Tuesday, November 22, 2011

A few observations before the break for the holidays

November 20, 2011, Berthoud Colorado (5030' elev., in a park lawn)

This month we continue to see how this weird weather is effecting our local plants. The latest weird thing was to see a new dandelion flower!! Not so unusual if you are in Alabama or Florida but for 5,030' elevation in Colorado in late November this is quite bizarre! We have been having plenty of frosty mornings, but very mild afternoons. Tomorrow will be in lower 60's for example. Apparently these well adapted plants have no problems with the morning frosts so are ready to put out new flowers and maybe made even more seeds in 2011!

A series of snow falls and hard frosts in late October and early this month have caused even the most hardy of our trees and shrubs to go dormant. The last ones were the oaks, some lilacs, shrubby cinquefoil, and the amazingly hardy european buckthorn (Rhamnus cathartica). This is quite a troublesome invasive weed in moist forested regions back east and a few riparian areas in the West. It has always amazed me that the leaves can be supple and green even after numerous frosts and snowfalls. But even this shrub now has brown leaves.

Even in the dead of winter there are always interesting things to see. This month has mostly been a matter of seeing when the last leaves fall as they say. Still waiting for northern red oak to lose its leaves. That will be the last regular budburst species and should be my last budburst observation for 2011!

Please post your sightings and questions on the budburst facebook page.

Thanks to all of you that submitted observations this year, making it a great year for budburst! Don't forget to submit the last of your observations from this last year. Its easy to forget to submit observations onto the computer. Winter is a great time to catch up on that and make your observations a valuable resource for our program and for all scientists and educators that are interested in how nature is responding to all these changes over time.

I will be taking a break from this blog until the start of the new year. Looking forward to the start of a new season soon!

Happy holidays!

Paul Alaback


top: the last new flower of 2011 for Berthoud!
bottom: Swamp white oak (Quercus bicolor), one of the very last trees to lose its leaves this year. Red oak, and European mountain ash are the other main trees still with leaves around our neighborhood.

Thursday, October 27, 2011

End of the Season comes to Colorado and many parts of the Northern US

It is always fun to try to predict when the growing season will end. In some places Halloween seems like a common time for the first big storm, in others right around Labor Day is when the first killing frost may come. And sometimes it comes early. The extremes of weather are usually quite important in determining what plants and animals can survive in a given place. Now is a great time to learn about how this works, and it is yet another great reason for the value of making regular walks outside and keeping track of what is going on outside, even this late in the season.

Yesterday our first winter storm hit hard. The day before it was nearly 80 degrees, today it is 11° here! So there has been a lot of frenzied activity all around town, everybody was blowing out their lawn sprinkler systems, putting up storm windows, and harvesting, covering up, or putting to bed, their veggie gardens, and digging out the snow shovel. Today there is a steady drone of chainsaws dealing with piles of twisted branches, broken fences, and blocked driveways and even streets. What a mess!

This has been quite a disaster for towns in the northern Front Range of Colorado because of the combination of a very late fall with leaves still being on trees, and a very heavy wet snow of up to 10" accumulation. Its a good example of how phenology can help explain why storms can sometimes be especially destructive to trees and our cities or towns. It also explains why scientists are so worried about the implications of climate change, since one of the predictions is an increase in wild weather events as we have seen this week.

One of the great pleasures in being more closely connected to the patterns in nature is appreciating how complex and intricate these seasonal changes can actually be, and having greater respect for these plants that have to take whatever comes! There is a real beauty and elegance in how plants and animals have adapted over the millennia to be ready for these often violent swings of weather that can come in the fall and spring. Of course all do not make it, but the native species usually come through pretty well.

Cities and other human designed enterprises are always trying to optimize efficiency by planning long ahead, including preparing for seasonal changes and also being ready to adapt suddenly if they need to. There are dates selected long in advance for when we should be buying or changing our wardrobe, getting the snow plows ready, winterizing our sprinklers and gardens. But nature often has different ideas. This year for example, as was mentioned in the blog last month, it has been quite a warm and extended fall. But it can all end quite abruptly!

As we have seen this year when you get warm weather, especially warmer night temperatures this can create a lot of havoc in how quickly we see fall colors and full hardening off of plants for winter. In New England, and many other parts of the eastern part of the country an epic season of rains and cloudy weather has drawn out the fall season resulting in either late colors or fewer bright colors this year. Here in the Rocky Mountain region we are getting reports from Montana down to Colorado and New Mexico of a very late fall season as well. In our case this appears to be due to an unseasonably warm fall as well.

Just before this storm there were still wildflowers in bloom. Golden aster (Heterotheca villosa), goldenrod (Solidago spp.), bush sunflower (Helianthus pumilus) and a couple of species of white aster (mostly Virgulus falcatum), and some weeds like mallow (Malva neglecta) were all open. Our annual Cosmos plants were still in full bloom in our garden too! These are all very hardy plants, so they should survive fine (or at least the seeds in the case of annuals) even with this sudden hard freeze. The critical tissues and resources for perennials growing next year are safely contained in roots or rhizomes deep underground. But it is still always fascinating to me that you can have plants in flower at 5,000' in Colorado at the end of October! I saw the same thing when I lived in Montana. One of our worst weeds, spotted knapweed (Centaurea stoebe), always had open flowers until very late in the fall or until the soil froze. This plant is very well adapted to cold northern climates!

Looking at how plants prepare for winter is a great way to better appreciate the richness and diversity of adaptation of the plant species that we have here. Some plants end the season very early, especially those that are sensitive to drought. This year for example wax currants (Ribes cereus) were dropping leaves in the middle of the summer. Several other shrubs native to our dry foothills areas do this. Sometimes they put out new leaves in September if there is enough rain, then drop them again sometime in October. Here as well in their native habitats back east, American linden (Tilia americana) and red maple are usually the first to lose their leaves, and oaks are generally the last. Everything else is somewhere in-between.

Right now green ash (Fraxinus pennsylvanica), chokecherry and plains cottonwood have been in full rich color for a few weeks, and leaves are beginning to fall. The trees in my yard just reached the 50% leaf fall stage the day before the storm. The late fall species such as northern red oak, burr oak, norway maple, mountain ash and others are just starting to change colors. It is likely they will drop as brown leaves this year since they will get a hard frost before they reach full color. So each of these plants has a slightly different cue as to when it is time to quit. Part of this also has to do with the structure of the leaves. Oaks for example have tough leathery leaves, so are more resilient to fall weather than silver maple or lindens. It is all a question of tradeoffs between growing a little longer and risking frost damage.

Almost two months ago many alpine plants ended their growing season here. A sudden frost and snowfall in late August took care of that. Just like here in the lowlands in late October, up there only a few hardy flowers were left at that time. One spot I was studying up on Niwot Ridge at 12,500' elevation, a major center for alpine research near Boulder, apparently had about a two week growing season! The late spring and heavy snowfall from last winter and spring resulted in very slow snowmelt on north facing slopes, and then an early snowstorm hit. It was just enough time for a few Parry's primroses (Primula parryi) and sedges to put out leaves and flowers before they got frozen again. So depending on where you are it was either a short or long growing season, and there are plants that can more or less adapt to this amazing range of conditions. The big question for scientists is to learn more about how well plants can adapt to even greater changes in weather and climate over the years as the climate changes. Our data from Budburst should be critical in figuring out which species will be most resilient or most stressed by these changes, and how this will change depending on where you are.

Stay tuned on what happens next. Maybe we will have another warm spell and some plants may put out new flowers. There is always something new to see out there. I look forward to hearing what you all discover this fall and winter. Please let us know on our Facebook page or leave comments to this blog.

Paul Alaback

All photos taken the the past few weeks around the Colorado Front Range by Paul Alaback.

1. Top: photos of Massachusetts Avenue in Berthoud, CO before and after our recent storm!

2. Norway maple illustrates what happens when trees with leaves get a wet heavy snow! Many branches were broken and the tree will probably have a new shape like many others here in town, especially the ornamental or exotic species which did not evolve in this weird climate.

3. Hiking along trail on Kenosha Pass, just south of Denver when quaking aspen was in full color.

4. Goathead (Tribulus terrestris) a terrible weed that punctures tires and flowers until the first deep freeze occurs.

5. Colorful view of mountains near Kenosha Pass taken a few weeks ago. Notice that aspen varies from green to yellow in most groves, showing a very slow transition to fall colors this year.

Saturday, October 8, 2011

Unusual Fall Colors in New England

View of the expanse of forest over the Hudson Valley in New York State on October 6th as seen from the top of Millbrook Mtn. Most of the trees are still green, except for several of the maples which have various shades of yellow.
As luck would have it I was able to combine work and pleasure with a trip to New England this year right at the time that it is usually at the peak of fall colors. It is so popular for people to want to view fall colors that it has become quite an industry, especially for regions famous for colors such as New England. In fact it was next to impossible to find even a room to stay this weekend since so many people planned to see the colors. Weekend festivals were also planned when the colors should peak. However, if phenological events like fall colors were so predictable just from the calendar date then there would no need for scientists to get more data from programs like project budburst to document the pattern! Mother nature made at least a few people I saw today disappointed or even mad! Instead of the classic pattern of intense reds, orange, and yellow we mostly saw a lot of green, some brown, a lot of dull yellow or maroon and every once in a bright red maple or dogwood. So why have the fall colors been so different this year?

As we described last month leaf colors are a product of many factors, mostly having to do with weather or climatic patterns combined with changes in daylength and the characteristics of each tree species.

Every year trees begin to prepare for the winter season as the days get shorter, but whether this leads to bright fall colors depends on many aspects of weather and climate. As we saw in much of the Rocky Mountain region a few years ago, if a hard frost occurs before colors have had a chance to develop you then are left with leaves that are abruptly killed by frost. So they turn brown, and may not even fall off the trees for months. On the other hand if you do not get crisp fall weather with cool nights and warm days you will miss peak fall colors as well. This appears to be the case this year. New England, and much of the east coast has had a really bizarre summer and fall weather this year. It is one of the wettest seasons on record, and also until very recently a warm season as well. Heavy cloud cover and rain generally leads to warmer night temperatures, which can retard or delay the hardening off process. This has resulted in many species of trees and shrubs keeping leaves green well into the fall season. Early turning species like green ash and red maple have slowly turned their leaves yellow or brown then shed their leaves before full colors developed on them. As of this writing (October 8th) the principle colors I have seen in the Hudson Valley region of New York and the Berkshire Mountain region of western Massachusetts have been various shades of yellow on maples (mostly sugar maples and red maples), with some scattered shades of red. In the mountains, shrubs like blueberry or huckleberry which would normally be brilliant red are mostly a maroon or dull red color this year. At higher elevations in the Berkshire and Green Mountains you can see more colors, but still, as local residents will tell you, it is a far cry from the brilliant rainbow of colors that people usually expect to see this time of the year.

All of this underscores the key point that nature is quite variable, and most of these patterns which seem at first glance to be a simple seasonal pattern are in fact a complex interplay of biological and environmental factors. This is what makes the study of ecology so challenging, and why it is so valuable to carefully document these patterns year after year with programs like budburst! Each year is often quite different and a product of the unique combination of factors that influence plants. Perhaps as we improve these records and observations both by having them over a wider range of places in the country and by seeing how things vary year to year, scientists can better learn how all these factors work together to create the amazing patterns of colors we see. In any event it can make fall observations quite interesting. There are plenty of surprises and mysteries yet to solve, and much to think about when you are out making phenology observations. I look forward to seeing what budburst volunteers discover in how the fall continues to develop both here in New England and other parts of the country!

Paul Alaback

October 10th update from Sunapee, New Hampshire:
Still an unusual pattern up here in the North. Very warm fall, even 80 degrees today! But clearly the red maple is in full color here, many are bright red, paper birch and sugar maple also in color, mostly yellow but still with some green leaves. Most other trees still green. Looks like the colors are changing fast up here and cold weather will be coming soon.

Photos: (all taken by P. Alaback October 5-8th)

top left: red maple leaf with tinges of red
top right: red maple turning yellow in the Shawangunk Mountains (Mohonk Preserve).
middle left: flowering dogwood shows more consistent reddish colors in woodlands on the campus of the Institute of Ecosystem Studies in Millbrook, NY.
Bottom: A large sprawling red maple on the top of the ridge of the Shawangunk Mountains shows a light yellow color.

Monday, September 19, 2011

Why Leaves Change Color

Red Oak in Tennessee, photo courtesy Ashley Bradford
There is hardly anything more beautiful than a forest at the height of color change, and the annual autumn show is already beginning in some parts of the country. Have you ever wondered why leaves change color?

Leaves contain many pigments. During most of the season the green chlorophyll is the predominant pigment and it masks the presence of the other pigments. Chlorophyll is the pigment that allows leaves to photosynthesize, creating the sugars that provide energy for the plant. Chlorophyll is not particularly stable so it is continuously synthesized and broken down when the weather is warm.

In the autumn, when the temperatures cool and day length shortens, chlorophyll synthesis shuts down. As it breaks down, the yellow and orange carotenes are unmasked. This gives many plants their characteristic yellow fall color.

Anthocyanins, which are red to purplish-blue, are the third type of plant pigment. Anthocyanin production can be triggered by many things including high sugar concentration in the leaf which happens when sugars from photosynthesis are trapped in the leaf as it prepares to separate from the plant. Anthocyanins can also be triggered by environmental stresses to a plant, such as too much or not enough water, too much or not enough nutrients, fungal disease, damage to the bark by animals or string trimmers, and many other things. If you see a tree, or part of tree, change color significantly earlier than others of the same species, it is likely due to stress!

Weather can also affect fall colors. The best colors are seen when there are sunny, warm days and cool, crisp (but not freezing) nights, as well as adequate soil moisture. So hope for good weather, enjoy nature’s spectacle this fall, and report your observations to Project BudBurst!

Kayri Havens-Young

(Editor's note: Kay Havens is on travel and asked me to submit this for her.)

Wednesday, September 14, 2011

Fall into Phenology - will be starting soon!

Fall Colors near Berthoud, Colorado last October

All across the country September marks an important transition to a new season. In some places, like here in Colorado it can become dramatic, going from complaints about hot summer nights, just a few weeks ago to the threat of the first snow or at least a killing frost. In other places it may still be warm, but now you can start getting storms coming in and more variation. And in many parts of the country people are recovering from record floods and winds associated with another very destructive year for natural disasters.

Just in the past two days we have had our first cool fall days, with temperatures in the 50's instead of the 70's or 80's. Even though our peak colors generally occur in October or even early November nearly a third of the green ash trees today had some bright yellow leaves, and I found one aspen and several cottonwoods with close to 50% leaf color. Clearly the crazy weather we have had this year, a warm summer, with a pronounced early monsoonal season, dry hot weather lately, and now cool weather is effecting how some of our plants are transitioning for the dormant winter season!

This variability in weather conditions makes it particularly interesting for scientists and budburst volunteers to try to figure out how plants are responding to these changes, and how they compare from region to region and from year to year. In theory, fall leaf color, and the development of fruits and flowers for species that reproduce this time of year should have some degree of consistency, at least compared to the spring season. This is because plants often have internal clocks, or ways they can judge the time of year, usually from measuring day length, which they use to determine when to start hardening off for the winter season. But many other factors of weather, habitat and plant condition can also influence the rate at which fall colors emerge, leaves drop, or fruits and flowers emerge. Each part of the country, especially this year, have been subject to different kinds of weather events so we should see some interesting patterns in how plants vary in their progression to the fall season.

This year, Project Budburst is launching its first ever "Fall into Phenology" fall campaign. The concept is to use this dynamic season as a special time to create a "snapshot" of how plants all across the country are responding to the fall season. We want to get as many volunteers and especially new volunteers as possible to make observations during a 10 day time period (Sept 17-26th) which surrounds the official or astronomical definition of fall, the fall equinox on Sept 23rd. We will make it easier than ever for people to make observations and contribute to Project Budburst, especially for the first time, since it only requires making a single observation during this 10 day period of time. Of course we still hope that all of you that are making regular budburst observations on your registered plants continue to submit your observations, but we would like to supplement this with a single pulse of observations from a larger group of people, in more locations to get an even broader picture of how fall is progressing from year to year. The goal is to collect at least 500 observations from around the country. Check out the Project BudBurst map as we update it with the latest observations coming in. There will also be highlights of the first observations from each state on the website and frequent updates on the Project BudBurst Facebook page.

To participate in Fall into Phenology volunteers simply need to make an observation with the new data sheet, or with the information written down on your smartphone or notepad, then share your observations, by entering the information directly onto the Budburst website. All the definitions for the stages you can note are provided in the datasheets which you can download (deciduous trees and shrubs, wildflowers, and grasses). You need to choose a plant and a location to make your observations. For example you might see a red maple tree along a walk you take on a day during this 10 day period. You could then make an observation on how many leaves had fall colors: (just a few (<10%), many, or most of the leaves (>90%). Then, you need to logon to the budburst website (budburst.org), to share the observation. If you have an Android phone, you can make observations and share them almost instantly with the Project BudBurst mobile app. We estimate it will only take about 10 minutes of your time to participate after you register. The whole idea is to make this very simple and straightforward, yet still scientifically accurate since everyone is using the same set of definitions and procedures.

Please spread the word on participating in this campaign. It should be a fun excuse to go outside with your family and friends and enjoy the beautiful weather that often occurs this time of year, and at the same time participate in an important scientific program!

We will report the results later in the season soon as we get all the data, so watch for an upcoming blog on this.

It should be interesting to see what we discover about how Fall is progressing this year. As always please also post comments or questions on our Facebook Page as you discover new or interesting things outside.

Paul Alaback

Photos taken on September 14th around Berthoud, Colorado
Green ash (Fraxinus pensylvanica) just beginning to turn colors, in the past few days.
Virginia creeper (Parthenocissus quinquefolia) with a full set of ripe fruit which just ripened in the last week.

Friday, August 19, 2011

The Dog Days of Summer

Lush green prairie in Devil's Backbone open space, near Loveland, CO on June 15th.

Same view on August 19th!

It is hard to believe, but school is about to start again in many parts of the country, and soon it will be fall with cool nights and wonderful colors. But it is just August 19th today and it still feels like the middle of summer. The hot days of summer are often called the dog days going back to traditions that started in ancient times. It was once believed that these hot days in August were due to one of the brightest and closest stars shining down on the Earth at the same time as the sun. This is the Star Sirius which is the brightest star in the constellation Canis Major or "big dog". Hence the dog days of summer. But actually the heat of summer just like the bitter cold of January and February is simply a consequence of the ability of the atmosphere to hold and retain heat (or cold), in this case over the course of a hot summer.

Anyway in these hot days of summer there are still plants out there that begin to flower, and some are key budburst species. It may seem odd for plants to wait until nearly the end of summer to flower, but there are often advantages to doing it this way. In the Rocky Mountains and Great Plains one common group of plants that flowers very late are the sagebrushes, including the big sagebrush (Artemisia tridentata), wild tarragon (Artemisia dracunculus) and prairie sagewort (Artemisia frigida). In Montana they first flower in early September. I would expect them to flower a little earlier further south in the Rockies in Colorado, but so far this year this does not seem likely. So what is the advantage of this very late flowering? Given that all these plants typically grow in dry places with long cold winters, and moist early springs, it may be that late flowering works well since they can quickly develop fruits that disperse by wind well in time for the fall storms, then the seeds will be ready for optimal germination in the spring. They are all wind pollinated, so the abundance of pollinators is not an issue either. If they are dispersing fruits after the leaves have fallen from deciduous shrubs or wildflowers, then the wind will be more effective at dispersing these fruits as well.

The other group that seems to often flower this time of year are agricultural and garden weeds, many in the sunflower family. It may be hard to find virtue in these plants that are the bane of every agriculturist. But they are certainly well adapted to what they do, and there would appear to be distinct advantages for them to flower late as well. It is well known that these species have literally evolved very quickly with our technology and approach to managing gardens and fields. This is easy to visualize when you think about any plant which somehow misses our trowels or hoes or chemicals is much more likely to grow and reproduce than those that succumb to our efforts to control them. In August many gardeners tire of the task of keeping up the rapidly growing garden and its prodigious harvest, resulting in letting many weeds go. Late flowering and fruiting may be a big advantage for these weeds!

One budburst species which is a common lawn weed flowers much earlier than other plants and can become well established before lawn grasses are active, providing an effective way to persist mowing later on. White clover (Trifolium repens) has long roots where many nutrients are stored, so that even if you pull the plant and get many of its roots, the remaining roots will have plenty of resources to quickly grow new leaves and stems. This same strategy is the hallmark of a spring and summer lawn weed, field bindweed (or common morning glory). I have spent many days pulling almost all of these plants out of the garden, only to find their survivors growing back at breakneck speed.

In moving to Colorado I have been introduced to quite an amazing weed called the puncture vine, or goathead (Tribulus terrestris or "terror of the Earth"). Amazing was not actually the first word that came to mind here after it punctured all my bike, garden cart and wheelbarrow tires. It turns out that this plant has a very unique fruit and structure so that it actually has its own family, the caltrop family. So what is a caltrop? This is an example of what I would call a form of "biomimickry". It turns out that this fruit has a unique structure. It has sharp thorns that are arranged such that no matter how it is blown or tossed about it will always have at least one sharp thorn facing upward, and braced by the others on the ground. This same structure has been used to make weapons designed to puncture animal hoofs or tires of vehicles since Roman times. Just this week I noticed its fruits are ripening, and will be ready for action soon.

Notice the brown fruits that are ripening on this puncture vine. It often spreads out onto trails for maximum effect!

If you live in a dry place you may already be seeing fall colors or at least leaves turning yellow or brown. Just today in a nearby shortgrass steppe or foothill scrubland I noticed that mountain mahogany and wax currant are losing their leaves. Wax currant actually has already achieved the budburst definition of leaf color (50%). Bitterbrush (Purshia tridentata), a budburst focal species should also be dormant by now, and will actually put out new leaves not in the spring, but in the fall. Again an adaptation for the pattern of weather in intermountain regions.
This wax currant (Ribes cereus) already has less than half green leaves

Nearly every month of the year in many parts of the country there is something to observe by looking at plants outside, that will give you some appreciation of the many amazing ways in which plants can adapt to the challenges that nature provides. So check out what is going on in your neighborhood, and you may find some interesting new things, and perhaps gain more respect for the many adaptations that they have. There is plenty to observe before fall colors come our way!

Paul Alaback

Thursday, July 28, 2011

Spectacular wildflower blooms this summer in the Rocky Mountains

This time of year foothill areas from Colorado north to Montana are usually brown and fire prone. This year, by contrast,
the hills are still lush and green with many wildflowers

It has truly been an odd year for weather in the Rockies, but the net result has been perfect conditions for intense displays of wildflower blooms in July through even August. In dry regions like this, spectacular blooms can occur every 10 years or so when the combination of large winter snowpack, warm sunny summer weather and summer showers converge. These events are of great scientific interest since this is when most of the fruits and seeds are produced for these plants, providing great opportunities for the establishment of new plants or even changes to the species mix on transitional habitats next year. This also the time to see unusual phenological events, such as long periods of floral blooms.

The reasons for these spectacular floral displays are many. In general when you have a cool spring, less energy is available for plants to flower, so flowering is delayed for many species. If the cool spring is followed by some warm summer weather then you may have both the late flowers from the spring as well as summer flowers in bloom all at once. A cool spring may also have, as in this year, above average precipitation. This then provides more resources for plants to produce more and larger flowers. In Montana for example flowers have been observed with many more leaves and much larger sizes even in low elevation prairies. In alpine or subalpine areas at high elevations these patterns can be even more dramatic. The growing season is normally quite short, but still you normally observe a regular pattern of different species coming into bloom at regular intervals over the season. In a cool spring by contrast you often observe many of these species flowering all at one time.

For example, when working in Alaska I observed several species of huckleberries (Vaccinium spp.) which flowered about 2 weeks apart. Early huckleberry was always first, then usually Alaska blueberry, then finally red huckleberry (V. ovalifolium, V. alaskaense, and V. parvifolium). In the alpine in a cool year all of them could be seen in flower at the same time. One intriguing but as far as I know unanswered question is what the implications of these changes in phenology are for pollination. It is generally assumed that plants that are closely related tend to flower at different times so that they minimize hybridization between species. So are there more hybrids after years like this?

The other ecological factor that goes along with moist cool summer and spring weather is long periods of floral bloom. As most gardeners have observed if your bulbs come out in cool moist weather flowers can be in full bloom many more weeks than when it is hot. The same pattern applies to wildflowers. Besides providing a beautiful display for us, these long displays can be very beneficial to wildflowers as well. In general the longer the flowers are in bloom the more likely they will be pollinated and produce large amounts of fruit. This is why it is always important to note when flowering ends for species that you observe for Budburst. Flowering time is a critical factor in helping scientists better understand how plants are adapting to climate change and environmental change in general.

This summer monsoonal rains have been so intense and frequent in Colorado that in some towns local residents are using 30% less water than in a normal year. This is also the first major break from a 10 or 11 year drought cycle in many parts of the region. So the summer rains are another key explanation for the spectacular wildflowers we are seeing, especially at lower elevations.

Of course the other general consequence of cool wet weather in a climate that is normally dry, is large amounts of lush vegetation. Grasslands that normally would be brown and dormant are now alive with many wildflowers and tall lush green grasses. So it should not be any surprise that this is also an epic year for grasshoppers. Just today walking through a local prairie, there was a constant noise of grasshoppers landing on grasses all along my hike.

So if you have a chance to get up to these mountains, this is the year to see them. You might as well bring your camera and contribute occasional observer observations on them for Budburst too!

Photos: Paul Alaback.

Top: lush low elevation meadow near Rocky Mountain National Park a few weeks ago.

Middle: mid afternoon monsoonal* storm in low elevation grassland near Berthoud, Colorado

Bottom: grasshopper nymph on old sunflower seedhead in a prairie open space preserve near Loveland, Colorado.

*These storms are called monsoonal since they occur in the middle of the summer and are connected with patterns of flow of humid tropical air from the Gulf of Mexico. This is a key factor of the climate of the southern Rockies.

Tuesday, June 21, 2011


Blanketflower (Gaillardia aristata) is usually a good sign that summer is on its way in
its native Rocky Mountain region

Summer is a great time to be outdoors exploring and also a a good time to make budburst observations. We don't usually get as many summer observations as spring ones, but it would be valuable to have a better record of how plants vary in their flowering patterns in the summer. In warm climates it is often assumed that the timing of flowers varies mostly as a function of moisture availability, not heat. Observations from the mountain West suggest that this may not always be true. The heat of the summer often leads to flowers that normally come out in the fall to actually emerge in the middle of the summer, like some aster species. Perhaps there is a lot more to learn about what influences summer flowers and especially how it varies from place to place in the country

Here in Colorado our trees and shrubs are very active in the late spring, Many put out their leaves in early May and flower a week or two later. Just this past week the last of our pines, eastern white pine, pinyon pine and bristlecone pine have started to disperse their pollen and send out new leaves. In the past few days catalpa trees have put out their showy white flowers, covering whole trees with blooms. The principle tree left to flower now are the various linden species (Tilia). Interestingly they have seemed to be in slow motion lately. Their odd strap like appendage and stalk for flowers has been out for nearly a month, but the flower buds are tightly rolled up in their buds. Maybe in another week or two they will finally be out. Lindens, in case you have not had the pleasure, are popular ornamental trees in most parts of the country not only because of the good shade and form of these trees but also because of their wonderful flowers. When in flower a whole yard can be filled with the fragrance of these flowers, and are a major attractant for bees as well.

In the summer many other budburst species first come into flower, in particular wildflowers. This year we also have the occasional observer protocol so you can make observations of wildflowers in your summer hikes or travels across the country. While on a road trip from Colorado to Arkansas a few weeks ago, for example, I was able to see lots of interesting patterns in phenology with species that were planted in many places along the way. Down there summer grasses were already in flower and spring wildflowers were either gone or well into the fruiting stages. Ponderosa was a common roadside tree all across Kansas and you could see it with fully developed new needles in the east, where the warmest temperatures occurred. Then going westward the phenology went back in time as we slowly climbed up towards Colorado. By the time we got back to the front range, north of Denver, ponderosas were back to the budswell stage, and it would be weeks before new needles emerged. Similarly a few weeks ago I took a trip up to Estes Park, at 7500' elevation where chokecherry and lilac were in full bloom. They have been done flowering for weeks at our more moderate elevation of 5030'.

Enjoy your summer adventures outdoors, and we look forward to seeing your observations. Maybe they can help us explain how these plants respond to the odd weather we have been having lately.