Natural events: orchard edition, February 2017

Featured this month:

  • Weather recap: Awful nice
  • Signs of an accelerated spring
  • Warm weather worries
  • Wood chipping and bark slipping
  • Lichens on locust
  • Orchard grasses
  • One desirable February fruit bloom

Weather recap: February’s weather was awful nice. On a daily basis, it’s hard not to enjoy weather in the 50s, 60s, and 70s, with a clear sunny sky. But a moment’s thought reveals February’s weather to be pretty awful, particularly from the perspective of an orchardist. Temperatures averaged well above normal, with multiple broken records: three record highs and two record-high lows (with one tie of a record high as well). Missouri weather tends to be variable at this time of year, but the low points of the swings this year essentially brought us down to the normal range; it never got cold. Many nights didn’t even go below freezing, resulting in a maple sugaring season that was hugely disappointing.And it was dry. By the end of the month, the Drought Monitor classification showed most of Missouri as Abnormally Dry or drier, with nearly two-thirds of the state (including us) in the Moderate Drought classification. The only meaningful rain came right at the end of the month in the form of a thunderstorm that delivered small hail along with brief rain.

Signs of an accelerated spring: On February 14 (early!), we had our first fresh-harvested salad from the garden, composed primarily of sorrel (left photo) and salad burnet, along with a little spinach. To be clear, this isn’t hoophouse salad; these plants are growing with no special protection or encouragement. We noted the first crocus bloom of spring on February 19. This technically did not beat our earliest observation of February 17 in 2013, but in that case the blooms were buried by nearly a foot of snow a few days later. We feel like crocus will respond rapidly to a short pulse of warmth, but Harbinger of Spring requires more persistent warmth to bring up the soil temperature in the forested bottomlands before it will bloom. So it’s telling that their February 25th bloom date trounced our previous first-observation date of March 6th (2009 & 2016). We don’t track the first date on which we see daffodil leaves (right photo), and they didn’t officially bloom here during February (but it was little surprise that their March 2nd bloom date broke a record in our observations as well).Warm weather worries: So, why all the fuss about the early warmth? One significant problem is that early warm weather can trigger an early start to bud swell, bloom, and leaf out on plants and trees. Once those processes are underway, the plants are more vulnerable to damage from a cold snap. Even “normal” cold can cause damage if plants are weeks ahead of schedule, and a true cold spell can spell disaster (think the “Easter Freeze” of 2007 which devastated fruit crops in Missouri). The photos above show early-swelling buds on our fruit trees (from left to right: peach, blueberry, sour cherry, and Asian pear). Last year, we experienced a warm winter and early spring, followed by an April freeze that wiped out most fruit buds and blossoms here and across much of northern Missouri. This year we’re facing a similar situation but even more advanced.

An associated concern relates to fulfillment of the chilling requirements for various plants. Many fruiting plants require a certain amount of winter cold weather before they’ll break dormancy. This provides some biological protection against brief winter warm spells; if a plant experiences a couple days of warmth in December or January, but it knows that it hasn’t yet been cold enough long enough for that warmth to signal real spring, then it will sit tight until more cold resumes. But what if it warms up so early that those winter chilling requirements aren’t met? Then plants behave abnormally when spring comes. Missouri winters tend to provide ample chill hours, so this normally isn’t something we need to remotely worry about in our location. However, with February temperatures so far above normal, it is hard not to wonder. We explored some chill models and calculations, and perhaps we will find time to write that up as another blog post.

Wood chipping and bark slipping: One of our big January/February/March tasks for orchard management is generating lots of hardwood chips for orchard mulch. We take the branches of trees we cut for firewood as well as small trees that we’re thinning. Then we feed these through a tractor-mounted chipper to generate some really lovely and pleasantly aromatic mulch for our perennial plantings. The chipper does a great job making cedar mulch (which has a reputation of not being a good plant mulch), but once in a while the chipper has trouble with hardwood, and we think we finally figured out why. Part way through the month, we noticed that the elm bark had begun to slip. The right photo shows bark that peeled away with almost no effort after making a tiny incision at one end. If we were to feed that branch into the chipper, the bark would likely peel off and wrap around the axle, causing problems. Post-bark slip, we kept elm out of the chipper, and the chipping job went smoothly. It seems that bark begins to slip as a plant comes out of dormancy, and given that elms bud out especially early, it is not surprising that it was the first to cause trouble. When it comes to orchard management, awareness of the timing of bark slip has another purpose: certain types of grafting are performed when the bark slips on fruit trees.

Lichens on locust: A few of the trees headed for the chipper were Honey Locusts. I couldn’t resist taking photos of the diverse and beautiful lichens on one of the locusts that Eric took down. We’ve noticed before that locusts tend to have a lot of lichens on them, and we’ve wondered why. Do the thorns provide protection against critters that might otherwise nibble on lichen? Or is there something else about Honey Locusts that encourages lichens? A quick web search didn’t yield any insight into that question. It’s a reminder, though, that the canopies of trees are home to many organisms, some macroscopic–such as these lichens–and others microscopic. Managing an orchard involves more than just managing individual trees; there’s a whole complex ecosystem in those canopies that we barely begin to understand.

Orchard grasses: The orchard’s understory includes a considerable amount of grass of a variety of species; here are photos of some of them. The upper row shows native grasses: Broomsedge (Andropogon virginicus), Elliott’s Broomsedge (Andropogon gyrans), wild rye (Elymus sp. not sure if it is Virginia or Canada), and Poverty Grass (Sporobolus vaginiflorus). Some of these are indicative of lousy soil, and that’s a fair assessment of what we’re working with in the orchard (thus the heavy emphasis on wood chip mulch). The lower row shows two non-native cool season grasses. On the left is the aggressive and annoying Tall Fescue (Festuca arundinacea), and on the right is Orchard Grass (Dactylis glomerata).

And now we interrupt the regularly scheduled programming for a brief aside on grammar and capitalization. Readers may note what may appears to be haphazard capitalization when we reference species, but we are following a systematic approach. When we reference a particular species, we capitalize it, a common approach in the birding community. So, for example, a birder will know that Yellow Warbler refers specifically to
Setophaga petechia, while yellow warbler could mean one of a wide assortment of warblers that have yellow markings. On this blog, we extend this approach to all organisms (even though botanists usually don’t). We use capitalization to indicate that we’re referring to a particular identified species (whether or not we include the scientific name). Thus, all of the photos above show orchard grass, but only ones shows Orchard Grass.

One desirable February fruit bloom: There’s one fruiting plant with February buds and blossoms that we could happily enjoy in February, and that’s our Meyer Lemon plant. It is, of course, a potted plant that spends the frost-prone months of the year in the safety of the house.

And now for the fruit forecast for 2017: The evidence suggests that life is going to give us lemons.

2 thoughts on “Natural events: orchard edition, February 2017

  1. I sure do enjoy your Monthly natural event posts. Thanks for sharing.
    A wood chipper is one of the thing I’ve really thought about purchasing for our farm, especially as it’s so difficult to find someone willing to dump bulk wood chips so far out of town like we are.

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