climate

Maple Buds and the Story They Tell (Part 2)

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We have all heard it (or said it) – once the maple trees ‘bud out’ the sap collection season is done.  “Done” meaning the sap has become buddy and making syrup for the season is over.  Our eyes see it and we know to expect it, but we all hold out for just one more day of collection before the tide turns.  That day or the very next, the sweet smell of sap turns sour.

The good news is you don’t have to rely completely on your nose when boiling that last batch of sap.  Keep a close eye on how the tree buds develop as the season progresses.  When you start the season the buds are tight.  As the season progresses and the weather changes towards spring, the tree buds tell the story. We can use our eyes to track bud development as the season progresses, the weather warms, and making syrup draws to a close.  The good news is that this progression is somewhat predictable if one understands how something called growing degree days (GDDs for short) correlate.  Read Part 1 released last week to learn how you can start tracking GDDs and incorporate them into your season planning.

Using a 60-power spotting scope we took pictures of our trees on March 17th, 23rd and 27th during the 2021 sap season.  The bud progression is for sugar maple and a red x silver native hybrid maple that are present at the Ohio State Mansfield sugarbush.  For reference, we deemed our sap no longer worth collecting on March 21st.

First the red x silver “mystery” maple – in the March 17th photos, the hybrid’s buds are noticeably swollen but the flowers have not burst forth yet.  In the branch I’m holding, you can see the flower buds cracking open with the leaf bud still tightly closed in the center (black arrow).  This is crucial to understand because trees have both flower buds and growth buds which break at different times and have different impacts on the sugaring season.

By March 23rd, despite the difficult lighting, the buds have clearly flowered.

This is even more apparent on March 27th when I took the last set of photographs.  Examine the leaf bud (in the black circle) which is protruding more but still closed surrounded by the bright red maple flowers.  Our operation’s sap edged towards being “buddy” in the last 2 days preceding the red maple buds popping completely out.

For the sugar maple photos, the differences are more subtle and the progression is slower – a timeline we talked about in Part 1 last week.  In the March 17th pictures, the buds were barely noticeable at the ends of the uppermost twigs of the trees; however, buds were more prominent 6 days later.

By March 27th and nearly a week after we had closed down the sugarbush, sugar maple buds were elongated and swollen and obviously scaled but not yet officially burst open.

All in all, this was a great exercise to watch how trees go through the season’s progression as the weather changes.  A set of binoculars is a handy tool for the sugar maker; pick some key trees in your woods and watch their buds next year.  Better yet, keep detailed notes and be a studious observer of 3 primary things: sap quality, tree bud development, and those GDDs we mentioned earlier.  Once you are familiar with what the bud progression looks like relative to your tree’s sap production, you will have information to align alongside GDDs for anticipating when the end of the season is near.

The Ohio State Phenology Calendar: Understanding Nature’s Biological Clock (Part 1)

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A special thanks to Denise Ellsworth from OSU’s Department of Entomology for contributing her phenology expertise that makes this article possible!

Phenology, sometimes referred to as the world’s oldest science, is the study of recurring biological events and their relationship to weather and climate. Examples of phenological events include bird migration, flowering of plants, and the seasonal appearance of insects. Because the growth and development of plants depend on temperatures, phenological events of plants, such as bud swelling or flowering time, may be useful for monitoring short-term weather patterns. Likewise, scientists can detect long-term changes due to climate change by tracking the pattern of phenological events over many years.

Insects emerge earlier in warmer years than in cooler years, and plants bloom earlier too. The critical assumption in the use of plant phenology to predict other biological events is that the phenological sequence (the order in which events occur) remains constant from year to year even when weather patterns differ greatly. It is no mystery, even to a novice sugar maker, why plant phenology matters in maple. The quality of maple syrup is at stake! Once the phenological calendar for a sequence is established, the biological calendar is easily monitored to anticipate when maple syrup quality drops. If phenology can be grasped, this can greatly simplify the logistics of planning and scheduling monitoring programs, post-season clean-up and sanitization, and other critical activities. And using phenological sequence is valuable to a whole host of applications beyond just maple—beekeepers, naturalists, and gardeners also use the predictable patterns of nature to predict plant bloom and other biological activity.

On The Ohio State University Phenology Calendar website, degree-day data and related plant bloom and pest emergence sequences are accessible for any location in Ohio.  A degree-day is a measure of the amount of heat that accumulates above a specified base temperature during a 24-hour period. A degree-day is also referred to as a growing degree-day (GDD), heat unit, or thermal unit. One GDD accumulates for each degree the average temperature remains above a specified base-temperature over those 24 hours. Several degree-days can accumulate during a 24-hour period.  However, it is important to understand that degree-days have meaning only in relation to the base temperature that has been specified. The Ohio State Phenology Calendar uses 50 degrees F as the base temperature. To provide an example, if the average temperature over a 24-hour period is only 47 degrees F with a base temperature of 50 F, no GDDs would accumulate. However, if the 24-hour average temperature was 55 degrees F, 5 GDDs would be added to the phenology calendar (more on degree day calculation here).

To inform The Ohio State Phenology Calendar, daily temperature data from 12 OARDC Research Stations and three USDA-ARS weather stations located throughout Ohio are used to calculate cumulative GDD in real-time.  Calculations for locations between weather stations are extrapolated from climatic isotherms for Ohio.  Upon entering a date and any Ohio zip code, degree-day accumulation for that location is calculated, and the user is directed to the appropriate spot on the phenology calendar to determine what plants are blooming and what pests are active in their locale.  By scrolling through the full phenological calendar, it is possible to see what blooming and pest events have already occurred, as well as what has yet to occur.  And by clicking on the Summary tab, you can get a year-by-year breakdown of GDD count for the same date and zip code location across the past 6 years.

It is important to define a couple terms as we launch into species-specific phenology.  First bloom is defined as the first flower opening to expose sexual parts. Full bloom is when just one out of twenty buds is still closed while all others are open to expose sexual parts.

Of particular interest to maple producers, silver maple is listed first with 34 GDD at first bloom. A bit further down the sequence, silver maple reappears with full bloom at 42 GDD.  Red maple first bloom follows at 44 GDD just after silver maple full bloom. Red maple full bloom averages 75 GDD.  Sugar maple is not currently listed on the GDD calendar; however, it is believed that sugar maple tracks very closely with black maple – another of the “hard” maples.  While there is some uncertainty about the exact GDD timing for sugar maples, they are definitely “late bloomers” as compared to their “soft” maple counterparts.

The consistency in phenological sequence from year to year demonstrates that even one year of observation is useful to expand the phenological sequence to other plants or insects not included on the OSU calendar. This means that users can readily create, expand, and customize their own biological calendars by observing plants in first or full bloom and taking note of the GDD for that date on the OSU calendar. Many observers use a journal or excel file to track plant and insect activity from year to year, adding in new plants or insects of interest. These calculations can even be made by referring to photographs that show first bloom or full bloom; the photo’s date and location can be entered on the OSU calendar to determine the GDD for that event. Insect observations should be of developmental stages, such as egg hatch or adult emergence.

For the maple producer, understanding the predictability of nature’s patterns is crucial for better anticipating the end of each maple season. For years and years, sugar maple bud break was the traditional visual signal to take down buckets and end the sap season. Unfortunately, lots of poor-quality sap was made waiting for those first buds to break. Now we know that physiological changes occur within the tree prior to actual bud break that bring seasons to a close earlier. And sanitation issues that result in “sour” sap (due to bacterial build-up) halt most sap seasons before “buddy” sap is rampant. While we are excited to continue tracking sugar maple performance relative to GDDs, keeping an eye on the 100 GDDs mark is a rough indicator for when things are winding down. Some woods will shut down earlier and others will stretch a bit later, but when the Forsythia approaches full bloom in your yard – which occurs right around 100 GDDs depending on variety – you can be sure the end of your sugaring season is nigh.

New Article Series Launches Next Monday

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This short post will serve as a sort of guidepost, a table of contents or roadmap if you will, for the next month or so worth of content.  We are excited to bring you a 4-article series on maple phenology.  Phenology is a fancy word for describing nature’s calendar.  We’ll discuss one of the most practical and accessible tools for tracking phenology – the growing degree day, or GDD for short.  Second, we’ll seek to understand and document how GDD is related to species-specific patterns in maple bud and bloom timing and why that matters for maple producers.  Then over the course of two installations, Les Ober will break down why an improvement of one’s understanding of maple season timing is particularly important towards the season’s end and how you can minimize and prevent unwanted bouts with “sour” or “buddy” sap.  After all, our main goal is promoting sustainable production of high quality maple syrup!

2022 Maple Season Forecast from a Climate Expert

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Please join us at 7:00 PM, Thursday January 13th to learn from OSU Extension’s Aaron Wilson about how weather, climate, and maples interrelate.  His talk has immediate implications for this current year’s sap run and a long ways into the future.  Those of you that have heard Aaron speak before know that it is a real treat to learn from his expertise.  Register here at the Woodland Stewards website.

Dr. Aaron Wilson is an Atmospheric Research Scientist with the Byrd Polar and Climate Research Center and Climate Specialist with a joint appointment in OSU Extension.  He will shed some light on how the coming maple season may turn out.  Dr. Wilson’s presentation will include the 2022 short-term forecast as well as how our changing climate may alter maple production in the future.  Future climate projections pose significant challenges to the future of maple production across southern maple producing zones.  Planning for the future and considering how best to meet those challenges is crucial for sustained maple production in the long-term.

Synopsis:  From increasing winter and spring temperatures to extreme weather events, climate change poses a risk to the maple syrup production community. These changes alter short-term conditions like quality and quantity of sap, while long-term changes in climate are having impacts on the health of trees, roots, and shifting areas where production is viable. Projections of future climate pose significant challenges to the future of maple production across southern zones. How might the community plan for and mitigate these impacts? Join us as we explore the influence of weather and climate change on the maple industry and discuss the implications for the future.

Register TODAY!

WATCH: Climate and Maple Webinar

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The OH / WV / PA maple collaboration produced a great webinar thanks to the expertise of Aaron Wilson, an Ohio State climate research scientist.

Here is a summary of the talk: The maple syrup industry is impacted by both seasonal weather and long-term changes in climate. While the short-term conditions impact annual production cycles and quality, long term changes in climate are having an impact as well. Temperatures across the maple syrup production areas of the US are warming, and climate change extends well beyond just temperature to include shifts in seasonal precipitation patterns and increasingly extreme events. Projections of future climate pose significant risks to the future of maple production across southern zones.

Watch the webinar on YouTube to explore the influence of weather and climate change on the maple industry and discuss the implications for the future.

Tune in next month on December 17th to another webinar in the same Out of the Woods: Enriching Your Maple Business series hosted by Future Generations University in West Virginia.

 

Upcoming Webinar (11/19): Climate Change Impacts and Risks to Southern Maple Production

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The maple syrup industry is impacted by both seasonal weather and long-term changes in climate. While the short-term conditions impact annual production cycles and quality, long-term changes in climate are having an impact as well. Temperatures across the maple syrup production areas of the US are warming, and climate change extends well beyond just temperature to include shifts in seasonal precipitation patterns and increasingly extreme events. Projections of future climate pose significant risks to the future of maple production across southern zones. Join the webinar (Register HERE) to explore the influence of weather and climate change on the maple industry and discuss the implications for the future.

Speaker: Aaron B. Wilson – Aaron is an Atmospheric Research Scientist at The Ohio State University, holding a joint appointment with the Byrd Polar & Climate Research Center and OSU Extension. He is also with the State Climate Office of Ohio.

The webinar is part of the Out of the Woods series hosted by Ohio State University, Future Generations University, and Penn State University.

 

 

When to Tap?

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The last 10 days of January 2018 had some very good weather for sap flow. If you live in the southern states or even southern Ohio, the decision to tap was a good one because you are never guaranteed a season past mid March. However, the decision to tap early becomes a lot more uncertain for producers further north. I present three maps for your consideration. The top graph is the temperature forecast for NE Ohio from AccuWeather. In my experience, their 30 day forecasts have been reasonably reliable.  The solid orange line is the average historical high temperature for the given dates, and the solid blue line is the historical low average. The broken orange line is the daily high forecasted temperature and the broken blue is the forecasted daily low temps. Once we get past the 5th of February, it appears we are going to drop below normal and stay there through the end of the month. Again this is a 30 day outlook, but it does match up with what all of the local weather stations are predicting.

february Forecast

The next graph is NOAA’s Weather Forecast for February. This Graph is indicating we will have equal chances of being above normal, normal or below normal, at least for Ohio. Looks like the likelihood for above normal weather extends up through New England.

Februar Temp

The last graph is the AccuWeather Forecast for Underhill, Vermont, home of the UVM Proctor Maple Research Center. I picked this location because they do a marvelous job of tracking weather data. The temperature graph appears to be slightly milder than the Ohio graph, with a couple of above normal spikes.  The thing to notice is the sharp rise in daily low and high temperatures at the end of February.

Underhill

I hope this information will help to make your decision easier and that you will seek out these planning resources in future years. Keep in mind that these are long-range forecasts with considerable margin of error.

Author: Les Ober, Geauga County OSU Extension

The Ohio Maple Syrup Season: Moving Forward?

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budded-red

Photo caption: Red Maple in Middlefield Township, Geauga County, Ohio, March 1, 2017

It is March 2nd, and we have just witnessed the warmest February on record in the Cleveland area. The 77 degree day that we experienced on Friday, February 24th, shattered every record for a high temperature in the month of February, and it was also the highest winter temperature in Cleveland for any winter month. The way the month of February ended cast a dark shadow on our ability to make maple syrup in Ohio. Now we are in March and the cold temperatures have come back but where does that leave us?

Many trees have already budded out. All of the silver maple and many red maples that are out in the open have full buds. The sugar maples though have not yet budded and this is one of the main reasons why we prize and select for this species of maple. Given the conditions we have had to date, one thing is for certain – if you have not tapped yet, the potential to make a significant amount of syrup is gone. The next warm spell will likely end the season for everyone.

Now let’s address the producers that have been making syrup and have the potential to make more syrup. If you have red maples, make sure you look at them very carefully or just pull the taps, especially trees in the open such as along a field edge or road side. Several producers with large populations of reds have called it quits altogether due to budding. For those with sugar maples, the potential is there to make more syrup, but you need to be careful not to spoil that sap by collecting sap from red maples too that have already budded.

At this point, a producer’s biggest enemy is bacteria. Everything needs to be cleaned out and drained. You could literally see high levels of bacteria building in the lines and tanks over the previous week of warm weather. Many producers just kept the vacuum pumps running during that period and hoped for the best. Many collected a fair amount of sap due to weather fronts that pushed through. I am certain it paid to operate the pumps keeping lines clear and tapholes as cool as possible. If you shut off the vacuum because the trees quit running, I hope you were using check valves because this would have given you some degree of bacterial protection at the taphole.

Now that the cold weather has returned, what kind of syrup will we make? The answer will come once your fire up the evaporator. If the sap is “buddy”, you will know it. And if it’s not, you’ll most likely be producing a darker grade of syrup. That is not necessarily bad because most producers made a good batch of Golden Delicate early on. If the producer chooses, the two could be blended but taste will determine that. You can blend for color but you cannot blend for taste. If your syrup has a slight off flavor from sour sap or budding, it will show up in the blended grade. There is virtually no way to mask a syrup’s off flavor once it is there, and there is no reason to ruin good syrup that you have already made. That is why some producers already chose to call it quits rather than risking a batch of off-flavored in the sugarhouse.

Producers that tapped in early January have had an average season. The biggest question is, after last year and this year, have we established a new normal for Ohio maple syrup production or maybe the two distinct zones of production in Ohio are just consolidating. I say this because if you produce syrup near the Ohio River, you would normally tap in January. If you live in NE Ohio you would normally tap in mid-February. Maybe we are now seeing a climate shift that will establish a universal tapping date for the entire state. After this year, producers must finally realize one can no longer tap solely by the calendar. If you produce maple syrup in Ohio, you must to be ready to go by New Year’s Day. If the season does not start until February, so be it – but at least you will be ready. Climate change is just that – change, and the only certainty in life is change. We change our systems, we change our tapping technology, we adapt.

Author: Les Ober, Geauga County OSU Extension

Should I Tap?

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I got up this morning (January 12, 2017) and it was 60 degrees! All I could think of was that a lot of my friends who make maple syrup saw the same thing I did and headed straight to the sugarhouse to find their drills. To say the least, 60 degrees in early January is unusually warm and the recent weather pattern has everyone scratching their heads.  The decision of when to tap is one of the most important decisions you will make in any given year – hear are my thoughts on the subject.

First a little science! To quote New York Maple Specialist Steve Childs, we need to know “how does sap happen.” Sap flow is the result of sap rising and falling through the tree’s vascular system known as sapwood. Sap flows to provide nutrients to all of the vegetative growth above ground. Sap flows from the roots to the very tips of branches nourishing the buds that will develop into leaves. This process is on a phenological clock that limits the amount of time that we have to intercept a very small portion of that sap to convert into maple syrup. Once the buds emerge or “break”, sap is no longer usable for syrup production. Sap rises because of fluctuation in spring temperatures that we call the freeze-thaw cycle. As a tree freezes, a suction draws nutrients and water from the ground and through the roots. Once the temperature rises above 32 degrees Fahrenheit, gases begin to form inside the tree which then pushes the sap through the sapwood all the way into the very tops of the branches. Considerable pressure is produced in the process. In fact, pressures have been measured at 40 psi (pounds per square inch). When you drill a hole in the tree sap leaks out into a bucket and continues until the tree quits pushing sap or it freezes again. We can increase that flow by applying vacuum to the tap with a vacuum pump and tubing. If temperatures stay warm, sap flow will gradually decline; however, sap may flow up to 72 hours without the repeat of the freeze-thaw cycle. Without freezing, the sap level in the tree drops below the taphole and flow stops. Once the temperatures drop below freezing, the whole cycle starts again. This is a very simple explanation of a very complex process.

What else may stop sap from flowing? Once a taphole is drilled into a tree, the maple season clock starts to run. Using buckets and open tapholes, that window of opportunity is around 4 weeks before the taphole starts to heal up and sap flow diminishes. This healing is the result of the taphole being exposed to air and from the growth of bacteria in and around the hole. Air dries out the taphole and supplies oxygen to bacteria that coat the hole with slime eventually sealing off the exposed sap wood – similar to what happens when you get a cut. Blood flows for a while but eventually it coagulates and the bleeding stops. A vacuum tubing system is different in that the taphole is not exposed directly to the outside air and sap is kept flowing under vacuum for a longer period of time. If operated correctly, the taphole will be kept free of bacteria for most of the season. This can be accomplished two ways. First, you can keep the vacuum running continuously whenever the air temperature is above freezing. This keeps the sap moving, keeps the lines clear, and keeps the taphole cool. Producers have found that they can gather enough sap during extended warm periods to make enough syrup to pay for the cost of running the pumps during that period of time. The other method is to us a vacuum system with check valves to prevent bacteria-laden sap from the lines being pulled back in the tree. A tree will draw sap from the lines just like a hose will siphon water from a tank when you turn the tap off. The sap, because it has been exposed to the tubing, has some amount of bacterial contamination – however slight – and will speed healing of the taphole if drawn back to the tree. Check valves close when vacuum is released, and these simple devices seal off the tapholes from sap backflow.

Now to answer the question – “Should I tap during an early warm spell?” My suggestion is first to obtain all the information from a variety of sources that you can about upcoming weather patterns. Next, consider your system. If you are a small producer or a backyard producer looking for the ideal 30 day window, January is most likely too early to tap. Your taps may dry out and you may miss some of the really good runs in late February and March. You could re-tap but that is hard on the tree and is never recommended. The best approach is to watch the weather and be ready to get those good runs in February and March. For those of us who have vacuum tubing. We can stretch the season with taphole sanitation techniques. Watch the weather and tap when the opportunity arises. You may get some very good early runs. If you are going to tap now make sure you change out last year’s spouts and/or use check valves. You have to create a closed system at the tree to prevent taphole healing. If you have enough taps, consider tapping the side of the woods that runs early now and then tapping the later running sections a bit later on the calendar, effectively spreading your season. The best you can realistically hope for is two months before your taps start to shut down. I have personally kept my system flowing from the 10th of February to the 10th of April with the use of check valves and continuous vacuum operation. No matter what you decide to do, it is a gamble. Here is hoping your decision pays off!

Author: Les Ober, Geauga County OSU Extension

How to Handle Extreme Cold Late Season Conditions in the Sugarbush

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It is now the 20th of February and temperatures have dipped to 20 below zero. In Rome, Ohio, of central Ashtabula County the temps dipped to 39 below zero. Enough already! Last year at this time many of us in Northeast Ohio were already headed to the woods to tap. In 2014, we had extremely cold temperatures but they occurred in January. None of us will forget the “Polar Vortex”. This was a new weather term and it quickly became the definition of extraordinarily cold weather. This time around we have to go back 20 years to become reacquainted with a very old weather term “The Siberian Express.” This is cold air that is literally pushed across the North Pole and driven deep into the heart of the United States. The last time we had this kind of outbreak was in 1994. We set a cold record on January 21, 1994. However, that did not affect maple syrup production that year; in fact, Ohio had one of its better years producing 90,000 gallons of syrup in 1994. The only difference was that the cold weather came in January.  We also had a hard winter in 2008 and experienced a break out year with 150,000 gallon produced.

The secret to producing syrup in a cold year is to be ready to go when the weather breaks…and it will break. Another thing you may have to deal with is tapping into frozen wood. Trees are like glass, very fragile in cold weather. Drive a spout too hard and you run the risk of splitting the tree above and below the spout. This crack will leak not only sap but vacuum. On the other hand, if your spout is seated too loose, it will need to be reset once the tree has thawed out. Under these conditions it is always better to underdrive the spout than overdrive splitting the tree. In many cases, you will probably need to reset a large percentage of spouts installed under frozen conditions anyways. This is something that large producers deal with annually because they often start tapping early during very cold weather to minimize lost production.

Snow in the woods is another thing that you will have to deal with unless we get a big thaw. The snow can be your enemy and it can be your friend. Snow creates all kinds of problems. Mainlines and laterals can be pinned under the snow and gathering trails may be blocked. In this case, I would much rather have to deal with a few lines under snow than having to clear trails. The amount of snow at the base of your trees is your guide to what has to be done first. With mainlines you may have to do some shoveling in the areas where the lines are close to the ground or if they are pinned by a fallen branch. Be very careful digging out around saddles, you do not want to damage your saddle connections. If you damage a hole where a saddle is connected you will run the risk of creating a vacuum leak. In this case you may have to splice the mainline so that you do not run the risk of a vacuum leak. There is no real good way to seal a damaged mainline at the saddle connection, and these can turn into some of your worst leakage problems. With pinned laterals you simply cut the lines, pull them out from under the snow and reconnect. Try to do this at existing connection points to avoid adding more splices. In many cases the line is down because a limb has fallen on it. This means that all of the connecting points have been stressed resulting in possible vacuum leaks.

In most cases, a few warm days will melt the snow away from the lines. The big thing is to be tapped when this happens. Having a snow pack in the woods can be beneficial in that it will keep your woods cool and wet. A slow melt off of a snow bank will not only keep the woods cool during the day but will promote reflective cooling at night often resulting in below freezing temperatures. A good thing! The slow release of moisture from melting snow is additional moisture to be sucked up by the trees stimulating a good sap flow. Something that often occurs in cold weather is portions of a sugar bush exposed to long periods of sunlight (often southern exposures) will run first and areas that are more shaded like a northern slope will run last. Using the above facts as a guide, get your traditionally warmer areas tapped first and then concentrate on the colder portions. In cold years, the cool areas hold snow longer and tend to run very good towards the end of the season. This can be a real season stretcher. However, do not use this as an excuse to put all of your taps on the warm side of the tree. This is an old wives’ tale and a bad practice. It is always best to follow some form of systematic tapping.

A few closing thoughts on getting around in deep snow cover, aka, snowshoes. I have tried them with mixed feelings. This will be one of the best cardio workouts you will ever experience. Do not expect to go to the metro park, try them out, and then think snowshoeing your woods will be easy. Walking on a groomed trail is way different than walking in the sugarbush. The size of the shoe required is determined by weight. Use as small of a pair as you can in the woods to prevent getting snagged on brush. Yes they keep you on top of the snow but for me it was like trying to walk with a bushel basket on each foot. On our first adventure, my partner and I looked like Yogi Bear and Boo Boo going through the woods. And one of the first things I learned was that snowshoes can quickly turn into skis on a slope. You need to master the side step or risk a dangerous slide into a ravine. Been there done that, not fun! Yes, snowshoes get the job done and will get you across the snow; however, I will leave snowshoes to the thin athletic New Englanders and French Canadians who promote them.

Have a good start to the season and until then stay warm.

Author: Les Ober, Geauga County OSU Extension