Sunday, June 09, 2013

Tree Buds

Weather: Winds and humidity were influenced by the fires and, possibly, hurricane Andrea; last rain 4/5/2013; 14:33 hours of daylight today.

A little rain fell Wednesday, the first in six weeks (last was 4/19). It wasn’t much, but it may have been enough to save some grasses in places where water collects. No doubt, it contained ash and whatever else was in the smoke-filled clouds.

What’s blooming in the area: Dr. Huey and hybrid roses, daylilies, silver lace vine, oriental poppies, Jupiter’s beard, purple salvia, blue flax, alfalfa, brome grass.

Beyond the walls and fences: Catalpa, tamarix, prickly pear, alfilerillo, yellow sweet clover, scurf, bush and sweet peas, tumble mustard, wild licorice, purple mat flower, fern-leaved and leather-leafed globe mallows, bindweed, greenleaf five-eyes, prairie white evening primrose, scarlet bee blossom, velvetweed, English plantain, common dandelion, goat’s beard, cream tips, Hopi tea, horsetail, needle and rice grasses.

In my yard, looking east: Persian rose, snow-in-summer, Bath pinks, sea pink, baby’s breath, pink evening primrose, winecup mallow, pink salvia; reseeding morning glories germinated.

Looking south: Rugosa, floribunda and miniature roses, oxalis.

Looking west: Johnson Blue geranium, Rumanian sage, catmints, purple and Husker’s red beardstongues, sea lavender, vinca, Shasta daisy.

Looking north: Golden spur columbine, Hartweig primrose, coreopsis, chocolate flowers, anthemia; buds on yellow yarrow.

In the open, along the drive: Dutch clover, first hollyhock, white yarrow, blanket flower, yellow Mexican hat; buds on coral beardstongues.

Bedding plants: Wax begonias, periwinkle, pansies, sweet alyssum, snapdragons, French marigolds.

Known unknowns: Native dandelion.

What’s blooming inside: Zonal geraniums, petunias.

Animal sightings: Rabbit, hummingbird, small brown birds, geckos, ladybug, cabbage butterfly and small bees on alfalfa, hornets, cricket, grasshoppers, harvester and smaller ants.

Weekly update: Trees, as we know them evolved some 60 to 100 million years ago. They emerged at a time when swamps were dominant, then adapted to glacial conditions. At some time they developed ways to cope with drought and unexpected frosts and fire, and all the other climatic variations that can occur.

Their common strategy seems to be overproduce, then ruthlessly prune if conditions are favorable. Each year, more leaf buds are created than are needed. Once the first buds successfully have turned into leaves, they produce chemicals which inhibit the continued growth of other buds. Some atrophy, some go dormant and are absorbed into the bark. When conditions change, the bud bank is activated.

Every year catalpas navigate a precarious path to bud burst. The weather warms, they start to leaf. Temperatures fall, the leaves die.

Time passes, while the tree adjusts its internal chemistry and reactivates the suppressed buds.

I’ve gotten used to their annual cycles, but never thought much about the universality of the underlying processes until this year.

Siberian elms bloomed the end of March, then halted their cycle. The leaves were late, and often sparse.

The mature trees of heaven didn’t even put out their canopies until this week. On the females, the leaves perched atop last year’s seed clusters.

I don’t know what role our three frosts played in changing their leafing schedules, but I suspect it was a factor.

When times get bad, some trees, like the cottonwood in the second picture, simply activate the buds nearest the canopy that can maintain the nutrient flow between the leaves and the roots.

The last two dry summers, and the current drought have rendered that strategy useless for many. The cottonwood in the top picture shed all its leaves and left the top to die. It’s found the resources to try again from the base.

Siberian elms and trees of heaven also are suckering, perhaps indicating problems not yet visible.

When all else fails, trees still are falling back on their oldest plan, produce more seeds.

1. Cottonwood down the road, 8 June 2013, sucker at base.

2. Two cottonwoods and a catalpa, 6 June 2013. All must have died back. The catalpa was cropped. The cottonwood on the left is struggling to survive. The one in the center is barren.

3. Buds sprouting from the stump of a recently cut down Russian olive, 8 June 2011.

4. Catalpa leaves in the late snow two years ago, 2 May 2011.

5. Catalpa second leaves ten days later, 12 May 2011.

6. Volunteer elm with sparse leaves, 8 June 2011.

7. Tree of heaven that’s just leaved out, 6 June 2011.

8. Close up of canopy in #2, 6 June 2013.

9. Close up of sucker in #1, 8 June 2013.

10. Mature elm down the road with suckers, 6 June 2013.

11. Seedling from same catalpa, 8 June 2011.

12. Tree of heaven down the road, with bare patches and suckers, 6 June 2011. You can see a hose they are using to keep the tree going.

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