Flowering trees revisited: the best way to save the bees

Inside: Flowering trees provide forage, shade, and habitat. They also extract CO2 from the air, break strong winds, and prevent runoff. If you want to do a good thing for the bees, for us, or for the planet, plant a tree. Nothing is more important.

Sky gardens: planting the overhead

When we consider planting for pollinators, we often focus on crop plants or garden flowers that bloom at eye level or below. These range from tiny forget-me-nots to swaths of clover to prickly jungles of raspberries.

For whatever reason, we rarely consider trees for our pollinator gardens. We may think trees are slow to grow, deposit messy litter on the lawn, or shed shade where we don’t want it. Or perhaps we overestimate the danger of a tree that grows close to the house.

But if there is one thing our planet needs more of, it’s trees. And lucky for us beekeepers, honey bees thrive on flowering trees. And so do we.

Square-foot gardening

A few years ago, so-called square-foot gardening was all the rage, especially in urban areas. The goal was to plant many species within neatly divided square-foot plots, usually in raised beds. Compared to planting in rows, aficionados touted this practice as more efficient and less wasteful of water and soil amendments.

But if you want to plant for honey bees, so much variety in a small space is counterproductive. At the very least, honey bees prefer to collect from a single species for the duration of a foraging trip. And a full day of trips is even better. When feeding honey bees, a bigger plot is better.

A variation on square-foot planting

Although I never got into checkerboard gardening, I think of it whenever I plant a tree. After clearing a little patch of soil — not much bigger than a square foot — I sink a hole in the center and plant my itsy-bitsy seedling. I tend it for a year or two, deleting weeds and adding water until it looks happy.

Afterward, I forget about it, sometimes for years. Then one day, I walk by and realize my twig is as big as a house — well, taller than a house, anyway. If only my bank account had the same vigor.

I’ve always been a tree planter. Each spring, I’ve purchased trees from my conservation district, usually in bundles of ten or twenty-five. Those trees are the reason my house is chilly on the sweatiest summer days (no air conditioning needed). They’re also the reason the paint lasts so long (no UV light to ruin it), and the reason my hives are in constant shade, something the bees don’t seem to mind at all.

A life strung together with trees

One day last summer, beneath an azure midwestern sky, I sat in the grass contemplating the biggest cottonwoods I’ve ever seen. The trees were iconic, rough-barked giants, with beefy branches as thick as full-grown sycamores with the kind of roots that tilt sidewalks and crack driveways. Their stately presence and look-at-me attitude unleashed a wash of tree memories.

Trees have been a lifetime source of happiness and contentment. I see my life as a string of beads where each bead is a different tree. I’ve simply gone from one to the next, admiring every one of them.

Trees for a healthy life

Is anything more magical than a fragrant manila rope hanging from a shady oak loud with chattering squirrels and squawking jays? My third-grade rope — coarse, shaggy, and redolent of rotting grass — ended in a fat knot that kept me from sliding to the ground. Despite calloused hands and ragged fingers, I spent lazy summers swinging in great arcs, hoping I would never grow up.

Besides providing wood and fruit and piles of musky leaves, trees in our neighborhoods purify the air, reduce road noise, provide privacy, lower our exposure to UV radiation, and keep us cooler. Trees lure us to the outdoors and introduce us to wildlife and sounds we remember for a lifetime: the squawking of birds, the chatter of chipmunks, and the cacophony of busy insects.

Playgrounds with shade are more popular than those in bright sun, and picnickers like a table under a tree despite bird droppings, seeds, pollen, and leaves that land there. Trees provide comfort like a well-worn security blanket. Nothing lures humanity like a tree.

Study after study confirms that green spaces promote emotional health and happiness. They ease anxiety and depression and can lessen anger. Studies have shown that inner-city crime and violence diminish in areas with shade trees, and kids are more likely to play outside.

Then too, trees provide private places. Even with people all around, trees help us collect our thoughts and sort through problems. People seek trees as places to read, talk to friends, or simply watch the world pass by. And since wildlife loves trees as much as we do, tree lovers are never truly alone but surrounded by companions of every size and disposition.

Trees can cut your energy bill

Years ago, while hiking with family members in the Anza-Borrego desert east of San Diego, we came across a stand of mortero palms. Entering the stand was physically shocking, like stepping into a walk-in freezer. But instead of dry, the air among the trees felt thick and damp and smelled like aging hay bales. Those astonishing trees grew straight and tall amid boulder piles in the scorching desert heat, yet wore layers of dead fronds like frilly petticoats that shaded the ground beneath.

Buildings shaded by trees can easily escape the huge energy loads of air conditioning. My home is a good example. Over the past thirty years, untold numbers of visitors have gushed. “Oh my, it’s so cool in here!” Or, “You must have heavy-duty air conditioning.”

Yet we have no air conditioning and never did. And even with warmer daytime temperatures, I still wear a hoody at my desk all summer long. One by one, our surrounding neighbors cut down their trees, and each expressed surprise when they could no longer bear the summer heat without air conditioning. Homes can be 10-15 degrees cooler just by leaving trees in place.

And if the trees are deciduous, you get a double benefit: cool shade in summer, and sunny warmth in winter. You couldn’t design a better system, no matter how much money you poured into it.

Trees thrive on carbon dioxide

With all the environmental problems we have, I’m surprised we continue to cut trees and clear the land just because we can. Now more than ever before, we need to give trees the respect they deserve.

Like all plants, trees take up carbon dioxide (CO₂) and water (H₂O) during the day. When we add sunlight, the chlorophyll in plants produces sugar (glucose) and oxygen (O₂) through photosynthesis. The oxygen enriches the atmosphere and the carbon-containing glucose gets stored in the plant.

But like animals, plants respire 24/7, using O₂ and giving off CO₂. During the day when photosynthesis occurs, plants use only some of the O₂ for respiration and release the rest into the air. During darkness, however, photosynthesis stops so plants must use O₂ from the air and give off CO₂. Despite this reversal, plants release less CO₂ at night than they use during the day. That means trees are carbon sinks: storage vaults for carbon.

In trees, most of the carbon gets stored in the wood. Later, if we burn that tree as firewood, the carbon dioxide goes back into the atmosphere, turning the wood into a carbon dioxide source.

Trees have a short carbon cycle

For many trees, such as Douglas fir, the carbon cycle takes about 60 years. The tree lives and stores carbon for roughly 60 before we cut it. If we build a house with it, the carbon remains in the wood. If we burn the wood, the CO₂ goes back into the atmosphere.

This cycle of collection and release is short in geologic terms. Before people began burning fossil fuels, the CO₂ regularly cycled between plants and the atmosphere, such that the atmospheric levels of CO2 remained very constant. But burning fossil fuels yields a very different result because it takes millions of years to recycle the CO₂ back into the ground and make coal or oil. As a result, our atmospheric CO₂ is rising quickly.

Recent research shows that trees release more carbon dioxide during respiration when temperatures are higher. But even in a warming atmosphere, trees will continue to be carbon sinks. Other research shows that older trees store more carbon than young trees, which means we should be cautious about cutting mature trees that cannot quickly be replaced.

Trees reduce runoff and keep water cleaner

The benefits of trees go far beyond carbon storage. The roots of trees create channels through the soil that direct water into the ground. Forested areas have little runoff, while rain in cleared areas runs freely into streams, rivers, lakes, and ponds. Along the way, the runoff collects pollutants, particles, and pesticides that taint our water and poison our wildlife. Predictably, sampling has proven that water sources protected by trees are cleaner and healthier.

Uncontrolled runoff also causes flooding. As we’ve all seen, areas that are newly logged, ravaged by wildfires, or cleared of vegetation are the first to flood in heavy rainstorms. Not only do trees use large amounts of water, but their networks of roots, from minuscule to huge, hold the soil in place and direct the water into subsurface layers.

Trees benefit wildlife and vice versa

Despite my best intentions, I eventually grew older, but I appeased this upsetting development with a “thinking tree.” My sugar maple was anchored to the bank of a murky pond. Years earlier, someone had twisted a secondary trunk into a spiral that grew into a fat, smooth barber pole. Below branches that strained toward the sun, the semi-stagnant water curated ducks, snapping turtles, bullfrogs, and shiny fish that leapt for bugs.

In salmon streams, trees are necessary to keep the water cool enough for the eggs to hatch. Because cold water holds more oxygen than warm water, the eggs need cold water to survive. If the water is too warm, the eggs will simply perish. In addition, tree roots stabilize the stream banks and create snags — safe havens for the fish to hide. Above the water, tree debris, including sticks, leaves, catkins, and seeds, drop into the water and provide food for insects. Then, as a bonus, the insects become food for the fish. What a system.

In a fascinating twist, research shows that the carcasses of salmon that die after spawning wash ashore and fertilize the trees along the stream beds. Biologists have found salmon biomarkers in the tops of some of the tallest and oldest trees living along salmon-bearing streams. These unexpected data are giving scientists a way to tell where salmon historically spawned and suggest where restoration efforts may be most successful.

Trees as windbreaks

Without trees to anchor the topsoil, it can all be blown away. For centuries we have used trees as windbreaks to reduce the erosion of topsoil. When wind that carries soil particles hits a row of trees, the speed of travel slows and soil particles drop to the ground. Without a system of foiling wind currents, soil can travel hundreds of miles from its origin, ruining farmland, polluting the air, and creating deserts.

Flowering trees for bees

When we think of pollinator plantings, it’s easy to forget about trees. Yet, one tree can equal an entire field of flowers, all growing out of that square foot of real estate. And many trees make tasty honey, even while they provide fruit, nuts, and animal forage.

If you want to plant flowering trees for honey bees, just about any fruit tree will do. Apples, crab apples, peaches, plums, and cherries are all great for bees. Some varieties get more flowers than others, so for maximum pollinator benefit, find out what locally grown varieties are best.

One of the quirky features of much tree honey is its high fructose content. This one component makes it much more resistant to crystallization than most honey produced by forbs.

I have big-leaf maple honey that’s twelve years old and still perfectly liquid (and exquisitely delicious). Other honeys that seem to stay liquid forever are cascara, tupelo, chestnut, and black locust.

If growing fruit is not your thing, there are plenty of flowering trees to choose from. Depending on your area, you might choose serviceberry, redbud, basswood, willows, maples, sourwood, or lack locust. You can easily find a tree that fits your lifestyle.

Some of the best flowering bee trees

I once stayed in a classic bed-and-breakfast in eastern Oregon. I had been photographing alkali bees in the fields of Touchet, Washington, but in the evening I enjoyed the dry winds escaping south from the Palouse. As I sat under a luxuriant tulip poplar helping a boy with his balsa-wood airplane, I heard an industrial-strength hum. I glanced around looking for the source until the boy pointed into the leaves overhead. “It’s them,” he said. “Bees.”

Many of the best trees for bees are already all around us. Often, we are so busy with daily life that we don’t notice the vast abundance of pollinators attending the blooms. Below, I’ve listed some of the best trees for bees.

Avocado (Persea americana): Avocado trees are evergreens that do well in warm climates. They produce deliciously dark molasses-like honey with an intense aroma.

Basswood or linden (Tilia americana) blooms with creamy white flowers in late spring. The fragrant blossoms are much admired by honey bees, culminating in a popular honey described as “woodsy” with hints of bitterness.

Black locust (Robinia pseudoacacia) produces clusters of aromatic white flowers in late spring. In good years, bees can store large amounts of light, vanilla-tinged honey in a matter of days. The honey, sometimes labeled “Acacia,” is especially slow to crystallize.

Black tupelo (Nyssa sylvatica): Tiny, inconspicuous greenish flowers make tempting honey with notes of cinnamon and citrus. The trees produce extraordinary fall colors.

Cascara (Rhamnus purshiana) is a small Northwest tree that produces oodles of dark purple berries that birds and other wildlife treasure. The inconspicuous green flowers produce medium amber honey with a rich, smoky taste.

Citrus (Citrus × sinensis and Citrus limon) produces the highly prized orange blossom honey with its distinctive orange flavor. Although these trees are reproduced by grafting, the flowers still produce plentiful nectar that honey bees prize.

Crape myrtle (Lagerstroemia): Common in the Southeast, crape myrtle is a favorite of honey bees, especially in late summer when little else is in bloom. They come in many varieties, most with showy flowers and vibrant fall foliage.

Fruit trees come in both fruiting and non-fruiting types. They include apples, cherries, crabapples, peaches, and pears. The bees love the pollen and we get to harvest the fruits of their labor.

Hawthorne (Crataegus): Considered one of the best bee trees, hawthorns are also known for attracting many types of wildlife.

Redbud (Cercis canadensis): Clusters of showy redbud flowers appear in early spring, emerging from the stems in flaming shades of pink. Bees in abundance, including honey bees, bumble bees, mason bees, mining bees, long-horn bees, and sweat bees enjoy both the nectar and pollen. The leaves are hosts for the larvae of some butterflies and moths.

Serviceberry (Amelanchier): Early spring blossoms appear before the leaves, yielding berries for birds and jam. The nectar-rich blooms are favorites of honey bees, mason bees, and mining bees.

Sourwood (Oxydendrum arboreum): Sourwood displays striking fall foliage in shades of tangerine, scarlet, and plum. In spring, lily-of-the-valley-shaped flowers dangle from the branches, attracting pollinators of all sorts, including honey bees. Lightly amber sourwood honey is prized for its spicy flavor topped with hints of caramel and nuts.

Southern magnolia (Magnolia grandiflora): Many people consider the stately southern magnolia a messy tree, always dropping something. But the big, fragrant flowers are well-attended by bees and other pollinators.

Sweetgum (Liquidambar): Small trees with lusty red and yellow leaves in fall, and small, inconspicuous bee-attracting flowers in spring.

Tulip trees (Liriodendron tulipifera): Large and fast-growing, tulip poplars have many greenish-yellow tulip-shaped flowers that yield both nectar and pollen. The strong and dark honey is often used for baking.

Willows (Salix): In general, the many willows are very early and extremely attractive to a wide variety of pollinators, including honey bees.

Beekeepers can make a difference

Although it was a long time coming, trees are finally making a comeback. Today, hundreds of organizations, large and small, global and local, promote trees to save the planet. As the rate of deforestation rises, people are fighting back and spreading the word.

As beekeepers, we understand the importance of a healthy environment for bees and other living things. We know a well-chosen tree can provide as much bee forage as a meadow, produce gallons of fine honey, and give wildlife a place to live (and our swarms a place to land). Beekeepers everywhere can score a win for the environment by planting a tree or three.

Beekeepers are in a unique position. We can easily help our bees thrive by providing vertical forage that feeds and protects them. At the same time, we can enhance our neighborhoods, keep our water clean, and reduce runoff and erosion. Planting a few extra trees can elevate our property values, cool our neighborhoods, make us happy, and extract pounds and pounds of carbon at the same time.

And don’t forget, we can also harvest from our trees. Not only honey, fruit, nuts, and wood but memories, the kind that can last a lifetime. What could be better than that?

Rusty
Honey Bee Suite

About Me

I backed my love of bee science with a bachelor’s degree in Agronomic Crops and a master’s in Environmental Studies. I write extensively about bees, including a current column in American Bee Journal and past columns in Two Million Blossoms and Bee Craft. I’ve endured multiple courses in melittology and made extensive identifications of North American bees for iNaturalist and other organizations. My master beekeeper certificate issued from U Montana. I’m also an English nerd. More here.