteers. It is nice to know that our volunteer work was not wasted. The great wet weather in August and early September, when the seeds of this species were maturing, presumably was responsible for these good results. Giant yellow hyssop is a threatened species that we have been successful in establishing at Pleasant Valley Conservancy. Sweet Indian plantain is a threatened species that is native at Pleasant Valley. Prairie dropseed is an attractive prairie grass that we have been working hard to establish over the past ten years. Although it has been a long time coming, we are finally getting populations established on our south-facing slope and in the drier parts of the Pocket Prairie (where the seeds were collected). Any germination percentage over 20% I would consider fairly good.
When looking at these data, remember that they represent only seeds which sent out roots and/or shoots. In the commercial seed laboratories, an additional test is done on those seeds which do not show signs of growth. This is the tetrazolium test, which is a measure of the presence in the seed of tissue capable of carrying out respiratory activity. Respiring seeds convert the colorless tetrazolium to an insoluble colored dye which becomes deposited within the seed embryo. Those seeds in a test which do not show growth are pierced with a needle (to permit the tetrazolium solution to penetrate) and then incubated for an additional day. If the tetrazolium chemical is respired, a red dye is deposited. The seed is then rated as dormant but viable. It is assumed that these viable seeds would eventually initiate growth under field conditions. |
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| 3/1/08 | Snow Shoeing on the Upper Crust A week ago we were plowing through two feet of powder snow on our snow shoes. During the week some warmer weather and sunshine settled the snow, creating a hard crust. Today instead of plowing through powder we walked on top of this crust. More or less. Sometimes we broke through, other times we were on top, and other times we started on top of the crust and then lost our tips below the surface. As long as we remained on top, walking was easy. The photo below shows me at the upper edge of the Pocket Prairie, with Unit 11C in the background. Most of the oaks on the lower slope are white oaks, whereas toward the top they are bur oaks. We had big plans to do important brush control on this unit, but the heavy snow has made this so far impossible. We still might be able to work here if the snow goes away soon and it doesn't warm up too quickly. In restoration ecology there is a continual battle between weather and work. You have to be prepared to work when conditions are right! In one of last weeks posts I mentioned that the heavy snow had bent lots of white oak saplings, some almost all the way to the ground. I assumed that once the weight of the snow was removed these saplings would start to right themselves, and they would eventually be fine again. A check today showed that I was mostly right. The saplings were standing up, although most were still somewhat bent. Would they continue to grow that way? A check of some large white oaks in the same area showed that many of them also had bent trunks but were otherwise healthy. Although the lumbering industry might not like these crooked oaks, they are otherwise fine.
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