11 Celtis (Hackberry Genus)

Galaxies Crossing

Each tree is a world unto itself. In the big picture, each tree is a galaxy of life gravitating around other galaxies, looping through the Universe. We are all made of the same stuff, just that some stuff tastes better than others, and feeds different species. What is toxic or disgustingly foul to one, can be healthy, nutritious and even delicious to another. The scientific database reveals general patterns from which to extrapolate. Evidence can verify postulations and theories, but no ‘galaxy’ provides an uncomplicated, black and white rule to describe it all. In the midst of this (or perhaps because of this), everything has its own beauty from the smallest speck to the highest mountain, wind, weather, rock, wing, human, slug, fungi, and so on to infinity. All is imbibed with love pouring from the sky above and coming up from the Earth below, enduring while warmly reassuring the connectedness of each to the other.

Trees offer a fascinating, endless exploration of other living beings. How much water they drink at night vs. during the day. How sweet their sap is, and what factors vary its sugar content. How responses change depending on the weather, the time of the day or night, the stressors faced, the interactions with helpful fungi as well as with fungi that hurt. What hormones are being released seasonally. What the timing is for leaf drop in fall and bud burst in spring.

Trees provide food sources for a multitude of creatures, not just animals and birds but also insects. One warm Spring day, I spotted a cecropia moth as I was exiting the grocery store. Newly emerged from its cocoon, it lay on the cement not far from the brusquely grating wheels of my cart rolling by. Knowing he would not be able to move until his wings dried, I gently encouraged him (it was a male) to walk onto my finger and then took him with me, placing the moth on the dashboard of my car. In this way, we both completed our business – me to run errands and he to finish drying while I drove around.

At last, letting him go when he was ready, we watched the cecropia flutter up past the porch and waft away over the roof. He will eat nothing, cannot do so. His only quest now was to use his over-sized, sensitive antennae to pick up the pheromones of a female cecropia lady-love waiting within a mile or so, to meet up with her and mate. Good luck, my friend!

Caterpillars will stick with the specific host plants they feed on. One of my favorite butterflies, the Mourning Cloak, loves the leaves of elm, willow, poplar and hackberry. Somehow, they just know the leaf is right for them and start chomping away. Some butterflies are so specialized with a tree species as its sole host that they are named after the tree, such as the Hackberry Emperor (Asterocampa celtis). Others, such as the cecropia moth, thrive on dozens of different plants as hosts and do just fine. Hackberry serves up a leaf buffet to a few other butterflies, including the Question Mark, Tawny Emperor and American Snout. While an oak tree hosts over 500 species of moth, butterflies and other insects, nonnative species like ginkgos host less than ten. This is another reason why native plants are so important to conserve. Plants do not exist alone. They exist, like all of us, within the web of life. Many forms of life rely upon the insects who rely upon those specific plants for feeding both themselves and their babies.

When I stand next to a tree and observe, for instance, an ant going about its business traveling up and down the contours of one deeply furrowed ridge of bark, a feeling of calm happiness descends on me. Here is an ant on the tree where it belongs.

Everything is as it should be.

Let’s enter the world of the hackberry, aka common hackberry (Celtis occidentalis). Notice how the alternatively growing branches are covered with deep green, simple (not compound) leaves. The edges, or margins of the oval leaves are toothed. For a moment, let’s find a spot on this September day beneath the tree to take a break and rest for a while. The hackberry tree‘s presence reveals itself as wonderfully quiet and restful. A safe place. Dangling from every branch midst the fluttering leaves are dark bluish purple, round little fruits about the size of a small pea. A bird over there has one of the fruits right now in its beak! A robin! And there’s a cedar waxwing, just come from the juniper grove perhaps, the taste lingering on his palate from a different sort of blue fruit. A squirrel far above us is also snacking as well, nibbling whatever he can reach. He could store some, and perhaps does, but his experience has taught him there is no need for this. These fruits have a high sugar content in their skin as well as a tendency towards dryness which preserves them and allows them to linger on the tree all through winter while remaining perfectly edible. Perhaps sometime in the cold weather ahead, a deer will come through and browse to the level where her head can reach. Whether revving up for winter, or soon to be migrating, or finding preserved food ready for the plucking over the next few months, this is the right place to be.

Hackberry fruits are actually not berries. Instead, in botany, these are called drupes. A drupe’s inner part of the ovary (endocarp) surrounds and protects the single seed kernel, forming a strong, stony pit around it. In a berry, this part would be very thin and flexible, and there would be more than one seed inside. Other examples of drupes are plums, peaches, apricots, olives, cherries and almonds.

“Can we eat the fruit?” someone asks.

“Yes, we can but don’t chew it; the seed inside is too hard,” I explain. “I like to pick one or two for fun while I’m walking and suck on the sweet, pulpy outer part, then spit out the rest when I’m done. It’s really delicious. The great thing about hackberries is that the whole thing is edible and nutritious, even the hard, inner seed.”

Pluck a hackberry with me now and enjoy the flavor of one of the oldest known plant foods humans have eaten for many thousands of years. Hackberry drupes are fantastically nutritious, packed with calories derived from proteins, carbohydrates and fats. They also contain vitamins and minerals including calcium carbonate and magnesium. Crush with a mortar and pestle, add to water, let sit overnight and then strain to make a drink. The Dakota people dried and pounded them into a condiment used for seasoning meat. The Pawnee mixed pounded hackberries with a little fat and parched corn, which sounds good to me as a useful snack item at home as well as for traveling. The list of Indigenous Americans preparing hackberries is long.

Archeological digs often turn up the very hard, stony seeds of hackberry pits which tend to hang around. Similar to the rough surface of a peach pit, the hackberry seed is coated with a protective latticework. These microscopic holes are stuffed with calcium carbonate. The amazing things is, the lattice work itself is composed of opal, just like the gemstone, albeit in very minute quantities. On learning the research that led to this remarkable discovery, my image of the hackberry has changed. My imagination now visualizes the profusion of drupes that penetrate from every level of the hackberry tree as a constellation of stars shining its opalescence out into the night.

Standing within our hackberry tree world, you might notice little nubs growing on the underside of many of the leaves. These green, protruding growths are called hackberry nipple galls and are formed from an insect that relies on the hackberry trees for its entire life cycle. Called Hackberry psyllids (Pachypsylla sp), pronounced “sill-ids”, the insects mate and lay eggs in spring. The eggs hatch and nymphs emerge to suck the sap from the leaves. Galls form from host tissue growing around and enclosing them inside. In late summer and fall, adults emerge from the gall to seek shelter in bark and leaf litter where they overwinter before completing their life cycle the next spring. The psyllids get a place to live unless a squirrel eats the gall as a healthy snack first! Many other creatures join in the buffet, especially during the exposed stages of the insects during spring and fall. Ants, flies and spiders eat the psyllid eggs in springtime and also in autumn during the adult emergence stage. All this insect activity attracts songbirds which is especially helpful as it coincides with their seasonal migrations. Hungry gray tree frogs, toads and lizards also sit down to dine in this busy café. The world within a hackberry galaxy is truly filled with a plethora of life.

Hackberries are not the only hosts for insect gall-inducers, however. Galls are common on many plants, and in fact, insects are not their only causes. Mites, fungi, dwarf mistletoe, and bacteria weigh in here, and each species prefers its own, particular host. Oaks support more than 200 gall-producing insects alone. The Linden Gall Mite, the Goldenrod Gall Fly, the Jumping Oak Gall, the Cooley Spruce Gall and Cedar Apple Rust (fungi-induced) are just a few colorful names for these invaders that arrive clad in their own unique regalia ready to create some oftentimes wildly interesting, abstract shapes. In general, galls do not usually affect the overall health of the plants they invade, although they often don’t exactly help much either. The wonderful result of galls, however, and their associated insects reveals itself in the seasonal food provisions they supply that other species rely on, adding to each plant’s particular, vibrant offering within the “web of life”.

One of the notes of condolence I received after my dad died was an email from a former Environmental Committee member. What she sent was so unexpected and yet, perfect to receive during that difficult time that I was very grateful to receive it. The short note accompanied a photo of what my dad had told her was his favorite tree in the park. I didn’t know he had a favorite tree in the park! Or if I did, it was only vague background information that I didn’t log on enough to find out what tree. Snow lies all around the darkly contrasting trunk in the photo, recently taken, but the highly recognizable bark of the hackberry stands out. Warty, textured, corky, deeply ridged and curving this way and that like contour lines on a topo map – these are all ways to describe the hackberry tree’s signature bark. The tree in the photo is, naturally, one of his tagged trees.

If I had any questions about whether or not those red metal tags of a different era I was sporadically discovering on my journey through the park, they were put to rest the day my brother told me one of the trees in my parents’ backyard was a tagged hackberry. He told me this, actually, the day of my first Tree Trek, right after I returned and showed off my mulberry stained hands.

“We’ve got those,” he said, “They’re hackberries. Mom and I have been picking them all morning. She really likes fruit!”

“What? We have a hackberry tree?”

“Yes, it even has a label Dad nailed onto it.”

“But those can’t be hackberries. It’s June! They’re not even ripe yet,” I said. “Wait, I’ll be right back.”

Immediately, I went outside to investigate this mystery. As it turns out, both a mulberry (Morus) AND a hackberry grow back there. Nailed up for all to see was another one of those important symbols of my dad’s life I hadn’t known about. Definitely hackberry bark! Following the line of the hackberry trunk upwards, I saw that it did not connect to the mulberry branches now dripping with thousands of berries (true berries, incidentally). Both trees are actually growing in the neighbor’s yard, not ours. The branches laden with juicy mulberries hang into our yard over a short fence, making it easy to pick their low hanging fruit. On the other tree, I saw where my dad had reached over to nail the hackberry label on, and again, it was a surreal, slightly shocking feeling to discover this large, healthy tree had been growing there most of my life completely unknown to me while it matter-of-factly continued going about its business of being a hackberry tree, calmly orbiting within its own web of life. Now, finally, the two of us had intersected.

After explaining to my brother and mom that he’d simply mistaken the mulberry branch as ending up on the hackberry tree, the three of us went back out with containers to pick more mulberries. When these berries produce, they are truly extravagant – even profligate in the way the unpicked fruit goes to waste. Overripe berries littered the ground beneath our feet and dyed the grass a purplish black. We stepped all over them and stained our shoes in the process, but the reward was well worth the effort!

My dad’s favorite tree in the park grows very near the lake. I have no idea why it was his favorite. He never shared that with me. In fact, his colleagues don’t know either. Which is fine. I could speculate that when the park’s new hackberry tag came in, my dad pulled off the old red one to use on the tree in the backyard. It’s a rational explanation, but I don’t know that for sure. It doesn’t matter. A few mysteries are healthy to keep around, and there is something to be said about the importance of realizing when you should simply stop looking.

Worlds collide and intersect in the same way whether made up of the tiniest atoms or the largest galaxies. They morph and change one another often to the point of no return. Parts glom on, others explode things into detritus and still others manage to stay neutral through the whole chaos. People do the same thing just living their lives. When thought, image and emotion collide inside a person, such moments can snap the mind into the present, waking one into an instant of being fully alive that can forever leave an imprint.

It’s now getting towards the end of another Tree Trek. I’ve just completed my remarks at our last stop, the black walnut (Juglans nigra), where we are grouped together on the pedestrian bridge. This bridge is a well-known landmark, a project the park built relatively recently, much needed because it connects the lake area to the rest of the park and opens up the two to each other. No longer do pedestrians and bicyclists have to worry about crossing through the busy traffic below. Another benefit is that the branches of the black walnut grow right next to the railing on the north side, in effect bringing us up into the heart of the tree where all the action is taking place.

I usually stop here to point out to the group the distinctive leaf scars of the black walnut. They are super easy to identify, and a great place to start for those who want to learn winter tree ID. A black walnut’s leaf scar presents a very charming face with a big smile that, once learned, is easily recognizable upon seeing it again. We usually don’t stay here long, though. Traffic noise is one reason, but also the fact that many people use this bridge and there isn’t a lot of room for our group of 20 plus to spread out. We’re just approaching the rise up to the apex when someone in the group says,

“Make room. Wheels coming.”

A very fit, athletic man is just entering the bridge at the black locust tree end behind us, heading our way. He’s on cross country ski rollers and taking up a good amount of space with his poling action. Relaxed and in control, he is clearly accomplished at what he’s doing. I immediately think of my dad who used to do this same activity during the summer and autumn months training for winter trips ahead. Some of those trips, such as out in Colorado, involved serious mountain skills and, if one is going to race (which my dad also did), the sport requires endurance training in the non-snow months. When my dad was done with his roller skis, he gave them to me to use which I did during one summer, rolling about town rather conspicuously, I should add. I may be the first and only person in our very small town ever to roller ski along the bike paths getting ready for the winter season.

As I watch the roller skier approach, these memories flash through my mind. I’m smiling as we make way for him. What he says next, without a doubt makes apparent what was forming his own observations as he was approaching our group. For one thing, the event has been advertised. For another, he sees a woman with binoculars around her neck (incidentally, the same ones my dad used) and people are gathered around as she speaks about a tree branch leaning against the railing. This may be why, as he moves through the center of our group, he calls out wholeheartedly,

“If this is Chet Mirocha’s Tree Trek continuing, great work! Keep it going!”

My mouth gapes open in surprise at his knowing Chet who is no longer with us, at his knowing this is Tree Trek! His genuine air of positivity instantly transfers into me a feeling of everything coalescing into one of those moments. Joy flows through. This is the right place to be, indeed, and I am doing exactly what I need to do right now. Everything is as it should be. All I can think of to say is,

“I’m Stephanie Mirocha!” to his receding back as he rolls away.

The gap closes, and we continue crossing. Quietly, I watch our roller skier round the apex of the bridge until he flows on down the other side and vanishes. I don’t know how or if he even knew my dad. Or skied with him. Again, it doesn’t matter. What matters is that the resultant wake of our two paths crossing spreads out in waves of exhilaration.

On the other side of the bridge, I turn to the group and conclude the tree trek. We are out of time.

“Thank you so much, everyone, for joining me today!”

I bow in grateful respect as they thank me in return.

Everything is as it should be.

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Tree Trek Copyright © 2022 by Stephanie Mirocha Ellison. All Rights Reserved.

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