How to harden off tomato plants to prepare them for the home garden?

Harden off your tomato plants before you set them out in the home garden. Outdoors can be a shock for them if they’re not ready. It’s up to you to prepare them for the real world.

Until now, your tomato seedlings have had an easy life. You’ve pampered them with plenty of light, water, food, and warmth.

That’s about to change.

In the outdoor garden, they’ll have to stand on their own roots and deal with sun, wind, and critters.

About 7-10 days before planting them outdoors, help acclimate them to temperatures, sunlight, and wind.

This process is called “hardening off.” Without hardening off, your tomatoes are more susceptible to sunburn, windburn, and breakage.


Gradual exposure helps your plants toughen up and reduces the possibility of injury. With proper hardening off, they’ll have an easier transition to the garden and begin producing fruit sooner.


Take these steps to harden off your tomato plants.

1. Start slowly. For the first day, set plants outside in the shade, next to the house, or in a protected area for an hour or two. Eastern or northern exposure out of direct sunlight also works. Bring seedlings in at night.
2. Raise exposure. Gradually increase the amount of time your plants are outside each day for several days, to include some direct sunlight. Light breezes help strengthen stems as long as movement isn’t too severe.
3. Monitor seedlings. Check them regularly for wilting and water appropriately if they droop. Move them to shade or a sheltered location if seedlings they appear stressed.
4. Finally, leave tomatoes out overnight. Make sure the forecast is for temperatures to be above 50°F during the night time.

Once your seedlings handle their outdoor sleepovers without problem, it’s time to move them into their new home: your garden.

How to help your crop succeed when you set seedlings out in the garden?

Planting tomatoes successfully in the garden takes just 4 easy steps: timing, spacing, digging, and planting.

Time It

1. Date. Check your local extension or a region map for recommended planting dates. Tomatoes do best when planted about 10-14 days after the last frost date.
2. Temperatures. Make sure it’s consistently warm both day and night. (Tomatoes don’t like to be cold.)
3. Weather. The perfect planting day is cloudy or overcast. If you must plant when it’s sunny, do it early or later in the day so that seedlings aren’t as stressed by the strong light.

Space It

Plan carefully for enough space between each plant and enough space between rows.

• Plants. Place tomato plants 24”-30” apart. Indeterminates need more space than determinates since they continue to grow until frost.
• Rows. Allow 5 or 6 feet between rows to allow room for plants and room for you to move to weed, water, fertilize, and pick.

Dig It

There are two best ways to make new homes for your tomatoes.

1. Hole. Dig a hole twice as big as the plant's root ball. Use one hole for every tomato plant.
2. Trench. Dig a trench 6 inches deep the length of your planting area. This is the best planting method for leggy plants (buried stems will develop additional roots), gardens in cold areas (soil will keep plants warm), or when you want your plants to get a head start on the season.

Plant It

• About an hour before planting, water your tomatoes thoroughly. Fill hole or trench 1/3 full with topsoil. (You can use what you just dug up).
• Add 1-2 scoops compost and a handful of bone meal or fertilizer. (Learn about best fertilizing techniques for tomatoes.)
• Mix everything well!
• Add water to the hole or trench.
• Clip off the lower set of leaves.

Planting Trees Along Route 66

Route 66 is the Automobile Age's Oregon Trail and Transcontinental Railroad, combined into one.  It has been the symbolic and frequently the actual route for Americans to migrate westward.  It is a  holiday route for Europeans who want to experience main street America - but who do not want to experience the America of interstates or airports.

Route 66 in blue with modern interstates in black.  This map shows how this highway connected the Heartland of the nation  (starting n Chicago and going through many small towns) with the West Coast (image from National Park Service, Public Domain)

Route 66 was the route the Joads took to escape the Dust Bowl in Tom Steinbeck's The Grapes of Wrath, in which the author called it "The Mother Road".  It is the subject of famous songs by Nat King Cole and again by The Rolling Stones, The Rolling Stones version is seen below:

A more recent movie (Cars by Disney, 2006) has also highlighted how Route 66 helped small towns along the route of the highway thrive.  Today, as most Americans fly cross country, much has been lost along this highway which once connected the eastern and western halves of our country.  We would venture to guess that most Americans have never driven even a small part of this famous road.

Today, America faces many challenges.  Much of our history is being forgotten.  The automobile and by extension this famous highway are becoming viewed more as the causes of problems (traffic, carbon dioxide emissions) rather than solutions to problems.

That is why an effort is being led by retired General Frank Schober of New Mexico and Pieter Hoff, inventor of the Groasis Waterboxx PlantCocoon®, of the Netherlands, to plant trees along the famous old Route 66.  The first leg of this effort has been already been completed, with Waterboxxes being purchased for use in Galena, Kansas.  You can see a video about that planting here.

This tree planting effort shows how a brilliant new technology, the Groasis Waterboxx PlantCocoon®, can allow trees and motorists to develop a symbiotic relationship.  The trees rely on the carbon dioxide emitted by the cars to grow, and the motorists get the fresher air and better scenery provided by the trees.  The Waterboxx PlantCocoon® allows this relationship to come about because it fundamentally changes how trees get water.

A schematic cutaway view of the Waterboxx, showing how the tree is planted in the center, rain and dew are collected on the tan lid and stored in the green reservoir, and released via the white wick into the soil below.  From Groasis.com

The Groasis Waterboxx PlantCocoon® is the ideal technology for planting trees along Route 66.  It collects and stores dew and rain water, and slowly funnels it to the roots of the growing tree sapling.  This forces the tree to grow deep tap roots which allow it to survive droughts, even after the Waterboxx PlantCocoon® is removed.  The Waterboxx PlantCocoon® can  be removed and reused to plant other trees for up to ten years.  We hope to plant many long lived trees with this device along Route 66 and in other deforested places.

If you own or care for land along Route 66 and would like to plant trees with the Waterboxx PlantCocoon®, it is available in business order sizes here or consumer order sizes here.

We would love to hear your comments below.

How Many Trees Are There On Earth?

A new study out in the Journal Nature states that there are almost 3 trillion trees on the Earth, or over 400 trees for every person currently living.  As trees are vital to our atmosphere (using carbon dioxide and producing oxygen), serving as the counterpoint to animals (which of course use oxygen and produce carbon dioxide), the large number of trees is good news.  However, the study showed a far more concerning fact - we are cutting down 15 billion trees a year, and replacing only 5 billion, for a net loss of 10 billion trees per year.  Humans have cut down almost 50% of all trees since the advent of civilization, a staggering fact that may explain much of the drying out of whole regions (as trees can make it rain).

A farmer who harvested a field and didn't replant it would soon starve or become bankrupt.  So, why are we cutting down so many trees and not replanting them?  The reasons are many - some of the land is turned to grazing, some to agricultural production, some to urban development.

It is unlikely that we would ever turn good agricultural land back into forest -especially with increasing food prices and an increasing number of mouths to feed on the Earth.  It is just as unlikely that we will demolish houses to plant trees.  However, trees' role in pulling carbon from the air and storing it for long periods, potentially millenia (in very long lived trees like sequoias) in their trunks or centuries (in wood used for construction) cannot be overstated.  So, what are we to do?  Don't we lack the land needed to grow new trees?  As we cannot demolish our neighborhoods, where are trees to be planted?

A giant sequoia, growing over two years with the Waterboxx PlantCocoon in Indiana.  This tree was never watered after planting with the Waterboxx PlantCocoon, not even after the Waterboxx PlantCocoon was removed.

First, in most areas where new homes and businesses are built, very few trees remain.  These construction sites are called "greenfield" for a reason - they are generally fields when construction is underway.  If you have a new home with a barren yard - congratulations - you get to choose the trees you plant there.  This is especially important for very large yards, as your tree choice will affect your home value more than almost anything else.  Throughout this site, we have tree recommendations for longevity and other virtues.  If you live in a fairly wet, temperate area in the United States and want to plant trees that will counteract your lifetime carbon emissions, may we suggest planting giant sequoias on large plots of land.  This may sound outlandish, but this tree grows throughout much of the U.S. (and the world), and has been planted from Scotland to New Zealand.  Small sequoias can be bought here and are much more likely to survive if planted with the Waterboxx PlantCocoon, sold here.  


Second, large parts of the western half of the United States is considered desert or near desert - and indeed it is by rainfall totals.  Little is thought to be able to grow there, so it is not used as agricultural land.  However, trees that establish deep roots are able to survive where other plants cannot.  The problem is that it is very hard for trees to get established in desert areas, especially as most rain falls in a short period and then there is no precipitation for many months.

The Algodones Sand Sea desert in California (Photo from USGS, by Peter Kresan, public domain).  Surely no tree could ever grow here - except with the Waterboxx PlantCocoon.

This dry spell once meant the death of any planted trees - until, that is, the invention of the Waterboxx PlantCocoon.  This device, which is best described as a intelligent plant incubator or a self-refilling water battery for young trees, collects dew and rain water, stores it in a reservoir, and slowly releases it to the roots of a growing tree sapling.  This tree is allowed to grow for about a year, when its roots will reach much deeper capillary water.  Once this happens, but before a tree gets too large, the Waterboxx PlantCocoon is removed and reused for other trees.  In this way, large areas of desert land can be planted with trees, providing shade, wood, habitat for wildlife, and potentially foliage for grazing animals (depending on tree selection).  You can see how the Waterboxx PlantCocoon works in the video below:

So, has the Waterboxx PlantCocoon ever been shown to work in the desert.  In fact, it has.  88% of salt cedar trees planted with the Waterboxx PlantCocoon survived in the Sahara desert, as seen below.

Salt Cedar trees growing with the Groasis Waterboxx PlantCocoon in the Sahara Desert in Morocco.  

 Ghaf trees (really more shrub or bush like plants) planted in the Kuwaiti desert with the Waterboxx PlantCocoon thrived after the Waterboxx PlantCocoon was removed.  These plants will completely change the character of the land over time, adding humus to the soil and allowing life to flourish.

Ghaf trees planted with the Groasis Waterboxx PlantCocoon in Kuwait - surviving after the Waterboxx PlantCocoon is removed.  

We hope you are as excited about planting trees in new locations as we were when we first saw the Waterboxx PlantCocoon.  We recommend you find trees that are growing somewhere in your area (you can find drought resistant broadleaf and evergreen tree suggestions on this site), and plant them with the Waterboxx PlantCocoon.  You can find out more about the Waterboxx PlantCocoon here.

We would love to hear your comments below.

Choosing Good City Trees for the Midwest

Trees have many benefits, detailed throughout this blog.  They reduce stress, reduce flooding and erosion, and increase rainfall, to name but three lesser known qualities.  However, choosing the correct trees ensures happiness with your (or your organization's) investment.  Below we have our recommendations for excellent city trees to grow in the Midwest, the area we define as between the Appalachians in the east and edge of the Great Plains in the west.

Our first and probably favorite choice is the Thornless Honeylocust (Gleditsia triancanthos form inermis).  This tree has it all.  It is fast growing, very drought tolerant, and has a downward pointing root system (meaning it generally won't buckle sidewalks with shallow, sideways spreading roots).  It grows in zones 3-9, We generally recommend buying these trees as smaller (and much more affordable) saplings from the Arbor Day Foundation and planting them with the Groasis Waterboxx PlantCocoon to ensure adequate water during the first year.

A airy Thornless Honeylocust providing shade for a picnic table along a well maintained walkway.  This path is actually a converted rail line called the B-Line Trail.

Bald Cypress (Taxodium distichum) is an incredible tree, tolerant of city pollution and many adverse conditions.  This tree is something of a contradiction, a deciduous evergreen that loses its light needles in the fall.  This is the famous tree of the Louisiana swamps, which grows broad "knees" when planted in swampy conditions.  However, it can grow far north of its original habitat (in zones 4-10), especially if planted with the Waterboxx PlantCocoon.  Although slow growing, it can grow up to 70 feet high as seen below, but looks verdant, light and airy within a few years of planting. It tolerates swampy conditions well making it well suited for planting along river greenways.  These trees are also drought tolerant.  It can be purchased here.

Mature Bald Cypress in the background, with a more recently planted Bald Cypress in the foreground.  We recommend this tree for medians and river greenways.  

Ginkgo trees (Ginkgo biloba), also called maidenhair trees for their unique leaf shape, are very interesting.  They are dioecious, meaning that each tree is either male or female.  It is very important to get male trees as females produce foul smelling fruit that is to be avoided.  It has a moderate rate of growth, but reaches up to 50 feet in height and has a 25 foot horizontal spread.  It is drought tolerant, and tolerates almost any soil conditions.  It will grow slowly initially, but does much better if given a consistent supply of water with the Waterboxx PlantCocoon.

A younger Ginkgo tree in a city park along a busy street in Indianapolis.

A more mature Ginkgo tree on a college campus in southern Indiana.

Any discussion of city trees would be incomplete without mention of oak trees.  These trees are renowned for their beauty, strength, shade quality, and wildlife value.

The Northern Red Oak (Quercus rubra) is a beautiful, straight, and fast growing tree well suited for Midwestern cities.  In our experience, it grows as fast as Silver Maple, but without any of Silver Maple's many problems.  It grows in zones 3-8, tolerates many soils, and has a beautiful fall color (hence its name).  It can be purchased here.

Northern Red Oak

Bur Oak (Quercus marcocarpa) is a great, drought resistant oak tree.  This tree will grow farther west than most other oaks (one exception being the Texas Escarpment Oak), but does tend to be slow growing.  It is large, growing 80 feet high with an 80 foot spread.  It grows in zones 3-8, and can be purchased here.  As this tree is slower growing, we strongly recommend planting it bare root with the Waterboxx PlantCocoon, which will provide consistent water and allow faster growth.

A beautiful Bur Oak, with two paths diverging under it.

We have mentioned the Groasis Waterboxx PlantCocoon throughout the above tree recommendations - so what is this?  The Waterboxx (for short) is a ingenious device for growing trees without irrigation or staking.  The Waterboxx consists of a basin for holding water, a special lotus leaf inspired lid to collect dew and rain water, and a capillary wick to slowly trickle water to the roots of the growing tree.  It is placed around a tree right after a tree is planted as a sapling, and provides all water needs for the tree for the first year.  The Waterboxx can then be removed and reused for other trees.  You can see a schematic view with a corner removed below.

A schematic, cut-away view of the Waterboxx PlantCocoon.  Water is collected from dew and rainwater on the tan lid, funneled into the green reservoir, and slowly released to the roots of the growing tree by the white wick.  The tree is induced to grow deeper roots because of the Waterboxx and is more resistant to drought in the future.  

Two trees we would strongly recommend against planting (despite their popularity currently) are Silver Maple (Acer saccharinum) and Bradford Pear (Pyrus callerycana).

The Silver Maple has many problems.  It is fast growing, which is its main (dare we say only) good quality.  However, this growth is accompanied by weak branches and a large number of sticks on the ground after high winds.  It also has very shallow roots which trip people and buckle sidewalks, and are also hit by lawnmowers.  Finally, it is not a strong or long lived tree, and will need to be replaced within a few decades.

The very shallow roots of a Silver Maple

These shallow roots of a Silver Maple have cracked the nearby sidewalk, allowing weeds to grow in the cracks and posing a safety hazard.  

The other tree we strongly recommend against planting is Bradford Pear.  This is also a fast growing, picturesque tree.  However, this tree is fantastically weak, and will split is light winds.  It is a waste of money to plant, and it pains us to see it planted in so many suburban driveways and yards.

This Bradford Pear collapsed in a light rain - no wind to speak of.

If you have any questions or suggestions for other excellent city trees for the Midwest region, please leave a comment below.  If you are interested in buying a Waterboxx, you can find them here in the U.S.

Crosses Between Cherry and Beefsteak Tomatoes

Whether a new cross is designed to be a F1 hybrid, which is sold as such commercially, or a breeding start for a program to develop new inbred/O.P. lines, selection of parents is critical.   Most breeders will select parents that complement each other, so that in the F1 (or F8) generation you capture the best characteristics of each parent.

We have now made and tested several dozen crosses between beefsteak and cherry types – hoping to capture some of the exquisite taste of the best cherries (think Sungold) in a larger fruited type.  We have also used early fruiting cherries to get earlier maturity in these hybrids and hybrid-derived Fx progeny.

There are some general patterns that we find interesting:

In crosses between smaller x larger fruit, the fruit size in the F1 generation will be much smaller than the mid-parent mean.  My tomato friend Bill Jeffers told me many years ago that fruit size in hybrids could be estimated using the mean of the square root of the fruit weight of the parents – for example (1oz x 9oz) –-> (√1 + √9)/2=2oz fruit wt for the F1.  I’ve found this to be a pretty good rule of thumb.

   

     In the F2 generation we have found almost the whole range of variation in fruit size, but heavily skewed toward smaller fruit.  The frequency distribution typically looks something like this: 

In this example, again the parents were a 1oz cherry and a 9oz medium beefsteak.  You need to look at a lot of F2 plants to find one that comes close to capturing the size of the large fruited parent.

The frequency distribution for maturity (i.e. earliness in fruit set) is similarly skewed toward the early parent, but in these F2 populations earliness and fruit size are negatively correlated – generally small fruited types are early, larger fruited types are later.   Thankfully we have been able to get earlier large fruited types by selecting primarily for size in the F2 and then for size and earliness in the F3 – again using large populations in both generations.

Our "go-to" cherry parent - derived from Sungold

Much of our recent crossing involves commercial hybrids (e.g. Bella Rosa, Mountain Merit, Panzer and Tasti-Lee) with exceptional disease resistance as the large fruited parent and very flavorful striped cherries as the small fruited parent, so we are also selecting in the F2 and F3 for flavor, stripes, plant health and fruit quality.  So far we are making progress on all fronts.  

Fruit from F5 line derived from cherry x beefsteak cross

The Planet's Lungs: Planting Giant Sequoias To Combat Carbon Dioxide

Carbon dioxide concentration in the atmosphere is increasing.  This is not controversial.  Global warming has been cited as the most dire problem from this increasing concentration of atmospheric carbon dioxide, but other problems (like ocean acidification) clearly exist.  Almost all of the proposed solutions to this carbon dioxide increase have been foolish and harmful to human prosperity - limiting driving, flying, air conditioning, home sizes, etc.  Few are discussing a much better solution that improves rather than worsens our living standards- planting very long lived and massive trees to absorb and store carbon dioxide.

Carbon dioxide concentration in the atmosphere as measured by the Mauna Loa Observatory on Hawaii.From NOAA, available at http://www.esrl.noaa.gov/gmd/ccgg/trends/.  The sawtooth pattern of the graph likely reflects the absorption of carbon dioxide by vegetation throughout the year.

The largest tree (and living thing, for that matter) on Earth is the giant sequoia tree (Sequoiadendron giganteum), specifically a single tree called "General Sherman".  We wished to calculate how much carbon dioxide a sequoia tree could conceivably sequester or "lock up" in a best case scenario.  Sequoias are ideal for sequestering carbon dioxide because of their great volume, extremely long lifespan (several thousand years), and the wide range in which they can be grown.  We are currently growing two giant sequoias in Indiana, which is hardly native habitat for the sequoia (native habitat is a small portion of California's Sierra Nevada).  We had planted 5 sequoias outdoors previously in our state, but saw all die during the summer dry spell - even with frequent watering.  We finally decided to use a device called the Groasis Waterboxx PlantCocoon® to grow our sequoias outdoors, with 100% success, in two different parts of our state.

We went through a fair amount of effort to determine how much carbon dioxide a giant sequoia can sequester.  We will spare you the details of this calculation here, but please see our footnote for our sources and calculations.

The "General Sherman" sequoia tree in California is the largest living thing on Earth by volume.  Its volume of 52,500 cubic feet, or about 1486 cubic meters, contains over one million kilograms (and over 2.2 million pounds) of stored carbon.  This volume of stored carbon pulled over 1400 metric tons of carbon dioxide out of the atmosphere.

Americans, on average, produce 16.6 metric tons of carbon dioxide emissions per year (although this number has been decreasing recently due to efficiency gains).  The General Sherman sequoia is so large that as a single tree it has stored about 86 years worth of a person's carbon emissions.  In other words, one very large tree has been able to counteract over a lifetime of carbon emissions for the average American.

The General Sherman  Giant Sequoia Tree, from National Park Service, found at http://www.nps.gov/seki/learn/nature/sherman.htm, public domain

These facts about the largest giant sequoia would be interesting but not particularly actionable if not for one simple fact.  The giant sequoia can be grown in most of the United States - not just California.  We ourselves are growing two giant sequoias in Indiana, both started with the Waterboxx PlantCocoon®.  The sequoia's main requirement is sufficient water, and its water needs can be significant.  However, the need for consistent water is most critical during the first few years of a sequoia's life outdoors.  We have found that due to soil evaporation, we could not manually water sequoias enough for them to stay alive.  Some other system was needed to prevent evaporation and ensure sufficient water available to the roots.  It was our interest in planting sequoias in a better way that got us interested in the Groasis Waterboxx PlantCocoon®.  One of our sequoias has now graduated from the Waterboxx PlantCocoon® - meaning the Waterboxx PlantCocoon® has been removed and used for other plants.  The tree is doing well even though we haven't manually watered it, even once. It takes about 18-24 months to establish a small (6 inch) sequoia with the Waterboxx PlantCocoon® in our state.  You can see our two sequoias in the pictures below.  Neither of these trees has had any water from us or any sort of irrigation after initial planting and set up with the Waterboxx PlantCocoon®.

Our giant sequoia was planted just outside Indianapolis, with these pictures above showing two years of growth.  This tree is now over a meter tall, with no watering at all after planting with the Waterboxx PlantCocoon®.  Even after the Waterboxx PlantCocoon® was removed, no watering was needed due to the deeper roots established by the tool.

This giant sequoia seen above, planted in Southern Indiana, was smaller when transplanted outdoors with the Waterboxx PlantCocoon®. In the 25 month time span seen in the photographs, it has dramatically increased in size, and will soon be able to survive without help.  

Regardless of your stance on global warming, increasing carbon dioxide in the atmosphere poses other risks (like ocean acidification mentioned above) as well as some benefits (like faster plant growth).  We can take advantage of both of these by planting giant sequoias.  If every set of grandparents came together to plant one sequoia each for every new grandchild in their family (for a total of two sequoias per child), that child's carbon dioxide emissions would likely be offset by the sequoias, and the carbon would be stored for thousands of years.  Also, we would find our neighborhoods more stately and shaded from these monumental trees.

If you are interested in trying to grow a giant sequoia, our preferred source is Giant-Sequoia.com.  To buy the Waterboxx, visit us at DewHarvest.com.

Footnote: Our Calculations and Sources 
Note: we use American mathematical nomenclature here (commas to separate 1000s, periods to indicate decimals)

When calculating carbon dioxide sequestered by a sequoia, it is first necessary to have the density of sequoia wood.  We were only able to find this information with great difficulty here after much searching.  We did also receive a generous sample of sequoia wood from our friend Joe Welker at giant-sequoia.com (where we bought our sequoia trees).  The measured density for a small piece of sequoia wood containing bark was approximately 0.48 grams/mL.  We obtained this by measuring a small piece of sequoia wood (36 grams) on a very accurate postal scale.  We then submerged this same piece in a graduated cylinder, which displaced 75 mL.  36/75 = .0.48g/mL which equals 0.48 g/cc as one milliliter is equal to one cubic centimeter, by convention.

This density of 0.48 g/cc is within the range of densities reported by Wolfgang Knigge in his scientific paper Giant Sequoia in Europe,  http://www.fs.fed.us/psw/publications/documents/psw_gtr151/psw_gtr151_06_knigge.pdf) . His reported densities found average values of 0.345 g/cc in European giant sequoias and 0.369 g/cc in California giant sequoias.  Our density of 0.48 g/cc converts to 480 kg//m^3 (the math for this conversion is 0.48g/cc x 1,000,000 cc/m^3.  This result is then multiplied by 1 kg/1000 g, equaling 480 kg/m^3).

Next we need to calculate how much mass the largest living sequoia tree, General Sherman, contains.  According to the National Park Service, the General Sherman sequoia has a volume of 1,486.6 cubic meters (http://www.nps.gov/seki/learn/nature/sherman.htm).  To get total mass of this tree, we multiply 1486.6 m^3 by 480kg/m^3.  This gives us a total mass of 713,568 kg for General Sherman.

This mass is of course not all carbon - much being oxygen, nitrogen, and other elements.  Most trees are about 50% carbon by mass.  However, as giant sequoias have more heartwood (more durable wood in the center of the trunk) than sapwood, and heartwood has a slightly higher carbon content, this value may be too low for sequoias.  According to Sean Thomas in his Paper Carbon Content of Tree Tissues: A Synthesis (See section 4.1, available here: http://www.mdpi.com/1999-4907/3/2/332/htm), giant sequoias are approximately 55% carbon by mass.  When we multiple our calculated mass for General Sherman of 713,568 kg x .55, we get a carbon mass of 392,462 kg.

We next need to convert the mass of carbon into metric tons, so we divide 392,462 kg by 1000 to get a value of 392.4 metric tons or carbon stored in General Sherman.

However, carbon is not the same as carbon dioxide.  Carbon dioxide has one carbon atom and two oxygen atoms per molecule.  Trees absorb the carbon when growing while (mostly) emitting the oxygen.  The atomic weight of carbon is 12.001115, while the atomic weight of oxygen is 15.9994. So the total atomic weight of CO2 is 43.999915.  With a little algebra, we see that since the ratio of carbon dioxide to carbon is 43.999915/12.001115 or 3.6663 units of carbon in the tree for every unit of carbon dioxide removed from the atmosphere.  We obtained this information from the Broward County Florida Climate Change website (https://www.broward.org/NaturalResources/ClimateChange/Documents/Calculating%20CO2%20Sequestration%20by%20Trees.pdf) as well as contact with Richard Campbell from Save The Redwoods).

We can thus multiply our total mass of carbon, 392.4 tons by our conversion factor 3.6663 from above to get 1438.892 total tons of CO2 removed by the General Sherman giant sequoia.

Americans, on average, produced 16.6 metric tons (or tonnes) of carbon dioxide per year in 2013 (the most recent year available) according to the Netherlands Envirornmental Assessment Agency (Table A1.2, page 49 found at http://edgar.jrc.ec.europa.eu/news_docs/jrc-2014-trends-in-global-co2-emissions-2014-report-93171.pdf).

When we divide 1438.892 metric tons of carbon dioxide removed by General Sherman by 16.6 metric tons, we get 86.7 years of CO2.  That is 86.7 years of carbon emissions sequestered in a single tree!  We find this number so impressive that we checked our math several times.

Caveats:  General Sherman is the largest sequoia now living, and any trees planted would be unlikely to get quite this large.  We chose this tree as good data was available on its volume, and as a vivid example.  Also, it likely took several hundred years to reach this size, with more carbon absorbed at larger sizes.  So any sequoias planted are unlikely to absorb a whole person's carbon dioxide output for several decades.  However, adults emit considerably more carbon dioxide than young children, so the growth and sequestration of a sequoia may roughly mirror a human's emissions.